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TFR2-Related Hereditary Hemochromatosis

Synonym: Type 3 Hereditary Hemochromatosis

, MD and , PhD.

Author Information
, MD
Professor, Internal Medicine
Universita Vita-Salute
Istituto Scientifico San Raffaele
Milano, Italy
, PhD
University of Torino
Azienda Ospedaliera San Luigi
Torino, Italy

Initial Posting: ; Last Update: June 9, 2011.

Summary

Disease characteristics. TFR2-related hereditary hemochromatosis (TFR2-HHC) is characterized by increased intestinal iron absorption resulting in iron accumulation in the liver, heart, pancreas, and endocrine organs. Age of onset is earlier than in HFE-associated HHC. Some individuals present in the second decade and others present as adults with fatigue and arthralgia and/or organ involvement including liver cirrhosis, diabetes mellitus, and arthropathy. In other individuals, TFR2-HHC may not be progressive even if untreated.

Diagnosis/testing. The diagnosis of TFR2-HHC in individuals with clinical symptoms and/or biochemical evidence of iron overload is typically based on serum transferrin-iron saturation (>45% in men and women) and serum ferritin concentration (usually >200 µg/L in females and >300 µg/L in males) as well as histologic assessment of hepatic iron stores on liver biopsy. TFR2 is the only gene in which mutations are known to cause TFR2-HHC.

Management. Treatment of manifestations: Removal of excess iron by routine phlebotomy to maintain serum ferritin concentration at 50 ng/mL or lower and transferrin-iron saturation below 50%; lifelong hormone replacement therapy for hypogonadism; gonadotropins for fertility/pregnancy; nonsteroidal anti-inflammatory drugs (NSAIDs) and joint replacement for arthropathy; diuretics; routine treatment for cardiac failure and diabetes mellitus.

Prevention of primary manifestations: Routine phlebotomy: see Treatment of manifestations.

Surveillance: Monitoring serum ferritin concentration every three to four months once serum ferritin concentration is lower than 50 ng/mL.

Agents/circumstances to avoid: Avoid medicinal iron, mineral supplements, excess vitamin C, uncooked seafood; restrict alcohol intake for those with liver involvement.

Evaluation of relatives at risk: If the disease-causing mutations in the family are known, molecular genetic testing of at-risk relatives to allow early diagnosis and treatment.

Genetic counseling. TFR2-HHC is inherited in an autosomal recessive manner. At conception, each sib of an affected individual has a 25% chance of being affected, a 50% chance of being an asymptomatic carrier, and a 25% chance of being unaffected and not a carrier. Heterozygotes (carriers) are asymptomatic and do not have abnormalities of iron parameters. Carrier testing for at-risk family members and prenatal testing for pregnancies at increased risk are possible if both disease-causing mutations have been identified in the family. Requests for prenatal testing for conditions such as TFR2-HHC that do not affect intellect and have effective treatment available are not common.

Diagnosis

Clinical Diagnosis

TFR2-related hereditary hemochromatosis (TFR2-HHC) should be suspected in any individual with findings of iron overload (including hepatomegaly, hepatic cirrhosis, diabetes mellitus, cardiomyopathy, hypogonadism, arthritis - especially if involving the metacarpophalangeal joints, and progressive increase in skin pigmentation) in whom HFE-associated hereditary hemochromatosis has been excluded.

More typically, individuals present with either of the following:

  • Early clinical findings of hereditary hemochromatosis (including vague nonspecific symptoms, e.g., abdominal pain, fatigue, arthralgia, decreased libido)
  • More frequently, biochemical evidence of iron overload in routinely used panels that include serum transferrin-iron saturation and serum concentrations of iron and ferritin

Note: No specific diagnostic guidelines are available for TFR2-related hemochromatosis; however, guidelines/recommendations of scientific societies or experts for HFE-associated hereditary hemochromatosis are available (see following and references cited).

Testing

Diagnosis of TFR2-HHC is suspected in individuals with the following:

  • Transferrin saturation higher than 45%. Normal range is between 20% and 35% saturation in both sexes.
  • Serum ferritin concentration usually higher than 200 µg/L in females and higher than 300 µg/L in males.
    • Normal ranges:
      • Children and adolescents: 15-150 µg/L
      • Adult males: 20-300 µg/L
      • Adult females: 20-200 µg/L
    • Note: The same biochemical iron parameters are used in diagnosis of HFE-associated hereditary hemochromatosis [Pietrangelo 2010].

Liver biopsy. Findings on liver biopsy have been reported in a few individuals with TFR2-HHC [Girelli et al 2002, Pietrangelo et al 2005, Hsiao et al 2007, Pelucchi et al 2009]. Liver biopsy is used to assess:

  • Histology; fibrosis or cirrhosis
  • Liver iron concentration (LIC)
  • Distribution of iron storage. Increased iron deposition in the hepatocytes and a decreasing gradient of iron stores are observed from portal to centrolobular areas [Girelli et al 2002, Pelucchi et al 2009], as in HFE-associated hereditary hemochromatosis).

Imaging. Noninvasive techniques including MRI [Gandon et al 2004, St Pierre et al 2005] and SQUID developed to quantitate liver iron concentration have been applied to HFE-associated hereditary hemochromatosis [Carneiro et al 2004] but rarely to TFR2-HHC [Piperno et al 2004, Biasiotto et al 2008, Pelucchi et al 2009].

Molecular Genetic Testing

Gene. TFR2 is the only gene in which mutations are known to cause TFR2-HHC.

Clinical testing

Table 1. Summary of Molecular Genetic Testing Used in TFR2-Related Hereditary Hemochromatosis

Gene SymbolTest MethodMutations DetectedMutation Detection Frequency by Test Method 1
TFR2Targeted mutation analysisc.88_89insC, c.313C>T, c.515T>A, c.750C>G, c.1861_1872del12<50% 2
Sequence analysisSequence variants 3>98%

1. The ability of the test method used to detect a mutation that is present in the indicated gene

2. Data are from the Italian population [Author, personal observation].

3. Examples of mutations detected by sequence analysis may include small intragenic deletions/insertions and missense, nonsense, and splice site mutations.

Testing Strategy

Confirmation of the diagnosis in a proband. In an individual with a clinical diagnosis of hemochromatosis and/or increased iron at liver biopsy (or MRI) and/or a family history of hemochromatosis AND no identifiable HFE mutations, molecular genetic testing for TFR2 mutations is appropriate.

Carrier testing for at-risk relatives requires prior identification of the disease-causing mutations in the family.

Note: Carriers are heterozygotes for an autosomal recessive disorder and are not at risk of developing the disorder.

Prenatal diagnosis and preimplantation genetic diagnosis (PGD) for at-risk pregnancies require prior identification of the disease-causing mutations in the family.

Clinical Description

Natural History

TFR2-related hereditary hemochromatosis (TFR2-HHC) is characterized by deregulated, increased intestinal iron absorption resulting in iron accumulation in the liver, heart, pancreas, and endocrine organs [Camaschella et al 2000, Camaschella & Poggiali 2009].

The age of onset in TFR2-HHC is earlier than in HFE-associated hereditary hemochromatosis. One child age 3.5 years had transferrin saturation and serum ferritin concentration that were increased for age [Piperno et al 2004]. Some individuals present with signs of iron overload in the second decade [Girelli et al 2002, Hattori et al 2003, Le Gac et al 2004, Piperno et al 2004, Biasiotto et al 2008, Gérolami et al 2008]. Others present as adults with abnormal serum iron studies or fatigue and arthralgia and/or signs of organ involvement (liver cirrhosis, diabetes, arthropathy) [Roetto et al 2001, Girelli et al 2002, Hattori et al 2003, Koyama et al 2005, Pelucchi et al 2009]. Severe joint involvement has been reported [Ricerca et al 2009].

