Clinical expression of haemochromatosis in Irish C282Y homozygotes identified through family screening

Hereditary haemochromatosis presenting to rheumatology clinic as inflammatory arthritis

Hereditary haemochromatosis (HH) is the most commonly identified genetic disorder in Caucasians. HH has a wide variety of clinical manifestations. As such, the presenting complaint in new diagnoses of HH can be non-specific such as fatigue; however, joint symptoms such as arthralgia are also common. These joint symptoms closely mimic the features of other musculoskeletal diseases such as rheumatoid arthritis (RA). Early diagnosis of HH is key to prevent long-term irreversible complications such as liver damage, diabetes and degenerative joint disease. We present a case of HH which was initially suspected to be early RA, with ultrasound findings of active synovitis. High clinical suspicion, a raised serum ferritin followed by genetic testing for C282Y mutation confirmed the diagnosis of HH. The synovitis responded to corticosteroids and was suspected to be due to pseudogout a known complication of HH. Early diagnosis and treatment resulted in a favourable outcome.

Genetic Causes of Liver Disease: When to Suspect a Genetic Etiology, Initial Lab Testing, and the Basics of Management

Genetic causes of liver disease lead to a wide range of presentations. This article describes hereditary hemochromatosis, Gilbert syndrome, alpha-1 antitrypsin deficiency, Wilson disease, PFIC, BRIC, and LAL-D. The most common cause of hereditary hemochromatosis is a C282Y mutation in the HFE gene. Gilbert syndrome is a benign cause of indirect hyperbilirubinemia. Alpha-1 antitrypsin deficiency causes both lung and liver disease. Wilson disease can cause neurologic disease and liver disease. Progressive familial intrahepatic cholestasis and benign recurrent intrahepatic cholestasis are rare causes of cholestasis. LAL-D is a rare disease that can appear similar to NAFLD in adults.

Genetic Testing in Liver Disease: What to Order, in Whom, and When

Genetic causes of liver disease lead to a wide range of presentations, from mildly abnormal liver tests to acute liver failure. This article discusses the indications for testing and what to test for hereditary hemochromatosis, progressive familial intrahepatic cholestasis, benign recurrent intrahepatic cholestasis, lysosomal acid lipase deficiency, Gilbert syndrome, alpha-1 antitrypsin deficiency, and Wilson disease.

Association of HFE gene C282Y and H63D mutations with liver cirrhosis in the Lithuanian population

BACKGROUND AND OBJECTIVE

Liver cirrhosis is the end-stage disease of chronic liver injury. Due to differences in the natural course of chronic liver diseases, identification of genetic factors that influence individual outcomes is warranted. HFE-linked hereditary hemochromatosis (HH) predisposes disease progression to cirrhosis; however, the role of heterozygous C282Y or H63D mutations in the development of cirrhosis in the presence of other etiological factors is still debated. The aim of this study was to determine the association between heterozygous C282Y and H63D mutations and non-HH liver cirrhosis in Lithuanian population.

MATERIALS AND METHODS

The patient cohort consisted of 209 individuals. Diagnosis of cirrhosis was confirmed by clinical, laboratory parameters, liver biopsy, and radiological imaging. Control samples were obtained from 1005 randomly selected unrelated healthy individuals. HFE gene mutations were determined using the PCR-RFLP method.

RESULTS

The most common causes of cirrhosis were hepatitis C (33.9%), hepatitis B (13.6%), and alcohol (25.8%). C282Y allele was associated with the presence of cirrhosis (OR=2.07; P=0.005); this was also observed under recessive model for C282Y (OR=2.06, P=0.008). The prevalence of C282Y allele was higher in cirrhotic men than in controls (7.0% vs. 2.8%, P=0.002). The carriage of H63D risk allele (OR=1.54; P=0.02), heterozygous C282Y/wt and homozygous H63D/H63D genotypes were associated with liver cirrhosis in males (OR=2.48, P=0.008, and OR=4.13, P=0.005, respectively).

