Primary Iron Overload in African Americans

Abstract

To report African Americans with primary iron overload diagnosed during life and to study iron stores in African Americans undergoing autopsy. We summarized information for 4 African-American patients diagnosed during life with iron overload not explainable by alcohol, blood transfusions, or ineffective erythropoiesis. We reviewed liver specimens and hospital records of 326 unselected adult African Americans who were autopsied, assessing Prussian blue-stained sections for hepatocellular iron and measuring iron quantitatively in specimens that stained positively. We calculated the hepatic iron index (the hepatic iron concentration in mumol/g dry weight divided by the age in years). In autopsy subjects we corrected the index to account for iron administered by blood transfusion (the adjusted hepatic iron index). The hepatic iron index is useful for distinguishing primary iron overload from the moderate siderosis that may accompany alcoholic liver disease. The normal index is < or = 1.0. An index > or = 1.7 cannot be explained by alcohol effects and an index > or = 1.9 indicates the magnitude of iron-loading found in Caucasian homozygous HLA-linked hemochromatosis. The 4 living patients, all males and 27 to 50 years of age, had elevated body iron burdens and one or more of the following: hepatomegaly, cirrhosis, cardiomyopathy, diabetes mellitus, and impotence. Hepatic iron indices were 2.3, 11.5, and 20.2 in the 3 whose liver iron concentrations were measured. Among the autopsy subjects, 4 (1.2%), 2 men and 2 women aged 50 to 63 years, had adjusted hepatic iron indices > or = 1.9 (range 1.9 to 5.6). Primary iron overload occurs in African Americans. Further studies are needed to define prevalence, pathophysiology and clinical consequences. Clinicians should look for this condition.