Haemochromatosis-associated HFE genotypes in English blood donors: age-related frequency and biochemical expression

Effect of HFE Gene Mutation on Changes in Iron Metabolism Induced by Nordic Walking in Elderly Women

Background

Excess iron accumulation in human tissue is associated with the diet, lack of exercise, or genetic factors. Iron accumulation increases the risk of acute myocardial infarction, diabetes, and cancer. On the other hand, exercise reduces the risk of several morbidities and influences iron metabolism. Here, we evaluated changes in iron metabolism induced by exercise in elderly women bearing the H63A HFE mutation.

Purpose

To identify a factor that modulates the effect of exercise on iron metabolism. We investigated whether regular exercise induces similar changes in iron metabolism, mainly manifested by lowered body iron stores, in individuals bearing the wild-type (WT) and mutated HFE gene.

Subjects and Methods

Seventy-six women (average age 69.2±5.6 years old) were enrolled in the study. Thirty-nine women participated in 12 weeks of Nordic walking (NW) training; the remaining participants were assigned to the control group. Based on the H63A HFE mutation status, the NW group was divided into women bearing the mutation (HET, n=12) and women with the WT gene (WT, n=27).

Results

The training resulted in a statistically significant reduction in the serum iron (p=0.03) and ferritin levels (p=0.001); hepcidin levels remained unchanged. No differences in these parameters were noted between the HET and WT groups.

Conclusion

These observations suggest that a reduction in body iron stores might constitute an important aspect of the health-promoting effect of exercise, regardless of the genetic background.

HFE Gene Mutations and Iron Status in 100 Healthy Polish Children

Iron participates in oxygen transport, energetic, metabolic, and immunologic processes. There are 2 main causes of iron overload: hereditary hemochromatosis which is a primary cause, is a metabolic disorder caused by mutations of genes that control iron metabolism and secondary hemochromatosis caused by multitransfusions, chronic hemolysis, and intake of iron rich food. The most common type of hereditary hemochromatosis is caused by HFE gene mutation. In this study, we analyzed iron metabolism in 100 healthy Polish children in relation to their HFE gene status. The wild-type HFE gene was predominant being observed in 60 children (60%). Twenty-five children (25%), presented with heterozygotic H63D mutation, and 15 children (15%), presented with other mutations (heterozygotic C282Y and S65C mutation, compound heterozygotes C282Y/S65C, C282Y/H63D, H63D homozygote). The mean concentration of iron, the level of ferritin, and transferrin saturation were statistically higher in the group of HFE variants compared with the wild-type group. H63D carriers presented with higher mean concentration of iron, ferritin levels, and transferrin saturation compared with the wild-type group. Male HFE carriers presented with higher iron concentration, transferrin saturation, and ferritin levels than females. This preliminary investigation demonstrates allelic impact on potential disease progression from childhood.

The impact of H63D HFE gene carriage on hemoglobin and iron status in children

The molecular mechanism that regulates iron homeostasis is based on a network of signals, which reflect on the iron requirements of the body. Hereditary hemochromatosis is a heterogenic metabolic syndrome which is due to unchecked transfer of iron into the bloodstream and its toxic effects on parenchymatous organs. It is caused by the mutation of genes that encode proteins that help hepcidin to monitor serum iron. These proteins include the human hemochromatosis protein -HFE, transferrin-receptor 2, hemojuvelin in rare instances, and ferroportin. HFE-related hemochromatosis is the most frequent form of the disease. Interestingly, the low penetrance of polymorphic HFE genes results in rare clinical presentation of the disease, predominantly in middle-aged males. Taking into account the wide dispersion of HFE mutation in our population and also its unknown role in heterozygotes, we analyzed the impact of H63D HFE carriage in the developmental age, with respect to gender, on the iron status and hemoglobin concentration of carriers in comparison to those of wild-type HFE gene (12.7 ± 3.07 years, 42 boys and 41 girls). H63D carriers presented higher blood iron, transferrin saturation, and ferritin concentration than wild-type probands (p < 0.05.) Interestingly, male H63D carriers showed higher hemoglobin concentration than the unburdened children. Moreover, in the H63D carrier group, a positive correlation between iron and hemoglobin was noted. In conclusion, this study demonstrates that changes in iron metabolism occur at a young age in HFE heterozygotes.

