Prevalence of abnormal iron studies in heterozygotes for hereditary hemochromatosis: an analysis of 255 heterozygotes.

Iron studies were compared in 434 patients from 80 hemochromatosis families classified as putative homozygotes, heterozygotes, and normal by HLA typing. There were 28 of 255 (11%) heterozygotes with an elevated serum ferritin and 22 of 255 (8.6%) with an elevated transferrin saturation. Serum ferritin (140 +/- 10.2 micrograms/liter; mean +/- standard error) was greater in heterozygotes than in normal subjects (87 +/- 8.5 micrograms/liter; P < .05, Mann Whitney test). Transferrin saturation was greater in heterozygotes (38% +/- 0.88%) than in normal patients (29% +/- 1.1%; P < .0001). Mean hepatic iron concentration was 54 +/- 6 mumol/g (n = 17), and the hepatic iron index was < 2 in these patients. Most heterozygotes for hemochromatosis have a normal serum ferritin and transferrin saturation. Heterozygotes with minor elevations in serum ferritin or transferrin saturation do not have significant iron overload as assessed by hepatic iron concentration.