Hemocromatosis: actualización clínica y diagnóstica / Hemochromatosis: clinical and diagnostic update

La hemocromatosis es un desorden en el cual la sobrecarga progresiva de hierro puede llevar a complicaciones sistémicas con gran morbimortalidad. Es una entidad clinicopatológica, con múltiples genes comprometidos y una fisiopatología común, con una expresión clínica y fenotípica variable, que depende de múltiples factores, tanto individuales como ambientales. Para su diagnóstico y seguimiento adecuado es necesario tener en cuenta elementos clínicos, bioquímicos y moleculares. En esta revisión, se presentan las generalidades de la hemocromatosis, además de sus mecanismos fisiopatológicos y moleculares, teniendo en cuenta su valor para el diagnóstico de la enfermedad. Adicionalmente, se describe la clasificación y un algoritmo diagnóstico propuestos recientemente por grupos de trabajo de expertos, así como las opciones de manejo y seguimiento de los pacientes con hemocromatosis

Hemochromatosis is a disorder in which progressive iron overload may lead to systemic complications with potential morbidity and mortality. It is a clinicopathologic entity that involves multiple genes and common pathophysiology, and has a variable clinical and phenotypic expression that depends on several individual and environmental factors. To make the diagnosis and perform a proper follow-up, clinical, biochemical, and molecular elements must be considered. This review aims to present the general characteristics of hemochromatosis, its molecular and pathophysiologic mechanisms, and their significance in the diagnosis of this disorder. In addition, a new classification and a proposed diagnostic algorithm by an expert working group are described, as well as management and follow-up options for patients with hemochromatosis

HFE hemochromatosis: an overview about therapeutic recommendations

Abstract Hemochromatosis is currently characterized by the iron overload caused by hepcidin deficiency. Large advances in the knowledge on the hemochromatosis pathophysiology have occurred due to a better understanding of the protein of the iron metabolism, the genetic basis of hemochromatosis and of other iron overload diseases or conditions which can lead to this phenotype. In the present review, the main aims are to show updates on hemochromatosis and to report a practical set of therapeutic recommendations for the human factors engineering protein (HFE) hemochromatosis for the p.Cys282Tyr (C282Y/C282Y) homozygous genotype, elaborated by the Haemochromatosis International Taskforce.

Lesões hepáticas associadas à hemocromatose hereditária / Liver lesions associated with hereditary hemochromatosis

RESUMO A hemocromatose hereditária (HH) é uma doença genética autossômica recessiva, a mais comum encontrada em caucasianos, causada pelo acúmulo de ferro em diferentes órgãos, predominantemente no fígado, causando sua disfunção. As mutações hereditárias relacionadas ao gene HFE representam quase 90% dos casos de hemocromatose entre as populações de descendência europeia. A absorção excessiva do ferro ocasiona acúmulo em órgãos como coração, pâncreas e fígado ocasionando diversas manifestações clínicas. Além dos sintomas gerais, a progressiva sobrecarga de ferro causa uma das principais complicações, a cirrose hepática. A regressão da fibrose pode ser alcançada após o tratamento, promovendo a remoção do estímulo e restaurando a função do fígado. Caso a HH não seja tratada ou o tratamento não tenha sido efetivo, o paciente pode evoluir para um estado fibrótico de cirrose irreversível, que pode culminar com o carcinoma hepatocelular (CHC), complicação responsável por 45% das mortes em pacientes com HH. Nesse sentido, nota-se a importância de compreender os métodos diagnósticos, rastreamento e tratamento, de maneira a possibilitar manejos precoces e evitar complicações potencialmente fatais. Além disso, o fato da população dos estados do sul do Brasil ser composta em sua maioria por descendentes norte-europeus - os mais acometidos pela HH - justifica a importância de literaturas e estudos clínicos mais recentes e realizados nessa região com o objetivo de compreender a evolução clínica da doença e estabelecer medidas preventivas para a manifestação de lesões hepáticas. PALAVRAS-CHAVE: Hemocromatose, HFE, diagnóstico, cirrose hepática, carcinoma hepatocelular