Dupuytren's Contracture in Alabama HFE Hemochromatosis Probands

BACKGROUND

Dupuytren's contracture (DC) and HFE hemochromatosis occur in some of the same at-risk populations and present with similar comorbid conditions.

METHODS

We estimated DC prevalence in two cohorts of white Alabama hemochromatosis probands (294 C282Y homozygotes, 67 C282Y/H63D compound heterozygotes) in a retrospective study. We performed logistic regressions on DC using the following independent variables: age, body mass index, heavy ethanol consumption, serum ferritin, elevated serum AST/ALT, non-alcoholic fatty liver disease, viral hepatitis, cirrhosis, and diabetes.

RESULTS

One man and two women with C282Y homozygosity had DC (prevalence 1.02%; 95% CI 0.35%-2.96%). A man with C282Y/H63D had DC (prevalence 1.49%; 95% CI 0.26%-7.98%). DC occurred as an autosomal dominant trait in his kinship. In regression analyses, no single variable predicted DC. We observed no new DC cases after the diagnosis of hemochromatosis (mean follow-up 12.9 ± 7.5 years (1 SD), and 9.0 ± 5.1 years, respectively).

CONCLUSIONS

Our prevalence estimates of DC in white Alabama hemochromatosis probands are similar to those found in the white US population cohorts. DC risk was unrelated to the variables we studied.

Increased mortality risk in patients with phenotypic hereditary hemochromatosis but not in their first-degree relatives

BACKGROUND & AIMS

Hereditary hemochromatosis (HH) is an autosomal-recessive disorder characterized by iron overload. Relatives of HH patients were screened and those with HH-associated mutations and an increased iron load were identified. However, little is known about their mortality or strategies for their management. We assessed mortality among Swedish patients with HH and their first-degree relatives using health and census registers.

METHODS

We performed a matched population-based cohort study of 3832 patients with HH and their 14,496 first-degree relatives using data collected from 1990 through 2007. Mortality data from these groups were compared with that of 38,969 population controls and their 143,349 first-degree relatives using Cox regression analyses.

RESULTS

Patients identified on the basis of hospitalization with HH had an increased risk (relative risk [RR]) for death (RR, 2.45; 95% confidence interval [CI], 2.27-2.64; 857 deaths). Patients identified through other means had a mortality risk that was lower than those identified in the hospital but higher than controls (RR, 1.15; 95% CI, 1.00-1.33; 216 deaths). Their first-degree relatives had only a marginally increased mortality risk (RR, 1.05; 95% CI, 1.01-1.10); this RR was similar to that of patients' spouses (RR, 1.09; 95% CI, 0.86-1.38; 82 deaths). Patients with HH who also had a family history of HH did not have an increased mortality risk compared with other groups (RR, 1.05; 95% CI, 0.67-1.62; 21 deaths).

CONCLUSIONS

Patients with HH have a modestly increased mortality risk compared with controls. The mortality of relatives is increased marginally compared with controls, and is similar among biological and nonbiological relatives.

Mutations in the HFE Gene and Cardiovascular Disease Risk

Background— Whether mutations in the hemochromatosis (HFE) gene increase cardiovascular disease risk is still undetermined. The main reason is the low frequency of the mutations, in particular of the compound C282Y/H63D genotype. We combined the data of 11 observational studies for an individual patient data meta-analysis.

Methods and Results— Individual patient data were obtained from published as well as unpublished studies that had information available on the C282Y mutation as well as the H63D mutation in relation to coronary heart disease risk. Individual records were provided on each of the 53 880 participants in 11 studies. In total, 10 541 patients with coronary events were documented, of whom 5724 had an acute myocardial infarction. The crude and adjusted association between HFE genotypes and coronary events was examined by logistic regression analysis. We explored potential effect modification of the association between traditional cardiovascular risk factors and coronary events by HFE genotypes. After full adjustment, the odds ratio for coronary heart disease was 1.12 (95% CI, 0.92 to 1.37) for subjects with the compound heterozygous (C282Y/H63D) genotype relative to those with the wild-type/wild-type genotype. The odds ratios for C282Y/C282Y, C282Y/wild-type, H63D/H63D, and H63D/wild-type were 0.78 (95% CI, 0.49 to 1.26), 0.98 (95% CI, 0.90 to 1.07), 1.16 (95% CI, 0.97 to 1.38), and 1.07 (95% CI, 1.00 to 1.14), respectively. There was no evidence for effect modification.

