Dominant Hemochromatosis Due to N144H Mutation of SLC11A3: Clinical and Biological Characteristics

Hereditary hemochromatosis is classically inherited as a recessive trait but is genetically heterogeneous. Mutations in the HFE and the TFR2 genes account for about 80% of patients and a third locus on chromosome 1q is responsible for juvenile hemochromatosis. We describe here the clinical and biological characteristics of autosomal dominant form of iron overload due to the N144H mutation of the SLC11A3 gene. Clinical signs of iron overload in patients include joint pains, cardiomyopathies, liver fibrosis and hormonal disorders including diabetes mellitus. The main and most common clinical symptoms in this family were joint complaints and early signs of arthrosis. Serum ferritin levels in iron overloaded subjects varied from 31 to 2179 ng/ml and the transferrin saturation from 13 to 88.6%. The iron overload is moderate compared to patients with type 1 hemochromatosis but the deferoxamine test was normal in all patients. The disease in this family segregated as a dominant trait. None of the patients was homozygous or compound heterozygous for any known mutation in the HFE or TFR2 genes. The disease in this family represents a non-classical form of iron overload caused by the N144H mutation in the SLC11A3 gene. The reports of other distinct mutations in SLC11A3 suggest that this gene may be of interest for further etiologic research.