A 64-year-old man was admitted due to ascites. Laboratory data showed hemoglobin 6.7 g/dl, mean corpuscular volume 82 fl, and ferritin 2,360 ng/ml. Liver biopsy showed hemochromatosis. The diagnosis of beta-thalassemia was suggested by a decreased ratio of beta/alpha-globin synthesis in vitro (0.26). Cloning of the beta-globin gene showed A-to-G mutation in the first base of the ATA box. He was confirmed to be homozygous for this specific allele by beta-gene complex analysis and analysis of Southern blot hybridization of the alpha- and beta-globin genes. His two sons were confirmed to be heterozygous for this allele.