CONCLUSIONS

Heterozygous C282Y mutation of the HFE gene was associated with liver cirrhosis in the Lithuanian population. In gender-related analysis, heterozygous C282Y and homozygous H63D mutations were linked to liver cirrhosis in men, not in women.

EMQN best practice guidelines for the molecular genetic diagnosis of hereditary hemochromatosis (HH)

Molecular genetic testing for hereditary hemochromatosis (HH) is recognized as a reference test to confirm the diagnosis of suspected HH or to predict its risk. The vast majority (typically >90%) of patients with clinically characterized HH are homozygous for the p.C282Y variant in the HFE gene, referred to as HFE-related HH. Since 1996, HFE genotyping was implemented in diagnostic algorithms for suspected HH, allowing its early diagnosis and prevention. However, the penetrance of disease in p.C282Y homozygotes is incomplete. Hence, homozygosity for p.C282Y is not sufficient to diagnose HH. Neither is p.C282Y homozygosity required for diagnosis as other rare forms of HH exist, generally referred to as non-HFE-related HH. These pose significant challenges when defining criteria for referral, testing protocols, interpretation of test results and reporting practices. We present best practice guidelines for the molecular genetic diagnosis of HH where recommendations are classified, as far as possible, according to the level and strength of evidence. For clarification, the guidelines' recommendations are preceded by a detailed description of the methodology and results obtained with a series of actions taken in order to achieve a wide expert consensus, namely: (i) a survey on the current practices followed by laboratories offering molecular diagnosis of HH; (ii) a systematic literature search focused on some identified controversial topics; (iii) an expert Best Practice Workshop convened to achieve consensus on the practical recommendations included in the guidelines.

Iron and the liver

Humans have evolved to retain iron in the body and are exposed to a high risk of iron overload and iron-related toxicity. Excess iron in the blood, in the absence of increased erythropoietic needs, can saturate the buffering capacity of serum transferrin and result in non-transferrin-bound highly reactive forms of iron that can cause damage, as well as promote fibrogenesis and carcinogenesis in the parenchymatous organs. A number of hereditary or acquired diseases are associated with systemic or local iron deposition or iron misdistribution in organs or cells. Two of these, the HFE- and non-HFE hemochromatosis syndromes represent the paradigms of genetic iron overload. They share common clinical features and the same pathogenic basis, in particular, a lack of synthesis or activity of hepcidin, the iron hormone. Before hepcidin was discovered, the liver was simply regarded as the main site of iron storage and, as such, the main target of iron toxicity. Now, as the main source of hepcidin, it appears that the loss of the hepcidin-producing liver mass or genetic and acquired factors that repress hepcidin synthesis in the liver may also lead to iron overload. Usually, there is low-grade excess iron which, through oxidative stress, is sufficient to worsen the course of the underlying liver disease or other chronic diseases that are apparently unrelated to iron, such as chronic metabolic and cardiovascular diseases. In the future, modulation of hepcidin synthesis and activity or hepcidin hormone-replacing strategies may become therapeutic options to cure iron-related disorders.

Genetics, Genetic Testing, and Management of Hemochromatosis: 15 Years Since Hepcidin

The discovery of hepcidin in 2000 and the subsequent unprecedented explosion of research and discoveries in the iron field have dramatically changed our understanding of human disorders of iron metabolism. Today, hereditary hemochromatosis, the paradigmatic iron-loading disorder, is recognized as an endocrine disease due to the genetic loss of hepcidin, the iron hormone produced by the liver. This syndrome is due to unchecked transfer of iron into the bloodstream in the absence of increased erythropoietic needs and its toxic effects in parenchymatous organs. It is caused by mutations that affect any of the proteins that help hepcidin to monitor serum iron, including HFE and, in rarer instances, transferrin-receptor 2 and hemojuvelin, or make its receptor ferroportin, resistant to the hormone. In Caucasians, C282Y HFE homozygotes are numerous, but they are only predisposed to hemochromatosis; complete organ disease develops in a minority, due to alcohol abuse or concurrent genetic modifiers that are now being identified. HFE gene testing can be used to diagnose hemochromatosis in symptomatic patients, but analyses of liver histology and full gene sequencing are required to identify patients with rare, non-HFE forms of the disease. Due to the central pathogenic role of hepcidin, it is anticipated that nongenetic causes of hepcidin loss (eg, end-stage liver disease) can cause acquired forms of hemochromatosis. The mainstay of hemochromatosis management is still removal of iron by phlebotomy, first introduced in 1950s, but identification of hepcidin has not only shed new light on the pathogenesis of the disease and the approach to diagnosis, but etiologic therapeutic applications from these advances are now foreseen.

