NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.

Feingold KR, Anawalt B, Boyce A, et al., editors. Endotext [Internet]. South Dartmouth (MA): MDText.com, Inc.; 2000-.

Cover of Endotext

Endotext [Internet].

Show details

Lipodystrophy Syndromes: Presentation and Treatment

, , and .

Author Information

Last Update: April 24, 2018.

ABSTRACT

Lipodystrophy syndromes are a heterogeneous group of diseases, characterized by selective absence of adipose tissue. In one sense, these diseases are lipid-partitioning disorders, where the primary defect is the loss of functional adipocytes, leading to ectopic steatosis, severe dyslipidemia and insulin resistance. These syndromes have attracted significant attention since the mid-1990s as the understanding of adipose tissue biology grew, initially spurred by the discovery of the pathways leading to adipocyte differentiation and maturation, and then by the discovery of leptin. Although lipodystrophy syndromes are known since the beginning of the 20th century, significant progress in understanding these syndromes were made in the last two decades, placing these syndromes at the forefront of the translational metabolism field. Currently, more than 15 distinctive molecular etiologies have been attributed to cause human diseases most of which map to adipocyte differentiation or lipid droplet pathways. Seemingly acquired syndromes are recently reported to have a genetic basis, suggesting that our “pre-genome” understanding of the syndromes was inadequate and that we need to likely change our classification schemes. Regardless of the etiology, it is the selective absence of adipose tissue and the reduced ability to store long-term energy that perturbs insulin sensitivity and lipid metabolism. The treatment of these syndromes has also attracted considerable interest. The most successful example of the treatment of these syndromes came from the demonstration that leptin replacement strategy improved insulin resistance and dyslipidemia in the most severely affected forms of the disease, leading to an FDA approved therapy for generalized lipodystrophy syndromes. In the partial forms of the disease, the phenotypes are more complex and the efficacy of leptin is not as uniform. Currently, numerous trials are in progress for the development of potential new treatments for the partial forms of the disease. These rare metabolic diseases are likely to fuel novel breakthroughs in the metabolism field in the foreseeable future. For complete coverage of all related areas of Endocrinology, please visit our on-line FREE web-text, WWW.ENDOTEXT.ORG.

INTRODUCTION

Lipodystrophy syndromes comprise a heterogeneous group of disorders characterized by either generalized or partial lack of adipose tissue depending on the type of lipodystrophy 1,2. Lipodystrophy classically has been classified as congenital or acquired. Patients with partial lipodystrophy may exhibit excess adipose tissue accumulation in other areas of the body. Lipodystrophy syndromes usually manifest with several metabolic abnormalities associated with severe insulin resistance that include diabetes mellitus, hypertriglyceridemia, and hepatic steatosis which can progress to steatohepatitis. Other common manifestations are acanthosis nigricans, polycystic ovarian syndrome (PCOS), and eruptive xanthomas (due to severe hypertriglyceridemia) 3,4. Metabolic derangements are mostly responsible for the serious comorbidities associated with lipodystrophy; some of which are chronic complications of poorly controlled diabetes, acute pancreatitis, hepatic cirrhosis, proteinuria and renal failure, and premature cardiovascular disease (Fig.1) 1,2. Typically, standard treatments fail to achieve good glycemic control in most patients with lipodystrophy, although episodes of diabetic ketoacidosis have been rarely reported5. The severity of the comorbidities depends on the subtype, extent of fat loss, and other clinical characteristics such as gender and age. Major causes of mortality are cardiovascular diseases 6-9, liver diseases2,10, acute pancreatitis 2, renal failure 10, and sepsis 3. Clinical characteristics of lipodystrophy are shown in Table 1. It is important to note that there are additional components of the disease that may be specific to each molecular etiology. In addition, we are beginning to recognize that patients often report reduced quality of life with increased overall pain (requiring frequent use of pain medications), sleep disturbances and sleep apnea, gastrointestinal dysmotility, mood disturbances such as depression and anxiety and psychiatric diseases 11,12.

Figure 1. Consequences of Lipodystrophy: The figure summarizes metabolic derangements and end-organ complications in patients with lipodystrophy (Left: MRI showing near total lack of adipose tissue; Right top: Liver biopsy shows hepatic steatosis in lipodystrophy (Hematoxylin and eosin staining; magnification 100X), Right bottom: CT of abdomen obtained during an episode of acute pancreatitis in lipodystrophy; Middle top: Diabetic foot ulcer in a patient with generalized lipodystrophy; Middle bottom: Renal biopsy specimens (Left: Electron microscopy image reveals lipid vacuoles which suggest ectopic lipid accumulation; Right: Light microscopy image documents chronic kidney disease in lipodystrophy (Hematoxylin and eosin staining; magnification 40X).

Figure 1Consequences of Lipodystrophy: The figure summarizes metabolic derangements and end-organ complications in patients with lipodystrophy (Left: MRI showing near total lack of adipose tissue; Right top: Liver biopsy shows hepatic steatosis in lipodystrophy (Hematoxylin and eosin staining; magnification 100X), Right bottom: CT of abdomen obtained during an episode of acute pancreatitis in lipodystrophy; Middle top: Diabetic foot ulcer in a patient with generalized lipodystrophy; Middle bottom: Renal biopsy specimens (Left: Electron microscopy image reveals lipid vacuoles which suggest ectopic lipid accumulation; Right: Light microscopy image documents chronic kidney disease in lipodystrophy (Hematoxylin and eosin staining; magnification 40X).

Table 1Clinical Characteristics That Raise Suspicion for Lipodystrophy

Loss or absence of adipose tissue in a partial or generalized fashion
Disproportionate hyperphagia (inability to stop eating, waking up to eat, fighting for food)
Muscle hypertrophy and prominent veins (phlebomegaly)
Cushingoid appearance
Pseudo-acromegaloid appearance
Progeroid appearance
Acanthosis nigricans (associated with insulin resistance)
Proteinuria, renal dysfunction
Reproductive dysfunction (reduced fertility, hyperandrogenism, oligomenorrhea, hirsutism and/or polycystic ovaries)
Musculoskeletal abnormalities (occasionally)
Cardiomyopathy (occasionally)
Low intelligence (occasionally)
Metabolic abnormalities
· Relatively early onset of insulin resistant diabetes which is severe in some patients with requirement for high doses of insulin, e.g., requiring ≥200 U/day, ≥2 U/kg/day, or U-500 insulin, early development of complications
· Dyslipidemia which is characterized by elevated triglycerides and low HDL cholesterol. Hypertriglyceridemia can be very severe (≥500 mg/dL) and is unresponsive to treatment with associated history of acute pancreatitis
· Hepatomegaly and/or elevated transaminases in the absence of a known cause of liver disease (e.g., viral hepatitis). Hepatic steatosis (e.g. radiologic evidence), Hepatomegaly, non-alcoholic steatohepatitis (NASH), cirrhosis.

Lipodystrophy is an exciting rare disease that helps us obtain a better understanding of the pathophysiology of metabolic abnormalities associated with insulin resistance. The main cause of insulin resistance in lipodystrophy is the fact that the excess energy cannot be stored in adipose tissue, which is secondary to either the near total lack of adipocyte expandability in patients with generalized lipodystrophy or a limited capacity to expand in partial lipodystrophy. Limited lipid storage capacity causes the failure of buffering postprandial lipids and secreting substantial adipokines, which in turn results in excessive levels of triglycerides and lipid intermediates in circulation. The body stores fat at ectopic sites such as the liver as a result of inability to store energy in the subcutaneous adipose depots (Fig.1). Levels of adipokines and hormones secreted from the adipose tissue, most characteristically leptin, are decreased in these patients 1,2,9,13,14. Leptin has a fundamental role in glucose and lipid homeostasis. Leptin is the key hormone responsible for regulating appetite 15. Low levels of leptin in lipodystrophy trigger hyperphagia, which is often extreme 16-18. Leptin protects pancreatic beta cells from lipotoxicity at least in rodent models. Leptin improves insulin sensitivity by increasing glucose uptake in peripheral tissues such as muscle via sympathetic nervous system activation. Leptin also decreases hepatic gluconeogenesis 19-21.

ANIMAL MODELS OF LIPODYSTROPHY

Several animal models of lipodystrophy have shown that adipose tissue dysfunction triggers the development of severe insulin resistance, which is associated with metabolic abnormalities and end-organ complications as mentioned above and also shown in Fig.1. An extensive and authoritative review of these studies can be found in an article by Dr. David B. Savage 22. The introduction of these animal models has allowed researchers to explore the fundamental characteristics of lipodystrophy and insulin resistance and allowed studies of the effects of different treatment approaches. Regardless of the strategy used, ablation of white adipose tissue led to the development of insulin resistance, hypertriglyceridemia, and hepatic steatosis (sometimes 6-fold elevation in total liver weight). In now classical experiments of Reitman and colleagues, fat transplantation from littermates rescued metabolic derangements in the famous A-ZIP mice 23-25. Dr. Beutler’s group recently identified kelch repeat and BTB (POZ) domain containing 2 (KBTBD2) deficiency as a cause of lipodystrophy associated with insulin resistance and diabetes and they also showed that transplantation of wild-type adipose tissue rescued diabetes and the hepatic steatosis phenotypes of Kbtbd2−/−mice 26. The infusion of leptin into aP2–SREBP-1c transgenic mice from the Brown and Goldstein laboratory resulted in dramatic benefits in glycemic parameters, insulin action, and hepatic steatosis, which could not be explained by its effect on food intake alone, providing the premise to undertake leptin replacement in human patients 27. What was also striking was that if fat from the leptin deficient obese mice was transplanted into littermates of the A-ZIP mice, the metabolic rescue was far less effective, suggesting that leptin played an important role in the regulation of metabolism in lipodystrophy in rodents 28. The replacement of deficient leptin in a small but severely affected cohort of human patients with lipodystrophy with recombinant human leptin (metreleptin) was first reported in 2002 and attracted further attention to lipodystrophy research 29. Longer-term studies subsequently confirmed the role of metreleptin therapy in lipodystrophy syndromes especially in the most severe forms 30-32.

DIAGNOSIS

The diagnosis of lipodystrophy is usually made clinically based on history, body distribution of adipose tissue, physical examination, and metabolic profile. Lipodystrophy should be suspected in any person with partial or complete lack of subcutaneous adipose tissue. However, the diagnosis of lipodystrophy is often delayed because of the rarity of these syndromes and the failure of the physicians to recognize this disease. Although patients with congenital generalized lipodystrophy lack subcutaneous adipose tissue from birth, specific diagnosis is usually made during childhood or even adulthood when they start developing metabolic abnormalities. This is at least partly because of the fact that the awareness of lipodystrophy is still low among physicians. The problem of recognition is much more common for partial lipodystrophy. The distribution of fat loss varies in different types of partial lipodystrophy. At first glance, certain types of partial lipodystrophy cannot be clearly distinguished from other common metabolic diseases (e.g. poorly controlled diabetes mellitus with truncal obesity) based on phenotype unless the physicians is suspicious for lipodystrophy and checks carefully for certain characteristic such as the appearance of the limbs which look thinner than in a normal person. Also, the onset of fat loss may be gradual and delay the diagnosis both in genetic and acquired forms 3,4. Lipodystrophy syndromes should be considered in the differential diagnosis in patients with relatively early onset insulin resistant diabetes mellitus, persistent hypertriglyceridemia, hepatic steatosis, PCOS and hepatosplenomegaly. Other diseases that should be considered in the differential diagnosis of lipodystrophy are listed in Table 2.

Table 2Differential Diagnosis of Lipodystrophy Syndromes

Generalized Lipodystrophy SyndromesUncontrolled diabetes mellitus
HIV-associated wasting
Anorexia nervosa, cachexia and starvation
Chronic infections
Adrenocortical insufficiency
Thyrotoxicosis
Diencephalic syndrome
Partial Lipodystrophy SyndromesCushing’s syndrome
Truncal obesity
Multiple symmetric lipomatosis
Progeroid syndromes
Acromegaly/gigantism

A thorough physical examination is required for clinical diagnosis of lipodystrophy. Clinicians should pay specific attention to evaluating the extremities and the gluteal region for leanness and muscularity. In addition, other body parts should be examined for accumulation of excessive amounts of fat. Due to marked abdominal obesity and excessive fat accumulation in the neck, patients with familial partial lipodystrophy (FPLD) may be misdiagnosed as Cushing’s syndrome 2. In the genetic forms of lipodystrophy, parental consanguinity and the mode of inheritance should be questioned 2.

The absence of subcutaneous fat can be quantified by using conventional anthropometric measurements, dual energy x-ray absorptiometry (DXA) scan, whole-body magnetic resonance imaging (MRI), and computed tomography (CT) scan 4. Anthropometry including skinfold thickness and limb circumference measurements are easy and affordable ways to estimate the fat loss and redistribution 9. For the facial fat loss, serial photography may be used to evaluate the gradual loss of facial fat. DXA, MRI, and CT scans are non-invasive modalities that may be used for quantification of fat on a tissue-specific basis, but at least in the United States, none are covered for this purpose by insurance companies 3,4,33.

