Coincidental nontransfusional iron overload and thalassemia minor: association with HLA-linked hemochromatosis.

A pedigree was studied in which five individuals with beta-thalassemia minor were found to have nontransfusional hemochromatosis. Three were children under the age of 10 and two were young male adults, ages 28 and 33. A 5-yr-old child without evidence of thalassemia also had hemochromatosis. Since hemochromatosis is transmitted as an HLA-linked autosomal recessive disorder, HLA haplotypes serve as markers of hemochromatosis alleles. In this pedigree, five identifiable HLA haplotypes were associated with hemochromatosis alleles. Only individuals with two hemochromatosis alleles (homozygosity) had heavy iron loads, whether beta-thalassemia minor was present or not. Individuals with beta-thalassemia minor but without a hemochromatosis allele had normal transferrin saturation. A 65-yr-old man with beta-thalassemia minor and a single hemochromatosis allele had only a minimally elevated transferrin saturation (54%). The presence of beta-thalassemia minor did not appear to accentuate the degree of iron loading expected in individuals homozygous or heterozygous for hemochromatosis alleles. Our findings suggest that nontransfusional hemochromatosis found in association with beta-thalassemia minor is due primarily to homozygosity for hemochromatosis.