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Finnish type amyloidosis

MedGen UID:
301243
Concept ID:
C1622345
Disease or Syndrome
Synonyms: Amyloid cranial neuropathy with lattice corneal dystrophy; Amyloidosis 5; Amyloidosis due to mutant gelsolin; Amyloidosis V; Amyloidosis, familial, Finnish type; AMYLOIDOSIS, HEREDITARY SYSTEMIC 4, FINNISH TYPE; Lattice corneal dystrophy associated with familial systemic amyloidosis; Lattice dystrophy of the cornea with hereditary generalized amyloidosis; Meretoja type amyloidosis; Meretoja's syndrome
Modes of inheritance:
Autosomal dominant inheritance
MedGen UID:
141047
Concept ID:
C0443147
Intellectual Product
Source: Orphanet
A mode of inheritance that is observed for traits related to a gene encoded on one of the autosomes (i.e., the human chromosomes 1-22) in which a trait manifests in heterozygotes. In the context of medical genetics, an autosomal dominant disorder is caused when a single copy of the mutant allele is present. Males and females are affected equally, and can both transmit the disorder with a risk of 50% for each child of inheriting the mutant allele.
 
Gene (location): GSN (9q33.2)
 
Monarch Initiative: MONDO:0007097
OMIM®: 105120
Orphanet: ORPHA85448

Definition

The Finnish type of systemic amyloidosis is characterized clinically by a unique constellation of features including lattice corneal dystrophy, and cranial neuropathy, bulbar signs, and skin changes. Some patients may develop peripheral neuropathy and renal failure. The disorder is usually inherited in an autosomal dominant pattern; however, homozygotes with a more severe phenotype have also been reported (Meretoja, 1973). Finnish hereditary amyloidosis, also known as Meretoja syndrome or AGel amyloidosis, is one of the most common diseases in the Finnish disease heritage. Symptoms commonly appear by age 40, with the first finding usually corneal lattice dystrophy (CLD), diagnosed by an ophthalmologist. Impaired vision, polyneuropathy, facial nerve paresis, and cutis laxa follow. These symptoms may develop slowly and simultaneously, since amyloid accumulates systemically at a constant rate (summary by Nikoskinen et al., 2015). For a discussion of genetic heterogeneity of hereditary systemic amyloidosis, see AMYLD1 (105210). [from OMIM]

Additional description

From MedlinePlus Genetics
Lattice corneal dystrophy type II is characterized by an accumulation of protein clumps called amyloid deposits in tissues throughout the body. The deposits frequently occur in blood vessel walls and basement membranes, which are thin, sheet-like structures that separate and support cells in many tissues. Amyloid deposits lead to characteristic signs and symptoms involving the eyes, nerves, and skin that worsen with age.

The earliest sign of this condition, which is usually identified in a person's twenties, is accumulation of amyloid deposits in the cornea (lattice corneal dystrophy). The cornea is the clear, outer covering of the eye. It is made up of several layers of tissue, and in lattice corneal dystrophy type II, the amyloid deposits form in the stromal layer. The amyloid deposits form as delicate, branching fibers that create a lattice pattern. Because these protein deposits cloud the cornea, they often lead to vision impairment. In addition, affected individuals can have recurrent corneal erosions, which are caused by separation of particular layers of the cornea from one another. Corneal erosions are very painful and can cause sensitivity to bright light (photophobia). Amyloid deposits and corneal erosions are usually bilateral, which means they affect both eyes.

As lattice corneal dystrophy type II progresses, the nerves become involved, typically starting in a person's forties. It is thought that the amyloid deposits disrupt nerve function. Dysfunction of the nerves in the head and face (cranial nerves) can cause paralysis of facial muscles (facial palsy); decreased sensations in the face (facial hypoesthesia); and difficulty speaking, chewing, and swallowing. Dysfunction of the nerves that connect the brain and spinal cord to muscles and to sensory cells that detect sensations such as touch, pain, and heat (peripheral nerves) can cause loss of sensation and weakness in the limbs (peripheral neuropathy). Peripheral neuropathy usually occurs in the lower legs and arms, leading to muscle weakness, clumsiness, and difficulty sensing vibrations.

The skin is also commonly affected in people with lattice corneal dystrophy type II, typically beginning in a person's forties. People with this condition may have thickened, sagging skin, especially on the scalp and forehead, and a condition called cutis laxa, which is characterized by loose skin that lacks elasticity. The skin can also be dry and itchy. Because of loose skin and muscle paralysis in the face, individuals with lattice corneal dystrophy type II can have a facial expression that appears sad.  https://medlineplus.gov/genetics/condition/lattice-corneal-dystrophy-type-ii