Laboratory testing is a valuable tool for physicians to support the diagnosis. If the physical phenotype is not recognized, hyperglycemia, insulin resistance and severe hypertriglyceridemia that is non-responsive to therapy may provide important clues for the diagnosis. When fat loss is not confirmed by the physical examination or by an imaging modality, hyperglycemia and hypertriglyceridemia that are resistant or unresponsive to conventional treatment may serve as surrogate indicators to the clinician that a patient may have lipodystrophy. Lipodystrophy should be suspected in patients requiring ≥200 units/day (≥2 units/kg/day) of insulin or triglyceride levels that remain persistently elevated (≥500 mg/dL) despite fully optimized therapy and diet modifications. All patients except those with localized lipodystrophy, should be tested for blood glucose levels, glycated hemoglobin (HbA1c), serum lipids (especially triglyceride levels), and liver function tests on the initial evaluation and during subsequent encounters. In addition to these laboratory evaluations, leptin levels may be used in support of the diagnosis. However, it should be noted that low leptin levels may be observed in other conditions such as hypothalamic amenorrhea and malnutrition. Thus, low leptin level is not specific for the diagnosis lipodystrophy 4,30. Circulating adiponectin though not a clinically available test, may be helpful in differentiating patients with generalized lipodystrophy from those who have constitutional leanness, fat loss due to calorie imbalance or excessive exercise as well as poorly controlled diabetes mellitus with insulin deficiency. In all of the cases except lipodystrophy, adiponectin levels will be normal or even higher than normal whereas in lipodystrophy including familial partial lipodystrophy, serum adiponectin levels are usually low.

Genetic testing is available for several genes in certain clinical and research laboratories. Because additional loci for genetic lipodystrophy syndromes are presumed to be present, negative genetic tests do not rule out a genetic condition.

Lipodystrophy syndromes can be classified as genetic or acquired. However, they are simply classified as generalized and partial in the clinical practice most of the time (Table 3).

Table 3Classification of Lipodystrophy Syndromes


Type

Lipodystrophy Phenotype

Subtype
(Genes Involved)

Key Clinical Features

Congenital Generalized Lipodystrophy (CGL)
Near total absence of the body fat starting at birth or shortly after, generalized muscularity, metabolic abnormalitiesCGL1 (AGPAT2)
Autosomal recessive
Loss of metabolically active fat with sparing of mechanically functioning fat
CGL2 (BSCL2)
Autosomal recessive
Generalized absence of adipose tissue
CGL3 (CAV1)
Autosomal recessive
Short stature, vitamin D resistance, hypocalcemia, hypomagnesemia
CGL4 (PTRF)
Autosomal recessive
Myopathy, skeletal abnormalities, pyloric stenosis and gastrointestinal motility problems, cardiac arrhythmias

Acquired Generalized Lipodystrophy (AGL)
Near total absence of the body fat commonly develops during childhood or adolescence, metabolic abnormalitiesAutoimmuneAGL follows an autoimmune disease; e.g. JDM
Panniculitis-associatedTender subcutaneous nodules that herald the onset of AGL
IdiopathicNo history of auto-immune disease or panniculitis

Familial Partial Lipodystrophy (FPLD)

Loss of fat from the limbs, metabolic abnormalities
FPLD1, Kobberling (Unknown)Loss of subcutaneous fat from the limbs, although they usually have truncal obesity. Palpable “ledge” formation between the normal and lipodystrophic areas
FPLD2, Dunnigan (LMNA)
Autosomal dominant
Increased muscularity and loss of fat in the limbs, excess fat accumulation in the face and neck
FPLD3 (PPARG)
Autosomal dominant
Loss of subcutaneous fat from the limbs, specifically distally
FPLD4 (PLIN1)
Autosomal dominant
Loss of subcutaneous fat from the limbs, histologically; small adipocytes, macrophage infiltration and fibrosis of adipose tissue
FPLD5 (CIDEC)
Autosomal recessive
Loss of subcutaneous fat from the limbs, small, multilocular lipid droplets in adipocytes
FPLD6 (LIPE)
Autosomal recessive
Increased visceral fat, dyslipidemia, hepatosteatosis, insulin resistance, and diabetes, some may present with muscular dystrophy and elevated serum creatine phosphokinase
Progeria associated lipodystrophyLMNA, ZMPSTE24, POLD1, WRN, FBN1, BANF1, KCNJ6, SPRTNProgeroid features
Other genes associated with lipodystrophyAKT2, PCYT1A, PIK3R1, MFN2, PSMB8, ADRA2AVarious presentations of lipodystrophy

Acquired Partial Lipodystrophy (APL)
Loss of subcutaneous fat starts from the face, neck, upper extremities, and progresses to the trunk. Lower limbs are typically spared, some patients have excess fat over the gluteal region, thighs and calvesAutoimmuneCoinciding autoimmune disorders; dermatomyositis/polymyositis and SLE are most commonly associated disorders
MPGN-associatedLow serum complement 3, glomerulonephritis, hematuria, urinary casts, proteinuria, nephritic syndrome, renal failure
IdiopathicNo history of auto-immune disease or MPGN

It is important to note that this classical method of disease classification will likely become inadequate as more disease-causing genes and pathways are identified.

GENERALIZED LIPODYSTROPHY SYNDROMES

Generalized lipodystrophy syndromes are rare disorders that are either inherited (Berardinelli-Seip Syndrome) 31,32,34or acquired (Lawrence Syndrome) 9.

Congenital Generalized Lipodystrophy

Congenital Generalized Lipodystrophy (CGL) or Berardinelli-Seip syndrome is a rare syndrome which manifests with near total absence of adipose tissue. It is inherited in an autosomal recessive manner. Fat loss is usually recognized shortly after birth or in the first years of life, although patients may be diagnosed later during teenage years or adulthood. There have been over 300 reported cases to date 13,35,36.

In addition to lack of subcutaneous fat, patients may present with hepatomegaly and umbilical protuberance during infancy. Extensive acanthosis nigricans and prominent musculature may also contribute to the striking phenotype of these patients 37. Affected females may have irregular menstrual cycles, oligomenorrhea, cliteromegaly, and hirsutism. Premature menarche and pubarche are also rarely seen. Most males were reported to be fertile whereas only a few females had successful pregnancies 38. Sperm abnormalities have been reported in CGL similar to BSCL2 knock-out mice that also exhibit male sterility 39. Other clinical manifestations include advanced bone age, mild mental retardation, cardiomyopathy and cardiac rhythm disturbances 40.

Children with CGL usually have a voracious appetite and accelerated growth. Basal metabolic rate may be increased. Hypertriglyceridemia usually presents with high levels of chylomicrons and very low-density lipoproteins (VLDL) and reduced levels of high density lipoproteins (HDL). Severe hypertriglyceridemia usually results in recurrent acute pancreatitis. Insulin resistance commonly results in diabetes in adolescence or later. Diabetes is rarely responsive to insulin therapy. Serum leptin levels are very low 30.

The genetic defect can be determined in vast majority of patients with CGL. There are at least four molecularly distinct types of CGL. Of note, several patients with CGL have been reported who do not possess any pathogenic variant in any of the following four genes.

CONGENITAL GENERALIZED LIPODYSTROPHY TYPE 1 (CGL1)

1-acylglycerol-3-phophate O-acyltransferase 2 (AGPAT2), a key enzyme in triglyceride synthesis, is deficient in CGL1. AGPAT2gene is located on chromosome 9q34. AGPAT2 catalyzes the acylation of lysophosphaditic acid to form phosphaditic acid, a key intermediate in the biosynthesis of triglyceride and glycerophospholipids 41. Precisely how AGPAT2 deficiency causes lipodystrophy remains unsolved, but possible mechanisms include impaired lipogenesis, altered differentiation of preadipocytes to adipocytes, altering normal activation of phosphatidylinositol 3-kinase (PI3K)/Akt and PPARγpathways in the early stages of adipogenesis, and apoptosis/necrosis of adipocytes 2,42,43. Adiposity is preserved in certain body parts such as orbits, palms and soles, which constitute the mechanically adipose tissue 30,44-46(Fig.2). AGPAT2pathogenic variants along with BSCL2pathogenic variants are responsible for the majority of the CGL cases.

Figure 2. Near total absence of adipose tissue in CGL1 (2A, 2C, 2D).

Figure 2

Near total absence of adipose tissue in CGL1 (2A, 2C, 2D). Magnetic resonance images document the lack of subcutaneous fat (2B). Liver biopsy reveals severe hepatic steatosis with both micro and macrovesicular steatosis (Hematoxylin and eosin staining; magnification 200X), 2E).

CONGENITAL GENERALIZED LIPODYSTROPHY TYPE 2 (CGL2)

CGL2 is caused by pathogenic variants in the BSCL2gene which have been mapped to chromosome 11q13. This gene encodes a 398-amino acid integral endoplasmic reticulum membrane protein calledseipin47. This protein is assumed to take part in lipid droplet formation and adipocyte differentiation 48,49. Patients with BSCL2pathogenic variants have the most severe disease and are born without any adipose tissue. Hypertriglyceridemia and hepatic steatosis can be detected in early childhood; and hepatic involvement can be more severe in CGL2 than other subtypes 50. Intellectual disability and cardiomyopathy are more common than in CGL1. CGL2 patients are also distinguished from the CGL1 patients with the loss of mechanical adipose tissue 51(Fig.3). Although the mechanism is not clear, adiponectin levels are relatively higher in patients with CGL2 despite severely suppressed leptin levels which can help in the differential diagnosis 52.

Figure 3. Near total absence of adipose tissue in a patient with CGL2 (3A, 3B).

Figure 3

Near total absence of adipose tissue in a patient with CGL2 (3A, 3B). Also note that the patient shown now deceased was only 29 years old at the time the picture was taken, suggesting the possibility of accelerated aging.

CONGENITAL GENERALIZED LIPODYSTROPHY TYPE 3 (CGL3)

CGL3 is caused by pathogenic variants in the CAV1gene which are located on chromosome 7q31 9,14,53. This gene encodes the protein caveolin-1, which is an integral part of caveolaefound in plasma membranes. Caveolin 1 binds fatty acids on the plasma membranes and translocates them into lipid droplets. Mutated caveolin 1 disrupts lipid droplet formation and adipocyte differentiation 54. CGL3 is distinguished from other CGLs by the presence of unique features such as preserved bone marrow fat, vitamin D resistance, hypocalcemia, hypomagnesemia, and decreased bone density 40. In addition to this classical presentation, whole exome sequencing has identified de novoheterozygous null CAV1pathogenic variants in two patients of European origin with generalized fat loss, thin mottled skin, and progeroid features at birth; however, no differences in the number and morphology of caveolae have been found in dermal fibroblasts 55, which suggests that this observation needs to be confirmed in further pedigrees. Heterozygous CAV1frameshift mutations have also been reported to be associated with partial lipodystrophy (Fig.4). Several features such as congenital cataracts and cerebellar progressive ataxia were also present 56.

Figure 4. Partial lipodystrophy associated with heterozygous CAV1 frameshift mutations in a male (4A, 4B, 4C) and female subject (4D, 4E).

Figure 4

Partial lipodystrophy associated with heterozygous CAV1 frameshift mutations in a male (4A, 4B, 4C) and female subject (4D, 4E). Patients shown were a father and a daughter pair.

CONGENITAL GENERALIZED LIPODYSTROPHY TYPE 4 (CGL4)

Type 4 CGL (CGL4) is caused by pathogenic variants in the PTRFgene. The product of this gene, cavin, is a polymerase 1 and transcript release factor which regulates caveolae 1 and 3 57. CGL4 can be recognized by distinct clinical characteristics. This rare subtype of CGL is associated with myopathy, pyloric stenosis, gastrointestinal dysmotility, arrhythmias that include exercise-induced ventricular tachycardia and sudden death, and skeletal abnormalities such as atlantoaxial instability and scoliosis 58-60(Fig.5).

Figure 5. Lack of subcutaneous fat (5A), scoliosis (5A), gastrointestinal dysmotility (5B), and exercise-induced ventricular arrhythmia (5C) in CGL4.

Figure 5Lack of subcutaneous fat (5A), scoliosis (5A), gastrointestinal dysmotility (5B), and exercise-induced ventricular arrhythmia (5C) in CGL4.