Disease progression is slower than in juvenile hereditary hemochromatosis, even in untreated individuals [De Gobbi et al 2002]. Even untreated, TFR2-HHC may not be progressive [Roetto et al 2001, Girelli et al 2002].

When TFR2-HHC is progressive, complications can include cirrhosis, hypogonadotropic hypogonadism, and arthritis. Cardiomyopathy and diabetes mellitus are rare [Riva et al 2004] and hepatocellular carcinoma has not been observed in the limited number of affected individuals reported to date.

Most individuals reported to date have been of Italian or Japanese ancestry. Individuals of Japanese ancestry were older at diagnosis than those of Italian ancestry and had hepatic iron loading; a few middle-aged Japanese males had cirrhosis [Hattori et al 2003, Koyama et al 2005].

Genotype-Phenotype Correlations

The limited number of individuals reported and the private nature of the mutations do not permit genotype-phenotype correlations.

Presence of the p.His63Asp allele of HFE (NP_000401.1; NM_000410.3) has been described in individuals with TFR2-HHC [Camaschella et al 2000, Piperno et al 2004]; however, the contribution of the p.His63Asp allele to the TFR2-related iron overload is unclear.

Inheritance of compound heterozygosity for the HFE mutations p.Cys282Tyr (NP_000401.1; NM_000410.3:c. 845G>A) and p.His63Asp and homozygosity for the TFR2 mutation p.Gln317* produced a phenotype of juvenile hemochromatosis in a single family [Pietrangelo et al 2005].

Penetrance

The penetrance of TFR2-HHC is less than 100%. In a family reported in the study by Roetto et al [2001], one middle-aged female homozygous for the p.Arg30Profs*31 mutation had no evidence of clinical disease; a second female had no signs of iron overload, and in fact had iron deficiency.

Nomenclature

TFR2-HHC is also known as hemochromatosis type 3 (HFE3); however, the term HFE3 seems inappropriate because HFE has no role in TFR2-HHC.

Prevalence

TFR2-HHC is rare. Fewer than 30 affected individuals have been reported worldwide, most commonly in Japan, Portugal, and Italy.

Single families from France [Le Gac et al 2004], Italy [Gérolami et al 2008, Pelucchi et al 2009], and Portugal [Mattman et al 2002, Mendes et al 2009] have been reported. One case was reported in Taiwan [Hsiao et al 2007].

Screening for TFR2 mutations on a large scale is not available.

Differential Diagnosis

TFR2-related hereditary hemochromatosis (TFR2-HHC, sometimes called type 3 HHC) needs to be distinguished from other primary iron overload disorders as well as from secondary iron overload disorders. No specific studies have evaluated the percentage of TFR2 mutations detected in individuals with non-HFE-associated hereditary hemochromatosis.

Primary Iron Overload Disorders

Primary overload disorders are characterized by increased absorption of iron from a normal diet.

HFE-related hereditary hemochromatosis (hemochromatosis type 1) is the most common form. HFE-associated hereditary hemochromatosis is characterized by excessive storage of iron, particularly in the liver, skin, pancreas, heart, joints, and pituitary, resulting in hypogonadotropic hypogonadism. Without therapy, males may develop symptoms between ages 40 and 60 years and females after menopause. Hepatic fibrosis or cirrhosis may occur in untreated individuals after age 40 years. A large fraction of homozygotes (98% in some series) [Asberg et al 2001, Beutler et al 2002] for mutations in this gene do not develop clinical symptoms (i.e., penetrance is low). Inheritance is autosomal recessive.

Juvenile hereditary hemochromatosis (sometimes called type 2 HHC) has an earlier age of onset and more severe clinical manifestations than HFE-related hereditary hemochromatosis. Two related genes (hence, two clinically indistinguishable "subtypes") have been identified: type 2A is caused by mutations in HJV encoding hemojuvelin; type 2B is caused by mutations in HAMP. Onset of severe iron overload typically occurs in the first to third decades of life. Males and females are equally affected. Prominent clinical features include hypogonadotropic hypogonadism, cardiomyopathy, arthropathy, and liver fibrosis or cirrhosis. Hepatocellular cancer has not been reported. The main cause of death is cardiac-related disease. If juvenile hemochromatosis is detected early enough and if blood is removed regularly through the process of phlebotomy to achieve iron depletion, morbidity and mortality are greatly reduced. Inheritance is autosomal recessive [Roetto et al 1999, Camaschella et al 2000, De Gobbi et al 2002].

Ferroportin-related hereditary hemochromatosis (hemochromatosis type 4) is caused by mutations in SLC40A1, or solute carrier family 40 (iron-regulated transporter) member 1, which encodes ferroportin. Onset is late. Unlike all other varieties of hemochromatosis, iron storage in most cases affects reticuloendothelial rather than parenchymal cells [Montosi et al 2001, Njajou et al 2001]. Inheritance is autosomal dominant.

Recently, two types of ferroportin disease have been recognized.

  • The more common “ferroportin disease type A” is caused by mutations that reduce the iron export from macrophages resulting in macrophage iron accumulation and low-normal transferrin saturation [Schimanski et al 2005].
  • The less common “ferroportin disease type B” is caused by hepcidin-resistant mutations that permit continued export of iron from macrophages resulting in disease that resembles HFE-associated hereditary hemochromatosis with high transferrin saturation and iron in hepatocytes [Drakesmith et al 2005, Wallace & Subramaniam 2007].
  • Some persons have an intermediate phenotype with a mixed pattern of liver iron accumulation.

Aceruloplasminemia is characterized by iron accumulation in the brain and the visceral organs, manifest as retinal degeneration, diabetes mellitus, and neurologic disease (movement disorders and ataxia) in individuals older than age 25 years. Early treatment with iron chelators can diminish iron accumulation and ameliorate symptoms. Aceruloplasminemia is caused by the complete lack of ceruloplasmin ferroxidase activity resulting from mutations in CP, which encodes ceruloplasmin. Inheritance is autosomal recessive.

African iron overload was originally described in Africans who drink a traditional beer brewed in non-galvanized steel drums. The disease does not develop in all beer drinkers, suggesting the existence of a genetic susceptibility. A missense change (NP_055400.1:p.Gln248His; NM_014585.5:c.744G>T) in SLC40A1 encoding ferroportin has been reported in Africans and African Americans with iron overload by independent groups [Beutler et al 2003, Gordeuk et al 2003], but the functional effect of this mutation in vitro is controversial [Drakesmith et al 2005, McNamara et al 2005, Barton et al 2007]. In the large HEIRS study the association of increased serum ferritin concentration and the polymorphism was found only in males [Rivers et al 2007].

In neonatal hemochromatosis iron overload occurs in the fetus, likely secondary to different causes. At birth, liver failure dominates the clinical picture. The disease is extremely severe, often fatal, unless liver transplantation is performed. Inheritance is unknown. Recently, an immunologic pathogenesis has been proposed for recurrent cases because treatment of at-risk pregnancies with high-dose IV IGg resulted in significant improvement of the outcome [Whitington & Hibbard 2004].

Secondary Iron Overload Disorders

Secondary iron overload disorders include iron excess resulting from different conditions. The most severe disorders result from transfusions for chronic anemia such as beta-thalassemia or sickle cell disease. Secondary iron overload may result from ingested iron in foods, cookware, and medicines, as well as parenteral iron from iron injections.

This group also includes a range of liver diseases associated with parenchymal liver disease (e.g., alcoholic liver disease, acute viral hepatitis or chronic hepatitis C, neoplasia, porphyria cutanea tarda) and inflammatory disorders such as rheumatoid arthritis (which are questionable because inflammatory disorders are not true iron-loading disorders).

