The spectrum of β-thalassemia genes in China and southeast Asia

To make possible prenatal diagnosis of β-thalassemia in China and Southeast Asia by direct detection of mutant β-globin genes, we have determined the spectrum of mutations producing the disorder in this region of the world. Seventy-eight β-thalassemia genes from Chinese and Southeast Asians were randomly obtained, and the relevant mutation was characterized in 76 (98%) of them. Seven different point mutations were found among the 78 genes studied. Of these seven β-thalassemia alleles, two constitute 62%, and two others account for 29% of the total. Since only four alleles make up 91% of the mutant genes, prenatal diagnosis of β-thalassemia in China and Southeast Asia should be feasible by simplified techniques for direct detection of point mutations.