HFE-related Hereditary Hemochromatosis Research Articles

HIF1A: A Putative Modifier of Hemochromatosis.

HFE-related hereditary hemochromatosis (HH) is characterized by marked phenotypic heterogeneity. Homozygosity for p.C282Y is a low penetrance genotype suggesting that the HFE-HH is a multifactorial disease resulting from a complex interaction involving a major gene defect, genetic background and environmental factors. We performed a targeted NGS-based gene panel to identify new candidate modifiers by using an extreme phenotype sampling study based on serum ferritin and iron removed/age ratio. We found an increased prevalence of the HIF1A p.Phe582Ser and p.Ala588Thr variants in patients with a severe iron and clinical phenotype. Accordingly, Huh-7 cells transfected with both variants showed significantly lower HAMP promoter activity by luciferase assay. The qRT-PCR assays showed a downregulation of hepcidin and an upregulation of the HIF1A target genes (VEGF, HMOX, FUR, TMPRSS6) in cells transfected with the HIF1A-P582S vector. We identified mutations in other genes (e.g., Serpina1) that might have some relevance in single cases in aggravating or mitigating disease manifestation. In conclusion, the present study identified HIF1A as a possible modifier of the HFE-HH phenotype cooperating with the genetic defect in downregulating hepcidin synthesis. In addition, this study highlights that an NGS-based approach could broaden our knowledge and help in characterizing the genetic complexity of HFE-HH patients with a severe phenotype expression.

Validation of the Hemochromatosis (2SNP+) Direct EUROArray Assay for the Molecular Diagnosis of HFE-Related Hereditary Hemochromatosis.

Aim: Two missense variants in the HFE gene, c.845G>A (p.Cys282Tyr) and c.187C>G (p.His63Asp), are commonly screened as part of the diagnostic workup for HFE-related hereditary hemochromatosis (HH) and iron overload. Identification of the two variants can be achieved by polymerase chain reaction (PCR)-based laboratory tests and other methods. Evaluation of the analytical performance of the test is essential to ensure that the assay is precise and accurate. The aim of this study was to evaluate the analytical performance of the DNA microarray-based Hemochromatosis (2SNP+) Direct assay on the EUROArray test system (EUROIMMUN, Lübeck, Germany). Materials and Methods: Evaluation of the commercial assay was performed on 50 clinical blood samples and 26 retrospective College of American Pathologists (CAP)-provided external quality assurance (EQA) DNA samples and compared to a laboratory-developed PCR-restriction enzyme digestion (PCR-RE) test and DNA sequencing. Results and Discussion: HFE genotyping results obtained from both Hemochromatosis (2SNP+) Direct and PCR-RE assays were 100% concordant with nucleotide sequencing for all clinical samples evaluated. One hundred percent accuracy was also achieved on the retrospective CAP EQA samples. Precision studies performed on wild type and c.845G>A/c.187C>G compound heterozygous whole blood samples showed 100% intra-run repeatability (N = 3) and 100% inter-run reproducibility (N = 3), respectively. Conclusion: The Hemochromatosis (2SNP+) Direct EUROArray test provides a rapid and accurate method of detection for both the c.845G>A and c.187C>G variants for molecular diagnosis of HFE-related HH.

Idiopathic brain calcification in a patient with hereditary hemochromatosis

BackgroundDetection of brain-MRI T2/T2* gradient echo images (T2*GRE)-hypointensity can be compatible with iron accumulation and leads to a differential diagnosis work-up including neurodegeneration with brain iron accumulation (NBIA) and Wilson Disease. Idiopathic or secondary brain calcification can be also associated with neurological involvement and brain-MRI T2/T2*GRE-hypointensity. Hereditary hemochromatosis (HH), characterized by systemic iron loading, usually does not involve the CNS, and only sporadic cases of neurological abnormalities or brain-MRI T2/T2*GRE-hypointensity have been reported.Case presentationA 59-year-old man came to our observation after a diagnosis of HH carried out in another hospital 2 years before. First-level genetic test had revealed a homozygous HFE p.Cys282Tyr (C282Y) mutation compatible with the diagnosis of HFE-related HH, thus phlebotomy treatment was started. The patient had a history of metabolic syndrome, type-2 diabetes, autoimmune thyroiditis and severe chondrocalcinosis. Brain-MRI showed the presence of bilateral T2*GRE hypointensities within globus pallidus, substantia nigra, dentate nucleus and left pulvinar that were considered expression of cerebral siderosis. No neurological symptoms or family history of neurological disease were reported. Neurological examination revealed only mild right-sided hypokinetic-rigid syndrome. Vitamin D–PTH axis, measurements of serum ceruloplasmin and copper, and urinary copper were within the normal range. A brain computed tomography (CT) was performed to better characterize the suspected and unexplained brain iron accumulation. On the CT images, the hypointense regions in the brain MRI were hyperdense. DNA sequence analysis of genes associated with primary familial brain calcification and NBIA was negative.ConclusionsThis report highlights the importance of brain CT-scan in ambiguous cases of suspected cerebral siderosis, and suggests that HH patients with a severe phenotype, and likely associated with chondrocalcinosis, may display also brain calcifications. Further studies are needed to confirm this hypothesis. So far, we can speculate that iron and calcium homeostasis could be reciprocally connected within the basal ganglia.