OTHER GENES ASSOCIATED WITH GENERALIZED LIPODYSTROPHY

Biallellic loss-of-function pathogenic variants in phosphate cytidylyltransferase 1 alpha (PCYT1A), the rate-limiting enzyme in the Kennedy pathway of de novo phosphatidylcholine synthesis, have been reported to be associated with generalized lipodystrophy, severe hepatic steatosis and low HDL cholesterol levels 61. Although widely involved in the familial partial lipodystrophy pathogenesis, several pathogenic variants in the LMNAand PPARGgenes have been associated with generalized lipodystrophy. Recently, heterozygous LMNAp.T10I pathogenic variant was reported to be associated with generalized lipodystrophy, diabetes mellitus, acanthosis nigricans, hypertriglyceridemia, and hepatomegaly (Fig.6) 62. Biallelic pathogenic variants at PPARGhas also been reported to cause generalized lipodystrophy 63.

Figure 6. Generalized lack of subcutaneous fat (6A), eruptive xanthomata (6B), and lipemia retinalis (6C) secondary to severe hypertriglyceridemia in a patient with heterozygous LMNA p.

Figure 6

Generalized lack of subcutaneous fat (6A), eruptive xanthomata (6B), and lipemia retinalis (6C) secondary to severe hypertriglyceridemia in a patient with heterozygous LMNA p.T10I pathogenic variant.

Acquired Generalized Lipodystrophy

Acquired generalized lipodystrophy (AGL), also known as Lawrence Syndrome, is very rare. Generalized fat loss is not present at birth but develops later in life. It occurs over a variable time period, ranging from a few weeks to years (Fig.7) 9.

Figure 7. Generalized loss of subcutaneous fat in two patients with AGL (7A-D).

Figure 7

Generalized loss of subcutaneous fat in two patients with AGL (7A-D). Note the distal fat loss around the feet as opposed to patients with CGL phenotypes.

Although the pathogenesis of AGL is unknown, it is hypothesized to be linked to autoimmune destruction of adipocytes. Autoantibodies against adipocyte membranes have been reported 64-66. AGL is associated with panniculitis in approximately 25% of the patients. This type may manifest with subcutaneous inflammatory nodules (panniculitis), which heal by localized loss of fat and eventually results in complete loss of subcutaneous fat 9. Another one fourth of the AGL patients present with an autoimmune disease that include juvenile dermatomyositis (JDM), Sjogren’s syndrome, rheumatoid arthritis, systemic sclerosis, and systemic lupus erythematosus 9,65. Of these, JDM particularly correlates with AGL. 8-40% of patients with JDM develop AGL (Fig.8) 66-68. In the remaining 50% of the cases, AGL is not associated with any autoimmune or inflammatory condition 9. Some patients with AGL exhibit low serum complement 4 levels and auto-immune hepatitis, sometimes together with Type 1 diabetes, which suggests the involvement of classical complement pathway in AGL pathogenesis 69.

As mentioned above, it is of note that some of the patients with AGL are recently recognized to have additional progeroid features and may harbor a specific pathogenic of LMNAgene at position 10 (p.T10I). We have reported clinical presentations of these patients recently in a case series report. One of these patients also had biopsy proven juvenile dermatomyositis suggesting that the long-recognized association between AGL and JDM may be linked through distinctive molecular mechanisms 62.

In patients with AGL, as a result of generalized fat loss, metabolic abnormalities associated with severe insulin resistance that include hypertriglyceridemia, diabetes mellitus, hepatic steatosis, acanthosis nigricans, menstrual irregularities and PCOS may develop soon after the recognition of fat loss. Patients have suppressed levels of leptin and adiponectin 9,30.

Figure 8. Generalized loss of subcutaneous fat in a patient with juvenile dermatomyositis associated AGL (8A, 8B).

Figure 8

Generalized loss of subcutaneous fat in a patient with juvenile dermatomyositis associated AGL (8A, 8B). Note the absence of muscle tissue as well in this severely affected patient.

PARTIAL LIPODYSTROPHY

Fat loss affects only part of the body in partial lipodystrophy. Partial lipodystrophy is categorized into inherited (familial partial lipodystrophy, FPLD) and acquired forms (acquired partial lipodystrophy, APL). Both patients with FPLD and APL start losing fat at some point during their life. Lower limbs are most frequently affected in FPLD. There might be accumulation of adipose tissue in the face and neck. On the other hand, APL is characterized by fat loss that spreads through a cephalocaudal distribution from the face, neck, shoulders, arms, and forearms and that extends to the thoracic region and upper abdomen. There are numerous genes associated with FPLD. Despite the growing number of proven genetic markers, about half of the patients do not have a discernible single gene variation.

Inherited Partial Lipodystrophy Syndromes

Patients with these syndromes usually notice partial fat loss around puberty. Fat loss pattern is very heterogeneous in patients with FPLD. Even among patients with pathogenic variants of the same gene, fat loss patterns may vary.

FAMILIAL PARTIAL LIPODYSTROPHY TYPE 1 (FPLD1)

The loss of adipose tissue is mainly limited to the extremities in patients with FPLD1 or Kobberling-type lipodystrophy 70. There is a normal or slightly increased fat in the face and neck. Truncal obesity is a common finding. The hallmark of this syndrome is the formation of a palpable “ledge” between the normal and lipodystrophic areas 71. It is believed that women are diagnosed more easily as they usually present with a more severe disease. Metabolic complications usually develop in early adulthood. Insulin resistant diabetes and metabolic syndrome are common and may cause premature coronary artery disease. Hypertriglyceridemia may trigger episodes of acute pancreatitis. Acanthosis nigricans is commonly seen. Leptin levels are variable and correlate with body mass index (BMI) which suggests that the levels of leptin are appropriate for the fat content in FPLD1 71. The Cambridge group recently reported that this form of lipodystrophy may have a polygenic etiology 72. There is a remarkable phenotypical heterogeneity among patients with FPLD1. In this spectrum of FPLD1, patients with significant central obesity are likely polygenic. This type of presentation is relatively more common, and it is sometimes difficult to make a distinction between FPLD1 and truncal obesity complicated with metabolic syndrome. The use of radiological methods such as DXA, CT or MRI can help in this population to further define body fat distribution in addition to physical examination and skinfold measurements. On the other hand, some FPLD patients without increased truncal fat are classified as FPLD1 by definition, if no disease-causing gene is identified to date. These latter patients will likely turn out to have a monogenic form of FPLD eventually. These two different presentations of FPLD1 are shown in Fig.9.

Figure 9. Heterogeneity in FPLD1.

Figure 9

Heterogeneity in FPLD1. Patient in A to D presented with decrease in peripheral fat depots and preservation of abdominal fat. Patient in E to H has increased abdominal adiposity. The formation of a palpable “ledge” between the normal and lipodystrophic areas is shown (9C and 9E). (Images E-H used with permission by Dr. Jonathan Q. Purnell from publication Diabetes Care 2003;26(6):1819-24)

FAMILIAL PARTIAL LIPODYSTROPHY TYPE 2 (FPLD2)

FPLD2 or Dunnigan Variety lipodystrophy is an autosomal dominant syndrome which is characterized by gradual onset of subcutaneous fat loss from the extremities during puberty. Affected individuals have prominent muscularity in their extremities. Excess fat accumulates in the neck causing a buffalo hump (Fig.10). This phenotype sometimes can be misdiagnosed as Cushing’s syndrome at first glance 14. Pathogenic variants in the LMNAgene, which is located on chromosome 1q21-22, cause FPLD2. The LMNAgene codes nuclear lamina proteins, lamin A and C. Pathogenic variants in the LMNAgene can be scattered across many exons of the gene and are missense mutations 73. Mutant lamins disrupt the interaction between nuclear lamina and chromatin and may result in apoptosis, which may be followed by premature adipocyte death 74.

Figure 10. Subcutaneous adipose tissue loss from the extremities, excess fat accumulation in the face and neck, and Cushingoid appearance in FPLD2 (10A-D; Note that one of the patients (10A) previously underwent liposuction for removal of unwanted excess fat from the neck).

Figure 10Subcutaneous adipose tissue loss from the extremities, excess fat accumulation in the face and neck, and Cushingoid appearance in FPLD2 (10A-D; Note that one of the patients (10A) previously underwent liposuction for removal of unwanted excess fat from the neck).

Females have a more recognizable phenotype and more severe metabolic complications 75. Most patients with FPLD2 develop diabetes in their twenties and thirties. Other components of insulin resistance are usually present. Patients with FPLD2 are at high risk for cardiovascular diseases that usually develop at relatively younger ages 76.

There is phenotypic heterogeneity among patients with FPLD2. For instance, less severe loss of fat has been reported in patients with exon 11 LMNApathogenic variants which affects only lamin A protein 77. LMNAR349W pathogenic variant (exon 6) is associated with facial fat loss which is uncommon in FPLD2 76,78,79. Exon 1 variants are associated with severe cardiac disease that require cardiac transplant at an early age and may be coupled with arrhythmias and conduction system abnormalities. Variants across exon 4 through 8 have been noted to cause muscular dystrophy related symptoms together with fat distribution abnormalities. LMNAgene pathogenic variants are also involved in the pathogenesis of progeroid disorders including Hutchinson-Gilford progeria syndrome (HGPS), mandibuloacral dysplasia, and atypical progeroid syndrome (APS).

FAMILIAL PARTIAL LIPODYSTROPHY TYPE 3 (FPLD3)

FPLD3 is caused by pathogenic variants in the PPARGgene, a key regulator of adipocyte differentiation. Patients with FPLD3 usually show milder fat loss; and there is no accumulation of adipose tissue in the face and neck (Fig.11); however, they manifest metabolic complications at a similar rate and severity to those with FPLD2 76,80-84.

Figure 11. Moderate partial subcutaneous adipose tissue loss in a patient with FPLD3 (11A-C).

Figure 11Moderate partial subcutaneous adipose tissue loss in a patient with FPLD3 (11A-C).

FAMILIAL PARTIAL LIPODYSTROPHY TYPE 4 (FPLD4)

FPLD4 is caused by pathogenic variants in the PLIN1gene encoding perilipin 1, which is an essential lipid droplet coat protein 85. Perilipin plays a key role in coordinating access of lipases to the core triacylglycerol. It is characterized by the loss of adipose tissue which is most striking in the lower limbs and femorogluteal depot, severe insulin resistance, diabetes, hypertriglyceridemia, and hepatic steatosis 86,87.

FAMILIAL PARTIAL LIPODYSTROPHY TYPE 5 (FPLD5)

FPLD5 is an autosomal recessive syndrome caused by pathogenic variants in the CIDECgene. It is characterized by partial lipodystrophy, acanthosis nigricans, severe insulin resistance leading to diabetes, and hepatic steatosis. The CIDECgene is located on chromosome 3 (3p25.3) and encodes the CIDEC protein, which is expressed in the lipid droplets. Pathogenic variants of the CIDECgene are postulated to result in the loss of ability of lipid droplets to store fat 88.

FAMILIAL PARTIAL LIPODYSTROPHY TYPE 6 (FPLD6)

FPLD type 6 is caused by pathogenic variants in the LIPE(lipase E, hormone sensitive type) gene which has an autosomal recessive inheritance 89. This FPLD subtype is characterized by late-onset partial fat loss from the lower extremities and also multiple symmetric lipomatosis and progressive distal symmetric myopathy at least in some cases 89,90. Hormone sensitive lipase is the predominant regulator of lipolysis from adipocytes. Pathogenic variants in the LIPEgene appear to result in impaired lipolysis which may induce lipomatosis and partial fat loss at the same time that is associated with hypertriglyceridemia, hepatic steatosis, and insulin resistant diabetes 90.

OTHER GENES ASSOCIATED WITH FAMILIAL PARTIAL LIPODYSTROPHY

FPLD has been reported to be caused by pathogenic variants in the AKT2gene 91. AKT is a serine/threonine protein kinase, which is involved in cell signaling/growth, glycogen synthesis, and insulin-stimulated glucose transport. Lipodystrophy in patients with AKT2mutations is thought to be due to defective adipocyte differentiation and post-receptor insulin signaling 92. Exome sequencing has identified a heterozygous variant in the adrenoceptor α 2A (ADRA2A) gene, which encodes the main presynaptic inhibitory feedback G protein–coupled receptor regulating norepinephrine release, in an African-American pedigree with atypical FPLD 93, which needs to be confirmed in additional pedigrees.

Progeroid Syndromes And Lipodystrophy

Mandibuloacral Dysplasia (MAD) is a rare progeroid syndrome which manifests with craniofacial, skeletal and cutaneous abnormalities and lipodystrophy (Fig.12) 94. The clinical manifestations present gradually over time, most commonly during childhood. There are two types of MAD currently recognized. Mandibuloacral dysplasia type A (MADA) is characterized by the loss of subcutaneous fat from the extremities along with normal or excessive fat in the face and the neck. Mandibuloacral dysplasia type B manifests with a more generalized loss of subcutaneous fat 94-97.

Figure 12. Hypoplasia of the mandible in a patient with Mandibuloacral Dysplasia.

