Carrier Screening and Prenatal Gene Diagnosis of β—thalassemia by PCR—RDB Technique

In order to identify the distribution of gene types of β-thalassemia and reduce the birthrates of β-thalassemia major in Guiyang area, 1054 pregnant women and their spouses from Affiliated Hospital, Guiyang Medical College were screened. The positive samples were analyzed with polymerase chain reaction and reverse dot blot method (PCR-RDB). When both partners were heterozygous identified as carriers for β- thalassemia, the risk of having a fetus who was homozygous or compound heterozygous was 2.66 %; the ratio of male to female was 1/1.15. Seven types of mutation were identified. CD17 and CD41-42 were dominant among them. Among the 4 cases subject to prenatal gene diagnosis, one fetus was completely normal and 3 fetuses were diagnosed as having β-thalassemia major (1 homozygous and 2 compound heterozygous). The fetuses diagnosed as β-thalassemia major were selectively terminated within two weeks. It was concluded that the birthrate of β-thalassemia major in Guiyang area was reduced and the target of improving birth outcome and child development has been achieved.