BAMH1 POLYMORPHISM IN THE CHINESE, MALAYS, AND INDIANS IN SINGAPORE AND ITS APPLICATION IN THE PRENATAL-DIAGNOSIS OF BETA-THALASSEMIA

The distribution of restriction fragment length polymorphism (RFLP) at the BamHl site of the beta-globin gene was investigated in the Chines e, Indian, and Malay race in Singapore. The sample comprised of 183 no rmal individuals and 35 beta-thalassemia carriers in which 13 were cou ples with at least one beta-major child. The results from this study i ndicate that BamH1 polymorphism will be informative in 22% of pregnanc ies at risk for beta-thalassemia major in Chinese, 19% in Malays and 7 % in Indians. In prenatal diagnosis using BamH1 polymorphism for one b eta-major affected family, the fetus was diagnosed to be normal or bet a-carrier. The validity of BamH1 polymorphism in the exclusion of beta -thalassemia major was subsequently confirmed at birth by globin chain biosynthesis.