Conclusions— The results of this large individual patient data meta-analysis do not support the view that HFE gene mutations are associated with an increased risk of coronary heart disease or acute myocardial infarction.

HFE genotypes in decompensated alcoholic liver disease: phenotypic expression and comparison with heavy drinking and with normal controls

OBJECTIVES

Predisposition to alcoholic liver disease (ALD) may be partly genetic. Heterozygosity for the HFE mutations C282Y and/or H63D has been associated with more severe disease in several liver conditions. Studies in ALD have not used controls matched for alcohol consumption and results have been conflicting.

METHODS

HFE genotyping was performed in two Caucasian heavy-drinking cohorts (>60 units/wk (M) or 40 units/wk (F) for >5 yr): (a) 254 patients with decompensated ALD (Child's grade B or C), (b) 130 controls with similar alcohol consumption but without liver disease. Results in males were also compared with those from another study of healthy male blood donors.

RESULTS

(1) Genotype distributions for the C282Y and H63D mutations were similar in ALD patients, heavy-drinking controls, and healthy blood donors. (2) ALD patients with and without HFE mutations had similar disease severity, age at presentation, and alcohol consumption. (3) Increased serum ferritin and % transferrin saturation were seen in 63% and 29% of ALD patients, regardless of HFE genotype; the increased % transferrin saturation was due to reduced unsaturated iron binding capacity, rather than increased serum iron. (4) Stainable liver iron was present in 52% of patients; grade was greater in patients with two HFE mutations than in those with one or with none. (5) Only the two C282Y homozygote patients had substantial iron overload.

CONCLUSIONS

Although serum iron abnormalities are common, C282Y and H63D mutation frequencies were not increased in heavy drinkers with decompensated liver disease. HFE mutations, although modestly influencing liver iron, do not predispose to clinically significant ALD.

Association between heterozygosity for HFE gene mutations and hepatitis viruses in hepatocellular carcinoma

Hepatitis B virus (HBV) and hepatitis C virus (HCV) infections are strong and independent risk factors for hepatocellular carcinoma (HCC) development. Patients with hereditary hemochromatosis (HH) are considered at risk of developing cancer. However, the interaction between HFE gene mutations and hepatitis viruses for HCC development has not been systematically searched for. To assess the interaction between HFE gene mutations and exogenous risk factors in the risk of HCC occurrence, a case-only approach, in which just a series of patients is enrolled, was used. Three hundred three cirrhotic patients (231 males, 72 females) from five liver units in different geographic areas of Italy, who developed HCC during regular follow-up between January 1999 and March 2003, and whose blood DNA was available, were analyzed. In all subjects, hepatitis B surface antigen (HBsAg), anti-HCV and HFE gene mutations were assayed; alcohol intake was recorded by history. The interaction between HFE genotypes and hepatitis viruses for HCC was estimated by multivariate analysis adjusting for the confounding effect of alcohol intake, area of residence and months of follow-up. Of the 303 HCC cases, 12 (4.0%) were heterozygous for the C282Y mutation, 93 (30.7%) for the H63D, and 198 (65.3%) homozygous for the wild allele. Multivariate analysis showed that C282Y heterozygous males were 3.8-fold (95% CI=1.0-15.2) more likely to be HBV positive and that H63D heterozygous females were 6.0-fold (95% CI=1.2-113.8) more likely to be HCV positive than wild type subjects. In conclusion, given the association between C282Y mutation and HBV infection in male patients with HCC, a careful evaluation and follow-up should be considered in the C282Y-positive subjects with hepatitis B virus related liver disease. The interaction between the H63D mutation and HCV, observed only in women, may reflect a higher sensitivity to H63D-induced iron metabolism abnormalities and a reduced antioxidant capability in the presence of an even minor increase of iron which may occur as a consequence of the coexistence of hepatitis C infection and heterozygosity for HH.