The Effects of HFE Polymorphisms on Biochemical Parameters of Iron Status in Arab Beta-Thalassemia Patients

Abstract

In this study, the potential effect of three HFE gene polymorphisms (C282Y, H63D and S65C) and the SLC40A1 A77D polymorphism on iron balance was investigated in 234 subjects (91 Arab beta-thalassemia major (BTM) patients, 34 beta-thalassemia trait (BTT) individuals and 109 health controls). Genotyping was done using restriction-fragment-length polymorphism and direct-sequencing. Serum-iron, total iron binding capacity, transferrin and ferritin were estimated in all BTT and BTM, and in 65 healthy controls. H63D was the only polymorphism detected in our cohort. Allele frequency was 13% in both BTM and BTT and 10% in controls with no significant difference. Serum iron, ferritin and transferrin saturation were significantly higher in normal males heterozygous for H63D as compared to homozygous wild-type males. Ferritin was significantly higher in BTT males with or without H63D polymorphism when compared to the healthy males with H/H genotype. No such difference was observed between H/H versus H/D BTT subgroups. We conclude that H63D is the only significant hemochromatosis-associated polymorphism in the Arabian Gulf region. The heterozygous state of H63D may significantly alter iron parameters in normal males. In BTT, it appears that the beta-thalassemia allele has an overriding influence on ferritin values, and this generally manifest in males.

Keywords: Arabs; Beta-thalassemia; Ferritin; Iron; Total iron binding capacity; Transferrin.

Fig. 1

a PCR products after amplification of DNA segments containing H63D and S65C (295 bp), C282Y (619 bp) and A77D (306 bp) SNPs. Lane 1 contains 100 bp DNA ladder and lane five contains negative control, (*) shows position of the 600 bp fragment. b Hinf1 treatment of the 295 bp amplicon containing HFE S65C variation. Lane 2 contains uncut amplicon (295 bp), homozygotes (AA) produce 147, 79, 69 bp bands (Lane 3, 4). c Ras1 treatment of 619 bp amplicon containing HFE C282Y variation. Lane 2 contains uncut amplicon (619 bp), wild type (GG) produces 234 and 385 bp bands (Lane 3 and 4). d Mob1 treatment of 295 bp amplicon containing HFE H63D variation. Lane 2 contains uncut amplicon (295 bp). The wild type produced 3 bands corresponding to 138, 99 and 58 bp fragments (Lane 3). The homozygous mutant type produced 237 and 58 bp bands (Lane 4). CG heterozygote produced 237, 138, 99 and 58 bp bands (Lane 5)