Figure 12Hypoplasia of the mandible in a patient with Mandibuloacral Dysplasia.

MAD is caused by mutations in the LMNAgene which results in the accumulation of prelamin A protein 98. This, in return disrupts the interaction between nuclear lamina and chromatin 97-99. Compound heterozygous pathogenic variants in the zinc metalloproteinase (ZMPSTE24) gene have been reported to cause MADB associated lipodystrophy 100,101. ZMPSTE24is essential in the post-translational proteolytic cleavage of carboxy terminal residues of farnesylated prelamin A to form mature lamin A and vimentin processing 100,102,103.

MDP (mandibular hypoplasia, deafness and progeroid features syndrome) has been reported to be caused by pathogenic variants of thePOLD1gene that encodes catalytic subunit of DNA polymerase δ which play an essential role in the lagging-strand DNA synthesis during DNA replication 104. In addition to progressive lipodystrophy and severe insulin resistance, patients with MDP suffer from mandibular hypoplasia, sensorineural deafness, progeroid features, scleroderma and skin telangiectasia, ligament contractures, reduced mass of limb muscles, hypogonadism and undescended testes in males 104-107. We recently observed a mother daughter pair with a different POLD1variant near the carboxyl terminal of the protein at a very highly conserved residue (Fig.13).

Figure 13. Partial lipodystrophy in a patient with POLD1 variant (13A-E).

Figure 13Partial lipodystrophy in a patient with POLD1 variant (13A-E).

Biallelic WRNnull mutations linked to partial lipodystrophy with severe insulin resistance in adult progeria Werner syndrome (Fig.14) 108. The WRNgene encodes a RecQ DNA helicase which plays a critical role in repairing damaged DNA 109.

Figure 14. Partial lipodystrophy in a patient with adult progeria also known as Werner syndrome.

Figure 14Partial lipodystrophy in a patient with adult progeria also known as Werner syndrome.

Fibrillin-1 (FBN1) gene pathogenic variants are found in more than 90% of patients with Marfan syndrome 110. Pathogenic variants in the penultimate exon of FBN1have been reported to be associated with a distinct phenotype of generalized lipodystrophy that share some clinical features with neonatal progeroid syndrome (Wiedemann–Rautenstrauch syndrome), a very severe disorder with only a few patients described who could reach their late childhood 111-113. Although these patients have marfanoid/progeroid appearance, skeletal features, dilated aortic bulb, bilateral subluxation of the lens, myopia in addition to the severe generalized lipodystrophy, no significant metabolic abnormality caused by the lack of adipose tissue has been reported 111,112,114.

Pathogenic variants in BANF1have been reported to be associated with progeroid features, growth retardation, decreased subcutaneous fat, thin limbs, and stiff joints. This disease is also called Néstor-Guillermo progeria syndrome (NGPS) 115.

Heterozygous pathogenic variants in KCNJ6(GIRK2), which encodes an inwardly rectifying potassium channel, cause Keppen-Lubinsky syndrome that is characterized by severe developmental delay and intellectual disability, microcephaly, large prominent eyes, an open mouth, progeroid appearance, and generalized lipodystrophy 116.

Pathogenic variants of the Spartan (SPRTN) gene, which encodes a protein that is essential in the maintenance of genomic stability, have reported to be associated progeroid features, lipodystrophy and hepatocellular carcinoma 117.

Other Syndromes And Genes Associated With Lipodystrophy

Pathogenic variants in the phosphatidylinositol 3-kinase, regulatory subunit 1 (PIK3R1), which mediates insulin’s metabolic actions, have been reported in patients with SHORT syndrome (short stature, joint hyperextensibility, ocular depression, Rieger anomaly, and teething delay) that is associated with lipodystrophy in many patients 118,119. It has also been reported that patients with C-terminal PIK3R1pathogenic variants exhibit severe insulin resistance but normolipidemia and no hepatic steatosis 120.

Pathogenic variants in the proteasome subunit, beta-type, 8 (PSMB8) gene, which encodes a catalytic subunit of the 20S immunoproteasomes called β5i, has been linked to an autosomal-recessive autoinflammatory syndrome characterized by joint contractures, muscle atrophy, microcytic anemia, and panniculitis-induced lipodystrophy (JMP syndrome)121-123.

CANDLE syndrome is another rare autoinflammatory syndrome characterized by chronic atypical neutrophilic dermatitis, recurrent fever, and partial loss of adipose tissue from the upper limbs and face 124. An eponym for the syndrome was proposed as Nakajo–Nishimura syndrome 125,126. Homozygous or compound heterozygous mutations in the gene PSMB8have been reported in patients with CANDLE syndrome 127,128.

Recently a pathogenic variant in the MFN2gene that encodes mitofusin 2, a membrane-bound mediator of mitochondrial membrane fusion and inter-organelle communication, have been reported to be associated with partial lipodystrophy, upper body adipose hyperplasia, and suppression of leptin expression 129(Fig.15).

Figure 15. Disease progression in a patient with a pathogenic variant in the MFN2 gene (15A-D).

Figure 15Disease progression in a patient with a pathogenic variant in the MFN2 gene (15A-D).

Two families with AREDYLD syndrome that is characterized by acrorenal field defect, ectodermal dysplasia, generalized lipodystrophy, and multiple abnor

malities have been reported 130,131. The genetic basis of this very rare syndrome is still unknown.

Acquired Partial Lipodystrophy

Acquired partial lipodystrophy (APL) is characterized by fat loss typically starting in childhood or early adulthood. Loss of adipose tissue first manifests in the face and gradually progresses to the upper extremities, thorax and upper abdomen symmetrically. It typically proceeds in a cephalocaudal fashion but spares the lower extremities (Fig.16). There might be accumulation of fat in the lower abdomen, gluteal region, and lower extremities.

Figure 16. Typical cephalocaudal adipose tissue loss pattern in two patients with APL (16A-D).

Figure 16

Typical cephalocaudal adipose tissue loss pattern in two patients with APL (16A-D). Note preservation of fat depots below the waist line.

Although the etiology of APL is still unknown, some patients may have coinciding autoimmune conditions. Systemic lupus erythematosus and dermatomyositis/polymyositis are among the most frequently associated auto-immune diseases 132. APL has been associated with abnormalities of the alternative complement pathway that may cause membranoproliferative glomerulonephritis (MPGN) 133. Subsequent chronic renal disease constitutes the major cause of morbidity in these patients. It has been suggested that C3-nephritic factor might be the cause for the lysis of adipocytes expressing factor D, although there is no solid evidence supporting this hypothesis 134.

Rare variants in LMNB2were previously reported in five patients with APL, but two of four variants were also present in normal controls 135. In addition, subcutaneous loss of fat from the legs and the gluteal region, presence of diabetes, type IV and V hyperlipoproteinemias were atypical presentations in these patients 135.

Metabolic complications are less common compared to other types of lipodystrophy syndromes 4. Not all patients develop insulin resistance, diabetes, or hypertriglyceridemia. Leptin levels vary from hypoleptinemia to normal range 30,132. However, patients may develop metabolic abnormalities such as diabetes, hypertriglyceridemia, low HDL cholesterol levels and hepatic steatosis in later stages of the disorder. In addition, several patients with APL has been reported to develop diabetes or other metabolic abnormalities at a relatively young age, which are apparently associated with insulin resistance 136. Thus, patients with APL should also be followed for metabolic abnormalities as is done for other subtypes of lipodystrophy.

TREATMENT

Currently, treatment modalities are restricted to ameliorating or preventing the comorbidities of the lipodystrophic syndromes. There is no cure for these syndromes. For the metabolic disturbances, lifestyle modification (diet and exercise as needed), metformin, and fibrates (and/or statins) are generally required. Insulin or other antidiabetics (e.g., metformin, thiazolidinediones) can also be used if needed. Metreleptin, a leptin analog, is indicated as an adjunct to diet as replacement therapy to treat the complications of leptin deficiency in patients with generalized lipodystrophy.

Lifestyle Modification

There is limited knowledge on the effectiveness of diet and exercise in the management of metabolic disturbances in patients with lipodystrophy. In general, a balanced macronutrient composition is recommended. In patients with severe hypertriglyceridemia, a balanced low- fat diet (<15% of daily caloric intake) is appropriate. To control diabetes, increased physical activity and carbohydrate restriction are advised. Dietary fiber intake and foods that are rich in omega-3 fatty acids are suggested 3.

Most patients with lipodystrophy are encouraged to be physically active. In patients with cardiomyopathy and cardiac arrhythmias strenuous exercise should be avoided. Patients with CGL4 should avoid exercise as they may develop exercise-induced ventricular arrhythmias 57,60. Contact sports are not advised to patients with severe hepatosplenomegaly and CGL patients presenting with lytic bone lesions.

Patients should abstain from drinking alcohol due to the risk of developing acute pancreatitis and non-alcoholic steatohepatitis (NASH). Patients should also be advised to avoid smoking and maintain an optimal blood pressure to decrease the risk of cardiovascular disease.

Insulin Resistance

In patients presenting with lipodystrophy and diabetes, both metformin and thiazolidinediones are somewhat effective to treat hyperglycemia and hyperlipidemia 137-141. Metformin is used as the first-line agent in insulin resistant diabetes. Thiazolidinediones may improve the metabolic profile in partial lipodystrophy syndromes 141. The very first thiazolidinedione to be approved in the United States troglitazone actually worked remarkably well in lowering both HbA1c and triglyceride levels in a cohort of patients with predominantly partial lipodystrophy syndromes. However, data on the currently approved thiazolidinediones are limited and contradictory 139,142,143. Thiazolidinediones should be considered in the management of diabetes in patients with partial lipodystrophy, however they should not be routinely used in generalized lipodystrophy as their efficacy has not been studied 3,141. Insulin is usually needed in very high doses and concentrated forms, such as U-500. Patients with extreme insulin resistance, however, may not respond to concentrated insulin. Administration of insulin-like growth factor-1 (IGF-1) has been shown to be effective in maintaining glycemic control and insulin resistance in short-term studies, as well as in type 2 diabetes 144-146. Many other hypoglycemic agents have been used in lipodystrophy, but their efficacy has not been studied 3.

Dyslipidemia

Statins are normally used as first-line agents to treat hypercholesterolemia but patients with FPLD have low tolerance to statins. Rosuvastatin and pravastatin have been proven to reduce total LDL cholesterol levels 147,148. Statins are used with caution to prevent side effects such as myopathy and hepatotoxicity. Along with diet, fibrates and fish oil rich in omega-3 fatty acids, should be prescribed for serum triglyceride levels >500 mg/dL and may be considered for triglycerides >200 mg/dL. Combining fibrates with statins has proved to be effective in dyslipidemia; however, there is an increased risk for muscle toxicity. Therapeutic apheresis is used in extreme hypertriglyceridemia to prevent recurrent episodes of acute pancreatitis 29.

Cosmetic Treatment

Cosmetic correction of lipoatrophy and fat excess is associated with improved quality of life in patients with lipodystrophy. Autologous adipose tissue transplantation, facial reconstruction with free flaps and silicone or other implants have been used in lipoatrophic areas. In addition, liposuction or surgical excision is used for removal of unwanted excess fat from body parts such as; the chin, buffalo hump and vulvar region.

Bariatric Surgery

Roux-en-Y Gastric Bypass Surgery (RYGB) is associated with effective weight loss and resolution of metabolic comorbidities in patients with obesity 149. RYGB was used with success in several patients with FPLD1 and with FPLD2 150-152. RYGB resulted in weight loss and significant improvements in metabolic parameters in patients with FPLD1 that allowed patients to stop using insulin 150. FPLD2 patients also benefited from RYBG. Substantial improvements in metabolic parameters and a significant weight loss were reported after the surgery 152,153.

Leptin

A large group of lipodystrophy patients present with low leptin levels. Metreleptin (r-metHuLeptin) is an analog of human leptin made through recombinant DNA technology. It has been tested in congenital and acquired forms of lipodystrophy and has been shown to ameliorate the metabolic derangements 29,34. Several studies show that leptin (0.04 to 0.08 mg/kg/day by subcutaneous injection) in patients with generalized lipodystrophy results in significant weight loss due to its effect on appetite and resting energy expenditure 34. Leptin replacement therapy is approved in Japan as a therapy indicated specifically for the treatment of diabetes and/or hypertriglyceridemia in patients with congenital or acquired lipodystrophy. In the United States, metreleptin, now called MYALEPT, has been approved by the FDA in 2014 for use in patients with congenital generalized or acquired generalized lipodystrophy for the treatment of metabolic complications of these diseases as an adjunct to diet and lifestyle modifications. There is no lower age limit for initiation of Myalept nor a specific degree of metabolic abnormality so long as the diagnosis of generalized lipodystrophy can be substantiated. However, it is not approved for use in human immunodeficiency virus (HIV)-related lipodystrophy, or in patients with metabolic diseases such as diabetes and hypertriglyceridemia, or partial lipodystrophy. The effects of leptin treatment in patients with lipodystrophy are summarized below.