Phenotypic analysis of hemochromatosis subtypes reveals variations in severity of iron overload and clinical disease

AbstractThe clinical progression of HFE-related hereditary hemochromatosis (HH) and its phenotypic variability has been well studied. Less is known about the natural history of non-HFE HH caused by mutations in the HJV, HAMP, or TFR2 genes. The purpose of this study was to compare the phenotypic and clinical presentations of hepcidin-deficient forms of HH. A literature review of all published cases of genetically confirmed HJV, HAMP, and TFR2 HH was performed. Phenotypic and clinical data from a total of 156 patients with non-HFE HH was extracted from 53 publications and compared with data from 984 patients with HFE-p.C282Y homozygous HH from the QIMR Berghofer Hemochromatosis Database. Analyses confirmed that non-HFE forms of HH have an earlier age of onset and a more severe clinical course than HFE HH. HJV and HAMP HH are phenotypically and clinically very similar and have the most severe presentation, with cardiomyopathy and hypogonadism being particularly prevalent findings. TFR2 HH is more intermediate in its age of onset and severity. All clinical outcomes analyzed were more prevalent in the juvenile forms of HH, with the exception of arthritis and arthropathy, which were more commonly seen in HFE HH. This is the first comprehensive analysis comparing the different phenotypic and clinical aspects of the genetic forms of HH, and the results will be valuable for the differential diagnosis and management of these conditions. Importantly, our analyses indicate that factors other than iron overload may be contributing to joint pathology in patients with HFE HH.

A Novel Approach to Improving Utilization of Laboratory Testing.

- The incorporation of best practice guidelines into one's institution is a challenging goal of utilization management, and the successful adoption of such guidelines depends on institutional context. Laboratorians who have access to key clinical data are well positioned to understand existing local practices and promote more appropriate laboratory testing. - To apply a novel approach to utilization management by reviewing international clinical guidelines and current institutional practices to create a reliable mechanism to improve detection and reduce unnecessary tests in our patient population. - We targeted a frequently ordered genetic test for HFE-related hereditary hemochromatosis, a disorder of low penetrance. After reviewing international practice guidelines, we evaluated 918 HFE tests and found that all patients with new diagnoses had transferrin saturation levels that were significantly higher than those of patients with nonrisk genotypes (72% versus 42%; P < .001). - Our "one-button" order that restricts HFE genetic tests to patients with transferrin saturation greater than 45% is consistent with published practice guidelines and detected 100% of new patients with HFE-related hereditary hemochromatosis. - Our proposed algorithm differs from previously published approaches in that it incorporates both clinical practice guidelines and local physician practices, yet requires no additional hands-on effort from pathologists or clinicians. This novel approach to utilization management embraces the role of pathologists as leaders in promoting high-quality patient care in local health care systems.

Key-interventions derived from three evidence based guidelines for management and follow-up of patients with HFE haemochromatosis.