ABSTRACT Hereditary hemochromatosis (HH) is an autosomal recessive genetic disease, the most common found in Caucasians, caused by the accumulation of iron in different organs, predominantly in the liver, causing its dysfunction. Inherited mutations related to the HFE gene represent almost 90% of cases of hemochromatosis among populations of European descent. Excessive iron absorption causes accumulation in organs such as the heart, pancreas and liver, causing several clinical manifestations. In addition to the general symptoms, progressive iron overload causes one of the main complications, liver cirrhosis. Regression of fibrosis can be achieved after treatment, promoting stimulus removal and restoring liver function. If HH is not treated or the treatment has not been effective, the patient may progress to a fibrotic state of irreversible cirrhosis, which can culminate in hepatocellular carcinoma (HCC), a complication responsible for 45% of deaths in patients with HH. In this sense, the importance of understanding diagnostic methods, screening and treatment is noted, in order to enable early management and avoid potentially fatal complications. In addition, the fact that the population of the southern states of Brazil is composed mostly of North European descendants ­ the most affected by HH ­ justifies the importance of more recent literature and clinical studies carried out in this region in order to understand the clinical course of the disease and establish preventive measures for the manifestation of liver damage. KEYWORDS: Hemochromatosis, HFE, diagnosis, liver cirrhosis, hepatocellular carcinoma

Aspectos relevantes en hemocromatosis hereditaria / Relevant features in hereditary hemochromatosis

La hemocromatosis hereditaria es una enfermedad que se caracteriza por la sobrecarga sistémica de hierro y se asocia a múltiples mutaciones genéticas que conducen a una producción inadecuadamente baja de la hormona hepcidina o a una alteración en la unión de la hepcidina a la ferroportina. Esto tiene como resultado un aumento de la absorción intestinal y el depósito de cantidades excesivas de hierro en las células, lo cual, a su vez, si no se corrige, genera daño tisular. La expresión clínica puede variar desde individuos completamente asintomáticos, hasta pacientes con cirrosis hepática a temprana edad, y eventualmente carcinoma hepatocelular. Habitualmente, el diagnóstico no es invasivo e incluye el examen clínico, la evaluación de los parámetros de hierro plasmático, imágenes y pruebas genéticas. El principal tratamiento es la flebotomía, pero terapias alternativas como la suplementación con hepcidina son un tema de investigación actual.

Hereditary hemochromatosis is a disease characterized by systemic iron overload of genetic origin, that leads to an inadequately low production of the hormone hepcidin or a reduction in hepcidinferroportin binding. This results in an increased intestinal absorption and the deposit of excessive amounts of iron in cells, which in turn results in tissue damage if not treated. The clinical expression can vary from completely asymptomatic individuals, to patients with liver cirrhosis at an early age, and eventually hepatocellular carcinoma. Diagnosis is usually noninvasive and includes clinical examination, assessment of plasma iron levels, imaging studies, and genetic testing. The main medical treatment is phlebotomy, but alternative therapies such as hepcidin supplementation are the subject of current research.

Analysis of HFE and Non-HFE Mutations in a Tibet Cohort with Iron Overload / 中国实验血液学杂志

OBJECTIVE@#The explore the molecular basis of iron-overload in Tibet nationality population of Tibet.@*METHODS@#The inpatients with iron-overload in our department from Dec. 1st 2014 to Jul.31st 2016 were enrolled in this study. Abdominal MRI and the mutation sites C282Y and H63D in HFE exon were examined. For HFE mutation-negative patients, the non-HFE mutation was detected, including 5 HJV mutations of G320V, p.Q312X, p.D249H, p.I281T, p.C321X and 2 TFR2 mutations: (Y250X, I238M), and 2 SLC40A1 mutations: (V162del, N144H).@*RESULTS@#Among 113 iron overload patients, only one showed homozygous p.H63D mutation, and one showed heterozygosis p.H63D mutation. In 73 patients accepted non-HFE gene detection, only one was heterozygosis p.D249N mutation in HJV, and one was heterozygosis p.I238M mutation in TFR2.@*CONCLUSION@#Currently, the pathogenic gene for Tibetan iron-overload has not yet been found.

