Allelic Diversity of the Hemochromatosis Gene (HFE) in Malays, Chinese and Indians

@#Introduction: Hereditary hemochromatosis (HH) is an autosomal recessive disorder that causes accumulation of iron in circulating blood and organs. The disease is associated with H63D, S65C and C282Y variants of the haemochromatosis (HFE) gene and, if not treated can cause organ damage and may prove fatal. The main objectives of the present survey were to screen these genetic variants and establish risk profiles for developing HH in Malays, Chinese and Indians. Methods: A total of two hundred and twenty-two unrelated and healthy individuals together representing Malay, Chinese and Indian ethnicities in Malaysia were scored for the H63D, S65C and C282Y variants using a polymerase chain reaction-restriction fragment length polymorphism technique. Results: There are clear differences in H63D, S65C and C282Y allele and genotype frequency distributions between Malays, Chinese and Indians. In particular, H63D is more common in Chinese (5.19%) and Indians (7.29%), while S65C is more common in Malays (1.03%) and Chinese (1.04%). In addition, a susceptibility genotype for HH (the compound heterozygote for C282Y and H63D) was only detected in Indians (0.02%). Conclusion: Overall, our study is the first to provide data on the prevalence of H63D, S65C, and C282Y genetic variants and HH risk profiles for Malays, Chinese and Indians.

Hipertransaminasemia, astenia, artralgias e hiperpigmentación cutánea / Hypertransaminasemia, asthenia, arthralgia and skin hyperpigmentation

RESUMEN La hemocromatosis hereditaria es una enfermedad metabólica infrecuente que afecta primariamente al hígado, y que se caracteriza por un incremento de la absorción intestinal de hierro. Se presentó un paciente de 49 años de edad, evaluado en consulta externa, desde alrededor de dos años atrás, por: astenia, anorexia, artralgias e hiperpigmentación cutánea, asociada a hipertransaminasemia y seronegatividad para virus B y C. Los niveles de saturación de transferrina y ferritina evidenciaron la sobrecarga de hierro, y el estado homocigoto para la mutación C282Y confirmó la sospecha diagnóstica; se descartaron otras condiciones como: hepatitis crónica por virus B y C, esteatohepatitis no alcohólica, anemia hemolítica crónica, anemia sideroblástica, talasemia mayor, u otras enfermedades metabólicas que afectan al hígado. La biopsia hepática mostró hallazgos típicos de esta condición. Las flebotomías semanales fueron bien toleradas y se logró una mejoría clínica del paciente y de los parámetros de laboratorio.

ABSTRACT Hereditary hemochromatosis is an uncommon metabolic disease, primarily affecting the liver in which increased intestinal absorption of iron is seen. We presented a 49- year -old patient who was evaluated in an outpatient clinic for suffering from asthenia, anorexia, arthralgia and skin hyperpigmentation associated with hypertransaminasemia and negative serology for B and C viruses from about two years ago. Serum ferritin, and transferrin saturation levels evidenced iron overload and homozygosity for the C282Y mutation confirmed the suspected diagnosis; other conditions were ruled out such as chronic hepatitis due to B and C viruses, non-alcoholic steatohepatitis, chronic hemolytic anemia, sideroblastic anemia, thalassemia major or some other metabolic diseases affecting the liver. Liver biopsy showed typical findings related to this condition. Weekly phlebotomies were well tolerated, as well as clinical improvement of the patient and laboratory parameters were achieved.

Hemocromatosis hereditaria: debut como cirrosis compensada de diagnóstico incidental. Reporte de un caso y revisión del tema / Hereditary hemochromatosis: debut as compensated cirrhosis of incidental diagnosis. Report of a case and review of the topic / Hemocromatose hereditária: estreia como cirrose compensada de diagnóstico incidental. Relatório de um caso e revisão do tópico

Resumen: La Hemocromatosis Hereditaria (HH) se define por la acumulación tisular de hierro, predominantemente en hígado, páncreas y miocardio, siendo una de las formas de sobrecarga férrica de causa congénita. El diagnóstico de HH en la edad adulta es poco frecuente en nuestro medio, y debe tenerse en cuenta ante hepatopatías crónicas de etiología incierta, más aún cuando se acompañan de elementos orientadores de afectación de otros tejidos. En este artículo se presenta el caso de un paciente alcoholista que debuta clínicamente con una hemorragia digestiva, contexto en el cual se establece el diagnóstico de cirrosis. Dados los antecedentes familiares de hepatopatía crónica de etiología incierta, el reciente diagnóstico de diabetes, y ante el hallazgo de un perfil de sobrecarga férrica, a pesar del consumo problemático de alcohol, se solicitaron los estudios destinados a confirmar el planteo de HH. El estudio genético en busca de homocigosis del alelo C282Y para el gen HFE resultó positivo. Se iniciaron flebotomías seriadas con buena evolución posterior. Se presenta el caso clínico y se realiza una revisión de la literatura.

