OBJECTIVETo analyze the detection rate and gene distribution characteristic of deletional α-thalassemia in Guangxi area, and to provide theoretic basis for thalassemia gene diagnosis and genetic counseling.

METHODSThe regular gene diagnosis of 3 types of α-thal (-- (SEA),- α(3.7),- α(4.2)) was performed by gap-PCR, multiple ligation probe and gene sequencing for globin α or β were used to detect those samples whose genotype and phenotype were not consistent. And the distribution characteristic of α-thalassemia gene in Guangxi area was then analyzed.

RESULTSOut of 51 191 suspected thalassemia patients, there were 19 853 cases of deletional a-thalassemia, accounted for 39.9% in total positive rate, including 19 780 cases of regular types(--(SEA), - α(3.7), - α(4.2)), 61 cases of Thailand-type deletion, 9 cases of triplet type (Hong Kong) (ααα(HK)), 1 case of 21.9 kb deletion type and 2 cases of 809 bp deletion type.

CONCLUSIONTypes of deletional a-thalassemia were complex and accounted for large proportion in Guangxi area. Special gene diagnoses were needed for those couples whose genotype and phenotype were not consistent, in order to provide reliable basis for genetic counseling and prenatal diagnosis.