BackgroundHFE-related hereditary haemochromatosis (HH) is a common autosomal recessive disorder with clinical manifestations ranging from asymptomatic disease to possible life-threatening complications. Cirrhosis, hepatocellular carcinoma, diabetes mellitus or osteoporosis can develop in HH patients not treated or monitored optimally. The purpose of this study was to develop key-interventions (KI’s) to measure and improve the quality of care delivered to patients diagnosed with HH.MethodsA RAND-Modified Delphi method was used to develop KI’s. In the first round of a scoring form to prioritize the recommendations extracted from evidence-based guidelines was circulated between experts. The results of this survey were discussed in a consensus meeting, followed by a final appraisal of the selected recommendations. This resulted in a list of measurable KI’s.ResultsInitially, 41 key recommendations on screening, diagnosis and treatment/management were extracted from three existing guidelines on HH (European Association for the Study of the Liver, American Association for the Study of Liver Diseases and Dutch guideline on HH). Finally, a core set of 24 recommendations resulted in 15 KI’s.ConclusionsThis manuscript presents the results of the process to develop KI’s to measure and improve the quality of care for patients with HH.Electronic supplementary materialThe online version of this article (doi:10.1186/s12913-016-1835-2) contains supplementary material, which is available to authorized users.

The global prevalence of HFE and non-HFE hemochromatosis estimated from analysis of next-generation sequencing data

The prevalence of HFE-related hereditary hemochromatosis (HH) among European populations has been well studied. There are no prevalence data for atypical forms of HH caused by mutations in HFE2, HAMP, TFR2, or SLC40A1. The purpose of this study was to estimate the population prevalence of these non-HFE forms of HH. A list of HH pathogenic variants in publically available next-generation sequence (NGS) databases was compiled and allele frequencies were determined. Of 161 variants previously associated with HH, 43 were represented among the NGS data sets; an additional 40 unreported functional variants also were identified. The predicted prevalence of HFE HH and the p.Cys282Tyr mutation closely matched previous estimates from similar populations. Of the non-HFE forms of iron overload, TFR2-, HFE2-, and HAMP-related forms are predicted to be rare, with pathogenic allele frequencies in the range of 0.00007 to 0.0005. Significantly, SLC40A1 variants that have been previously associated with autosomal-dominant ferroportin disease were identified in several populations (pathogenic allele frequency 0.0004), being most prevalent among Africans. We have, for the first time, estimated the population prevalence of non-HFE HH. This methodology could be applied to estimate the population prevalence of a wide variety of genetic disorders.Genet Med 18 6, 618-626.

The role of genetic factors in patients with hepatocellular carcinoma and iron overload - a prospective series of 234 patients.

Iron overload (IO) in HFE-related hereditary haemochromatosis is associated with increased risk of liver cancer. This study aimed to investigate the role of other genes involved in hereditary IO among patients with hepatocellular carcinoma (HCC). Patients with HCC diagnosed in our institution were included in this prospective study. Those with ferritin levels ≥300 μg/L (males) or ≥200 μg/L (females) and/or transferrin saturation ≥50% (males) or ≥45% (females) had liver iron concentration (LIC) evaluated by MRI. HFE C282Y and H63D mutations were screened. Genetic analyses of genes involved in hereditary IO (HFE, HJV/HFE2, HAMP, TFR2, SLC40A1, GNPAT) were performed in patients with increased LIC. A total of 234 patients were included; 215 (92%) had common acquired risk factors of HCC (mainly alcoholism or chronic viral hepatitis). 119 patients had abnormal iron parameters. Twelve (5.1%) were C282Y homozygotes, three were compound C282Y/H63D heterozygotes. LIC was measured by MRI in 100 patients. Thirteen patients with a LIC>70 μmol/g were enrolled in further genetic analyses: two unrelated patients bore the HAMP:c.-153C>T mutation at the heterozygous state, which is associated with increased risk of IO and severe haemochromatosis. Specific haplotypes of SLC40A1 were also studied. Additional genetic risk factors of IO were found in 18 patients (7.7%) among a large series of 234 HCC patients. Screening for IO and the associated at-risk genotypes in patients who have developed HCC, is useful for both determining etiologic diagnosis and enabling family screening and possibly primary prevention in relatives.

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.

