Frequency and clinical expression of HFE gene mutations in a Spanish population of subjects with abnormal iron metabolism

Frequency of hereditary hemochromatosis gene mutations and their effects on iron overload among beta thalassemia patients of Chennai residents

<abstract> <p>Hereditary Hemochromatosis (HH) is an autosomal recessive disorder of iron metabolism associated with <italic>HFE</italic> gene mutations, characterized by increased iron absorption and accumulation leading to multi-organ damage caused by iron overload toxicity. Beta thalassemia is caused by a mutation in the human beta globin gene. Imbalanced production of globin chain results in beta thalassemia, where the unpaired alpha chains precipitates in red cell precursors leading to ineffective erythropoiesis and reduced RBC survival. Both HH and beta thalassemia condition results in rapid accumulation of iron lead to iron overload in tissues and organs. The study aims to analyze the frequency of <italic>HFE</italic> variants among beta thalassemia cases and their effect on iron overload. The frequency of three <italic>HFE</italic> variants C282Y, H63D, S65C was analyzed by PCR RFLP method among Beta Thalassemia Trait (BTT) (n = 203), Beta Thalassemia Major (BTM) (n = 19) and age and sex-matched control samples (n = 200). The present study furnished allele frequency of H63D variant in BTT, BTM and controls 8.13, 15.8 and 6% respectively. Ten out of 33 heterozygous H63D variants exhibited iron overload with higher ferritin levels indicating <italic>HFE</italic> variant might aggravate the absorption of iron. The C282Y variant was present in heterozygous state in 1 case among beta thalassemia carriers. The C282Y variant was absent among BTM and control cases. S65C <italic>HFE</italic> variant was absent in the present study. Iron overload was completely absent in the control cases among all three <italic>HFE</italic> genotypes. Hence it is inferred from the present investigation, analysis of <italic>HFE</italic> genes and iron status will remarkably help to reason out the probable reason behind the iron status and support in proper management of beta thalassemia cases.</p> </abstract>

Low frequency of HFE gene mutations in Croatian patients suspected of having hereditary hemochromatosis

Background

Hereditary hemochromatosis (HH) is a common autosomal recessive disorder in populations of European descent. It is characterized by a variable prevalence of mutations in the hemochromatosis gene (HFE) in different countries and a complex relationship between the HFE genotype and the HH phenotype. Genetic analysis has not been conducted in Croatian patients with iron overload. The aim of this study was to determine whether HFE mutations, C282Y, H63D, and S65C were correlated with clinical and biochemical parameters in Croatian patients with suspected HH.

Material/Methods

Clinical examination, biochemical analysis, and genotyping were performed in 175 patients suspected of having HH. The control group consisted of 350 healthy blood donors.

Results

Among the patients, 20% had genotypes related to HH – 7.4% were homozygous for C282Y, 6.3% were compound heterozygous for C282Y and H63D, 5.7% were homozygous for H63D, and 0.6% was compound heterozygous for C282Y and S65C. The allelic frequencies were 14.6% for C282Y mutation, 23.7% for H63D mutation, and 1.4% for S65C mutation. A comparison of the clinical and laboratory profiles of patients revealed that C282Y homozygotes had higher frequencies of all clinical symptoms and higher levels of biochemical parameters than others. The C282Y/H63D compound heterozygotes and H63D homozygotes were found to be clinically important, despite the fact that they were associated with less severe disease.

Conclusions

Our results show that HFE mutations are responsible for only about 20% of Croatian patients with suspected HH. Screening with biochemical methods and HFE genotyping may be not sufficient for diagnoses in the Croatian population.

Serum iron parameters, HFE C282Y genotype, and cognitive performance in older adults: results from the FACIT study

Although iron homeostasis is essential for brain functioning, the effects of iron levels on cognitive performance in older individuals have scarcely been investigated. In the present study, serum iron parameters and hemochromatosis (HFE) C282Y genotype were determined in 818 older individuals who participated in a 3-year randomized, placebo-controlled double-blind trial examining the effects of folic acid on carotid intima-media thickness. All participants had slightly elevated homocysteine levels and were vitamin B12 replete. Cognitive functioning was assessed at baseline and after 3 years by means of a neuropsychological test battery. At baseline, increased serum ferritin was associated with decreased sensorimotor speed, complex speed, and information-processing speed and increased serum iron was associated with decreased sensorimotor speed. Cognitive performance over 3 years was not associated with HFE C282Y genotype or iron parameters. In conclusion, serum iron parameters do not show a straightforward relationship with cognitive functioning, although elevated iron levels may decrease cognitive speed in older individuals susceptible to cognitive impairment.