Note to clinicians: For a patient-specific ‘simultaneous consult’ related to this disorder, go to Image SimulConsult.jpg, an interactive diagnostic decision support software tool that provides differential diagnoses based on patient findings (registration or institutional access required).

Management

Evaluations Following Initial Diagnosis

To establish the extent of disease in an individual diagnosed with TFR2-related hereditary hemochromatosis (TFR2-HHC), the following are recommended (based on recommendations for HFE-associated hereditary hemochromatosis):

  • Liver biopsy for evaluation of abnormal liver function tests and establishing prognosis when serum ferritin concentration is greater than 1000 ng/mL and/or when hepatomegaly is present [Guyader et al 1998]
  • Serum concentration of gonadotropins (FSH and LH) to assess pituitary function. Depending on the results, a GnRH stimulation test may be necessary.
  • Serum concentration of testosterone to assess testicular function; serum concentration of estradiol to assess ovarian function
  • Radiographs of the affected joint(s) to assess persistent arthralgia or arthropathy
  • Cardiac evaluation (ECG and echocardiography) for all symptomatic individuals and those with severe iron overload (ferritin >1000 ng/mL)
  • Screening for diabetes mellitus by fasting serum glucose concentration and oral glucose tolerance test (OGTT)

Treatment of Manifestations

The following recommendations are based on guidelines proposed for HFE-associated hereditary hemochromatosis in Europe [European Association for the Study of the Liver 2010 (full text)] and an expert review [Adams & Barton 2010]. However, it should be emphasized that since TFR2-HHC is rare and may progress differently from HFE-associated hemochromatosis, individual treatment is important.

Individuals with increased serum ferritin concentration should be treated by the same protocol as for HFE-associated hereditary hemochromatosis.

Therapeutic phlebotomy. Periodic phlebotomy (i.e., removal of a unit of blood) is a simple, inexpensive, safe, and effective way to remove excess iron. Each unit of blood (400-500 mL) with a hematocrit of 40% contains approximately 160-200 mg of iron.

The usual therapy is weekly phlebotomy; however, twice weekly phlebotomy may be useful initially to accelerate iron depletion. On average, men require removal of twice as many units of blood as women.

Weekly phlebotomy is carried out until the serum ferritin concentration is 100 ng/mL or lower. Serum ferritin concentration should be measured following each phlebotomy or every other phlebotomy [Adams & Barton 2010]:

  • Once the serum ferritin concentration is approximately 50 ng/mL, monitoring serum ferritin concentration every three to four months is adequate.
  • If the serum ferritin concentration is 50 ng/mL or higher despite a significant reduction in hematocrit, phlebotomies need to be spaced further apart.

Note: Although experience is limited because of the small number of affected individuals identified worldwide, it should be noted that transferrin saturation remains high in TFR2-related hereditary hemochromatosis when serum ferritin concentration is low (<50 ng/mL), even after intensive phlebotomy [Girelli et al 2011; Camaschella & Roetto, unpublished observation].

Maintenance therapy. The goal is to maintain serum ferritin concentration around 50 ng/mL and transferrin-iron saturation below 50%. Phlebotomy to prevent reaccumulation of iron is performed about every three to four months for men and once or twice a year for women.

Iron chelation therapy is not recommended unless an individual has an elevated serum ferritin concentration and concomitant anemia that makes therapeutic phlebotomy impossible. Iron chelators such as subcutaneous desferrioxamine are used as a first choice in case of concomitant anemia [Riva et al 2004] or cardiac dysfunction.

Note: At present, oral iron chelators are not available to treat hemochromatosis. However, a phase I/II trial has been completed with daily administration of deferasirox in persons with newly diagnosed HFE-HHC with iron overload and without evidence of liver cirrhosis. The trial demonstrated that treatment is feasible, safe, and effective; side effects were mostly related to the GI tract [Phatak et al 2010].

Treatment of clinical complications

  • Cirrhosis should be treated and followed up as in other conditions. Although cirrhosis is not reversible by phlebotomy, individuals with cirrhosis benefit from iron removal in that it reduces the risk of hepatocellular cancer.
  • Hypogonadism is irreversible and requires lifelong hormone replacement therapy in males and females. Use of gonadotropins has successfully restored fertility and induced pregnancy in women who have been treated for other forms of hemochromatosis.
  • Arthropathy requires nonsteroidal anti-inflammatory drugs (NSAIDs) and is barely influenced by phlebotomy. In some cases, joint replacement has been performed.
  • Cardiac failure is treated with diuretics, ACE inhibitors, cardiac glycosides, and iron chelation by intravenous or subcutaneous deferioxamine.
  • Diabetes mellitus may require lifelong insulin treatment. Iron removal may improve control of diabetes mellitus but cannot reestablish normal glucose metabolism.

Prevention of Primary Manifestations

In affected individuals with increased serum ferritin concentration, prevention of primary manifestations is accomplished by weekly phlebotomy to deplete iron stores (see Treatment of Manifestations).

Surveillance

Once the serum ferritin concentration is around 50 ng/mL, monitoring serum ferritin concentration every three to four months is adequate.

Although hepatocellular carcinoma has not been reported in individuals with TFR2-associated hereditary hemochromatosis, surveillance for its development should be performed in persons with cirrhosis by monitoring liver ultrasound examinations and serum concentrations of alpha-fetoprotein, as in persons with cirrhosis with HFE-associated hereditary hemochromatosis.

Agents/Circumstances to Avoid

Avoid the following:

  • Medicinal iron
  • Mineral supplements
  • Excess vitamin C
  • Uncooked seafood (because of the risk of infection from microorganisms thriving under conditions of excess iron)

For those with hepatic involvement, alcohol intake should be restricted because it increases iron absorption and is toxic to the hepatocytes.

Evaluation of Relatives at Risk

If the disease-causing mutations in the family are known, it is appropriate to offer molecular genetic testing to at-risk relatives to allow early diagnosis and treatment.

See Genetic Counseling for issues related to testing of at-risk relatives for genetic counseling purposes.

Pregnancy Management

Women with hemochromatosis do not need treatment during pregnancy because the fetal utilization of maternal iron effectively reduces the mother’s iron load during pregnancy.

Therapies Under Investigation

Search ClinicalTrials.gov for access to information on clinical studies for a wide range of diseases and conditions. Note: There may not be clinical trials for this disorder.

Genetic Counseling

Genetic counseling is the process of providing individuals and families with information on the nature, inheritance, and implications of genetic disorders to help them make informed medical and personal decisions. The following section deals with genetic risk assessment and the use of family history and genetic testing to clarify genetic status for family members. This section is not meant to address all personal, cultural, or ethical issues that individuals may face or to substitute for consultation with a genetics professional. —ED.

Mode of Inheritance

TFR2-related hereditary hemochromatosis (TFR2-HHC) is inherited in an autosomal recessive manner.

Risk to Family Members

Parents of a proband

  • The parents of an affected individual are obligate heterozygotes and thus carry one mutant allele.
  • Heterozygotes (carriers) are asymptomatic and do not have abnormalities of iron parameters.

Sibs of a proband

  • At conception, each sib of an affected individual has a 25% chance of being affected, a 50% chance of being an asymptomatic carrier, and a 25% chance of being unaffected and not a carrier.
  • Once an at-risk sib is known to be unaffected, the risk of his/her being a carrier is 2/3
  • Heterozygotes (carriers) are asymptomatic and do not have abnormalities of iron parameters.

Offspring of a proband. The offspring of an individual with TFR2-HHC are obligate heterozygotes (carriers) for a disease-causing mutation in TFR2.

Other family members of a proband. Each sib of the proband's parents is at a 50% risk of being a carrier.

Carrier Detection

Carrier testing using molecular genetic testing for at-risk family members is possible once the mutations have been identified in the family.