Abstract: Hereditary Hemochromatosis (HH) is defined by tissue accumulation of iron, predominantly in theliver, pancreas and myocardium, being one of the forms of iron overload of congenital cause. The diagnosis of HH in adulthood is rare in our environment and must be taken into account in the presence of chronic liver disease of uncertain etiology. In this article we present a clinical case of an alcoholic patient who debuted clinically with a digestive bleeding, context in which the diagnosis of cirrhosis was established. Given the family history of chronic liver disease of uncertain etiology, the recent diagnosis of diabetes, and the finding of a profile of iron overload, despite problematic alcohol consumption, studies were requested to confirm the HH approach. The genetic study in search of homozygosis of the C282Y allele for the HFE gene was positive. Serial phlebotomies were started with favourable evolution at follow-up. The clinical case is presented, and a review of the literature is made.

Resumo: Hemocromatose hereditária (HH) por acumulação de ferro no tecido é definido predominantemente no fígado, no pâncreas e enfarte, uma das formas de sobrecarga de ferro causa congénita. Diagnóstico HH na idade adulta é raro em nossa área, e deve ser considerada a doença hepática crônica de etiologia desconhecida, mesmo quando acompanhadas por elementos de guia de envolvimento de outros tecidos. Este artigo apresenta o caso de um paciente com alcoolismo que estreou clinicamente com uma hemorragia digestiva, um contexto no qual o diagnóstico de cirrose é estabelecido. Dada a história familiar de doença hepática crônica de etiologia desconhecida, o diagnóstico recente de diabetes e antes da conclusão de um perfil de sobrecarga de ferro, apesar do uso problemático de álcool, estudos para confirmar a proposição de HH foram solicitados. O estudo genético em busca de homozigose do alelo C282Y para o gene HFE foi positivo. Flebotomias seriadas com boa evolução posterior foram iniciadas. O caso clínico é apresentado e uma revisão da literatura é feita.

Frecuencia de las mutaciones C282Y y H63D del gen HFE en pacientes con diagnóstico de deficiencia de alfa-1-antitripsina / Frequency of the mutations C282Y and H63D of the HFE gene in patients diagnosed with deficiency of Alpha-1-Antitrypsin

Introducción: debido a la alta frecuencia de las mutaciones C282Y y H63D del gen HFE, promotor de la hemocromatosis tipo 1 y de las mutaciones S o Z, causantes de la deficiencia de alfa-1-antitripsina (def-A1AT), se han reportado su coexistencia en varios pacientes, por lo que algunos autores han mencionado a las mutaciones en el gen HFE como posible contribuyente al desarrollo de las manifestaciones hepáticas en pacientes con def-A1AT. Objetivo: determinar la frecuencia de las mutaciones C268Y y H63D en pacientes con hepatopatías y diagnóstico presuntivo de def-A1AT. Materiales y métodos: se realizó un estudio descriptivo, conformado por 65 pacientes con hepatopatías, remitidos al laboratorio de biología molecular del Centro Nacional de Genética Médica, para el diagnóstico molecular de las mutaciones S y Z del gen de la alfa-1-antitripsina. Para la amplificación de las mutaciones C282Y y H63D se empleó el método de reacción en cadena de la polimerasa, con polimorfismos en los tamaños de los fragmentos de restricción (PCR-RFLP). Resultados: la frecuencia de las mutaciones C282Y y H63D del gen HFE en los pacientes con diagnostico presuntivo de deficiencia de alfa-1-antitripsina fue de 5,3 % y 17 %, respectivamente. Conclusiones: este estudio mostró que la frecuencia de estas dos mutaciones en la población cubana es alta. Igualmente, se pudo apreciar que ambas mutaciones, aun en estado heterocigoto, parecen jugar un papel fundamental en el desarrollo de diferentes patologías.

Introduction: Due to the high frequency of C282Y and H63D mutations in the HFE gene, promoter type 1 hemochromatosis, and mutations S or Z causing the deficiency of alpha-1-antitrypsin (def-A1AT), studies have shown their coexistence in several patients. As a result, many scientists consider mutations in the HFE gene as a possible contributor to the development of hepatic events in patients with A1AT-def. Aim: To determine the frequency of C268Y and H63D mutations in patients with liver disease and presumptive diagnosis of A1AT-def. Materials and methods: We conducted a descriptive study that involved 65 patients with liver disease who were referred to the Molecular Biology Laboratory of the National Center of Medical Genetics for the molecular diagnosis of S and Z mutations of the gene for alpha-1 antitrypsin. We used the polymerase chain reaction method with polymorphisms in the sizes of the restriction fragments (PCR-RFLP). Results: The frequency of C282Y and H63D mutations of the HFE gene in patients with presumptive diagnosis of deficiency of alpha-1 antitrypsin was 5.3% and 17% respectively. Conclusions: this study showed that the frequency of these two mutations in Cuban population is high. We also observed that both of them, even in heterozygous state, seem to play a main role in the development of different diseases.

