Detection of α thalassemia 1 gene among 142 β thalassemia gene carriers

Objective To investigate the coincidental rate of double heterozygous state of β thalassemia and α thalassemia 1 in Guangdong area.Methods One hundred and forty two DNA samples with β thalassemia trait were amplified by polymerase chain reaction(PCR) to detect α thalassemia 1 gene.The positive cases were further detected by mutant primer PCR or by reverse dot blot hybridization (ASO/RDB) to confirm their β thalassmia mutations.Results Thirteen cases (9 15%) were identified to combine with α thalassemia 1 gene.The mutant loci of β globin gene in these cases were that 5 were in CD 41 42 (-TCTT), 3 in IVS 2 654(C→T),2 in CD 17 (A→T) and 3 in CD 71 72 (+A),CD 43(G→T) and -28(A→G),respectively.Conclusions The occurrence of this dual heterozygotes among β thalassemia trait is relatively frequent and it should be paid much attention to in genetic counselling and prenatal diagnosis of thalassemia in this area.