Determinants for Iron Overload-Related Disease in Siblings of Probands with Clinically Detected HFE Hereditary Hemochromatosis: The Hemochromatosis Family Study.

The clinical expression of HFE-associated hereditary hemochromatosis (HH) gen is highly variable and may be influenced by nongenetic factors and coinherited genetic modifiers, complicating early screening options to prevent iron-overload related disease. The aim of this study was to verify the existence of HH-related disease in C282Y homozygous siblings of C282Y homozygous probands with clinically detected HFE-related HH and to identify factors predictive for the iron-related disease within these siblings. To this end, C282Y homozygous (n=110, males n=53) and non-homozygous siblings (n=318, males n=145) of 224 probands were compared for levels of serum iron parameters, and self-reported environmental and lifestyle factors and previously diagnosed HH-related diseases. Compared to non-homozygous C282Y siblings, C282Y homozygous siblings more often mentioned to have been diagnosed with arthropathy (Odds Ratio [OR] 2.76, 95% Confidential Interval [CI] 1.71–4.46) and liver disease (OR 2.90, 95%CI 1.27– 6.62). Using multivariate logistic regression modelling, genotype (OR 2.29, 95%CI 1.04– 5.02), age (OR 1.07, 95% CI 1.04–1.09) and gender (OR 1.71, 95%CI 1.04–2.80) were found predictive for the development of iron-associated organ disease. With genotype in the model, there was neither an additive predictive value of the serum iron parameters, nor of body mass index (BMI) or alcohol intake. However, when the predictive value of the iron parameters was analyzed in siblings above 55 yrs, the input of the serum ferritin levels was also significant, with a less prominent influence of gender. In conclusion, our results show that the prevalence of hemochromatosis-attributed morbid conditions is increased in the C282Y homozygous siblings compared to their non-homozygous counterparts. Results furthermore suggest that age and gender, but not BMI and alcohol intake, add to the identification of C282Y homozygous siblings most at risk to develop hemochromatosis-associated disease. These findings will be instrumental in the definition of a high-risk group for iron overload-related disease among siblings of clinically detected C282Y homozygous probands and may contribute to the cost-effectiveness of family screening.