Haptoglobin polymorphism and iron homeostasis.

BACKGROUND There is a marked difference in the degree of expression of the homozygous C282Y HFE genotype that is associated with hereditary hemochromatosis. It has been reported that individuals with the haptoglobin 2-2 type manifest increased iron concentrations, including serum iron, transferrin saturation, and ferritin. METHODS We studied 232 patients, 115 homozygous for the c.845G-->A (C282Y) mutation and 117 matched controls with the wild-type HFE genotype, for haptoglobin phenotypes. Haptoglobin types were determined by electrophoresis of the denatured protein. The HFE genotype was determined by allele-specific oligonucleotide hybridization. Ferritin and transferrin saturation were measured by standard methods. RESULTS There was no relationship between haptoglobin type and ferritin concentration or transferrin saturation. CONCLUSIONS The effect of haptoglobin type on iron homeostasis cannot account for the marked phenotypic variation that is seen in patients homozygous for the HFE C282Y mutation.