[Hemochromatosis]

Hereditary hemochromatosis is a frequent autosomal recessive iron storage disease in northern and western Europe. The classical clinical triad of liver cirrhosis, hyperpigmentation and diabetes is nowadays rare, most probably because of early recognition. The homozygous C282Y mutation in the HFE gene is responsible for most cases of hereditary hemochromatosis, although other much rarer mutations in other genes have been recently identified. Progressive iron overload not only causes liver cirrhosis but also triggers development of a characteristic arthropathy. Bony swelling with intermittent arthritis of the second and third metacarpophalangeal joints is typical as well as occurrence of chondrocalcinosis in wrists and knee joints. The therapy of choice is excess iron removal by phlebotomy. Treatment usually prevents or even reverses liver damage but does not alter the course of hemochromatosis arthropathy.

HFE genotyping in patients with elevated serum iron indices and liver diseases

Iron abnormalities in chronic liver disease may be the result of genetic diseases or secondary factors. The present study aimed to identify subjects with HFE-HH in order to describe the frequency of clinical manifestations, identify risk factors for iron elevation, and compare the iron profile of HFE-HH to other genotypes in liver disease patients. A total of 108 individuals with hepatic disease, transferrin saturation (TS) > 45%, and serum ferritin (SF) > 350 ng/mL were tested for HFE mutations. Two groups were characterized: C282Y/C282Y or C282Y/H63D genotypes (n = 16) were the HFE hereditary hemochromatosis (HFE-HH) group; and C282Y and H63D single heterozygotes, the H63D/H63D genotype, and wild-type were considered group 2 (n = 92). Nonalcoholic liver disease, alcoholism, and chronic hepatitis C were detected more frequently in group 2, whereas arthropathy, hepatocarcinoma, diabetes, and osteoporosis rates were significantly higher in the HFE-HH group. TS > 82%, SF > 2685 ng/mL, and serum iron > 178 μg/dL were the cutoffs for diagnosis of HFE-HH in patients with liver disease. Thus, in non-Caucasian populations with chronic liver disease, HFE-HH diagnosis is more predictable in those with iron levels higher than those proposed in current guidelines for the general population.

HFE-related hemochromatosis: an update for the rheumatologist

Hereditary hemochromatosis is a frequent disease in Caucasian populations. It leads to progressive iron overload in a variety of organs. The most common cause is the C282Y homozygous mutation in the HFE gene. The classical triad of skin hyperpigmentation, diabetes, and liver cirrhosis is nowadays rare but musculoskeletal symptoms are common in HFE-related hemochromatosis. Typically the second and third metacarpophalangeal joints, and the wrist, hip, and ankle joints are affected. Clinical symptoms include osteoarthritis-like symptoms, pseudogout attacks, and synovitis sometimes resembling rheumatoid arthritis. Radiographs show degenerative changes with joint space narrowing, osteophytes, and subchondral cysts. Chondrocalcinosis in the wrist and knee joints is seen in up to 50 % of patients. Although most other organ manifestations regress during phlebotomy, musculoskeletal symptoms often persist or even become worse. Importantly, patients are at an increased risk of severe large-joint arthritis necessitating joint replacement surgery. Therefore, future research should focus on the pathogenesis and treatment options for HH arthropathy.

