A Japanese Family with Ferroportin Disease Caused by a Novel Mutation of SLC40A1 Gene: Hyperferritinemia Associated with a Relatively Low Transferrin Saturation of Iron

Ferroportin disease, autosomal-dominant reticuloendothelial iron overload, may be more prevalent than hemochromatosis in Japan. Hyperferritinemia of 822 ng/ml with 24.8% transferrin saturation of iron was incidentally noted in a 43-year-old man. His iron overload was selective in Kupffer cells of the liver. Subsequently, his father was found to have asymptomatic hyperferritinemia of 2,283 ng/ml with 62.1% saturation. These affected subjects were heterozygous for 1467A>C (R489S) in SLC40A1, and without other mutations of the hemochromatosis genes. Here, we report a Japanese family with ferroportin disease, characterized by hyperferritinemia with relatively low transferrin saturations of iron.