Carrier testing using biochemical testing is not possible because iron parameters are normal in heterozygotes.

Related Genetic Counseling Issues

See Management, Evaluation of Relatives at Risk for information on evaluating at-risk relatives for the purpose of early diagnosis and treatment

Family planning

  • The optimal time for determination of genetic risk, clarification of carrier status, and discussion of the availability of prenatal testing is before pregnancy.
  • It is appropriate to offer genetic counseling (including discussion of potential risks to offspring and reproductive options) to young adults who are affected, are carriers, or are at risk of being carriers.

DNA banking is the storage of DNA (typically extracted from white blood cells) for possible future use. Because it is likely that testing methodology and our understanding of genes, mutations, and diseases will improve in the future, consideration should be given to banking DNA of affected individuals.

Prenatal Testing

Prenatal diagnosis for pregnancies at increased risk is possible by analysis of DNA extracted from fetal cells obtained by amniocentesis usually performed at approximately 15 to 18 weeks’ gestation or chorionic villus sampling (CVS) at approximately ten to 12 weeks’ gestation. Both disease-causing alleles of an affected family member must be identified in the family before prenatal testing can be performed.

Note: Gestational age is expressed as menstrual weeks calculated either from the first day of the last normal menstrual period or by ultrasound measurements.

Requests for prenatal testing for conditions which (like TFR2-HHC) do not affect intellect and have effective treatment available are not common. Differences in perspective may exist among medical professionals and within families regarding the use of prenatal testing, particularly if the testing is being considered for the purpose of pregnancy termination rather than early diagnosis. Although most centers would consider decisions about prenatal testing to be the choice of the parents, discussion of these issues is appropriate.

Preimplantation genetic diagnosis (PGD) may be an option for some families in which the disease-causing mutations have been identified.

Resources

GeneReviews staff has selected the following disease-specific and/or umbrella support organizations and/or registries for the benefit of individuals with this disorder and their families. GeneReviews is not responsible for the information provided by other organizations. For information on selection criteria, click here.

  • Iron Overload and Hemochromatosis: Frequently Asked Questions
    Centers for Disease Control and Prevention (CDC)
  • National Digestive Diseases Information Clearinghouse (NDDIC)
    2 Information Way
    Bethesda MD 20892-3570
    Phone: 800-891-5389 (toll-free); 866-569-1162 (TTY)
    Fax: 703-738-4929
    Email: nddic@info.niddk.nih.gov
  • National Human Genome Research Institute (NHGRI)
  • NCBI Genes and Disease
  • Iron Disorders Institute (IDI)
    PO Box 675
    Taylors SC 29687
    Phone: 888-565-4766 (Toll-free Information Request Line); 864-292-1175
    Fax: 864-292-1878
    Email: info@irondisorders.org
  • National Library of Medicine Genetics Home Reference

Molecular Genetics

Information in the Molecular Genetics and OMIM tables may differ from that elsewhere in the GeneReview: tables may contain more recent information. —ED.

Table A. TFR2-Related Hereditary Hemochromatosis: Genes and Databases

Gene SymbolChromosomal LocusProtein NameLocus SpecificHGMD
TFR27q22​.1Transferrin receptor protein 2TFR2 @ LOVDTFR2

Data are compiled from the following standard references: gene symbol from HGNC; chromosomal locus, locus name, critical region, complementation group from OMIM; protein name from UniProt. For a description of databases (Locus Specific, HGMD) to which links are provided, click here.

Table B. OMIM Entries for TFR2-Related Hereditary Hemochromatosis (View All in OMIM)

604250HEMOCHROMATOSIS, TYPE 3; HFE3
604720TRANSFERRIN RECEPTOR 2; TFR2

Molecular Genetic Pathogenesis

TFR2-encoded protein is highly expressed in the hepatocytes and its function is likely related to the hepcidin pathway that regulates iron homeostasis.

The hepatic peptide hepcidin (encoded by HAMP) is a circulating hormone that regulates the absorption of dietary iron from the duodenum. Hepcidin expression is inappropriately decreased in hereditary hemochromatosis and is abnormally increased in the anemia of chronic diseases. Other hepatic proteins essential for normal iron homeostasis, including HFE, transferrin receptor protein 2 (TfR2), and hemojuvelin, function at least in part by modulating the expression of hepcidin [Hentze et al 2010].

Individuals with homozygous TFR2 mutations have increased intestinal iron absorption that causes iron overload. Low/absent levels of urinary hepcidin have been reported in TFR2-related hereditary hemochromatosis [Nemeth et al 2005], suggesting that TFR2 is a modulator of hepcidin. A time course of serum hepcidin after a single dose of oral iron in two individuals homozygous for a TFR2 mutation revealed absence of hepcidin response [Girelli et al 2011]. A similar finding of down-regulation (or lack of up-regulation following iron loading) of mRNA of hepcidin in liver has been documented in mice with inactive Tfr2 [Kawabata et al 2005, Wallace et al 2005].

Normal allelic variants. TFR2 is 2471 bp long and consists of 18 exons. There are two main alternatively spliced variants (see Figure 1):

Figure 1

Figure

Figure 1. Schematic representation of the localization of TFR2 mutations. Causal mutations are illustrated in bold above the gene; exonic normal variants are marked below the gene (see Table 2). The two alternatively spliced TFR2 transcripts are also (more...)

Several exonic normal DNA variants have been described (see Figure 1); they are either silent or missense mutations present also in control individuals [Lee et al 2001, Biasiotto et al 2008]. Two nucleotide normal variants have been identified in the non-coding region of TFR2 [Meregalli et al 2000, Biasiotto et al 2008]. A TFR2 intronic SNP (rs7385804) was associated with physiologic serum iron modification in genome-wide association studies [Pichler et al 2011].

Pathologic allelic variants. Seventeen causal mutations have been reported; most are rare or private [Roetto et al 2002, Lee & Barton 2006, Hsiao et al 2007, Biasiotto et al 2008, Gérolami et al 2008, Pelucchi et al 2009] (see Table 2):

For more information, see Table A and Figure 1.

Table 2. Selected TFR2 Allelic Variants

Class of Variant AlleleDNA Nucleotide Change
(Alias 1)
Protein Amino Acid Change
(Alias 1)
Reference SequencesReference
Normalc.97C>Ap.His33AsnNM_003227​.3
NP_003218​.2
Biasiotto et al [2008]
c.224C>Tp.Ala75ValBiasiotto et al [2003]
c.473+49C>A
(IVS3+49)
--Biasiotto et al [2008]
c.1851C>T
(1878C>T)
p.(=) 2
(Ala617Ala)
Meregalli et al [2000]
c.714C>Gp.Ile238MetLee et al [2001]
c.1364G>Ap.Arg455GlnHofmann et al [2002]
c.1770C>Tp.(=)
(Asp590Asp)
Lee et al [2001]
c.1851C>Tp.(=)
(Ala617Ala)
Lee et al [2001]
c.2228C>Tp.Ala743ValLee et al [2001]
Pathologicc.64G>A p.Val22IleBiasiotto et al [2003]
c.88_89insC
(ins88C)
p.Arg30Profs*31
(E60X)
Roetto et al [2001]
c.313C>Tp.Arg105*
(E60X)
Le Gac et al [2004]
c.515T>Ap.Met172LysRoetto et al [2001]
c.2137-1G>A
(IVS17+5636)
--Biasiotto et al [2008]
c.750C>Gp.Tyr250*Camaschella et al [2000]
c.949C>Tp.Gln317*Pietrangelo et al [2005]
c.1186C>Tp.Arg396*Lee & Barton [2006]
c.1231_1233delp.Asn411delBiasiotto et al [2008]
c.1330G>A p.Ala444ThrBiasiotto et al [2008]
c.1403G>Ap.Arg468His
(Arg481His)
Hsiao et al [2007]
c.1469T>Gp.Leu490ArgKoyama et al [2005]
c.1665delCp.Ser556Alafs*6
(Val561X)
Koyama et al [2005]
c.1861_1872del12p.Ala621_Gln624del
(AVAQ621-624del)
Girelli et al [2002]
c.2069A>Cp.Gln690Pro
c.2374G>Ap.Gly792ArgLee & Barton [2006]

Note on variant classification: Variants listed in the table have been provided by the author(s). GeneReviews staff have not independently verified the classification of variants.