High prevalence of fibromyalgia in patients with HFE-related hereditary hemochromatosis

OBJECTIVES

Subjects with HFE-related hereditary hemochromatosis (HH) may present with arthralgias, fatigue, and stiffness, yet little is known on the presence of fibromyalgia syndrome (FMS) in these subjects. We determined the prevalence of FMS in a cohort of subjects with HH and evaluated its relationship to subject demographics, disease status, and quality of life.

METHODS

In a cross-sectional study we collected data on 395 consecutive subjects diagnosed with HH who were attending a tertiary referral Hepatology outpatient clinic at Galway University Hospital, Ireland (between October 2009 and June 2010). Subjects underwent a standard assessment including history, clinical examination, and functional assessments for pain and disability. Univariate logistic regression was applied to determine risk factors independently associated with prevalent FMS in these subjects.

RESULTS

Three hundred ninety-five subjects met the inclusion criteria. Mean age was 43 years (range, 21 to 59 y) and 260 (66%) were males. One hundred seventy (43%) of the subjects were diagnosed with FMS. Among those with fibromyalgia fatigue and ≥ 11 tender points were present in all of the subjects, widespread pain in 150 (88%), depression in 70 (41%), and arthralgia/joint stiffness in 70 (41%). In subjects with FMS 33% reported some functional impairment (HAQ-DI>0), with 10% reporting moderate-severe functional impairment (HAQ-DI ≥ 1.5).

CONCLUSIONS

This study reveals a high prevalence of FMS (43%) among subjects with HFE-related hemochromatosis. Prospective studies are needed to better understand the risk factors for FMS in such patients.

Molecular diagnosis of hemochromatosis

INTRODUCTION

The discovery of hemochromatosis genes and the availability of molecular-genetic tests considerably modified the knowledge of the disease relative to physiopathology, penetrance, and expression, and had major impact in the diagnostic settings.

AREAS COVERED

Hemochromatosis is a heterogenous disorder at both genetic and phenotypic level. The review discusses criteria to define patients' iron phenotype and to use molecular tests to diagnose HFE-related and non-HFE hemochromatosis. The material examined includes articles published in the journals covered by PubMed US National Library of Medicine. The author has been working in the field of iron overload diseases for several years and has contributed 18 of the papers cited in the references.

EXPERT OPINION

Hemochromatosis genotyping is inseparable from phenotype characterization. A full clinical assessment is needed and DNA test performed when data suggest a clear indication of suspicion of being at risk for HH. HFE testing for p.Cys282Tyr mutation and p.His63Asp variant is the first molecular diagnostic step. Genotyping for rare mutations can be offered to patients with negative first-level HFE testing who have iron overload with no other explanation and should be performed in referral centers for iron overload disorders that can provide genetic advice and in-house genotyping services.

Personalized medicine in human space flight: using Omics based analyses to develop individualized countermeasures that enhance astronaut safety and performance

Space flight is one of the most extreme conditions encountered by humans. Advances in Omics methodologies (genomics, transcriptomics, proteomics, and metabolomics) have revealed that unique differences exist between individuals. These differences can be amplified in extreme conditions, such as space flight. A better understanding of individual differences may allow us to develop personalized countermeasure packages that optimize the safety and performance of each astronaut. In this review, we explore the role of "Omics" in advancing our ability to: (1) more thoroughly describe the biological response of humans in space; (2) describe molecular attributes of individual astronauts that alter the risk profile prior to entering the space environment; (3) deploy Omics techniques in the development of personalized countermeasures; and (4) develop a comprehensive Omics-based assessment and countermeasure platform that will guide human space flight in the future. In this review, we advance the concept of personalized medicine in human space flight, with the goal of enhancing astronaut safety and performance. Because the field is vast, we explore selected examples where biochemical individuality might significantly impact countermeasure development. These include gene and small molecule variants associated with: (1) metabolism of therapeutic drugs used in space; (2) one carbon metabolism and DNA stability; (3) iron metabolism, oxidative stress and damage, and DNA stability; and (4) essential input (Mg and Zn) effects on DNA repair. From these examples, we advance the case that widespread Omics profiling should serve as the foundation for aerospace medicine and research, explore methodological considerations to advance the field, and suggest why personalized medicine may become the standard of care for humans in space.

