Genetic and metabolic factors are associated with increased hepatic iron stores in a selected population of p.Cys282Tyr heterozygotes

Abstract

Heterozygosity for p.Cys282YTyr is not ordinarily associated with a hemochromatosis phenotype, unless associated in the compound heterozygous state with other HFE mutations. The aims of the study were to identify factors responsible for iron overload in patients who were only heterozygous for p.Cys282Tyr at first genetic testing. Since 2001, twelve p.Cys282Tyr heterozygous patients with iron overload, defined by increased transferrin saturation, serum ferritin and hepatic iron stores, were identified. Four patients showed rare nonsense or missense HFE mutations in the compound heterozygous state with p.Cys282Tyr. One mutation (p.Gln233X) was never described before. The other 8 patients did not carry any other causal mutations in iron-related genes, but showed a very high prevalence of hepatic steatosis and steato-hepatitis, and metabolic alterations. Serum ferritin levels did not differ between the two groups, but transferrin saturation, hepatic iron amount and distribution significantly did. These last indices should be then strongly considered to decide for additional genetic characterization in p.Cys282Tyr heterozygotes. Our results also highlights the influence of metabolic alterations on serum iron indices and pattern of hepatic iron accumulation.