Clinical features

From HPO
Nephrotic syndrome
MedGen UID:
10308
Concept ID:
C0027726
Disease or Syndrome
Nephrotic syndrome is a collection of findings resulting from glomerular dysfunction with an increase in glomerular capillary wall permeability associated with pronounced proteinuria. Nephrotic syndrome refers to the constellation of clinical findings that result from severe renal loss of protein, with Proteinuria and hypoalbuminemia, edema, and hyperlipidemia.
Urolithiasis
MedGen UID:
141536
Concept ID:
C0451641
Disease or Syndrome
Renal stones are formed within the kidneys, and this is called nephrolithiasis. Urolithiasis is a condition that occurs when these stones exit the renal pelvis and move into the remainder of the urinary collecting system, which includes the ureters, bladder, and urethra.
Renal insufficiency
MedGen UID:
332529
Concept ID:
C1565489
Disease or Syndrome
A reduction in the level of performance of the kidneys in areas of function comprising the concentration of urine, removal of wastes, the maintenance of electrolyte balance, homeostasis of blood pressure, and calcium metabolism.
Stage 5 chronic kidney disease
MedGen UID:
384526
Concept ID:
C2316810
Disease or Syndrome
A degree of kidney failure severe enough to require dialysis or kidney transplantation for survival characterized by a severe reduction in glomerular filtration rate (less than 15 ml/min/1.73 m2) and other manifestations including increased serum creatinine.
Renal glomerular amyloid deposition
MedGen UID:
1711455
Concept ID:
C5397635
Finding
Amyloid deposits located in the glomeruli in a focal segmental, diffuse segmental or diffuse global fashion. This abnormality can be accompanied by mesangial involvement and in later stages also involvement of the peripheral capillaries.
Cardiomyopathy
MedGen UID:
209232
Concept ID:
C0878544
Disease or Syndrome
A myocardial disorder in which the heart muscle is structurally and functionally abnormal, in the absence of coronary artery disease, hypertension, valvular disease and congenital heart disease sufficient to cause the observed myocardial abnormality.
Decreased heart rate variability
MedGen UID:
1639159
Concept ID:
C4703580
Finding
Reduced variation of beat-to-beat intervals of the heart that occurs in conjunction with the respiratory cycle.
Orthostatic hypotension
MedGen UID:
43803
Concept ID:
C0020651
Disease or Syndrome
A form of hypotension characterized by a sudden fall in blood pressure that occurs when a person assumes a standing position.
Polyneuropathy
MedGen UID:
57502
Concept ID:
C0152025
Disease or Syndrome
A generalized disorder of peripheral nerves.
Bulbar palsy
MedGen UID:
898626
Concept ID:
C4082299
Disease or Syndrome
Bulbar weakness (or bulbar palsy) refers to bilateral impairment of function of the lower cranial nerves IX, X, XI and XII, which occurs due to lower motor neuron lesion either at nuclear or fascicular level in the medulla or from bilateral lesions of the lower cranial nerves outside the brain-stem. Bulbar weakness is often associated with difficulty in chewing, weakness of the facial muscles, dysarthria, palatal weakness and regurgitation of fluids, dysphagia, and dysphonia.
Cardiac amyloidosis
MedGen UID:
488730
Concept ID:
C0268407
Disease or Syndrome
Extracellular deposition in cardiac tissue of a proteinaceous material that, when stained with Congo red, demonstrates apple-green birefringence under polarized light and that has a distinct color when stained with sulfated Alcian blue. Viewed with electron microscopy, the amyloid deposits are seen to be composed of a beta-sheet fibrillar material. These nonbranching fibrils have a diameter of 7.5 to 10 nm and are the result of protein misfolding.
Generalized amyloid deposition
MedGen UID:
354872
Concept ID:
C1862968
Finding
A diffuse form of amyloidosis.
Cutis laxa
MedGen UID:
8206
Concept ID:
C0010495
Disease or Syndrome
Wrinkled, redundant, inelastic and sagging skin.
Cataract
MedGen UID:
39462
Concept ID:
C0086543
Disease or Syndrome
A cataract is an opacity or clouding that develops in the crystalline lens of the eye or in its capsule.
Lattice corneal dystrophy
MedGen UID:
56355
Concept ID:
C0155127
Disease or Syndrome
The presence of fine, branching linear opacities in Bowman's layer in the central area that may spread to the periphery in the clinical course. The deep corneal stroma may be involved but the process does not reach Descemet's membrane. Recurrent corneal erosion may occur. Histologic examination reveals amyloid deposits in the collagen fibers of the cornea.
Optic neuropathy
MedGen UID:
854546
Concept ID:
C3887709
Disease or Syndrome
Disorder of the optic nerve.

Term Hierarchy

Follow this link to review classifications for Finnish type amyloidosis in Orphanet.

Professional guidelines

PubMed

Stern LK, Patel J
Methodist Debakey Cardiovasc J 2022;18(2):59-72. Epub 2022 Mar 14 doi: 10.14797/mdcvj.1050. PMID: 35414852Free PMC Article
Adams D, Ando Y, Beirão JM, Coelho T, Gertz MA, Gillmore JD, Hawkins PN, Lousada I, Suhr OB, Merlini G
J Neurol 2021 Jun;268(6):2109-2122. Epub 2020 Jan 6 doi: 10.1007/s00415-019-09688-0. PMID: 31907599Free PMC Article
Maurer MS, Bokhari S, Damy T, Dorbala S, Drachman BM, Fontana M, Grogan M, Kristen AV, Lousada I, Nativi-Nicolau J, Cristina Quarta C, Rapezzi C, Ruberg FL, Witteles R, Merlini G
Circ Heart Fail 2019 Sep;12(9):e006075. Epub 2019 Sep 4 doi: 10.1161/CIRCHEARTFAILURE.119.006075. PMID: 31480867Free PMC Article

Recent clinical studies

Etiology

Schmidt EK, Atula S, Tanskanen M, Nikoskinen T, Notkola IL, Kiuru-Enari S
Ann Med 2016 Aug;48(5):352-8. Epub 2016 May 2 doi: 10.1080/07853890.2016.1177197. PMID: 27137880

Prognosis

Schmidt EK, Atula S, Tanskanen M, Nikoskinen T, Notkola IL, Kiuru-Enari S
Ann Med 2016 Aug;48(5):352-8. Epub 2016 May 2 doi: 10.1080/07853890.2016.1177197. PMID: 27137880
Nikoskinen T, Schmidt EK, Strbian D, Kiuru-Enari S, Atula S
Ann Med 2015;47(6):506-11. Epub 2015 Sep 4 doi: 10.3109/07853890.2015.1075063. PMID: 26339870

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