Review article: the iron overload syndromes

BACKGROUND

Iron overload syndromes encompass a wide range of hereditary and acquired conditions. Major developments in the field of genetics and the discovery of hepcidin as a central regulator of iron homeostasis have greatly increased our understanding of the pathophysiology of iron overload syndromes.

AIM

To review advances in iron regulation and iron overload syndrome with special emphasis on hereditary haemochromatosis, the prototype iron overload syndrome.

METHODS

A PubMed search using words such as 'iron overload', 'hemochromatosis', 'HFE', 'Non-HFE', 'secondary iron overload' was undertaken.

RESULTS

Iron overload is associated with significant morbidity and mortality. Sensitive diagnostic tests and effective therapy are widely available and can prevent complications associated with iron accumulation in end- organs. Therapeutic phlebotomy remains the cornerstone of therapy for removal of excess body iron, but novel therapeutic agents including oral iron chelators have been developed for iron overload associated with anaemia.

CONCLUSIONS

Iron overload disorders are common. Inexpensive screening tests as well as confirmatory diagnostic tests are widely available. Increased awareness of the causes and importance of early diagnosis and knowledge of the appropriate use of genetic testing are encouraged. The availability of novel treatments should increase therapeutic options for patients with iron overload disorders.

Health check-ups and family screening allow detection of hereditary hemochromatosis with less advanced liver fibrosis and survival comparable with the general population

OBJECTIVE

The information concerning the morbidity and mortality of hereditary hemochromatosis is based primarily on clinical cohorts of symptomatic patients. The major aim of this study was to analyze the long-term prognosis for Swedish patients with this condition, with respect to both clinical features and survival, in relation to the route by which the disease was detected.

PATIENTS AND METHODS

373 patients with hemochromatosis detected through routine health check-ups (n = 153), family screening (n = 44), symptoms of arthralgia (n = 23), investigation of other diseases/symptoms (n = 108) or signs of liver disease (n = 45) were monitored for a mean period of 11.9 ± 5.8 years. The degree of liver fibrosis and survival were analyzed.

RESULTS

Overall survival among these patients was not significantly different from that of a matched normal population. The patients diagnosed through health check-ups and family screening were detected at an earlier age and had the highest rate of survival. Liver biopsy at the time of diagnosis revealed cirrhosis in 9% of those detected through the health check-ups and 5% in the case of family screening, compared with 13% for the group with arthralgia, 17% for other diseases/symptoms and 42% for liver disease.

CONCLUSION

Health check-ups and family screening allow detection of hereditary hemochromatosis at an earlier age and with less advanced liver fibrosis, although a few of these patients have already developed cirrhosis. Our study indicates that iron indices should be included in health check-ups, and if abnormal, should lead to further investigation.

Defective bone morphogenic protein signaling underlies hepcidin deficiency in HFE hereditary hemochromatosis

Hereditary hemochromatosis (HH) is a common inherited iron overload disorder. The vast majority of patients carry the missense Cys282Tyr mutation of the HFE gene. Hepcidin, the central regulator of iron homeostasis, is deficient in HH, leading to unchecked iron absorption and subsequent iron overload. The bone morphogenic protein (BMP)/small mothers against decapentaplegic (Smad) signaling cascade is central to the regulation of hepcidin. Recent data from HH mice models indicate that this pathway may be defective in the absence of the HFE protein. Hepatic BMP/Smad signaling has not been characterized in a human HFE-HH cohort to date. Hepatic expression of BMP/Smad-related genes was examined in 20 HFE-HH males with significant iron overload, and compared to seven male HFE wild-type controls using quantitative real-time reverse transcription polymerase chain reaction. Hepatic expression of BMP6 was appropriately elevated in HFE-HH compared to controls (P = 0.02), likely related to iron overload. Despite this, no increased expression of the BMP target genes hepcidin and Id1 was observed, and diminished phosphorylation of Smad1/Smad5/Smad8 protein relative to iron burden was found upon immunohistochemical analysis, suggesting that impaired BMP signaling occurs in HFE-HH. Furthermore, Smad6 and Smad7, inhibitors of BMP signaling, were up-regulated in HFE-HH compared to controls (P = 0.001 and P = 0.018, respectively).