Note on nomenclature: GeneReviews follows the standard naming conventions of the Human Genome Variation Society (www​.hgvs.org). See Quick Reference for an explanation of nomenclature.

1. Variant designation that does not conform to current naming conventions

2. The designation p.(=) means that no effect on protein level is expected.

Normal gene product. TfR2 is a type II transmembrane glycoprotein characterized by short intracellular and transmembrane domains and a large extracellular domain. The TfR2 full-length transcript (the alpha form) originates an 801-amino acid transmembrane protein. Residues 1-80 correspond to the cytoplasmic domain, residues 81-104 correspond to the transmembrane, and amino acids 105-801 correspond to the extracellular domain. Cysteines 89-98 and 108-111 are involved in disulfide bonds, likely responsible for TFR2 homodimerization. A YQRV amino acid motif in the cytoplasmic domain, similar to the internalization signal (YTRF) of transferrin receptor (TFRC), could have the same function.

TfR2 is highly expressed in hepatoma (HEPG2) and in erythroleukemia cell lines (K562) [Kawabata et al 1999]. It is expressed in the liver, especially in the hepatocytes, and at low levels in Kuppfer cells [Zhang et al 2004]. Recently it has been shown that TfR2 protein is expressed in erythroid cells in mice and humans and that TfR2 protein interacts with the erythropoietin receptor [Forejtnikovà et al 2010]. It remains to be determined if this erythroid expression has some relationship with hepcidin inhibition in erythroid expansion.

Alpha-TfR2 binds and internalizes transferrin. However, binding occurs at low affinity (25- to 30-fold lower) [Kawabata et al 2000], as compared to that of the transferrin receptor (TFRC). Alpha-TfR2 protein shows significant amino acid homology with TFRC and the prostate-specific membrane antigen (PSMA), especially in the extracellular portion [Kawabata et al 1999]. Expression of TfR2 is in fact reported in several cancer cell lines and primary tumor cells [Calzolari et al 2009, Calzolari et al 2010]

Beta-TfR2 lacks the cytoplasmic and transmembrane domains and could be an intracellular protein.

TFR2 has no IRE elements in its 5' or 3' UTR and is not transcriptionally regulated by iron. TFR2 does not bind HFE in vitro because residues involved in HFE binding in TFRC are not conserved in TFR2 [West et al 2000]. TFR2 is also expressed by early erythroid progenitors but not by bone marrow precursors [Calzolari et al 2004, Forejtnikovà et al 2010].

TFR2-encoded protein in HepG2 cell line is stabilized by diferric transferrin, which increases TFR2-encoded protein half-life [Johnson & Enns 2004, Robb & Wessling-Resnick 2004]. In addition, TFR2 mediates a biphasic pattern of transferrin uptake associated with ligand delivery to multivesicular bodies [Robb et al 2004]. Tfr2 stabilization by transferrin reduces Tfr2 lysosomal degradation and directs TFR2 toward the recycling endosome [Johnson et al 2007].

The cytoplasmic domain is that involved in membrane stabilization after TF binding [Chen & Enns 2007]. In the present model, TfR2 stabilized on plasma membrane binds HFE to activate hepcidin [Gao et al 2009] but the molecular mechanism remain unclear.

Animal models of the disease have been developed:

More recently other models have been developed: a murine line with selective inactivation of the Tfr2-beta isoform (KI mice), Tfr2 knock out animals within the identical genetic background, and a model with inactivation of both Tfr2-alpha and -beta isoforms in the liver and Tfr2-beta isoform in the other tissues (LCKO-KI) The latter animals develop earlier and more severe iron overload than KO, while KI animals have normal iron parameters and iron gene expression, but develop severe iron overload in the spleen [Roetto et al 2010]. Simultaneous inactivation of Tfr2 and Hfe in mice induces a more severe iron overload and a more marked hepcidin deficiency than inactivating the single genes [Wallace et al 2009]. This suggests some additive function for the two genes in hepcidin control [Wallace et al 2009].

Abnormal gene product. The pathologic variants produce a truncated protein or an abnormally structured protein (e.g., p.Ala621_Gln624del, p.Leu490Arg, p.Gln690Pro). The mutation p.Met172Lys is of interest because it causes a missense in the alpha form but alters methionine, which is the putative initiation codon of beta TFR2 [Roetto et al 2001, Majore et al 2006].

