Abstract
Background. Hereditary hemochromatosis (HHC) is a common inherited disorder and the vast majority of cases are associated with HFE gene mutations; about 80% are homozygous for the C282Y HFE mutation. Although homozygosity for C282Y is relatively common among individuals of northern European descent, the penetrance, as measured by clinically relevant iron overload, is low. Both environmental and genetic factors have been implicated in modulating disease expression. Most clinicians and patients attribute at least some of the observed variation to differences in dietary patterns.
Methods: 28 C282Y homozygous subjects who had completed de-ironing therapy at our center, and were on stable maintenance phlebotomy treatments, participated in a previously validated dietary survey. We examined the influence of dietary iron, heme iron, fiber, ascorbic acid and alcohol intake on disease expression as measured by liver iron, phlebotomy-mobilized iron and maintenance phlebotomy requirement.
Results. We developed a maintenance iron score (Maint Fe) which was the iron in milligrams removed per month by phlebotomy treatments in order to maintain serum ferritin in the 25–75 μG/L range. Maint Fe ranged from 36.8–203 mg/month in our patients (87.8 ± 37.7). Liver iron ranged from 30.5 to 505.4 micromoles per gram dry weight (192.7 ± 123). Phlebotomy-mobilized iron ranged from 2.35–18.03 G (6.43 ± 4.08). The Spearman’s Rank Correlation was used to compare dietary parameters with each of the above measures of disease expression. No significant correlation was found.
Conclusions. Disease expression varied considerably in our C282Y homozygous subjects as measured by liver iron, phlebotomy-mobilized iron and Maint Fe. The observed variation is not explained by variations in dietary iron, fiber, ascorbic acid or ethanol intake. Our data suggests that other unknown environmental variables or alternatively, modifier genes, may play a role in modulating disease expression in these patients. Contrary to popular belief, dietary variation does not appear to play a major role.
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