CONCLUSION

New data arising from this study suggest that impaired BMP signaling underlies the hepcidin deficiency of HFE-HH. Moreover, the inhibitory Smads, Smad6, and Smad7 are identified as potential disruptors of this signal and, hence, contributors to the pathogenesis of this disease.

Hereditary hemochromatosis: pathogenesis, diagnosis, and treatment

In the late 1800s, hemochromatosis was considered an odd autoptic finding. More than a century later, it was finally recognized as a hereditary, multi-organ disorder associated with a polymorphism that is common among white people: a 845G-->A change in HFE that results in C282Y in the gene product. Hemochromatosis is now a well-defined syndrome characterized by normal iron-driven erythropoiesis and the toxic accumulation of iron in parenchymal cells of liver, heart, and endocrine glands. It can be caused by mutations that affect any of the proteins that limit the entry of iron into the blood. In mice, deletion of the iron hormone hepcidin and any of 8 genes that regulate its biology, including Hfe, transferrin receptor 2 (Tfr2), and hemojuvelin (Hjv) (which all sense the accumulation of iron that hepcidin corrects) or ferroportin (Fpn) (the cellular iron exporter down-regulated by hepcidin), cause iron overload but not organ disease. In humans, loss of TfR2, HJV, and hepcidin itself or FPN mutations result in full-blown hemochromatosis. Unlike these rare instances, in white people, homozygotes for C282Y polymorphism in HFE are numerous, but they are only predisposed to hemochromatosis; complete organ disease develops in a minority, when these individuals abuse alcohol or from other unidentified modifying factors. HFE gene testing can be used to diagnose hemochromatosis, but analyses of liver histology and clinical features are still required to identify patients with rare, non-HFE forms of the disease. The role of hepcidin in the pathogenesis of hemochromatosis reveals its similarities to endocrine diseases such as diabetes and indicates new approaches to diagnosis and management of this common disorder in iron metabolism.

EASL clinical practice guidelines for HFE hemochromatosis

Iron overload in humans is associated with a variety of genetic and acquired conditions. Of these, HFE hemochromatosis (HFE-HC) is by far the most frequent and most well-defined inherited cause when considering epidemiological aspects and risks for iron-related morbidity and mortality. The majority of patients with HFE-HC are homozygotes for the C282Y polymorphism [1]. Without therapeutic intervention, there is a risk that iron overload will occur, with the potential for tissue damage and disease. While a specific genetic test now allows for the diagnosis of HFE-HC, the uncertainty in defining cases and disease burden, as well as the low phenotypic penetrance of C282Y homozygosity poses a number of clinical problems in the management of patients with HC. This Clinical Practice Guideline will therefore, focus on HFE-HC, while rarer forms of genetic iron overload recently attributed to pathogenic mutations of transferrin receptor 2, (TFR2), hepcidin (HAMP), hemojuvelin (HJV), or to a sub-type of ferroportin (FPN) mutations, on which limited and sparse clinical and epidemiologic data are available, will not be discussed. We have developed recommendations for the screening, diagnosis, and management of HFE-HC.

Severity of iron overload of proband determines serum ferritin levels in families with HFE-related hemochromatosis: the HEmochromatosis FAmily Study

BACKGROUND/AIMS

In families of patients with clinically detected hereditary hemochromatosis (HH) early screening has been suggested to prevent morbidity and mortality. Here, we aim to identify determinants for iron overload in first-degree family members of C282Y homozygous probands with clinically detected HH.