APPETITE

Metreleptin decreases hyperphagia, leading to weight loss that usually stabilize with long-term treatment 29,154-156. This effect can be noted by the patients right after the treatment with metreleptin. Functional MRI studies combined with behavioral assessments showed that metreleptin treatment is associated with long-term improvements of hedonic and homeostatic central nervous networks regulating appetite and food intake 157-159. Food related neural activity and formation of satiety feeling have been shown to be effectively restored by leptin replacement in lipodystrophy 160.

METABOLIC PARAMETERS

Metabolic changes become prominent in several weeks after metreleptin. Metreleptin therapy has been shown to improve fasting plasma glucose levels starting from the first week 151. In a subset of patients undergoing hyperinsulinemic-euglycemic clamp studies, leptin replacement therapy improved peripheral glucose disposal and decreased both hepatic glucose output and hepatic steatosis 161. Metreleptin lowered HbA1c by 2% within the first year 162. It is recommended to lower the insulin doses by 50% on initiation of metreleptin therapy to avoid hypoglycemia in well-controlled diabetic patients. Metreleptin treatment has no suppressive effect on beta cell function in patients with lipodystrophy 163. On the contrary it has been reported that metreleptin therapy improves insulin secretion in diabetic patients with lipodystrophy 164.

Metreleptin lowers triglycerides starting from the first week. It is effective in providing a 60% reduction in triglyceride levels within the first year 162. It should be noted that acute withdrawal of metreleptin therapy might result in acute pancreatitis episodes 165,166. Metreleptin also decreased total cholesterol and LDL-cholesterol levels but did not alter HDL cholesterol levels 165,167.

The beneficial effect of metreleptin on glycemic and lipid measures in generalized lipodystrophy are clear and usually dramatic. Although the response is variable in patients with partial lipodystrophy and it is not approved yet in this patient population, studies have shown that these patients can benefit from metreleptin treatment. A selected cohort of partial lipodystrophy patients with moderately to severely low leptin and significant baseline metabolic abnormalities is more likely to benefit from metreleptin therapy 12,162,168,169.

LIVER

Leptin replacement therapy improves hepatic steatosis and lowers serum transaminases within 6-12 months (Fig.17) 156,161,170. The liver volume decreases 155,170. Although the mechanism is not fully understood, leptin therapy resulted in significant increase in insulin suppression of hepatic glucose production 161. This improvement in insulin action helps reverse hepatic steatosis by decreasing triglyceride content 161. Nonalcoholic steatohepatitis (NASH) score has been reported to improve after metreleptin treatment and no progression in hepatic fibrosis has been reported 171. When treated at least for a year, the vast majority of patients showed improved liver histology, steatosis and hepatocyte ballooning, and only 33% of patients continued fulfilling the criteria for NASH after 1 year of treatment with metreleptin 172,173. A significant improvement in the non-alcoholic fatty liver disease (NAFLD) score has been reported after metreleptin treatment in pediatric patients who underwent liver biopsies 174. Metreleptin has also been reported to result in rapid clearance of fat from the liver and normalization of liver histology in an AGL patient with recurrence of NAFLD in the first few months of liver transplantation 175.

Figure 17. Liver histology shows regression of hepatic steatosis and ballooning injury after metreleptin treatment (left before metreleptin and right 4 months on metreleptin treatment, Hematoxylin and eosin staining; magnification 200X).

Figure 17Liver histology shows regression of hepatic steatosis and ballooning injury after metreleptin treatment (left before metreleptin and right 4 months on metreleptin treatment, Hematoxylin and eosin staining; magnification 200X).

KIDNEYS

Patients with lipodystrophy may develop proteinuric kidney disease. Metreleptin decreased proteinuria in most patients 156,176. The reduction in proteinuria coincided with improvement in hyperfiltration in 11 of 15 patients treated with metreleptin. However, four patients had worsening renal function. Hence, renal functions should be closely monitored during metreleptin therapy 176.

REPRODUCTIVE SYSTEM

In females, metreleptin was found to normalize gonadotropin secretion. It led to normal progression of puberty, normalized menstrual cycles, and improved fertility 156,177-179. Leptin replacement improved low estradiol levels and corrected the attenuated luteinizing hormone (LH) response to luteinizing hormone-releasing hormone (LHRH) in young women with lipodystrophy and leptin deficiency 177. One-year treatment with metreleptin resulted a significant decrease in testosterone and sex hormone binding globulin (SHBG) levels in lipodystrophic women with PCOS 180. Several pregnancies have occurred in patients with lipodystrophy while they were on metreleptin without any evidence for teratogenicity 38,181, although it has not been approved for use in pregnancy. Leptin replacement was associated with a small increase (clinically non-significant) in serum testosterone and SHBG in males. No change was observed in serum LH response to LHRH 178. No impact of leptin therapy on bone mineral density and content and bone metabolism has been reported in both sexes 170,182,183.

ADVERSE EFFECTS

Approximately 30% of patients treated with metreleptin experienced adverse effects 165. The most common side effects were hypoglycemia, and injection site reactions e.g. erythema and urticaria. Headache, fatigue, weight loss, and abdominal pain were also seen. There may also be a need to make dose adjustments or cessation of concomitant treatments such as insulin, oral antidiabetics, and lipid lowering drugs after metreleptin therapy. In some cases, in vivo neutralizing antibodies to metreleptin have been reported 184,185and is the main reason underlying the FDA's restriction of metreleptin use. Anti-metreleptin antibodies developed in most patients with lipodystrophy; however, neutralizing activity concurrent with worsened metabolic control has been reported only in a small number of patients treated with metreleptin 181,184. In addition, in the few patients who presented with neutralizing antibody formation, occurrence of severe infections such as sepsis has been reported. Two of these patients developed multiple sepsis episodes around the time of detection of neutralizing antibody 184. T-cell lymphoma has been reported in three patients with acquired generalized lipodystrophy receiving metreleptin 186. In acquired lipodystrophy patients with autoimmunity and immunodeficiency before metreleptin therapy, T-cell lymphoma development was also described 186,187, suggesting that lymphoma development in acquired lipodystrophy is more likely to be associated with the disease itself rather than being related to metreleptin treatment.

In other cases with acquired generalized lipodystrophy, progression of kidney disease and liver disease have been observed while receiving metreleptin therapy 188. Since patients with AGL with distinct autoimmune conditions clearly benefit from metreleptin, treatment for their metabolic abnormalities should be considered in patients with AGL with close clinical follow up in light of the cautionary preclinical data 189,190.

More recently attention has been devoted to emergence of new cancers while on metreleptin therapy. Data on these parameters will be reported in short order.

Investigational Treatments For Lipodystrophy

Since in the United States partial lipodystrophy has been without medical therapy, a number of companies with interesting compounds have initiated development of their products for this indication. Current investigational treatments with registered studies in ClinicalTrials.gov are presented in Table 4. Data on these trials will be updated as results become available.

Table 4Investigational Therapies For Lipodystrophy


Investigational agent

Status

Type of lipodystrophy

Primary outcome
Volanesorsen
(anti-sense oligonucleotide to apoC-III)
Active, not recruitingFamilial partial lipodystrophyChange in fasting triglycerides
Obeticholic Acid
(farnesoid X receptor agonist)
RecruitingFamilial partial lipodystrophyChange in liver triglycerides
Cholic Acid
(primary bile acid)
Active, not recruitingVarious forms of lipodystrophyReduction in liver triglyceride content
Setmelanotide
(melanocortin-4 receptor agonist)
Expanded access in a single patientPartial lipodystrophy associated with leptin deficiencyTreatment of refractory hypertriglyceridemia leading to recurrent bouts of pancreatitis
Gemcabene
(monocalcium salt of a dialkyl ether dicarboxylic acid)
RecruitingFamilial partial lipodystrophyChange in fasting triglycerides, hepatic steatosis
Baricitinib
(inhibitor of Janus kinases 1 and 2 “JAK1/2”)
Expanded access availableAutoinflammatory syndromesClinical benefit from JAK 1/2 inhibition
Evinacumab
(Anti-ANGPTL3)
Not yet recruitingPatients with severe hypertriglyceridemiaPercent lowering of triglycerides

CONCLUSION

Lipodystrophy syndromes are a group of fascinating diseases that are caused by mechanisms that disrupt predominantly adipocyte differentiation or lipid droplet formation. LMNAgene defects, the most common single gene defects leading to the development of lipodystrophy syndromes, leads to lipodystrophy possibly due to inducing adipocyte apoptosis or death, but more work is needed on this front. Regardless of the mechanism and whether the diseases present with generalized or partial fat loss, common metabolic complications include severe insulin resistance, hypertriglyceridemia, and ectopic fat deposition, especially hepatic steatosis. This common theme is recapitulated in numerous animal models as well. The diseases are typically progressive and lead to multi-organ involvement and increased mortality. Molecular advances in the understanding of disease mechanisms may lead to better and specific treatments for lipodystrophy syndromes. So far, the most exciting therapeutic development for the treatment of lipodystrophy syndromes has been the approval of leptin replacement therapy for generalized lipodystrophy in the form of metreleptin. While Metreleptin is not approved for treatment of partial lipodystrophy syndromes in the United States, there are a number of global studies ongoing for the treatment of predominant partial lipodystrophy syndromes with other agents at this time.

