Biochemical expression of heterozygous hereditary hemochromatosis.
Background: Hereditary hemochromatosis (HH) is a common autosomal recessive disease caused by an iron overload. Two mutations (C282Y and H63D) on the responsible HFE gene have been described. HH heterozygotes may have a slight iron overload that does not cause clinical disease. Compound heterozygosity may be associated with higher iron stores than C282Y heterozygosity. We studied biochemical iron parameters in HH C282Y and compound heterozygotes without a clinically significant iron overload. Methods: Data on hemoglobin, hematocrit, mean corpuscular volume, serum ferritin, serum iron, transferrin, and transferrin saturation were obtained from 40 C282 wild type controls (irrespective of H63D genotype), 61 C282Y heterozygotes, and 18 compound (C282Y/H63D) heterozygotes without clinical iron overload disease. Results: Serum ferritin levels were significantly higher in female HH heterozygotes, particularly in compound heterozygotes, than in normal women. In male heterozygotes, no difference in serum ferritin was found. We found higher mean serum iron and transferrin saturation levels in male and female HH heterozygotes than in normal controls, the highest in the group of compound heterozygotes. Conclusions: Mean serum ferritin (only in women), serum iron, and transferrin saturation are highest in compound heterozygotes and lowest in controls. C282Y heterozygotes seem to be an intermediate group between compound heterozygotes and the normal population.
de Valk B
Department of Internal Medicine and Eijkman-Winkler Institute for Microbiology, Infectious Diseases and Inflammation, University Medical Center, P.O. Box 85500, 3508 GA, Utrecht, The Netherlands
Witlox
RS
van der Schouw YT
Marx
JJ