References

Literature Cited

  1. Adams PC, Barton JC. How I treat hemochromatosis. Blood. 2010;116:317–25. [PubMed: 20308595]
  2. Aguilar-Martinez P, Esculie-Coste C, Bismuth M, Giansily-Blaizot M, Larrey D, Schved JF. Transferrin receptor-2 gene and non-C282Y homozygous patients with hemochromatosis. Blood Cells Mol Dis. 2001a;27:290–3. [PubMed: 11358390]
  3. Aguilar-Martinez P, Bismuth M, Picot MC, Thelcide C, Pageaux GP, Blanc F, Blanc P, Schved JF, Larrey D. Variable phenotypic presentation of iron overload in H63D homozygotes: are genetic modifiers the cause? Gut. 2001b;48:836–42. [PMC free article: PMC1728323] [PubMed: 11358905]
  4. Asberg A, Hveem K, Thorstensen K, Ellekjter E, Kannelonning K, Fjosne U, Halvorsen TB, Smethurst HB, Sagen E, Bjerve KS. Screening for hemochromatosis: high prevalence and low morbidity in an unselected population of 65,238 persons. Scand J Gastroenterol. 2001;36:1108–15. [PubMed: 11589387]
  5. Barton EH, West PA, Rivers CA, Barton JC, Acton RT. Transferrin receptor-2 (TFR2) mutation Y250X in Alabama caucasian and African American subjects with and without primary iron overload. Blood Cells Mol Dis. 2001;27:279–84. [PubMed: 11358388]
  6. Barton JC, Acton RT, Lee PL, West C. SLC40A1 Q248H allele frequencies and Q248H-associated risk of non-HFE iron overload in persons of sub-Saharan African descent. Blood Cells Mol Dis. 2007;39:206–11. [PMC free article: PMC1986732] [PubMed: 17490902]
  7. Beutler E, Barton JC, Felitti VJ, Gelbart T, West C, Lee PL, Waalen J, Vulpe C. Ferroportin 1 (SCL40A1) variant associated with iron overload in African-Americans. Blood Cells Mol Dis. 2003;31:305–9. [PubMed: 14636643]
  8. Beutler E, Felitti VJ, Koziol JA, Ho NJ, Gelbart T. Penetrance of 845G>A (C282Y) HFE hereditary haemochromatosis mutation in the USA. Lancet. 2002;359:211–8. [PubMed: 11812557]
  9. Biasiotto G, Belloli S, Ruggeri G, Zanella I, Gerardi G, Corrado M, Gobbi E, Albertini A, Arosio P. Identification of new mutations of the HFE, hepcidin, and transferrin receptor 2 genes by denaturing HPLC analysis of individuals with biochemical indications of iron overload. Clin Chem. 2003;49:1981–8. [PubMed: 14633868]
  10. Biasiotto G, Camaschella C, Forni GL, Polotti A, Zecchina G, Arosio P. New TFR2 mutations in young Italian patients with hemochromatosis. Haematologica. 2008;93:309–10. [PubMed: 18245657]
  11. Calzolari A, Deaglio S, Maldi E, Cassoni P, Malavasi F, Testa U. TfR2 expression in human colon carcinomas. Blood Cells Mol Dis. 2009;43:243–9. [PubMed: 19729324]
  12. Calzolari A, Larocca LM, Deaglio S, Finisguerra V, Boe A, Raggi C, Ricci-Vitani L, Pierconti F, Malavasi F, De Maria R, Testa U, Pallini R. Transferrin receptor 2 is frequently and highly expressed in glioblastomas. Transl Oncol. 2010;3:123–34. [PMC free article: PMC2847320] [PubMed: 20360937]
  13. Calzolari A, Deaglio S, Sposi NM, Petrucci E, Morsilli O, Gabbianelli M, Malavasi F, Peschle C, Testa U. Transferrin receptor 2 protein is not expressed in normal erythroid cells. Biochem J. 2004;381:629–34. [PMC free article: PMC1133871] [PubMed: 15084147]
  14. Camaschella C, Roetto A, Cali A, De Gobbi M, Garozzo G, Carella M, Majorano N, Totaro A, Gasparini P. The gene TFR2 is mutated in a new type of haemochromatosis mapping to 7q22. Nat Genet. 2000;25:14–5. [PubMed: 10802645]
  15. Camaschella C, Poggiali E. Rare types of genetic hemochromatosis. Acta Haematol. 2009;122:140–5. [PubMed: 19907151]
  16. Carneiro AA, Vilela GR, Fernandes JB, Araújo D, Baffa O, Elias J, St Pierre G, Angulo IL, Covas DT. In vivo tissue characterization using magnetic techniques. Neurol Clin Neurophysiol. 2004;2004:85. [PubMed: 16012653]
  17. Chen J, Enns CA. The Cytoplasmic domain of transferrin receptor 2 dictates its stability and response to holo-transferrin in Hep3B cells. J Biol Chem. 2007;282:6201–9. [PubMed: 17202145]
  18. De Gobbi M, Barilaro MR, Garozzo G, Sbaiz L, Alberti F, Camaschella C. TFR2 Y250X mutation in Italy. Br J Haematol. 2001;114:243–4. [PubMed: 11472377]
  19. De Gobbi M, Roetto A, Piperno A, Mariani R, Alberti F, Papanikolaou G, Politou M, Lockitch G, Girelli D, Fargion S, Cox TM, Gasparini P, Cazzola M, Camaschella C. Natural history of juvenile haemochromatosis. Br J Haematol. 2002;117:973–9. [PubMed: 12060140]
  20. Drakesmith H, Schimanski LM, Ormerod E, Merryweather-Clarke AT, Viprakasit V, Edwards JP, Sweetland E, Bastin JM, Cowley D, Chinthammitr Y, Robson KJ, Townsend AR. Resistance to hepcidin is conferred by hemochromatosis-associated mutations of ferroportin. Blood. 2005;106:1092–7. [PubMed: 15831700]
  21. European Association for the Study of the Liver; EASL clinical practice guidelines for HFE hemochromatosis. J Hepatol. 2010;53:3–22. [PubMed: 20471131]
  22. Fleming RE, Ahmann JR, Migas MC, Waheed A, Koeffler HP, Kawabata H, Britton RS, Bacon BR, Sly WS. Targeted mutagenesis of the murine transferrin receptor-2 gene produces hemochromatosis. Proc Natl Acad Sci USA. 2002;99:10653–8. [PMC free article: PMC125003] [PubMed: 12134060]
  23. Forejtnikovà H, Vieillevoye M, Zermati Y, Lambert M, Pellegrino RM, Guihard S, Gaudry M, Camaschella C, Lacombe C, Roetto A, Mayeux P, Verdier F. Transferrin receptor 2 is a component of the erythropoietin receptor complex and is required for efficient erythropoiesis. Blood. 2010;116:5357–67. [PubMed: 20826723]
  24. Gao J, Chen J, Kramer M, Tsukamoto H, Zhang AS, Enns CA. Interaction of the hereditary hemochromatosis protein HFE with transferrin receptor 2 is required for transferrin-induced hepcidin expression. Cell Metab. 2009;9:217–27. [PMC free article: PMC2673483] [PubMed: 19254567]
  25. Gandon Y, Olivie D, Guyader D, Aube C, Oberti F, Sebille V, Deugnier Y. Non-invasive assessment of hepatic iron stores by MRI. Lancet. 2004;363:357–62. [PubMed: 15070565]
  26. Gérolami V, Le Gac G, Mercier L, Nezri M, Bergé-Lefranc JL, Férec C. Early-onset haemochromatosis caused by a novel combination of TFR2 mutations(p.R396X/c.1538-2 A>G) in a woman of Italian descent. Haematologica. 2008;93:e45–6. [PubMed: 18450729]
  27. Girelli D, Bozzini C, Roetto A, Alberti F, Daraio F, Colombari R, Olivieri O, Corrocher R, Camaschella C. Clinical and pathologic findings in hemochromatosis type 3 due to a novel mutation in transferrin receptor 2 gene. Gastroenterology. 2002;122:1295–302. [PubMed: 11984516]
  28. Girelli D, Trombini P, Busti F, Campostrini N, Sandri M, Pelucchi S, Westerman M, Ganz T, Nemeth E, Piperno A, Camaschella C. A time course of hepcidin response to iron challenge in patients with HFE and TFR2 hemochromatosis. Haematologica. 2011;96:500–6. [PMC free article: PMC3069225] [PubMed: 21173098]
  29. Glockner G, Scherer S, Schattevoy R, Boright A, Weber J, Tsui LC, Rosenthal A. Large-scale sequencing of two regions in human chromosome 7q22: analysis of 650 kb of genomic sequence around the EPO and CUTL1 loci reveals 17 genes. Genome Res. 1998;8:1060–73. [PMC free article: PMC310788] [PubMed: 9799793]
  30. Gordeuk VR, Caleffi A, Corradini E, Ferrara F, Jones RA, Castro O, Onyekwere O, Kittles R, Pignatti E, Montosi G, Garuti C, Gangaidzo IT, Gomo ZA, Moyo VM, Rouault TA, MacPhail P, Pietrangelo A. Iron overload in Africans and African-Americans and a common mutation in the SCL40A1 (ferroportin 1) gene. Blood Cells Mol Dis. 2003;31:299–304. [PubMed: 14636642]
  31. Guyader D, Jacquelinet C, Moirand R, Turlin B, Mendler MH, Chaperon J, David V, Brissot P, Adams P, Deugnier Y. Noninvasive prediction of fibrosis in C282Y homozygous hemochromatosis. Gastroenterology. 1998;115:929–36. [PubMed: 9753496]
  32. Hattori A, Wakusawa S, Hayashi H, Harashima A, Sanae F, Kawanaka M, Yamada G, Yano M, Yoshioka K. AVAQ 594-597 deletion of the TfR2 gene in a Japanese family with hemochromatosis. Hepatol Res. 2003;26:154–6. [PubMed: 12809944]
  33. Hayashi H, Wakusawa S, Motonishi S, Miyamoto K, Okada H, Inagaki Y, Ikeda T. Genetic background of primary iron overload syndromes in Japan. Intern Med. 2006;45:1107–11. [PubMed: 17106152]
  34. Hentze MW, Muckenthaler MU, Galy B, Camaschella C. Two to tango: regulation of Mammalian iron metabolism. Cell. 2010;142:24–38. [PubMed: 20603012]
  35. Hofmann WK, Tong XJ, Ajioka RS, Kushner JP, Koeffler HP. Mutation analysis of transferrin-receptor 2 in patients with atypical hemochromatosis. Blood. 2002;100:1099–100. [PubMed: 12150153]
  36. Hsiao PJ, Tsai KB, Shin SJ, Wang CL, Lee ST, Lee JF, Kuo KK. A novel mutation of transferrin receptor 2 in a Taiwanese woman with type 3 hemochromatosis. J Hepatol. 2007;47:303–6. [PubMed: 17562347]
  37. Johnson MB, Chen J, Murchison N, Green FA, Enns CA. Transferrin receptor 2: evidence for ligand-induced stabilization and redirection to a recycling pathway. Mol Biol Cell. 2007;18:743–54. [PMC free article: PMC1805103] [PubMed: 17182845]
  38. Johnson MB, Enns CA. Diferric transferrin regulates transferrin receptor 2 protein stability. Blood. 2004;104:4287–93. [PubMed: 15319290]
  39. Kawabata H, Fleming RE, Gui D, Moon SY, Saitoh T, O'Kelly J, Umehara Y, Wano Y, Said JW, Koeffler HP. Expression of hepcidin is down-regulated in TfR2 mutant mice manifesting a phenotype of hereditary hemochromatosis. Blood. 2005;105:376–81. [PubMed: 15345587]
  40. Kawabata H, Germain RS, Vuong PT, Nakamaki T, Said JW, Koeffler HP. Transferrin receptor 2-alpha supports cell growth both in iron-chelated cultured cells and in vivo. J Biol Chem. 2000;275:16618–25. [PubMed: 10748106]