REFERENCES

  1. Chan JL, Oral EA. Clinical classification and treatment of congenital and acquired lipodystrophy. Endocr Pract 2010;16:310-23.
  2. Garg A. Clinical review#: Lipodystrophies: genetic and acquired body fat disorders. J Clin Endocrinol Metab 2011;96:3313-25.
  3. Brown RJ, Araujo-Vilar D, Cheung PT, et al. The Diagnosis and Management of Lipodystrophy Syndromes: A Multi-Society Practice Guideline. The Journal of clinical endocrinology and metabolism 2016;101:4500-11.
  4. Handelsman Y, Oral EA, Bloomgarden ZT, et al. The clinical approach to the detection of lipodystrophy - an AACE consensus statement. Endocr Pract 2013;19:107-16.
  5. Robbins DC, Sims EA. Recurrent ketoacidosis in acquired, total lipodystrophy (lipoatrophic diabetes). Diabetes Care 1984;7:381-5.
  6. Jackson SN, Howlett TA, McNally PG, O'Rahilly S, Trembath RC. Dunnigan-Kobberling syndrome: an autosomal dominant form of partial lipodystrophy. QJM 1997;90:27-36.
  7. Lupsa BC, Sachdev V, Lungu AO, Rosing DR, Gorden P. Cardiomyopathy in congenital and acquired generalized lipodystrophy: a clinical assessment. Medicine (Baltimore) 2010;89:245-50.
  8. Bjornstad PG, Semb BK, Trygstad O, Seip M. Echocardiographic assessment of cardiac function and morphology in patients with generalised lipodystrophy. Eur J Pediatr 1985;144:355-9.
  9. Misra A, Garg A. Clinical features and metabolic derangements in acquired generalized lipodystrophy: case reports and review of the literature. Medicine (Baltimore) 2003;82:129-46.
  10. Seip M. Generalized lipodystrophy. Ergeb Inn Med Kinderheilkd 1971;31:59-95.
  11. Ajluni N, Meral R, Neidert AH, et al. Spectrum of disease associated with partial lipodystrophy: lessons from a trial cohort. Clin Endocrinol (Oxf) 2017;86:698-707.
  12. Ajluni N, Dar M, Xu J, Neidert AH, Oral EA. Efficacy and Safety of Metreleptin in Patients with Partial Lipodystrophy: Lessons from an Expanded Access Program. J Diabetes Metab 2016;7.
  13. Garg A, Misra A. Lipodystrophies: rare disorders causing metabolic syndrome. Endocrinol Metab Clin North Am 2004;33:305-31.
  14. Garg A. Acquired and inherited lipodystrophies. N Engl J Med 2004;350:1220-34.
  15. Caron A, Lee S, Elmquist JK, Gautron L. Leptin and brain-adipose crosstalks. Nat Rev Neurosci 2018;19:153-65.
  16. Musso C, Cochran E, Moran SA, et al. Clinical course of genetic diseases of the insulin receptor (type A and Rabson-Mendenhall syndromes): a 30-year prospective. Medicine (Baltimore) 2004;83:209-22.
  17. Oral EA, Chan JL. Rationale for leptin-replacement therapy for severe lipodystrophy. Endocr Pract 2010;16:324-33.
  18. Melvin A, O'Rahilly S, Savage DB. Genetic syndromes of severe insulin resistance. Curr Opin Genet Dev 2018;50:60-7.
  19. D'Souza A M, Neumann UH, Glavas MM, Kieffer TJ. The glucoregulatory actions of leptin. Mol Metab 2017;6:1052-65.
  20. Triantafyllou GA, Paschou SA, Mantzoros CS. Leptin and Hormones: Energy Homeostasis. Endocrinol Metab Clin North Am 2016;45:633-45.
  21. Meek TH, Morton GJ. The role of leptin in diabetes: metabolic effects. Diabetologia 2016;59:928-32.
  22. Savage DB. Mouse models of inherited lipodystrophy. Dis Model Mech 2009;2:554-62.
  23. Moitra J, Mason MM, Olive M, et al. Life without white fat: a transgenic mouse. Genes Dev 1998;12:3168-81.
  24. Reitman ML, Gavrilova O. A-ZIP/F-1 mice lacking white fat: a model for understanding lipoatrophic diabetes. Int J Obes Relat Metab Disord 2000;24 Suppl 4:S11-4.
  25. Gavrilova O, Marcus-Samuels B, Graham D, et al. Surgical implantation of adipose tissue reverses diabetes in lipoatrophic mice. J Clin Invest 2000;105:271-8.
  26. Zhang Z, Turer E, Li X, et al. Insulin resistance and diabetes caused by genetic or diet-induced KBTBD2 deficiency in mice. Proc Natl Acad Sci U S A 2016;113:E6418-E26.
  27. Shimomura I, Hammer RE, Ikemoto S, Brown MS, Goldstein JL. Leptin reverses insulin resistance and diabetes mellitus in mice with congenital lipodystrophy. Nature 1999;401:73-6.
  28. Colombo C, Cutson JJ, Yamauchi T, et al. Transplantation of adipose tissue lacking leptin is unable to reverse the metabolic abnormalities associated with lipoatrophy. Diabetes 2002;51:2727-33.
  29. Oral EA, Simha V, Ruiz E, et al. Leptin-replacement therapy for lipodystrophy. N Engl J Med 2002;346:570-8.
  30. Haque WA, Shimomura I, Matsuzawa Y, Garg A. Serum adiponectin and leptin levels in patients with lipodystrophies. J Clin Endocrinol Metab 2002;87:2395.
  31. Seip M. Lipodystrophy and gigantism with associated endocrine manifestations. A new diencephalic syndrome? Acta Paediatr 1959;48:555-74.
  32. Berardinelli W. An undiagnosed endocrinometabolic syndrome: report of 2 cases. J Clin Endocrinol Metab 1954;14:193-204.
  33. Goodpaster BH. Measuring body fat distribution and content in humans. Curr Opin Clin Nutr Metab Care 2002;5:481-7.
  34. Tsoukas MA MC. Endocrinology Adult and Pediatric. In: Jameson JL DL, ed. 7 ed: Saunders, In Press.
  35. Agarwal AK, Simha V, Oral EA, et al. Phenotypic and genetic heterogeneity in congenital generalized lipodystrophy. The Journal of clinical endocrinology and metabolism 2003;88:4840-7.
  36. Van Maldergem L, Magre J, Khallouf TE, et al. Genotype-phenotype relationships in Berardinelli-Seip congenital lipodystrophy. J Med Genet 2002;39:722-33.
  37. Capeau J, Magre J, Caron-Debarle M, et al. Human lipodystrophies: genetic and acquired diseases of adipose tissue. Endocr Dev 2010;19:1-20.
  38. Maguire M, Lungu A, Gorden P, Cochran E, Stratton P. Pregnancy in a woman with congenital generalized lipodystrophy: leptin's vital role in reproduction. Obstet Gynecol 2012;119:452-5.
  39. Jiang M, Gao M, Wu C, et al. Lack of testicular seipin causes teratozoospermia syndrome in men. Proc Natl Acad Sci U S A 2014;111:7054-9.
  40. Patni N, Garg A. Congenital generalized lipodystrophies--new insights into metabolic dysfunction. Nat Rev Endocrinol 2015;11:522-34.
  41. Garg A, Wilson R, Barnes R, et al. A gene for congenital generalized lipodystrophy maps to human chromosome 9q34. J Clin Endocrinol Metab 1999;84:3390-4.
  42. Fernandez-Galilea M, Tapia P, Cautivo K, Morselli E, Cortes VA. AGPAT2 deficiency impairs adipogenic differentiation in primary cultured preadipocytes in a non-autophagy or apoptosis dependent mechanism. Biochem Biophys Res Commun 2015;467:39-45.
  43. Subauste AR, Das AK, Li X, et al. Alterations in lipid signaling underlie lipodystrophy secondary to AGPAT2 mutations. Diabetes 2012;61:2922-31.
  44. Simha V, Agarwal AK, Aronin PA, Iannaccone ST, Garg A. Novel subtype of congenital generalized lipodystrophy associated with muscular weakness and cervical spine instability. Am J Med Genet A 2008;146A:2318-26.
  45. Garg A, Fleckenstein JL, Peshock RM, Grundy SM. Peculiar distribution of adipose tissue in patients with congenital generalized lipodystrophy. J Clin Endocrinol Metab 1992;75:358-61.
  46. Simha V, Garg A. Phenotypic heterogeneity in body fat distribution in patients with congenital generalized lipodystrophy caused by mutations in the AGPAT2 or seipin genes. J Clin Endocrinol Metab 2003;88:5433-7.
  47. Magre J, Delepine M, Khallouf E, et al. Identification of the gene altered in Berardinelli-Seip congenital lipodystrophy on chromosome 11q13. Nat Genet 2001;28:365-70.
  48. Cartwright BR, Goodman JM. Seipin: from human disease to molecular mechanism. J Lipid Res 2012;53:1042-55.
  49. Cartwright BR, Binns DD, Hilton CL, Han S, Gao Q, Goodman JM. Seipin performs dissectible functions in promoting lipid droplet biogenesis and regulating droplet morphology. Mol Biol Cell 2015;26:726-39.
  50. Akinci B, Onay H, Demir T, et al. Natural History of Congenital Generalized Lipodystrophy: A Nationwide Study From Turkey. J Clin Endocrinol Metab 2016;101:2759-67.
  51. Altay C, Secil M, Demir T, et al. Determining residual adipose tissue characteristics with MRI in patients with various subtypes of lipodystrophy. Diagnostic and Interventional Radiology 2017;23:428-34.
  52. Antuna-Puente B, Boutet E, Vigouroux C, et al. Higher Adiponectin Levels in Patients with Berardinelli-Seip Congenital Lipodystrophy due to Seipin as compared with 1-Acylglycerol-3-Phosphate-O-Acyltransferase-2 Deficiency. Journal of Clinical Endocrinology & Metabolism 2010;95:1463-8.
  53. Kim CA, Delepine M, Boutet E, et al. Association of a homozygous nonsense caveolin-1 mutation with Berardinelli-Seip congenital lipodystrophy. J Clin Endocrinol Metab 2008;93:1129-34.
  54. Garg A, Agarwal AK. Caveolin-1: a new locus for human lipodystrophy. J Clin Endocrinol Metab 2008;93:1183-5.
  55. Garg A, Kircher M, Del Campo M, Amato RS, Agarwal AK, University of Washington Center for Mendelian G. Whole exome sequencing identifies de novo heterozygous CAV1 mutations associated with a novel neonatal onset lipodystrophy syndrome. Am J Med Genet A 2015;167A:1796-806.
  56. Cao H, Alston L, Ruschman J, Hegele RA. Heterozygous CAV1 frameshift mutations (MIM 601047) in patients with atypical partial lipodystrophy and hypertriglyceridemia. Lipids Health Dis 2008;7:3.
  57. Hayashi YK, Matsuda C, Ogawa M, et al. Human PTRF mutations cause secondary deficiency of caveolins resulting in muscular dystrophy with generalized lipodystrophy. J Clin Invest 2009;119:2623-33.
  58. Rajab A, Straub V, McCann LJ, et al. Fatal cardiac arrhythmia and long-QT syndrome in a new form of congenital generalized lipodystrophy with muscle rippling (CGL4) due to PTRF-CAVIN mutations. PLoS Genet 2010;6:e1000874.
  59. Shastry S, Delgado MR, Dirik E, Turkmen M, Agarwal AK, Garg A. Congenital generalized lipodystrophy, type 4 (CGL4) associated with myopathy due to novel PTRF mutations. Am J Med Genet A 2010;152A:2245-53.
  60. Akinci G, Topaloglu H, Akinci B, et al. Spectrum of clinical manifestations in two young Turkish patients with congenital generalized lipodystrophy type 4. Eur J Med Genet 2016;59:320-4.
  61. Payne F, Lim K, Girousse A, et al. Mutations disrupting the Kennedy phosphatidylcholine pathway in humans with congenital lipodystrophy and fatty liver disease. Proc Natl Acad Sci U S A 2014;111:8901-6.
  62. Hussain I, Patni N, Ueda M, et al. A Novel Generalized Lipodystrophy-associated Progeroid Syndrome due to recurrent heterozygous LMNA p.T10I Mutation. J Clin Endocrinol Metab 2017.
  63. Dyment DA, Gibson WT, Huang L, Bassyouni H, Hegele RA, Innes AM. Biallelic mutations at PPARG cause a congenital, generalized lipodystrophy similar to the Berardinelli-Seip syndrome. Eur J Med Genet 2014;57:524-6.
  64. Arioglu E, Andewelt A, Diabo C, Bell M, Taylor SI, Gorden P. Clinical course of the syndrome of autoantibodies to the insulin receptor (type B insulin resistance): a 28-year perspective. Medicine (Baltimore) 2002;81:87-100.
  65. Pope E, Janson A, Khambalia A, Feldman B. Childhood acquired lipodystrophy: a retrospective study. J Am Acad Dermatol 2006;55:947-50.
  66. Bingham A, Mamyrova G, Rother KI, et al. Predictors of acquired lipodystrophy in juvenile-onset dermatomyositis and a gradient of severity. Medicine (Baltimore) 2008;87:70-86.
  67. Verma S, Singh S, Bhalla AK, Khullar M. Study of subcutaneous fat in children with juvenile dermatomyositis. Arthritis Rheum 2006;55:564-8.
  68. Billings JK, Milgraum SS, Gupta AK, Headington JT, Rasmussen JE. Lipoatrophic panniculitis: a possible autoimmune inflammatory disease of fat. Report of three cases. Arch Dermatol 1987;123:1662-6.
  69. Eren E, Ozkan TB, Cakir ED, Saglam H, Tarim O. Acquired generalized lipodystrophy associated with autoimmune hepatitis and low serum C4 level. J Clin Res Pediatr Endocrinol 2010;2:39-42.
  70. Guillin-Amarelle C, Sanchez-Iglesias S, Castro-Pais A, et al. Type 1 familial partial lipodystrophy: understanding the Kobberling syndrome. Endocrine 2016;54:411-21.
  71. Herbst KL, Tannock LR, Deeb SS, Purnell JQ, Brunzell JD, Chait A. Kobberling type of familial partial lipodystrophy: an underrecognized syndrome. Diabetes Care 2003;26:1819-24.