Targeted Next Generation Sequencing of the Five Hemochromatosis Genes in Italian Patients with Iron Overload and Non-Diagnostic First Level Genetic Test: A Pilot Study

▪Background and Aim: Molecular diagnosis of HFE-related hereditary hemochromatosis (HH) is typically made by searching for the C282Y and H63D mutations (first level genetic test). However, in the Mediterranean area up to one third of patients with HH phenotype do not have the “diagnostic” genotypes (C282Y homozygosity, or C282Y/H63D compound heterozygosity). This pilot study was designed to develop a “second level” next generation sequencing (NGS)-based test for rapid and simultaneous analysis of the five HH genes (HFE, HFE2, HAMP, TFR2 and SLC40A1).Methodology: we studied 61 patients with relevant biochemical signs of iron overload (IO) and non-diagnostic first level genetic test suggesting a possible “non-HFE” HH. The five HH genes were captured by Halo-Plex™ technology, and then sequenced using aNGS platform (Illumina HiSeq 1000). Sequenced reads were aligned against human reference HG19 and analyzed by GoldenHelix™ software to annotate all the variants possibly involved in the disease.Results: In IO patients a large number of new non-synonymous variants (according to bioinformatics tools based on publicly available databases including the 1000-genomes project) were found. Many of them were relatively frequent and detected also in controls, thus being considered likely “non-pathogenic”, unless clearly enriched in patients. On the other hand, some rare variants (i.e. limited to a single or very few individuals), particularly in SCL40A1, TFR2, and HFE, were found exclusively in patients, and could be considered “potentially pathogenic”.Conclusions: The combination of the Halo-Plex™ approach with NGS platform and GoldenHelix™ algorithm appears a suitable approach for a better molecular characterization of patients with unexplained HH phenotype, and could represent a good option for second level genetic testing in referral centers. However, establishing the clinical relevance of NGS-detected “novel” genetic variants in a prevalently autosomal recessive disorder like HH remains a difficult task, requiring further functional studies and national/international collaborative efforts. DisclosuresNo relevant conflicts of interest to declare.

Transferrin Receptor 2 and HFE Regulate Hepcidin Levels Independently of Bmp6 and Hemojuvelin

Hereditary hemochromatosis (HH) is a genetically heterogeneous disorder characterized by elevated iron absorption from the diet, with consequent iron overload and tissue injury. Adult-onset forms of HH are caused by mutations in the HFE gene and in the gene for transferrin receptor 2 (TFR2). Human patients and mouse models of TFR2 and HFE-related HH show inappropriately low expression of hepcidin, the central regulator of iron metabolism. However, although these genes have been discovered far more than a decade ago, the mechanisms by which HFE and TFR2 influence hepcidin expression remain unclear.The bone morphogenetic protein BMP6 plays a key role in the regulation of hepcidin expression. BMP6 binds to type I (ALK3) and type II serine threonine kinase receptors, and to the coreceptor hemojuvelin (HJV), which phosphorylates intracellular SMAD proteins. Phosphorylated SMADs then bind to SMAD4 and translocate to the nucleus to induce the transcription of hepcidin. Inactivation of Bmp6 or Hjv in mice leads to considerably reduced hepcidin production and severe hepatic iron overload. However, there are major differences in hepcidin expression and extrahepatic tissue iron loading between Bmp6 or Hjv KO males and females, due to the suppressive effect of testosterone on hepcidin in males. In contrast to males, Bmp6-/- and Hjv-/-females still produce some hepcidin and do not massively accumulate iron in the pancreas, heart, or kidneys.The goal of this study was to investigate the role of Hfe and Tfr2 in the residual hepcidin production observed in the absence of Bmp6 in females. We used Bmp6-/-, Tfr2-/-, and B2m-/- mice to generate wild-type, single KO (Bmp6-/-, Tfr2-/-, or B2m-/-) and double KO (Tfr2-/- and Bmp6-/-, or B2m-/- and Bmp6-/-) mice, and we assessed Smad5 phosphorylation, hepcidin expression, and the sites of iron accumulation in the different groups of mice. Notably, B2m-/- mice develop spontaneously hepatic iron overload with a distribution similar to that seen in the liver of Hfe-/-mice and the lack of CD8+ lymphocytes and the absence of classical class I molecules in these mice are not responsible for their iron phenotype.Interestingly, the lack of functional Hfe or the lack of Tfr2 in Bmp6-/- females leads to a very similar phenotype that is much more severe than the single impairment of Bmp6, with massive iron loading in extrahepatic tissues, most notably the exocrine pancreas, the heart, and the kidney. Hepcidin mRNA and pSmad levels in the two categories of double KO females were much more strongly downregulated than in single Bmp6-/- females and, in contrast to Bmp6-/-females, no protein was detectable by ELISA in the double KO mice.Our findings clearly demonstrate that Hfe and Tfr2 regulate hepcidin production independently of Bmp6. The symmetrical phenotype of double Bmp6 and Tfr2, or double Bmp6 and Hfe KO mice suggests that Hfe and Tfr2 could participate in the same signaling complex affecting pSmad levels, even if they do not physically interact. Two complexes, one made of ALK3 and HJV, and the other made of ALK2, ALK3, HFE, and TFR2, very likely affect pSMAD levels independently of each other. Signaling through the second complex occurs in the absence of BMP6 and is most probably initiated by another BMP, for instance BMP2 or BMP4 that are also expressed in the liver and, although not regulated by iron, are capable of stimulating hepcidin expression in hepatocytes. Regulation of hepcidin expression by these two complexes would explain why, whereas Alk3, double Bmp6/Hfe, and double Bmp6/Tfr2 deficient females present with iron overload in extrahepatic tissues as do hepcidin KO mice, Bmp6 and Hjv single KO females present with early-onset iron overload only in the liver, similarly to patients with juvenile HH, and mice KO for Alk2, Hfe, or Tfr2 have the least severe phenotype, comparable with that of patients with adult-onset HH. Notably, TFR2 was also shown to localize in lipid rafts where it promotes MAPK activation. Thus, in addition to its role in the complex affecting pSMAD levels, TFR2 could also regulate hepcidin through a parallel pathway involving ERK1/2 signaling. This would explain the more severe phenotype of mice with combined deletion of Hfe and Tfr2 and the fact that, whereas Tfr2-/- mice do not respond to acute iron loading, Hfe-/-mice still have a significant, although blunted hepcidin response.This work was funded in part by FRM (DEQ2000326528) and ANR (ANR-13-BSV3-0015-01). DisclosuresNo relevant conflicts of interest to declare.

