Diabetes and hemochromatosis.

The common form of hereditary hemochromatosis is an autosomal recessive disorder most prevalent in Caucasians that results in excessive iron storage. The clinical manifestations of hemochromatosis are protean. HFE genotype, which determines the degree of iron overload and duration of disease have profound effects on disease expression. The prevalence of diabetes in this population has likely been underestimated because of studies that include a broad range of ethnicities and associating diabetes with allele frequency in spite of the decreased risk of diabetes in heterozygotes compared with homozygotes. Loss of insulin secretory capacity is likely the primary defect contributing to development of diabetes with insulin resistance playing a secondary role. Phlebotomy can ameliorate the defects in insulin secretion if initiated early. Screening a select population of individuals with type 2 diabetes may identify patients with hemochromatosis early and substantially impact individual clinical outcomes.