Porphyria Cutanea Tarda and HFE Gene Mutations in Argentina.

Aims: Porphyria Cutanea Tarda (PCT), the most common of porphyrias is triggered by several factors, including iron overload. Type I Hereditary Hemochromatosis is inherited as an autosomal recessive trait of the mutation p.C282Y or as a compound heterozygous form p.C282Y/p.H63D in HFE gene. Our aim was to study the frequency of HFE mutations in Argentinean PCT patients and in control subjects. Place and Duration of Study: CIPYP, CONICET, Hospital de Clínicas José de San Martín: Av. Córdoba 2351, 1º subsuelo, Buenos Aires, Argentina (1120). Between March 2008 and March 2010. Methodology: We analyzed HFE mutations in 103 PCT patients (67 males, 36 females) and in 93 control subjects (63 males and 30 females). PCT patients were classified as familial, sporadic or Type III PCT measuring URO-D activity in red blood cells. HFE mutations were detected by amplification and automatic sequencing of exons 2 and 4 in the HFE gene. In some cases p.H63D and p.C282Y mutations were also detected by digestion with restriction enzymes (Mbo I for p.H63D and Rsa I for p.C282Y), followed by 3% polyacrilamide gel electrophoresis. Results: In PCT group, 34.9% carried mutation p.H63D (26.2% heterozygous, 5.8% homozygous and 2.9% as p.C282Y/p.H63D) and 7.8% carried mutation p.C282Y (2.9% in heterozygocity, 1.9% in homozygocity and 2.9% as p.C282Y/p.H63D). In the control group, 30.1% carried p.H63D (28% in heterozygous and 2.1% in homozygous), and 5.4% had p.C282Y in heterozygosity. There were no significant differences between sporadic and familial PCT and neither between PCT and control groups. Our findings are in agreement with the prevalence of the Mediterranean origin of our patients, where p.C282Y mutation is less common than p.H63D mutation. Conclusion: We conclude that mutations in HFE gene do not play a relevant role in the triggering of PCT in our country.

Mutations in the HFE gene and sporadic amyotrophic lateral sclerosis risk: a meta-analysis of observational studies

Iron homeostasis dysregulation has been regarded as an important mechanism in neurodegenerative diseases. The H63D and C282Y polymorphisms in the HFE gene may be involved in the development of sporadic amyotrophic lateral sclerosis (ALS) through the disruption of iron homeostasis. However, studies investigating the relationship between ALS and these two polymorphisms have yielded contradictory outcomes. We performed a meta-analysis to assess the roles of the H63D and C282Y polymorphisms of HFE in ALS susceptibility. PubMed, MEDLINE, EMBASE, and Cochrane Library databases were systematically searched to identify relevant studies. Strict selection criteria and exclusion criteria were applied. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of associations. A fixed- or random-effect model was selected, depending on the results of the heterogeneity test. Fourteen studies were included in the meta-analysis (six studies with 1692 cases and 8359 controls for C282Y; 14 studies with 5849 cases and 13,710 controls for H63D). For the C282Y polymorphism, significant associations were observed in the allele model (Y vs C: OR=0.76, 95%CI=0.62-0.92, P=0.005) and the dominant model (YY+CY vs CC: OR=0.75, 95%CI=0.61-0.92, P=0.006). No associations were found for any genetic model for the H63D polymorphism. The C282Y polymorphism in HFE could be a potential protective factor for ALS in Caucasians. However, the H63D polymorphism does not appear to be associated with ALS.

Hemocromatosis hereditaria tipo I: a propósito de cuatro casos confirmados / Hereditary hemochromatosis type I: apropos of four confirmed cases

La hemocromatosis hereditaria es un trastorno genético. En los últimos años se ha profundizado en el conocimiento de su fisiopatología y diagnóstico. Estos síndromes se caracterizan por sobrecarga de hierro y se distinguen varios subtipos de acuerdo con la mutación existente. Dentro de ellas, las mutaciones en el gen HFE o hemocromatosis hereditaria tipo I es la más común. Esta enfermedad tiene una gran morbilidad y mortalidad asociada a la sobrecarga del mineral. Se presentan 4 pacientes en los que por primera vez en Cuba se identificaron las mutaciones del gen HFE

Hereditary hemochromatosis is a genetic disorder. Detailed studies on its physiopathology and diagnosis have been carried out over the last years. The syndromes are characterized by iron overload and several subtypes are distinguished according to the existing mutation. Among them, the mutations in HFE gene or hereditary hemochromatosis type I is the most common. This disease has a great morbidity and mortality associated to mineral overload. For the first time in Cuba, we report four patients with confirmed mutations in HFE genes