[Homozygous beta(+)-thalassemia due to -31 A to G mutation].

A 20-year-old Japanese woman was admitted to our hospital with anemia and mild splenomegaly. Peripheral blood examination revealed Hb 9.4 g/dl, Ht 29.3%, RBC 4.74 x 10(6)/microliters, reticulocytes 2.4%, WBC 5,200/microliters, platelets 24.9 x 10(4)/microliters, MCV 61.7 fl, and MCH 19.9 pg. Poikilocytosis with target cells was recognized on the peripheral blood smear. A bone marrow aspirate revealed erythroid hyperplasia. Serum iron and ferritin were in the normal range. beta-thalassemia was suggested by the increase in HbA2 (6.5%) and HbF (7.5%). Analysis of beta globin DNA by single strand conformation polymorphism (SSCP) and amplification refractory mutation system (ARMS) confirmed a diagnosis of homozygous beta(+)-thalassemia due to -31 A to G mutation. A familial study revealed that her parents were heterozygous for this allele. This is the 8th case of homozygous beta(+)-thalassemia due to -31 A to G mutation in Japan.