The spectrum of beta-thalassemia mutations in northern and northeastern Thailand.

A total of 123 beta-thalassemia genes from northern (n = 113) and northeastern (n = 10) Thailand were examined. Using five oligonucleotide probes, the mutation in 108 genes (88%) was identified: 50 nonsense 17, 49 frameshift 41-42, 4-28(A----G), 2 IV1 nt5(G----C), 2IVS2 nt654, and 1 deletion removing the entire beta-globin gene. The nonsense 17 mutation (n = 39) was linked to a single haplotype, whereas the frameshift 41-42 mutation occurred with several haplotypes. The results of the present study indicate that prenatal diagnosis of clinically important beta-thalassemia syndromes using a limited set of oligonucleotides is feasible in approximately 80% of affected families in northern Thailand and most of the families with beta-thalassemia-Hb E disease in northeastern Thailand.