HFE gene mutations in hyperferritinemia associated with one or more components of metabolic syndrome

Hyperferritinemia is a common abnormality. This study determined the prevalence of hepatic iron overload in subjects of northern European origin with hyperferritinemia.Fifty-two consecutive subjects referred for evaluation of suspected iron overload (serum ferritin level >350 μg/L) were divided into 3 groups: group 1, increased transferrin saturation and no significant hemochromatosis gene product (HFE) mutations (N = 17); group 2, increased transferrin saturation and C282Y homozygosity or C282Y/H63D compound heterozygosity (N = 22); and group 3, normal transferrin saturation and no significant HFE mutations (N = 13). All subjects underwent magnetic resonance R2 relaxometry for quantitation of hepatic iron concentration (HIC).The HIC was significantly higher in group 2 subjects (123 ± 22 μmol/g) compared with groups 1 and 3 subjects (39 ± 4 and 36 ± 5 μmol/g, respectively) (P < .01). Nine of 22 subjects in group 2 had an increase of their HIC to greater than 3 times the upper limit of normal compared with none in the other 2 groups (P < .01).An increase of HIC to greater than 3 times the upper limit of normal is highly unlikely in hyperferritinemic subjects who do not have HFE-related hereditary hemochromatosis or causes of secondary iron overload.

Liver transplantation normalizes serum hepcidin level and cures iron metabolism alterations inHFEhemochromatosis

Defects in human hemochromatosis protein (HFE) cause iron overload due to reduced hepatic hepcidin secretion. Liver transplantation (LT) is a key treatment for potential complications from HFE-related hereditary hemochromatosis (HH). This study evaluated hepcidin secretion and iron burden after LT to elucidate HH pathophysiology. Patients (n=18) homozygous for the p.Cys282Tyr mutation in the HFE gene underwent LT between 1999 and 2008. Serum iron, serum hepcidin, and hepatic iron concentrations were determined before LT and at the end of follow-up (median 57 months). Mortality and causes of death were determined. Survival was compared to that of the overall patient population that received LT. Before LT, serum hepcidin levels were low (0.54 ± 2.5 nmol/L; normal range: 4-30 nmol/L). After LT, 11 patients had iron evaluations; none received iron depletion therapy; all had normal transferrin saturation. The mean serum ferritin was 185 (± 99) μg/L. Magnetic resonance imaging showed that iron overload was absent in nine patients, mild in one patient with metabolic syndrome, and high (180 μmol/g) in one patient with hereditary spherocytosis discovered after LT. At the end of follow-up, serum hepcidin was normal in 10 patients (11.12 ± 7.6 nmol/L; P<0.05) and low in one patient with iron deficiency anemia. Survival was 83% and 67% at 1 and 5 years, respectively. Survival was similar for patients with HH and patients that received LT for other causes. In HH, LT normalized hepcidin secretion and prevented recurrence of hepatic iron overload. Survival was similar to that of patients who received LTs for other liver diseases.

