MOLECULAR-BASIS AND HEMATOLOGICAL CHARACTERIZATION OF HB-H-DISEASE INSOUTHEAST-ASIA

We molecularly characterized sixty-seven cases of Hb H disease by the polymerase chain reaction. The strategy depends on amplifying the alph a-thalassemia-1 (alpha-thal-1) gene by primers flanking the breakpoint and sequence differences of the 3' end of the alpha-globin gene and t he nonhomologous elements I, II, and III among different types of alph a-thala-2. In the 67 cases studied, all involved alpha-thal-1 of the S outheast Asia type (SEA) in combination with deletional or nondeletion al alpha-thal-2. Thirty-two cases were of the deletion form and 35 cas es were of the nondeletion form. In 32 cases of the deletion form, 29 cases were rightward deletion (-alpha(3.7)), and three cases were left ward deletion (-alpha(4.2) ). We found that all of the nondeletion for ms were alpha-thal-1 of SEA type with Hb CS. After the subtyping of Hb H with -alpha(3.7), 26 out Of 29 were type I deletion and 3 out of 29 were type II deletion. Comparisons of clinical data of deletion forms and the nondeletion form showed that there were earlier occurrence of anemic symptoms and a larger erythrocyte volume in the nondeletion fo rm group (P < 0.005). (C) 1994 Wiley-Liss,Inc.