METHODS

Data on HFE-genotype, iron parameters, demographics, lifestyle factors and health, were collected from 224 Dutch C282Y homozygous patients with clinically diagnosed HH and 735 of their first-degree family members (FDFM), all participating in the HEmochromatosis FAmily Study (HEFAS).

RESULTS

The best predictive multivariable model forecasted 45% of variation of the serum ferritin levels. In this model severity of iron overload in the proband significantly predicted serum ferritin levels in FDFM. Other significant determinants in this model consisted of C282Y homozygosity, compound heterozygosity, age at testing for serum ferritin and supplemental iron intake, whereas a low body mass index showed a protective effect.

CONCLUSIONS

This study provides a model to assess the risk of development of iron overload for relatives of probands with HH. These results might be instrumental in the development of an optimal strategy for future family screening programs.

The biochemical and clinical penetrance of individuals diagnosed with genetic haemochromatosis by predictive genetic testing

BACKGROUND

HFE-related genetic haemochromatosis (GH) is the commonest inherited genetic disorder in Caucasian populations with approximately one in 180 of individuals in the west of Scotland homozygous for the common C282Y mutation. The clinical diagnosis of GH, however, remains relatively uncommon - suggesting either under diagnosis or low clinical penetrance.

AIM

We aimed to assess the biochemical and clinical penetrance of GH in first-degree relatives of patients with known GH, who subsequently themselves screened positive for the common GH mutations.

METHODS

Individuals were identified from two large teaching hospitals in North Glasgow from July 1997 to July 2005 diagnosed with GH after predictive genetic testing after a relative was found to have GH. Details of patient history, biochemistry and known comorbidity at diagnosis and results of related further investigations were collected.

RESULTS

Sixty-three individuals were identified, 31 (49%) of whom were males. Fifty-five individuals (87%) were C282Y homozygous and the remaining eight were compound heterozygotes for C282Y and H63D. All 31 male patients were found to have evidence of iron overload as opposed to 63% of females. Elevated liver enzyme levels were encountered in 15 patients (24%). All except one had evidence of iron overload. Four individuals underwent a liver biopsy, two of whom had hepatic fibrosis. Four patients were found to be diabetic. A full clinical history was obtained from 54 of 63 individuals, 38 (70%) of whom were entirely asymptomatic. Thirteen individuals complained of joint pains and a further nine complained of fatigue.

CONCLUSION

This study suggests that although biochemical penetrance of GH is high, the clinical penetrance is low.

Haemochromatosis

Since the discovery of the haemochromatosis gene (HFE; chromosome 6p21.3) associated with haemochromatosis in 1996, many studies about diverse aspects of this common genetic disorder have been done. Some patients present with cirrhosis and show high mortality, whereas many asymptomatic homozygotes for the C282Y mutation in the haemochromatosis gene identified in population screening studies, who have been followed up for many years, do not develop iron overload. Studies described the usefulness of transferrin saturation and serum ferritin tests, and the acceptability of genetic testing for haemochromatosis. Phlebotomy therapy improves hepatic fibrosis. Here, we summarise some new findings in haemochromatosis, a disorder first described in 1865.

Penetrance of the C28Y/C282Y genotype of the HFE gene

OBJECTIVE

Hereditary hemochromatosis is a common genetic disease caused by accumulation of iron in the body. Most cases are homozygous for the C282Y mutation in the HFE gene, but only a minority of homozygotes will ever suffer from clinical hemochromatosis. Estimates of the penetrance of the C282Y/C282Y genotype vary greatly. The purpose of this study was to estimate the penetrance using a stringent definition, i.e. liver cirrhosis.

MATERIAL AND METHODS

The results from previous phenotypic population screening for hereditary hemochromatosis were combined with findings in hospital databases in order to estimate the number of C282Y homozygotes with and without liver cirrhosis in a Norwegian county. The penetrance of the C282Y/C282Y genotype was estimated as the fraction of C282Y homozygotes with liver cirrhosis. We also calculated the expected number of male C282Y homozygotes with liver cirrhosis using figures for age-specific accumulated risk.