Ingesta de hierro y gen HFE en varones adultos de Buenos Aires / Iron intake and HFE gen in male adults from Buenos Aires

El consumo excesivo de hierro (Fe) en portadores de mutaciones en el gen HFE puede resultar en sobrecarga. Para evaluar el riesgo de sobrecarga de Fe fueron investigados 166 varones adultos donantes de sangre de la ciudad de Buenos Aires. Se estimó la ingesta diaria de Fe (IFe), de Fe hemínico y de Fe proveniente de harinas enriquecidas con SO4Fe. Se determinó ferritina sérica y porcentaje de saturación de transferrina (criterio de sobrecarga de Fe: ferritina sérica > 300 ng/ml y saturación de transferrina ≥ 50%). Las mutaciones C282Y, H63D y S65C fueron investigadas en sangre mediante PCR-RFLP. Todos los participantes cubrieron ampliamente el requerimiento estimado promedio de Fe (6 mg Fe/día) y 3.0% superó el máximo tolerable (45 mg Fe/día). El Fe hemínico correspondió al 9.4% de la IFe y el de harinas enriquecidas al 47.7%. Se observó una asociación entre el aumento de IFe y el de ferritina sérica (p = 0.0472), y el 2.3% de los donantes presentaron ferritina sérica > 300 ng/ml y saturación de transferrina ≥ 50%. El 29.3% de los donantes eran portadores de los genotipos H63D, S65C o C282Y, asociados a hemocromatosis hereditaria, y tenían valores de saturación de transferrina significativamente mayores a los de los donantes wild type (p = 0.0167). Si bien la incidencia clínica de hemocromatosis hereditaria fue baja en el grupo estudiado (1.2%), el consumo excesivo de Fe plantea un riesgo potencial para la salud de individuos que ignoran sus antecedentes familiares de sobrecarga de Fe.

Excess iron (Fe) intake in subjects carrying certain mutations in the HFE gene may result in Fe overload. To estimate risk of Fe overload, 166 male blood donors (19-65 years) from Buenos Aires city were investigated. Daily Fe intake (FeI), hem Fe intake, and Fe intake from SO4Fe enriched flours were estimated (SARA Computer Program and Food Composition Table, USDA). Serum ferritin and transferrin saturation were determined; criteria for Fe overload was serum ferritin > 300 ng/ml and transferrin saturation ≥ 50%. HFE genotypes C282Y, H63D and S65C were analyzed by PCR-RFLP in blood samples. No participant presented FeI lower than the estimated average requirement (6 mg Fe/day) and 3.0% was over the upper level (45 mg Fe/day). Hem Fe and Fe from flour enrichment were 9.4% and 47.7% of daily Fe intake, respectively. A significant association was observed between the increase in serum ferritin (ng/ml) and the increase in FeI (p = 0.0472); 2.3% of the donors presented serum ferritin > 300 ng/ml and transferrin saturation ≥ 50%. Genotypes associated with hereditary hemochromatosis (H63D, S65C and C282Y) were found in 29.3% of the donors. The percentage of transferrin saturation was higher in subjects carrying mutation than in wild type subjects (p = 0.0167). Although penetrance of hereditary hemochromatosis in the studied group was only 1.2%, an excessive Fe intake could enhance adverse effects in individuals unaware of any family history of Fe overload.

HFE genetic variability and risk of alcoholic liver disease: A meta-analysis / 华中科技大学学报（医学）（英德文版）

Studies examining the association of hemochromatosis (HFE) gene polymorphisms and susceptibility to alcoholic liver disease (ALD) yielded inconsistent results. Thus, we performed a metaanalysis to investigate whether the variations in HFE gene increase the risk of ALD. The studies published up to Feb. 2014 were identified by searching PubMed/MEDLINE, ISI Web of Science, EMBASE and China National Knowledge Infrastructure databases, which was complemented by screening the references of the retrieved studies. For all genotypes and alleles, the odds ratios (ORs) with 95% confidence intervals (CIs) according to the heterogeneity were pooled using fixed-effect model. Sixteen studies with 1933 cases and 9874 controls were included for this meta-analysis. C282Y/C282Y, C282Y/wild type, H63D/wild type and C282Y/H63D were found not to be associated with susceptibility to ALD, but increased risk of H63D/H63D (OR: 1.52, 95% CI: 1.05-2.22, P=0.029) was observed for ALD when compared to total control. Comparison of ALD patients with alcoholics without liver damage revealed a significant association of D allele, as well as a marginal association of H63D/wild type with ALD, while H63D/H63D was not significantly associated with ALD although increased value of OR was obtained. The presence of Y allele and other genotypes yielded insignificant findings when ALD patients were compared with alcoholics without liver damage. No evident publication bias or significant heterogeneity among studies was detected in this meta-analysis. In conclusion, our metaanalysis showed a marginal higher prevalence of H63D variant in ALD but did not support an increased risk of C282Y mutation.