  72. Lotta LA, Gulati P, Day FR, et al. Integrative genomic analysis implicates limited peripheral adipose storage capacity in the pathogenesis of human insulin resistance. Nat Genet 2017;49:17-26.
  73. Hegele RA, Joy TR, Al-Attar SA, Rutt BK. Thematic review series: Adipocyte Biology. Lipodystrophies: windows on adipose biology and metabolism. J Lipid Res 2007;48:1433-44.
  74. Agarwal AK, Barnes RI, Garg A. Genetic basis of congenital generalized lipodystrophy. Int J Obes Relat Metab Disord 2004;28:336-9.
  75. Garg A. Gender differences in the prevalence of metabolic complications in familial partial lipodystrophy (Dunnigan variety). J Clin Endocrinol Metab 2000;85:1776-82.
  76. Akinci B, Onay H, Demir T, et al. Clinical presentations, metabolic abnormalities and end-organ complications in patients with familial partial lipodystrophy. Metabolism 2017;72:109-19.
  77. Garg A, Vinaitheerthan M, Weatherall PT, Bowcock AM. Phenotypic heterogeneity in patients with familial partial lipodystrophy (dunnigan variety) related to the site of missense mutations in lamin a/c gene. J Clin Endocrinol Metab 2001;86:59-65.
  78. Fountas A, Giotaki Z, Dounousi E, et al. Familial partial lipodystrophy and proteinuric renal disease due to a missense c.1045C > T LMNA mutation. Endocrinol Diabetes Metab Case Rep 2017;2017.
  79. Mory PB, Crispim F, Freire MB, et al. Phenotypic diversity in patients with lipodystrophy associated with LMNA mutations. Eur J Endocrinol 2012;167:423-31.
  80. Monajemi H, Zhang L, Li G, et al. Familial partial lipodystrophy phenotype resulting from a single-base mutation in deoxyribonucleic acid-binding domain of peroxisome proliferator-activated receptor-gamma. J Clin Endocrinol Metab 2007;92:1606-12.
  81. Ludtke A, Buettner J, Wu W, et al. Peroxisome proliferator-activated receptor-gamma C190S mutation causes partial lipodystrophy. J Clin Endocrinol Metab 2007;92:2248-55.
  82. Al-Shali K, Cao H, Knoers N, Hermus AR, Tack CJ, Hegele RA. A single-base mutation in the peroxisome proliferator-activated receptor gamma4 promoter associated with altered in vitro expression and partial lipodystrophy. J Clin Endocrinol Metab 2004;89:5655-60.
  83. Agarwal AK, Garg A. A novel heterozygous mutation in peroxisome proliferator-activated receptor-gamma gene in a patient with familial partial lipodystrophy. J Clin Endocrinol Metab 2002;87:408-11.
  84. Demir T, Onay H, Savage DB, et al. Familial partial lipodystrophy linked to a novel peroxisome proliferator activator receptor -gamma (PPARG) mutation, H449L: a comparison of people with this mutation and those with classic codon 482 Lamin A/C (LMNA) mutations. Diabet Med 2016;33:1445-50.
  85. Gandotra S, Lim K, Girousse A, Saudek V, O'Rahilly S, Savage DB. Human frame shift mutations affecting the carboxyl terminus of perilipin increase lipolysis by failing to sequester the adipose triglyceride lipase (ATGL) coactivator AB-hydrolase-containing 5 (ABHD5). J Biol Chem 2011;286:34998-5006.
  86. Gandotra S, Le Dour C, Bottomley W, et al. Perilipin deficiency and autosomal dominant partial lipodystrophy. N Engl J Med 2011;364:740-8.
  87. Kozusko K, Tsang V, Bottomley W, et al. Clinical and molecular characterization of a novel PLIN1 frameshift mutation identified in patients with familial partial lipodystrophy. Diabetes 2015;64:299-310.
  88. Rubio-Cabezas O, Puri V, Murano I, et al. Partial lipodystrophy and insulin resistant diabetes in a patient with a homozygous nonsense mutation in CIDEC. EMBO Mol Med 2009;1:280-7.
  89. Farhan SM, Robinson JF, McIntyre AD, et al. A novel LIPE nonsense mutation found using exome sequencing in siblings with late-onset familial partial lipodystrophy. Can J Cardiol 2014;30:1649-54.
  90. Zolotov S, Xing C, Mahamid R, Shalata A, Sheikh-Ahmad M, Garg A. Homozygous LIPE mutation in siblings with multiple symmetric lipomatosis, partial lipodystrophy, and myopathy. Am J Med Genet A 2017;173:190-4.
  91. George S, Rochford JJ, Wolfrum C, et al. A family with severe insulin resistance and diabetes due to a mutation in AKT2. Science 2004;304:1325-8.
  92. Tan K, Kimber WA, Luan J, et al. Analysis of genetic variation in Akt2/PKB-beta in severe insulin resistance, lipodystrophy, type 2 diabetes, and related metabolic phenotypes. Diabetes 2007;56:714-9.
  93. Garg A, Sankella S, Xing C, Agarwal AK. Whole-exome sequencing identifies ADRA2A mutation in atypical familial partial lipodystrophy. JCI Insight 2016;1.
  94. Simha V, Garg A. Body fat distribution and metabolic derangements in patients with familial partial lipodystrophy associated with mandibuloacral dysplasia. J Clin Endocrinol Metab 2002;87:776-85.
  95. Garavelli L, D'Apice MR, Rivieri F, et al. Mandibuloacral dysplasia type A in childhood. Am J Med Genet A 2009;149A:2258-64.
  96. Lombardi F, Gullotta F, Columbaro M, et al. Compound heterozygosity for mutations in LMNA in a patient with a myopathic and lipodystrophic mandibuloacral dysplasia type A phenotype. J Clin Endocrinol Metab 2007;92:4467-71.
  97. Agarwal AK, Zhou XJ, Hall RK, et al. Focal segmental glomerulosclerosis in patients with mandibuloacral dysplasia owing to ZMPSTE24 deficiency. J Investig Med 2006;54:208-13.
  98. Novelli G, Muchir A, Sangiuolo F, et al. Mandibuloacral dysplasia is caused by a mutation in LMNA-encoding lamin A/C. Am J Hum Genet 2002;71:426-31.
  99. Garg A, Cogulu O, Ozkinay F, Onay H, Agarwal AK. A novel homozygous Ala529Val LMNA mutation in Turkish patients with mandibuloacral dysplasia. J Clin Endocrinol Metab 2005;90:5259-64.
  100. Agarwal AK, Fryns JP, Auchus RJ, Garg A. Zinc metalloproteinase, ZMPSTE24, is mutated in mandibuloacral dysplasia. Hum Mol Genet 2003;12:1995-2001.
  101. Miyoshi Y, Akagi M, Agarwal AK, et al. Severe mandibuloacral dysplasia caused by novel compound heterozygous ZMPSTE24 mutations in two Japanese siblings. Clin Genet 2008;73:535-44.
  102. Peinado JR, Quiros PM, Pulido MR, et al. Proteomic profiling of adipose tissue from Zmpste24-/- mice, a model of lipodystrophy and premature aging, reveals major changes in mitochondrial function and vimentin processing. Mol Cell Proteomics 2011;10:M111 008094.
  103. Akinci B, Sankella S, Gilpin C, Ozono K, Garg A, Agarwal AK. Progeroid syndrome patients with ZMPSTE24 deficiency could benefit when treated with rapamycin and dimethylsulfoxide. Cold Spring Harb Mol Case Stud 2017;3:a001339.
  104. Weedon MN, Ellard S, Prindle MJ, et al. An in-frame deletion at the polymerase active site of POLD1 causes a multisystem disorder with lipodystrophy. Nat Genet 2013;45:947-50.
  105. Shastry S, Simha V, Godbole K, et al. A novel syndrome of mandibular hypoplasia, deafness, and progeroid features associated with lipodystrophy, undescended testes, and male hypogonadism. J Clin Endocrinol Metab 2010;95:E192-7.
  106. Pelosini C, Martinelli S, Ceccarini G, et al. Identification of a novel mutation in the polymerase delta 1 (POLD1) gene in a lipodystrophic patient affected by mandibular hypoplasia, deafness, progeroid features (MDPL) syndrome. Metabolism 2014;63:1385-9.
  107. Elouej S, Beleza-Meireles A, Caswell R, et al. Exome sequencing reveals a de novo POLD1 mutation causing phenotypic variability in mandibular hypoplasia, deafness, progeroid features, and lipodystrophy syndrome (MDPL). Metabolism 2017;71:213-25.
  108. Donadille B, D'Anella P, Auclair M, et al. Partial lipodystrophy with severe insulin resistance and adult progeria Werner syndrome. Orphanet J Rare Dis 2013;8:106.
  109. Sidorova JM. Roles of the Werner syndrome RecQ helicase in DNA replication. DNA Repair (Amst) 2008;7:1776-86.
  110. Becerra-Munoz VM, Gomez-Doblas JJ, Porras-Martin C, et al. The importance of genotype-phenotype correlation in the clinical management of Marfan syndrome. Orphanet J Rare Dis 2018;13:16.
  111. Graul-Neumann LM, Kienitz T, Robinson PN, et al. Marfan syndrome with neonatal progeroid syndrome-like lipodystrophy associated with a novel frameshift mutation at the 3' terminus of the FBN1-gene. Am J Med Genet A 2010;152A:2749-55.
  112. Takenouchi T, Hida M, Sakamoto Y, et al. Severe congenital lipodystrophy and a progeroid appearance: Mutation in the penultimate exon of FBN1 causing a recognizable phenotype. Am J Med Genet A 2013;161A:3057-62.
  113. Rautenstrauch T, Snigula F, Wiedemann HR. [Neonatal progeroid syndrome (Wiedemann-Rautenstrauch). A follow-up study]. Klin Padiatr 1994;206:440-3.
  114. Davis MR, Arner E, Duffy CR, et al. Expression of FBN1 during adipogenesis: Relevance to the lipodystrophy phenotype in Marfan syndrome and related conditions. Mol Genet Metab 2016;119:174-85.
  115. Cabanillas R, Cadinanos J, Villameytide JA, et al. Nestor-Guillermo progeria syndrome: a novel premature aging condition with early onset and chronic development caused by BANF1 mutations. Am J Med Genet A 2011;155A:2617-25.
  116. Masotti A, Uva P, Davis-Keppen L, et al. Keppen-Lubinsky syndrome is caused by mutations in the inwardly rectifying K+ channel encoded by KCNJ6. Am J Hum Genet 2015;96:295-300.
  117. Lessel D, Vaz B, Halder S, et al. Mutations in SPRTN cause early onset hepatocellular carcinoma, genomic instability and progeroid features. Nat Genet 2014;46:1239-44.
  118. Chudasama KK, Winnay J, Johansson S, et al. SHORT syndrome with partial lipodystrophy due to impaired phosphatidylinositol 3 kinase signaling. Am J Hum Genet 2013;93:150-7.
  119. Thauvin-Robinet C, Auclair M, Duplomb L, et al. PIK3R1 mutations cause syndromic insulin resistance with lipoatrophy. Am J Hum Genet 2013;93:141-9.
  120. Huang-Doran I, Tomlinson P, Payne F, et al. Insulin resistance uncoupled from dyslipidemia due to C-terminal PIK3R1 mutations. JCI Insight 2016;1:e88766.
  121. Agarwal AK, Xing C, DeMartino GN, et al. PSMB8 encoding the beta5i proteasome subunit is mutated in joint contractures, muscle atrophy, microcytic anemia, and panniculitis-induced lipodystrophy syndrome. Am J Hum Genet 2010;87:866-72.
  122. Garg A, Hernandez MD, Sousa AB, et al. An autosomal recessive syndrome of joint contractures, muscular atrophy, microcytic anemia, and panniculitis-associated lipodystrophy. J Clin Endocrinol Metab 2010;95:E58-63.
  123. Kitamura A, Maekawa Y, Uehara H, et al. A mutation in the immunoproteasome subunit PSMB8 causes autoinflammation and lipodystrophy in humans. J Clin Invest 2011;121:4150-60.
  124. Torrelo A, Patel S, Colmenero I, et al. Chronic atypical neutrophilic dermatosis with lipodystrophy and elevated temperature (CANDLE) syndrome. J Am Acad Dermatol 2010;62:489-95.
  125. Kanazawa N. Nakajo-Nishimura syndrome: an autoinflammatory disorder showing pernio-like rashes and progressive partial lipodystrophy. Allergol Int 2012;61:197-206.
  126. Torrelo A. CANDLE Syndrome As a Paradigm of Proteasome-Related Autoinflammation. Front Immunol 2017;8:927.
  127. Cavalcante MP, Brunelli JB, Miranda CC, et al. CANDLE syndrome: chronic atypical neutrophilic dermatosis with lipodystrophy and elevated temperature-a rare case with a novel mutation. Eur J Pediatr 2016;175:735-40.
  128. Arima K, Kinoshita A, Mishima H, et al. Proteasome assembly defect due to a proteasome subunit beta type 8 (PSMB8) mutation causes the autoinflammatory disorder, Nakajo-Nishimura syndrome. Proc Natl Acad Sci U S A 2011;108:14914-9.
  129. Rocha N, Bulger DA, Frontini A, et al. Human biallelic MFN2 mutations induce mitochondrial dysfunction, upper body adipose hyperplasia, and suppression of leptin expression. Elife 2017;6.
  130. Pinheiro M, Freire-Maia N, Chautard-Freire-Maia EA, Araujo LM, Liberman B. AREDYLD: a syndrome combining an acrorenal field defect, ectodermal dysplasia, lipoatrophic diabetes, and other manifestations. Am J Med Genet 1983;16:29-33.
  131. Breslau-Siderius EJ, Toonstra J, Baart JA, Koppeschaar HP, Maassen JA, Beemer FA. Ectodermal dysplasia, lipoatrophy, diabetes mellitus, and amastia: a second case of the AREDYLD syndrome. Am J Med Genet 1992;44:374-7.