  41. Kawabata H, Yang R, Hirama T, Vuong PT, Kawano S, Gombart AF, Koeffler HP. Molecular cloning of transferrin receptor 2. A new member of the transferrin receptor-like family. J Biol Chem. 1999;274:20826–32. [PubMed: 10409623]
  42. Koyama C, Wakusawa S, Hayashi H, Suzuki R, Yano M, Yoshioka K, Kozuru M, Takayamam Y, Okada T, Mabuchi H. Two novel mutations, L490R and V561X, of the transferrin receptor 2 gene in Japanese patients with hemochromatosis. Haematologica. 2005;90:302–7. [PubMed: 15749661]
  43. Le Gac G, Mons F, Jacolot S, Scotet V, Férec C, Frébourg T. Early onset hereditary hemochromatosis resulting from a novel TFR2 gene nonsense mutation (R105X) in two siblings of north French descent. Br J Haematol. 2004;125:674–8. [PubMed: 15147384]
  44. Lee PL, Barton JC. Hemochromatosis and severe iron overload associated with compound heterozygosity for TFR2 R455Q and two novel mutations TFR2 R396X and G792R. Acta Haematol. 2006;115:102–5. [PubMed: 16424658]
  45. Lee PL, Halloran C, West C, Beutler E. Mutation analysis of the transferrin receptor-2 gene in patients with iron overload. Blood Cells Mol Dis. 2001;27:285–9. [PubMed: 11358389]
  46. Majore S, Milano F, Binni F, Stuppia L, Cerrone A, Tafuri A, De Bernardo C, Palka G, Grammatico P. Homozygous p.M172K mutation of the TFR2 gene in an Italian family with type 3 hereditary hemochromatosis and early onset iron overload. Haematologica. 2006;91(8) Suppl:ECR33. [PubMed: 16923517]
  47. Mattman A, Huntsman D, Lockitch G, Langlois S, Buskard N, Ralston D, Butterfield Y, Rodrigues P, Jones S, Porto G, Marra M, De Sousa M, Vatcher G. Transferrin receptor 2 (TfR2) and HFE mutational analysis in non-C282Y iron overload: identification of a novel TfR2 mutation. Blood. 2002;100:1075–7. [PubMed: 12130528]
  48. McNamara L, Gordeuk VR, MacPhail AP. Ferroportin (Q248H) mutations in African families with dietary iron overload. J Gastroenterol Hepatol. 2005;20:1855–8. [PubMed: 16336444]
  49. Mendes AI, Ferro A, Martins R, Picanço I, Gomes S, Cerqueira R, Correia M, Nunes AR, Esteves J, Fleming R, Faustino P. Non-classical hereditary hemochromatosis in Portugal: novel mutations identified in iron metabolism-related genes. Ann Hematol. 2009;88:229–34. [PubMed: 18762941]
  50. Meregalli M, Pellagatti A, Bissolotti E, Fracanzani AL, Fargion S, Sampietro M. Molecular analysis of the TFR2 gene: report of a novel polymorphism (1878C>T). Hum Mutat. 2000;16:532. [PubMed: 11102989]
  51. Montosi G, Donovan A, Totaro A, Garuti C, Pignatti E, Cassanelli S, Trenor CC, Gasparini P, Andrews NC, Pietrangelo A. Autosomal-dominant hemochromatosis is associated with a mutation in the ferroportin (SLC11A3) gene. J Clin Invest. 2001;108:619–23. [PMC free article: PMC209405] [PubMed: 11518736]
  52. Nemeth E, Roetto A, Garozzo G, Ganz T, Camaschella C. Hepcidin is decreased in TFR2-Hemochromatosis. Blood. 2005;105:1803–6. [PubMed: 15486069]
  53. Njajou OT, Vaessen N, Joosse M, Berghuis B, van Dongen JW, Breuning MH, Snijders PJ, Rutten WP, Sandkuijl LA, Oostra BA, van Duijn CM, Heutink P. A mutation in SLC11A3 is associated with autosomal dominant hemochromatosis. Nat Genet. 2001;28:213–4. [PubMed: 11431687]
  54. Pelucchi S, Mariani R, Trombini P, Coletti S, Pozzi M, Paolini V, Barisani D, Piperno A. Expression of hepcidin and other iron-related genes in type 3 hemochromatosis due to a novel mutation in transferrin receptor-2. Haematologica. 2009;94:276–9. [PMC free article: PMC2635389] [PubMed: 19144662]
  55. Phatak P, Brissot P, Wurster M, Adams PC, Bonkovsky HL, Gross J, Malfertheiner P, McLaren GD, Niederau C, Piperno A, Powell LW, Russo MW, Stoelzel U, Stremmel W, Griffel L, Lynch N, Zhang Y, Pietrangelo A. A phase 1/2, dose-escalation trial of deferasirox for the treatment of iron overload in HFE-related hereditary hemochromatosis. Hepatology. 2010;52:1671–779. [PMC free article: PMC3034044] [PubMed: 20814896]
  56. Pichler I, Minelli C, Sanna S, Tanaka T, Schwienbacher C, Naitza S, Porcu E, Pattaro C, Busonero F, Zanon A, Maschio A, Melville SA, Grazia Piras M, Longo DL, Guralnik J, Hernandez D, Bandinelli S, Aigner E, Murphy AT, Wroblewski V, Marroni F, Theurl I, Gnewuch C, Schadt E, Mitterer M, Schlessinger D, Ferrucci L, Witcher DR, Hicks AA, Weiss G, Uda M, Pramstaller PP. Identification of a common variant in the TFR2 gene implicated in the physiological regulation of serum iron levels. Hum Mol Genet. 2011;20:1232–40. [PMC free article: PMC3043660] [PubMed: 21208937]
  57. Pietrangelo A, Caleffi A, Henrion J, Ferrara F, Corradini E, Kulaksiz H, Stremmel W, Andreone P, Garuti C. Juvenile hemochromatosis associated with pathogenic mutations of adult hemochromatosis genes. Gastroenterology. 2005;128:470–9. [PubMed: 15685557]
  58. Pietrangelo A. Hereditary hemochromatosis: pathogenesis, diagnosis, and treatment. Gastroenterology. 2010;139:393–408. [PubMed: 20542038]
  59. Piperno A, Roetto A, Mariani R, Pelucchi S, Corengia C, Daraio F, Piga A, Garozzo G, Camaschella C. Homozygosity for transferrin receptor-2 Y250X mutation induces early iron overload. Haematologica. 2004;89:359–60. [PubMed: 15020277]
  60. Ricerca BM, Radio FC, De Marinis L, De Bernardo C, Castori M, Sacco E, Grammatico P, Majore S. Natural history of TFR2-related hereditary hemochromatosis in a 47-yr-old Italian patient. Eur J Haematol. 2009;83:494–6. [PubMed: 19549277]
  61. Riva A, Mariani R, Bovo G, Pelucchi S, Arosio C, Salvioni A, Vergani A, Piperno A. Type 3 hemochromatosis and beta-thalassemia trait. Eur J Haematol. 2004;72:370–4. [PubMed: 15059075]
  62. Rivers CA, Barton JC, Gordeuk VR, Acton RT, Speechley MR, Snively BM, Leiendecker-Foster C, Press RD, Adams PC, McLaren GD, Dawkins FW, McLaren CE, Reboussin DM. Association of ferroportin Q248H polymorphism with elevated levels of serum ferritin in African Americans in the Hemochromatosis and Iron Overload Screening (HEIRS) Study. Blood Cells Mol Dis. 2007;38:247–52. [PMC free article: PMC3727273] [PubMed: 17276706]
  63. Robb A, Wessling-Resnick M. Regulation of transferrin receptor 2 protein levels by transferrin. Blood. 2004;104:4294–9. [PubMed: 15319276]
  64. Robb AD, Ericsson M, Wessling-Resnick M. Transferrin receptor 2 mediates a biphasic pattern of transferrin uptake associated with ligand delivery to multivesicular bodies. Am J Physiol Cell Physiol. 2004;287:C1769–75. [PubMed: 15317665]
  65. Roetto A, Daraio F, Alberti F, Porporato P, Cali A, De Gobbi M, Camaschella C. Hemochromatosis due to mutations in transferrin receptor 2. Blood Cells Mol Dis. 2002;29:465–70. [PubMed: 12547237]
  66. Roetto A, Di Cunto F, Pellegrino RM, Hirsch E, Azzolino O, Bondi A, Defilippi I, Carturan S, Miniscalco B, Riondato F, Cilloni D, Silengo L, Altruda F, Camaschella C, Saglio G. Comparison of 3 Tfr2-deficient murine models suggests distinct functions for Tfr2-alpha and Tfr2-beta isoforms in different tissues. Blood. 2010;115:3382–9. [PubMed: 20179178]
  67. Roetto A, Totaro A, Cazzola M, Cicilano M, Bosio S, D'Ascola G, Carella M, Zelante L, Kelly AL, Cox TM, Gasparini P, Camaschella C. Juvenile hemochromatosis locus maps to chromosome 1q. Am J Hum Genet. 1999;64:1388–93. [PMC free article: PMC1377875] [PubMed: 10205270]
  68. Roetto A, Totaro A, Piperno A, Piga A, Longo F, Garozzo G, Cali A, De Gobbi M, Gasparini P, Camaschella C. New mutations inactivating transferrin receptor 2 in hemochromatosis type 3. Blood. 2001;97:2555–60. [PubMed: 11313241]
  69. Schimanski LM, Drakesmith H, Merryweather-Clarke AT, Viprakasit V, Edwards JP, Sweetland E, Bastin JM, Cowley D, Chinthammitr Y, Robson KJ, Townsend AR. In vitro functional analysis of human ferroportin (FPN) and hemochromatosis-associated FPN mutations. Blood. 2005;105:4096–102. [PubMed: 15692071]
  70. St Pierre TG, Clark PR, Chua-anusorn W, Fleming AJ, Jeffrey GP, Olynyk JK, Pootrakul P, Robins E, Lindeman R. Noninvasive measurement and imaging of liver iron concentrations using proton magnetic resonance. Blood. 2005;105:855–61. [PubMed: 15256427]
  71. Wallace DF, Subramaniam VN. Non-HFE haemochromatosis. World J Gastroenterol. 2007;13:4690–8. [PubMed: 17729390]
  72. Wallace DF, Summerville L, Lusby PE, Subramaniam VN. First phenotypic description of transferrin receptor 2 knockout mouse, and the role of hepcidin. Gut. 2005;54:980–6. [PMC free article: PMC1774629] [PubMed: 15951546]
  73. Wallace DF, Summerville L, Subramaniam VN. Targeted disruption of the hepatic transferrin receptor 2 gene in mice leads to iron overload. Gastroenterology. 2007;132:301–10. [PubMed: 17241880]
  74. Wallace DF, Summerville L, Crampton EM, Frazer DM, Anderson GJ, Subramaniam VN. Combined deletion of Hfe and transferrin receptor 2 in mice leads to marked dysregulation of hepcidin and iron overload. Hepatology. 2009;50:1992–2000. [PubMed: 19824072]
  75. West AP Jr, Bennett MJ, Sellers VM, Andrews NC, Enns CA, Bjorkman PJ. Comparison of the interactions of transferrin receptor and transferrin receptor 2 with transferrin and the hereditary hemochromatosis protein HFE. J Biol Chem. 2000;275:38135–8. [PubMed: 11027676]
  76. Whitington PF, Hibbard JU. High-dose immunoglobulin during pregnancy for recurrent neonatal haemochromatosis. Lancet. 2004;364:1690–8. [PubMed: 15530630]
  77. Zhang AS, Xiong S, Tsukamoto H, Enns CA. Localization of iron metabolism-related mRNAs in rat liver indicate that HFE is expressed predominantly in hepatocytes. Blood. 2004;103:1509–14. [PubMed: 14563638]