The Implication and Significance of Beta 2 Microglobulin: A Conservative Multifunctional Regulator / 中华医学杂志(英文版)

<p><b>OBJECTIVE</b>This review focuses on the current knowledge on the implication and significance of beta 2 microglobulin (β2M), a conservative immune molecule in vertebrate.</p><p><b>DATA SOURCES</b>The data used in this review were obtained from PubMed up to October 2015. Terms of β2M, immune response, and infection were used in the search.</p><p><b>STUDY SELECTIONS</b>Articles related to β2M were retrieved and reviewed. Articles focusing on the characteristic and function of β2M were selected. The exclusion criteria of articles were that the studies on β2M-related molecules.</p><p><b>RESULTS</b>β2M is critical for the immune surveillance and modulation in vertebrate animals. The dysregulation of β2M is associated with multiple diseases, including endogenous and infectious diseases. β2M could directly participate in the development of cancer cells, and the level of β2M is deemed as a prognostic marker for several malignancies. It also involves in forming major histocompatibility complex (MHC class I or MHC I) or like heterodimers, covering from antigen presentation to immune homeostasis.</p><p><b>CONCLUSIONS</b>Based on the characteristic of β2M, it or its signaling pathway has been targeted as biomedical or therapeutic tools. Moreover, β2M is highly conserved among different species, and overall structures are virtually identical, implying the versatility of β2M on applications.</p>

Hemocromatose hereditária relacionada ao gene HFE / Hereditary hemochromatosis HFE gene related

A Hemocromatose Hereditária (HH) é a desordem hereditária mais comum em caucasianos. Mais de 90% dos casos de HH resultam da simples substituição do aminoácido Cisteína pela Tirosina no gene HFE. Essa mutação causa uma doença recessiva que resulta no acúmulo tissular de ferro. O mecanismo através do qual o HFE influencia a homeostase do ferro nas células e no corpo permanece obscuro. A doença é subdiagnosticada na população em geral devido à inespecificidade de sua apresentação clínica. O prognóstico envolve a detecção precoce da doença e a terapêutica adequada utilizando a flebotomia em fase oportuna. Essa revisão descreve os conceitos atuais a respeito das manifestações clínicas, fisiopatologia, prognóstico e tratamento da Hemocromatose Hereditária relacionada ao gene HFE.

Hereditary hemochromatosis (HH) is the most common inherited disorder in caucasians. Over 90% of the cases of HH result from a single mutation of a Cys to Tyr in the HFE gene. This mutation causes a recessive disease resulting in iron acumulation in selected tissues. The mechanism by which HFE influences iron homeostasis in cells and in the body remains elusive. The disease is underdiagnosed in general population due to inespecific clinical manifestations. Prognosis is related to early diagnostic and correct treatment using pheblotomy. This review describe the current concepts concerning the clinical features, pathophisiology, prognosis and treatment of HFE-related hemochromatosis hereditary.

Study on HFE gene mutations in patients with myelodysplastic syndromes and aplastic anemia / 中华血液学杂志

<p><b>OBJECTIVE</b>To detect the incidence of the HFE gene C282Y and H63D mutations in patients with myelodysplastic syndromes (MDS) and aplastic anemia (AA), and analyze the relationship of these mutations with iron metabolism, and organs impairment from iron overload.</p><p><b>METHODS</b>The incidence of the C282Y and H63D mutations in 271 MDS, 402 AA patients and 1615 normal subjects was measured by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) combining with DNA sequencing. Iron metabolism parameters and iron overload indices were retrospectively compared between HFE gene mutation and unmutation groups in MDS and AA patients with no transfusion history.</p><p><b>RESULTS</b>No C282Y and C282Y/H63D compound mutation was detected in all the three groups. The incidence of H63D heterozygous and homozygous genotype did not significantly differ between AA cases and controls (9.7% vs 10.2%, 0.25% vs 0.24% respectively, both P > 0.05). The frequency of H63D heterozygous genotype in MDS patients was significantly lower than that in controls (4.1% vs 10.2%, P = 0.002). H63D homozygous was not found in MDS patients. In both MDS and AA patients with no RBC transfusion history, serum ferritin (SF), transferrin saturation value (TS), serum iron concentration (SI) were close to or higher than normal; and unsaturated iron-binding capacity (UIBC) value was significantly lower. There was no significant difference in SF, SI, TS values between HFE-mutation and -unmutation MDS patients. For AA patients, only the level of SI was significantly higher in HFE-mutant group than in -unmutation group [42.6 (24.6-60.4) micromol/L vs 32.0 (8.4-63.3) micromol/L, P = 0.011]. There was no significant difference in the values of liver enzyme, fasting blood sugar (FBS), abnormal electrocardiogram (ECG), peripheral blood indices between HFE-mutation and -unmutation MDS and AA groups (all P > 0.05).</p><p><b>CONCLUSION</b>The distribution of C282Y and H63D mutations has ethnic and genetic disparity, the frequency in Chinese population is lower than that in Caucasian. It seems that MDS and AA patients are susceptible to iron overload, in the diseases itself and the mutations of HFE gene are not the major factor for iron overload in the patients.</p>