  132. Misra A, Peethambaram A, Garg A. Clinical features and metabolic and autoimmune derangements in acquired partial lipodystrophy: report of 35 cases and review of the literature. Medicine (Baltimore) 2004;83:18-34.
  133. Savage DB, Semple RK, Clatworthy MR, et al. Complement abnormalities in acquired lipodystrophy revisited. J Clin Endocrinol Metab 2009;94:10-6.
  134. Mathieson PW, Wurzner R, Oliveria DB, Lachmann PJ, Peters DK. Complement-mediated adipocyte lysis by nephritic factor sera. J Exp Med 1993;177:1827-31.
  135. Hegele RA, Cao H, Liu DM, et al. Sequencing of the reannotated LMNB2 gene reveals novel mutations in patients with acquired partial lipodystrophy. Am J Hum Genet 2006;79:383-9.
  136. Akinci B, Koseoglu FD, Onay H, et al. Acquired partial lipodystrophy is associated with increased risk for developing metabolic abnormalities. Metabolism 2015;64:1086-95.
  137. Vantyghem MC, Vigouroux C, Magre J, et al. Late-onset lipoatrophic diabetes. Phenotypic and genotypic familial studies and effect of treatment with metformin and lispro insulin analog. Diabetes Care 1999;22:1374-6.
  138. Luedtke A, Boschmann M, Colpe C, et al. Thiazolidinedione response in familial lipodystrophy patients with LMNA mutations: a case series. Horm Metab Res 2012;44:306-11.
  139. Moreau F, Boullu-Sanchis S, Vigouroux C, et al. Efficacy of pioglitazone in familial partial lipodystrophy of the Dunnigan type: a case report. Diabetes Metab 2007;33:385-9.
  140. McLaughlin PD, Ryan J, Hodnett PA, O'Halloran D, Maher MM. Quantitative whole-body MRI in familial partial lipodystrophy type 2: changes in adipose tissue distribution coincide with biochemical improvement. AJR Am J Roentgenol 2012;199:W602-6.
  141. Arioglu E, Duncan-Morin J, Sebring N, et al. Efficacy and safety of troglitazone in the treatment of lipodystrophy syndromes. Ann Intern Med 2000;133:263-74.
  142. Sleilati GG, Leff T, Bonnett JW, Hegele RA. Efficacy and safety of pioglitazone in treatment of a patient with an atypical partial lipodystrophy syndrome. Endocr Pract 2007;13:656-61.
  143. Iwanishi M, Ebihara K, Kusakabe T, et al. Clinical characteristics and efficacy of pioglitazone in a Japanese diabetic patient with an unusual type of familial partial lipodystrophy. Metabolism 2009;58:1681-7.
  144. Kuzuya H, Matsuura N, Sakamoto M, et al. Trial of insulinlike growth factor I therapy for patients with extreme insulin resistance syndromes. Diabetes 1993;42:696-705.
  145. Moses AC, Morrow LA, O'Brien M, Moller DE, Flier JS. Insulin-like growth factor I (rhIGF-I) as a therapeutic agent for hyperinsulinemic insulin-resistant diabetes mellitus. Diabetes Res Clin Pract 1995;28 Suppl:S185-94.
  146. Satoh M, Yoshizawa A, Takesue M, Saji T, Yokoya S. Long-term effects of recombinant human insulin-like growth factor I treatment on glucose and lipid metabolism and the growth of a patient with congenital generalized lipodystrophy. Endocr J 2006;53:639-45.
  147. Johns KW, Bennett MT, Bondy GP. Are HIV positive patients resistant to statin therapy? Lipids Health Dis 2007;6:27.
  148. Macallan DC, Baldwin C, Mandalia S, et al. Treatment of altered body composition in HIV-associated lipodystrophy: comparison of rosiglitazone, pravastatin, and recombinant human growth hormone. HIV Clin Trials 2008;9:254-68.
  149. Lager CJ, Esfandiari NH, Subauste AR, et al. Roux-En-Y Gastric Bypass Vs. Sleeve Gastrectomy: Balancing the Risks of Surgery with the Benefits of Weight Loss. Obes Surg 2017;27:154-61.
  150. Melvin A, Adams C, Flanagan C, et al. Roux-en-Y Gastric Bypass Surgery in the Management of Familial Partial Lipodystrophy Type 1. J Clin Endocrinol Metab 2017;102:3616-20.
  151. Utzschneider KM, Trence DL. Effectiveness of gastric bypass surgery in a patient with familial partial lipodystrophy. Diabetes Care 2006;29:1380-2.
  152. Ciudin A, Baena-Fustegueras JA, Fort JM, Encabo G, Mesa J, Lecube A. Successful treatment for the Dunnigan-type familial partial lipodystrophy with Roux-en-Y gastric bypass. Clin Endocrinol (Oxf) 2011;75:403-4.
  153. Grundfest-Broniatowski S, Yan J, Kroh M, Kilim H, Stephenson A. Successful Treatment of an Unusual Case of FPLD2: The Role of Roux-en-Y Gastric Bypass-Case Report and Literature Review. J Gastrointest Surg 2017;21:739-43.
  154. McDuffie JR, Riggs PA, Calis KA, et al. Effects of exogenous leptin on satiety and satiation in patients with lipodystrophy and leptin insufficiency. J Clin Endocrinol Metab 2004;89:4258-63.
  155. Moran SA, Patten N, Young JR, et al. Changes in body composition in patients with severe lipodystrophy after leptin replacement therapy. Metabolism 2004;53:513-9.
  156. Ebihara K, Kusakabe T, Hirata M, et al. Efficacy and safety of leptin-replacement therapy and possible mechanisms of leptin actions in patients with generalized lipodystrophy. J Clin Endocrinol Metab 2007;92:532-41.
  157. Schlogl H, Muller K, Horstmann A, et al. Leptin Substitution in Patients With Lipodystrophy: Neural Correlates for Long-term Success in the Normalization of Eating Behavior. Diabetes 2016;65:2179-86.
  158. Schlogl H, Muller K, Horstmann A, et al. Leptin-substitution in patients with congenital lipodystrophy increases connectivity in reward-related brain structures: an fMRI study. Exp Clin Endocr Diab 2014;122.
  159. Schlogl H, Muller K, Horstmann A, et al. Leptin-substitution increases connectivity in reward-related brain areas in patients with congenital lipodystrophy. Diabetologia 2015;58:S71-S.
  160. Aotani D, Ebihara K, Sawamoto N, et al. Functional magnetic resonance imaging analysis of food-related brain activity in patients with lipodystrophy undergoing leptin replacement therapy. The Journal of clinical endocrinology and metabolism 2012;97:3663-71.
  161. Petersen KF, Oral EA, Dufour S, et al. Leptin reverses insulin resistance and hepatic steatosis in patients with severe lipodystrophy. J Clin Invest 2002;109:1345-50.
  162. Diker-Cohen T, Cochran E, Gorden P, Brown RJ. Partial and generalized lipodystrophy: comparison of baseline characteristics and response to metreleptin. J Clin Endocrinol Metab 2015;100:1802-10.
  163. Muniyappa R, Brown RJ, Mari A, et al. Effects of leptin replacement therapy on pancreatic beta-cell function in patients with lipodystrophy. Diabetes Care 2014;37:1101-7.
  164. Vatier C, Fetita S, Boudou P, et al. One-year metreleptin improves insulin secretion in patients with diabetes linked to genetic lipodystrophic syndromes. Diabetes Obes Metab 2016;18:693-7.
  165. Chan JL, Lutz K, Cochran E, et al. Clinical effects of long-term metreleptin treatment in patients with lipodystrophy. Endocr Pract 2011;17:922-32.
  166. Kamran F, Rother KI, Cochran E, Safar Zadeh E, Gorden P, Brown RJ. Consequences of stopping and restarting leptin in an adolescent with lipodystrophy. Hormone research in paediatrics 2012;78:320-5.
  167. Chong AY, Lupsa BC, Cochran EK, Gorden P. Efficacy of leptin therapy in the different forms of human lipodystrophy. Diabetologia 2010;53:27-35.
  168. Simha V, Subramanyam L, Szczepaniak L, et al. Comparison of efficacy and safety of leptin replacement therapy in moderately and severely hypoleptinemic patients with familial partial lipodystrophy of the Dunnigan variety. J Clin Endocrinol Metab 2012;97:785-92.
  169. Park JY, Javor ED, Cochran EK, DePaoli AM, Gorden P. Long-term efficacy of leptin replacement in patients with Dunnigan-type familial partial lipodystrophy. Metabolism 2007;56:508-16.
  170. Simha V, Szczepaniak LS, Wagner AJ, DePaoli AM, Garg A. Effect of leptin replacement on intrahepatic and intramyocellular lipid content in patients with generalized lipodystrophy. Diabetes Care 2003;26:30-5.
  171. Javor ED, Ghany MG, Cochran EK, et al. Leptin reverses nonalcoholic steatohepatitis in patients with severe lipodystrophy. Hepatology 2005;41:753-60.
  172. Safar Zadeh E, Lungu AO, Cochran EK, et al. The liver diseases of lipodystrophy: the long-term effect of leptin treatment. Journal of hepatology 2013;59:131-7.
  173. Machado MV, Cortez-Pinto H. Leptin in the treatment of lipodystrophy-associated nonalcoholic fatty liver disease: are we there already? Expert Rev Gastroenterol Hepatol 2013;7:513-5.
  174. Brown RJ, Meehan CA, Cochran E, et al. Effects of Metreleptin in Pediatric Patients With Lipodystrophy. J Clin Endocrinol Metab 2017;102:1511-9.
  175. Casey SP, Lokan J, Testro A, et al. Post-liver transplant leptin results in resolution of severe recurrence of lipodystrophy-associated nonalcoholic steatohepatitis. Am J Transplant 2013;13:3031-4.
  176. Javor ED, Moran SA, Young JR, et al. Proteinuric nephropathy in acquired and congenital generalized lipodystrophy: baseline characteristics and course during recombinant leptin therapy. J Clin Endocrinol Metab 2004;89:3199-207.
  177. Oral EA, Ruiz E, Andewelt A, et al. Effect of leptin replacement on pituitary hormone regulation in patients with severe lipodystrophy. J Clin Endocrinol Metab 2002;87:3110-7.
  178. Musso C, Cochran E, Javor E, Young J, Depaoli AM, Gorden P. The long-term effect of recombinant methionyl human leptin therapy on hyperandrogenism and menstrual function in female and pituitary function in male and female hypoleptinemic lipodystrophic patients. Metabolism 2005;54:255-63.
  179. Abel BS, Muniyappa R, Stratton P, Skarulis MC, Gorden P, Brown RJ. Effects of Recombinant Human Leptin (Metreleptin) on Nocturnal Luteinizing Hormone Secretion in Lipodystrophy Patients. Neuroendocrinology 2016;103:402-7.
  180. Lungu AO, Zadeh ES, Goodling A, Cochran E, Gorden P. Insulin resistance is a sufficient basis for hyperandrogenism in lipodystrophic women with polycystic ovarian syndrome. J Clin Endocrinol Metab 2012;97:563-7.
  181. Meehan CA, Cochran E, Kassai A, Brown RJ, Gorden P. Metreleptin for injection to treat the complications of leptin deficiency in patients with congenital or acquired generalized lipodystrophy. Expert Rev Clin Pharmacol 2016;9:59-68.
  182. Christensen JD, Lungu AO, Cochran E, et al. Bone mineral content in patients with congenital generalized lipodystrophy is unaffected by metreleptin replacement therapy. J Clin Endocrinol Metab 2014;99:E1493-500.
  183. Simha V, Zerwekh JE, Sakhaee K, Garg A. Effect of subcutaneous leptin replacement therapy on bone metabolism in patients with generalized lipodystrophy. J Clin Endocrinol Metab 2002;87:4942-5.
  184. Chan JL, Koda J, Heilig JS, et al. Immunogenicity associated with metreleptin treatment in patients with obesity or lipodystrophy. Clin Endocrinol (Oxf) 2016;85:137-49.
  185. Beltrand J, Lahlou N, Le Charpentier T, et al. Resistance to leptin-replacement therapy in Berardinelli-Seip congenital lipodystrophy: an immunological origin. Eur J Endocrinol 2010;162:1083-91.
  186. Brown RJ, Chan JL, Jaffe ES, et al. Lymphoma in acquired generalized lipodystrophy. Leuk Lymphoma 2016;57:45-50.
  187. Aslam A, Savage DB, Coulson IH. Acquired generalized lipodystrophy associated with peripheral T cell lymphoma with cutaneous infiltration. Int J Dermatol 2015;54:827-9.
  188. Lebastchi J, Ajluni N, Neidert A, Oral EA. A Report of Three Cases With Acquired Generalized Lipodystrophy With Distinct Autoimmune Conditions Treated With Metreleptin. J Clin Endocrinol Metab 2015;100:3967-70.
  189. Park JY, Chong AY, Cochran EK, et al. Type 1 diabetes associated with acquired generalized lipodystrophy and insulin resistance: the effect of long-term leptin therapy. The Journal of clinical endocrinology and metabolism 2008;93:26-31.
Copyright © 2000-2019, MDText.com, Inc.

This electronic version has been made freely available under a Creative Commons (CC-BY-NC-ND) license. A copy of the license can be viewed at http://creativecommons.org/licenses/by-nc-nd/2.0/.

Bookshelf ID: NBK513130PMID: 29989768

Views

  • PubReader
  • Print View
  • Cite this Page

Links to www.endotext.org

Similar articles in PubMed

See reviews...See all...

Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...