Suggested Reading

  1. Beutler E. Hemochromatosis: genetics and pathophysiology. Annu Rev Med. 2006;57:331–47. [PubMed: 16409153]
  2. Camaschella C. Understanding iron homeostasis through genetic analysis of hemochromatosis and related disorders. Blood. 2005;106:3710–7. [PubMed: 16030190]
  3. Drake SF, Morgan EH, Herbison CE, Delima R, Graham RM, Chua AC, Leedman PJ, Fleming RE, Bacon BR, Olynyk JK, Trinder D. Iron absorption and hepatic iron uptake are increased in a transferrin receptor 2 (Y245X) mutant mouse model of hemochromatosis type 3. Am J Physiol Gastrointest Liver Physiol. 2007;292:G323–8. [PubMed: 16935854]
  4. Merle U, Theilig F, Fein E, Gehrke S, Kallinowski B, Riedel HD, Bachmann S, Stremmel W, Kulaksiz H. Localization of the iron-regulatory proteins hemojuvelin and transferrin receptor 2 to the basolateral membrane domain of hepatocytes. Histochem Cell Biol. 2007;127:221–6. [PubMed: 16932966]
  5. Pietrangelo A. Non-HFE hemochromatosis. Semin Liver Dis. 2005;25:450–60. [PubMed: 16315138]
  6. Roetto A, Camaschella C. New insights into iron homeostasis through the study of non-HFE hereditary haemochromatosis. Best Pract Res Clin Haematol. 2005;18:235–50. [PubMed: 15737887]

Chapter Notes

Revision History

  • 9 June 2011 (me) Comprehensive update posted live
  • 5 August 2008 (cd) Revision: prenatal diagnosis available clinically
  • 15 May 2008 (me) Comprehensive update posted to live Web site
  • 7 August 2006 (ar) Revision: change in mutation nomenclature from AVAQ594-597del to AVAQ621-624del
  • 5 December 2005 (ar) Revision: targeted mutation analysis clinically available; mutation scanning no longer available
  • 29 August 2005 (me) Review posted to live Web site
  • 1 February 2005 (ar) Original submission
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