[Analysis of RFLP haplotypes in the beta-globin gene cluster and the identification of beta-thalassemia genes in patients from Guangdong Province]

Abstract

RFLP haplotypes of 69 chromosomes from members of 18 families affected with beta-thalassemia (beta T) in Guangdong Province were analyzed. 17 haplotypes were found. Haplotypes 1, 2 and 3 accounted for most of them and 4 new haplotypes were identified, three of which were associated with beta T genes. In 9 families, the haplotype data could be used for definitive prenatal diagnosis. In 7 families, 50% exclusive diagnosis could be achieved. In order to know the frequencies of various beta T genes in Guangdong Province and to improve prenatal diagnosis, we identified the beta T genes of 46 affected children in Guangdong Province by amplifying beta-globin gene sequences with the polymerase chain reaction (PCR) and hybridization with allele specific oligonucleotide (ASO) probes. 82 beta T genes hybridized with 6 probes. The most common beta T mutations were frameshift 41/42-TCTT, -28 A----G and IVS-2 nt654 G----T, accounting for 80% of the total. In 36 families PCR combined with hybridization using 6 ASO probes could provide definitive prenatal diagnosis.