HFE gene mutations an Apulian population: allele frequencies

Analysis of HFE genes C282Y, H63D, and S65D in patients with hyperferritinemia from northeastern Brazil

BACKGROUND

Hereditary hemochromatosis (HH) is a genetic disease caused by the high absorption and deposition of iron in several organs. This accumulation results in several clinical complications such as cirrhosis, arthritis, cardiopathies, diabetes, sexual disorders, and skin darkening. The H63D and C282Y mutations are well defined in the HH etiology. The objective of this article is identification of the H63D and C282Y mutations in the HFE protein gene and the frequency assessment of these mutations in patients with persistent increase of serum ferritin in patients from Natal City from state of Rio Grande do Norte, located in northeastern Brazil.

RESULTS

Of the 299 patients studied for C282Y and H63D, 48.49% showed absence of mutation and 51.51% showed some sort of mutation: heterozygous C282Y mutation in 4.35% patients, homozygous C282Y mutation in 2.67% patients, heterozygous H63D mutation in 31.44% patients, homozygous H63D mutation in 8.03% patients, and heterozygous for the mutation in both genes (C282Y/H63D) in 5.02% patients. The S65C mutation was studied in 112 patients and heterozygous mutation (S65D/WT) in 2.67% of patients and double mutation (H63D/S65C) in 1.78% of patients were observed.

CONCLUSION

Due to the high prevalence of hemochromatosis, its genetic diagnosis has become a challenge, especially in the high-risk group.

An open population screening study for HFE gene major mutations proves the low prevalence of C282Y mutation in Central Italy

BACKGROUND

The C282Y mutation in the HFE gene is responsible for most cases of hereditary haemochromatosis.

AIM

To investigate the allele frequency of HFE mutations and the associations between mutations and cases of iron overload or liver diseases in an open population of Central Italy.

METHODS

A total of 502 individuals over 8 years of age, comprising 203 males and 299 females, who were residents in Arsita (a small town in Central Italy), were assayed for: C282Y, H63D and S65C mutations of the HFE gene by TaqMan probes; body mass index, serum ferritin, transferrin saturation, transaminases, GGT, glucose, insulin, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, HBV and HCV serum markers. Information was obtained on alcohol intake. Liver ultrasound was performed in 334 (67%) subjects.

RESULTS

The allele frequencies for C282Y, H63D and S65C were 2%, 15%, and 0.01%, respectively. C282Y/wt was found in 19 subjects (4%), H63D/wt in 127 (25%), H63D/H63D in 11 (2%) and S65C/wt in one (2.0 per thousand). No homozygosity for C282Y or compound mutation (C282Y/H63D) was found in the study population, but 27 subjects (5%) had TfSat >45% (including 10 subjects with high serum ferritin). Overall, 49 subjects (9.8%) were HCV-RNA-positive. Logistic regression analysis indicated that male gender (P = 0.000) and hepatic steatosis (P = 0.017) were independent variables correlating to a high serum ferritin.

CONCLUSION

C282Y HFE mutation is less frequent in Central Italy than in Northern Italy.

HFE gene mutations in patients with acute leukemia

An increased incidence of HFE gene mutations has been described in hematologic malignancies. In the present study, we investigated the allelic frequency of HFE gene mutations in 154 adult patients with acute leukemia (AL) [107 acute myeloid leukemia (AML), 20 acute promyelocytic leukemia (APL) and 27 acute lymphoblastic leukemia (ALL)]. The allelic frequency of the H63D mutation was 29% in AL patients and 25% in the healthy controls [P = 0.41; odds ratio (OR) = 1.20; 95% confidence interval (CI) = 0.77 - 1.93]. No difference was found between controls and AML or APL patients, whereas the H63D mutation was significantly more frequent in ALL than controls (44% vs. 25%, P = 0.04; OR = 2.37; 95% CI = 1.05 - 5.36). The overall comparison of the mutation among the three subtypes of AL demonstrated a higher allelic frequency in ALL (P = 0.02). In conclusion, our data demonstrate a correlation between the presence of the H63D mutation and the occurrence of ALL in adult patients.

Frequency of the C282Y and H63D mutations of the hemochromatosis gene (HFE) in a cohort of 1,000 neonates in Madrid (Spain)

For centuries in Europe, population movements have contributed to ethnic groups, cultures, and consequently, inheritance mixing. There are certain genetic diseases such as hereditary hemochromatosis whose distribution is directly related to the population movements. The objective of the present investigation was to determine the C282Y and H63D mutation frequency of the HFE gene in a cohort study of 1,000 neonates in the Community of Madrid (Spain), thus contributing to the HFE gene mutations distribution research in Europe and establishing the origin of the mutations in Spain. The allelic frequency of C282Y mutation was 1.7% (CI 95% 1.1-2.3) and the H63D allele was present in 16.4% of chromosomes (CI 95% 14.8-18). In Spain, the presence of C282Y mutation and its distribution could be due more to Celtic than to Viking legacy, whereas it is assumed that the one in relation to the H63D variant occurred in the Basque Country during the Paleolithic Period.

Unique genetic profile of hereditary hemochromatosis in Russians: high frequency of C282Y mutation in population, but not in patients

Hereditary hemochromatosis (HH) is a common cause of primary iron overload induced by genetic impairment of iron metabolism. More than 80% of HH patients in populations of European origin are homozygotes for a single mutation C282Y, or compound heterozygotes for C282Y and H63D mutations in the HFE gene. However, in the majority of Asian, African, Australasian, and Amerindian populations, frequencies of C282Y are close to zero. Data on the prevalence of HFE mutations in Russian population and in Russian patients with HH are very limited. In this work, we determined frequencies of C282Y and H63D in ethnical Russians living in the Central European region of Russia. Furthermore, we tested whether homozygocity for C282Y is the major cause of HH in Russians. We found that, in the Russian population, the frequency of C282Y mutation in the HFE gene is relatively high and corresponds to mean European levels. However, in contrast to the majority of European populations, homozygocity for C282Y is found only in a small proportion (5%) of patients with biochemical and clinical signs of HH. These data suggest that either the penetrance of C282Y in Russia is lower than in Western countries, or that a more frequent non-HFE dependent mechanism of primary iron overload dominates in Russian population.

Inherited iron loading: genetic testing in diagnosis and management

Elucidation of the molecular pathways of iron transport through cells and its control is leading to an understanding of genetic iron loading conditions. The general phenotype of haemochromatosis is iron accumulation in liver parenchymal cells, a raised serum transferrin saturation and ferritin concentration. Four types have been identified: type 1 is the common form and is an autosomal recessive disorder of low penetrance strongly associated with mutations in the HFE gene on chromosome 6(p21.3); type 2 (juvenile haemochromatosis) is autosomal recessive, of high penetrance with causative mutations identified in the HFE2 gene on chromosome 1 (q21) and the HAMP gene on chromosome 19 (q13); type 3 is also autosomal recessive with mutations in the TfR2 gene on chromosome 3 (7q22); type 4 is an autosomal dominant condition with heterozygous mutations in the ferroportin 1 gene. In type 4, iron accumulates in both parenchymal and reticuloendothelial cells and the transferrin saturation may be normal. There are also inherited neurodegenerative conditions associated with iron accumulation. The current research challenges include understanding the central role of the HAMP gene (hepcidin) in controlling iron absorption and the reasons for the variable penetrance in HFE type 1.