RESULTS

The prevalence of liver cirrhosis in male homozygotes is between 3.4% and 5.0%. This figure is compatible with an accumulated risk of liver cirrhosis that increases from 0.2% at 35 years to about 10% at 65 years of age. In female homozygotes, the prevalence of liver cirrhosis is 0.3%.

CONCLUSIONS

A small but significant number of Norwegian male C282Y homozygotes will contract liver cirrhosis if their hemochromatosis is not diagnosed and treated in time. The penetrance is much lower in women than in men.

Perceptions and attitudes about HFE genotyping among college-age adults

PURPOSE

Examine young adults' attitudes about HFE genotyping.

METHODS

121 college students read about hemochromatosis, transferrin saturation measurement (iron test), and HFE genotyping. Interest in testing and knowledge and attitudes about genetic testing were assessed. Participants were randomly assigned to predict either their response to a positive HFE genotype (genotype group) or a positive iron test (phenotype group).

RESULTS

71% preferred the iron test, but most would undergo either test. Learning risk and early detection/prevention were the most commonly perceived benefits; limited information about health and negative emotional consequences were the most commonly perceived disadvantages. The genotype and phenotype groups did not differ in expected worry, perceived severity, perceived risk, and preventability of organ damage. After reading the description provided, participants answered 78% of knowledge questions correctly.

CONCLUSIONS

Young adults view HFE genotyping positively and report few disadvantages, but prefer the iron test for its information about current health. They appear to be receptive to public health screening for hemochromatosis.

Review article: the modern diagnosis and management of haemochromatosis

Haemochromatosis is the most common genetic disease in populations of European ancestry. Despite estimates based on genetic testing in Caucasian populations of 1 in 227, many physicians consider haemochromatosis to be a rare disease. The diagnosis can be elusive because of the non-specific nature of the symptoms. Of all the symptoms, liver disease has the most consistent relationship to haemochromatosis and the prognosis of haemochromatosis is most closely linked to the degree of iron overload. With the discovery of the HFE gene in 1996, comes new insights into the pathogenesis of the disease and new diagnostic strategies. However, a growing number of new iron-related genes have been discovered and linked to other iron overload syndromes.

Disparate phenotypic expression of ALAS2 R452H (nt 1407 G → A) in two brothers, one with severe sideroblastic anemia and iron overload, hepatic cirrhosis, and hepatocellular carcinoma

We report the case of a man with severe X-linked sideroblastic anemia, severe iron overload, and hepatic cirrhosis who died of hepatocellular carcinoma. Evaluation of family members using DNA sequencing revealed that he was hemizygous for the novel ALAS2 mutation R452H (exon 9; nt 1407 G --> A). The proband's brother, an ALAS2 R452H hemizygote, had mild anemia and mild iron overload. Four female relatives were ALAS2 R452H heterozygotes, but they had mild or no anemia and no iron overload. Sequencing of TFR2, HFE, FPN1 (SLC40A1), HAMP, HJV, and the erythrocyte pyruvate kinase genes of family members was also performed. We thus detected the novel TFR2 missense mutation I449V (exon 10; nt 1345 A --> G) in the proband's wife and daughter, neither of whom had anemia or iron overload. Possible explanations for the disparate red blood cell and iron phenotypes of the proband and his family members are discussed.

Haemochromatosis: find them or forget about them?

Haemochromatosis continues to be considered an uncommon disease despite large scale population screening studies demonstrating a high prevalence of C282Y homozygotes of approximately 1 in 200. Since many of the C282Y homozygotes that are discovered through screening are asymptomatic, or have non-specific symptoms commonly found in the ageing population, the attribution of any symptoms to haemochromatosis has become increasingly difficult. The demonstration of significant liver disease in family members is a strong reminder of the vital importance of pedigree studies when a typical haemochromatosis patient is identified.