Insufficient Referral for Genetic Counseling in the Management of Hereditary Haemochromatosis in Portugal: A Study of Perceptions of Health Professionals Requesting HFE Genotyping

There is a general consensus that HFE- related Hereditary Haemochromatosis (HFE-HH) should be diagnosed at early stages in pre-symptomatic individuals, in order to prevent the most severe consequences of iron overload. In Portugal, despite an increasing number of requests for genetic diagnosis of this rare disease, there is not a corresponding increase in requests for genetic counselling. The objective of the present study was to evaluate physicians' main motivations for requesting HFE genotyping or genetic counselling for HFE-HH. We assessed current medical practices regarding family testing and diagnosis and discuss whether these can be improved in order to increase the effectiveness of disease prevention. Our results show there is a general lack of knowledge about the selection of patient cases that should be sent for genetic counseling or for molecular testing of HFE-HH by physicians (especially by general practitioners). The lack of family-based screening may indirectly compromise the efficiency of disease prevention in terms of early diagnosis and treatment. We concluded it is necessary to circulate more information about Hereditary Haemochromatosis among health professionals in order to improve strategies for its early diagnosis.

High Prevalence of Fibromyalgia in Patients with HFE-related Hereditary Hemochromatosis

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. 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. 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). 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.

Hemocromatosis: etiopatogenia, diagnóstico y estrategia terapéutica

Hereditary hemochromatosis (HH) constitutes several inherited disorders characterized by an increased intestinal absorption of iron with its subsequent accumulation in tissues. Most (approximately 90%) patients with HH have mutations in HFE. Aproximately 95% of persons with HFE-related HH are homozygous for the C282Y mutation. Population studies indicate that the penetrane of the C282Y mutation is incomplete. Mutations in the iron-related genes encoding for hemojuvelin, hepcidin, ferroportin, trasnferrin receptor 2 and ferritin result in non-HFE related HH. In HFE-related HH the excess iron is preferentially deposited in the cytoplasm of parenhymal cells of varios organs, including the liver, pancreas, heart, endocrine glands, skin and joints. Symptoms are related to damage of this organs. The diagnosis includes iron studies, genetic testing and liver biopsy to assess the hepatic iron concentration and degree of liver injury. Because phlebotomy prevents and reverses the accumulation of excess iron, is the treatment of choice.

The Control of Iron Homeostasis: microRNAS Join the Party

Castoldi M, Spasic MV, Altamura S, et al. (Department of Pediatric Hematology, Oncology, and Immunology, University of Heidelberg, Heidelberg, Germany; others). The liver-specific microRNA miR-122 controls systemic iron homeostasis in mice. J Clin Invest 2011;121:1386–1396. Our understanding of the regulation of iron homeostasis has increased rapidly in the last decade. The identification of the iron regulatory hormone hepcidin, and the genes underlying iron disorders such as hereditary hemochromatosis have been instrumental in identifying the molecules necessary for the control of iron balance....

A novel Y231del mutation of HFE in hereditary haemochromatosis provides in vivo evidence that the Huh‐7 is a human haemochromatotic cell line

Hereditary haemochromatosis (HH), which is mainly associated with a C282Y polymorphism in HFE, is common among Caucasians of north European descent, but is very rare among Asians. Herein, we report a 43-year-old Japanese man who was diagnosed as having HH. A laboratory examination revealed an elevated serum iron level (280 μg/dl), hyperferritinemia (1698 ng/ml) and a low serum level of hepcidin-25 (4.0 ng/ml). Abdominal magnetic resonance imaging revealed findings suggestive of iron accumulation in the liver and pancreas. HFE gene sequencing in the patient revealed a novel homozygous TAC nucleotide deletion (c. 691_693del) responsible for the loss of a tyrosine at position 231 (p. Y231del) of the HFE protein. This homozygous Y231del mutation was recently found in the Huh-7 hepatoma cell line and was shown to prevent the translocation of HFE to the cell surface. This clinical case provides in vivo evidence suggesting that Huh-7 is undoubtedly a human haemochromatotic cell line and, as such, is a valuable tool for investigating the pathogenesis of HFE-related HH in humans.