Correlation between hepatic immunological markers and virus genotype in patients with chronic hepatitis C / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate the hepatic expression of immunological markers relevant to a cytotoxic response in relation to viral genotype.</p><p><b>METHODS</b>The frozen liver biopsies were obtained from 28 HF genotyped patients and made the sections stained. The morphometry was used to analyze the major histocompatibility complex class I (MHC-I), CD8, beta(2)-microglobulin (beta(2) -mG), HFE and CD68 in the stained sections. Biopsy data of response to therapy with interferon were available in 18 cases.</p><p><b>RESULTS</b>CD8+ was usually clustered together and localized in portal tracts and sinusoids, and seen to interact with MHC I positive lining cells. MHC-I and beta(2) -mG were expressed mainly in endothelial and Kupffer cells. HFE was expressed in most round and dendritic CD68+ cells. Patients with virus genotype 3a had higher hepatic MHC-I and HFE expression, and a better sustained response to interferon (IFN) therapy than patients without.</p><p><b>CONCLUSION</b>The MHC-I expression in the liver of patient with chronic hepatitis C virus infection seems to relate to viral-genotype. The hepatic MHC-I and HFE expression are higher in patients with virus genotype 3a than that in patients with non-3a genotype.</p>

Association of mutations of HFE gene and hepatocellular carcinoma following chronic hepatitis B / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To investigate the frequency of HFE gene variants in patients with hepatocellular carcinoma following chronic hepatitis B and to analyze their relationships.</p><p><b>METHODS</b>56 patients with hepatocellular carcinoma following chronic hepatitis B (HCC group) and 60 healthy blood donors (control group) were studied for the amino acid dimorphism at codon 63 (His63Asp=H63D) and codon 282 (Cys282Tyr = C282Y) of the HFE gene. The codon 63 and 282 dimorphisms were defined by PCR amplification of genomic DNA samples and restriction enzyme digestion using RsaI for C282Y and BclI for H63D. The association between hepatocellular carcinoma following chronic hepatitis B and HFE mutations were analyzed by Chi-square test.</p><p><b>RESULTS</b>The genotype frequency of C2/C2 in the HCC group was markedly higher than that in the normal control group (10.7% vs 0) and there was a significant correlation between them. At the same time, the allele frequency of C2 in the HCC group was markedly higher than that in the normal control group (16.1% vs 1.7%) and there was a significant correlation between them also.</p><p><b>CONCLUSION</b>The mutation of C282Y may be related with susceptibility to HCC after chronic hepatitis B. This outcome suggests that host HFE mutation may be an important factor related to the pathogenesis of HCC.</p>

Relationship between HFE gene and hereditary hemochromatosis / 中华医学遗传学杂志

HFE gene is a major histocompatibility complex class I-like gene, which was identified as a candidate gene for hemochromatosis in 1996. The proposed role for HFE is its part in the regulation of the interaction of the transferrin receptor with transferrin. Hemochromatosis, the common autosomal recessive disease of iron overload, affects at least 1 in 300 Caucasians. The identification of the C282Y mutation in the HFE gene has led to population screening studies. Much of this work has also included the analysis of a second mutation, H63D, which appears to have a low penetrability. HFE protein was recently found to coprecipitate with the transferrin receptor and to affect the reaction between transferrin and the transferrin receptor. Functional data suggest that the mutation C282Y abolishes the association of the HFE protein with beta 2-microglobulin (beta 2M), making the complex unable to reach the cell surface. Clearly, if the mutation protein is unable to reach the cell surface, this regulatory feature is missing. The role of a second mutation in the HFE gene, H63D, is less clear. Current data suggest that this mutation protein can associate with beta 2-microglobulin and does reach the cell surface and that the defect lies in a failure to modify the affinity of the transferrin receptor for transferrin. This does not explain the low degree of penetrability associated with this mutation.