A phase 1/2, dose-escalation trial of deferasirox for the treatment of iron overload in HFE-related hereditary hemochromatosis

Hereditary hemochromatosis (HH) is characterized by increased intestinal iron absorption that may result in iron overload. Although phlebotomy is widely practiced, it is poorly tolerated or contraindicated in patients with anemias, severe heart disease, or poor venous access, and compliance can vary. The once-daily, oral iron chelator, deferasirox (Exjade) may provide an alternative treatment option. Patients with HH carrying the HFE gene who were homozygous for the Cys282Tyr mutation, serum ferritin levels of 300-2000 ng/mL, transferrin saturation ≥45%, and no known history of cirrhosis were enrolled in this dose-escalation study to characterize the safety and efficacy of deferasirox, comprising a core and an extension phase (each 24 weeks). Forty-nine patients were enrolled and received starting deferasirox doses of 5 (n = 11), 10 (n = 15), or 15 (n = 23) mg/kg/day. Adverse events were generally dose-dependent, the most common being diarrhea, headache, and nausea (n = 18, n = 10, and n = 8 in the core and n = 1, n = 1, and n = 0 in the extension, respectively). More patients in the 15 mg/kg/day than in the 5 or 10 mg/kg/day cohorts experienced increases in alanine aminotransferase and serum creatinine levels during the 48-week treatment period; six patients had alanine aminotransferase >3× baseline and greater than the upper limit of normal range, and eight patients had serum creatinine >33% above baseline and greater than upper limit of normal on two consecutive occasions. After receiving deferasirox for 48 weeks, median serum ferritin levels decreased by 63.5%, 74.8%, and 74.1% in the 5, 10, and 15 mg/kg/day cohorts, respectively. In all cohorts, median serum ferritin decreased to <250 ng/mL. Conclusion: Deferasirox doses of 5, 10, and 15 mg/kg/day can reduce iron burden in patients with HH. Based on the safety and efficacy results, starting deferasirox at 10 mg/kg/day appears to be most appropriate for further study in this patient population. (Hepatology 2010)

Reply

We thank Dr. Castiella and co-workers for the kind comments on our article. He asked about the characterization of HFE gene mutations of patients defined as non-HFE hereditary hemochromatosis (HH), i.e., non-C282Y homozygotes, and compound C282Y (Cys282 → Tyr282)/H63D (His63 → Asp63) and C282Y/S65C (Ser65 → Cys65) heterozygotes. Of the 114 patients with non-HFE–related hemochromatosis, 12 (10%) were homozygous for the H63D mutation, 29 (25%) were heterozygous for the C282Y mutation, and 16 (14%) were heterozygous for the H63D mutation. Of these patients, only six (5%) had established genetic determinants of iron overload. Three patients had a phenotype consistent with juvenile HH which was linked to chromosome 1q or homozygosity for hemojuvelin missense mutation, one patient had iron overload associated with a missense ferroportin-1 mutation, and two patients had homozygosity for transferrin receptor-2 missense mutation.1, 2 Only a few other patients were found to be affected by possible hereditary risk factors for iron overload: one was a heterozygous carrier of the E302K hemojuvelin mutation, and two were positive for the −72C→T hepcidin promoter mutation. Regarding patients homozygous for the C282Y mutation, we completely agree with Dr. Castiella that the coexistence of non-HFE gene mutations may cause a more severe iron overload, as reported by Island et al.,3 but we have not yet completed the characterization of our patients. The second point raised by Dr. Castiella is that patients negative for HFE mutations usually have milder iron overload. All patients included in our study had iron overload compatible with the diagnosis of HH with no significant difference between HFE and non-HFE HH. In addition, although it has recently been demonstrated that hepatitis C virus infection and alcohol may contribute to iron accumulation by interfering with hepcidin transcription,4, 5 only noncirrhotic patients with HFE-related HH had a significantly more severe iron overload when acquired risk factors coexisted. Heterogeneity of genetic and acquired determinants possibly responsible for iron overload may account for the different severity of iron overload in patients with HH. Silvia Fargion*, * Department of Internal Medicine, Universita' degli Studi di Milano, Milan, Italy.