[Large-scale population-based genetic screening and prenatal diagnosis for thalassemias in Zhuhai City of Guangdong Province].

To report the results of preventive control program of severe thalassemias in Zhuhai City of Guangdong Province from 1998 to 2010.As the guide centre of marriage and childbearing and the greatest maternity hospital in Zhuhai City of Guangdong Province, Zhuhai Municipal Maternity and Child Healthcare Hospital constructed the genetic screening network for thalassemias testing and referred for follow-up and for genetic counseling. The couples for premarital medical examination or regular healthcare examination in pregnancy were enrolled to this preventive control program. A conventional strategy of screening for heterozygote was used to identify the α- and β-thalassemia traits in women and their spouses according to the standard procedures of hematological phenotype analysis which was recommended by Thalassemia International Federation (TIF). Then those suspected couples at risk were diagnosed for α- and β-thalassemia by PCR-based DNA assays. The couples at risk for severe thalassemias were counseled and offered prenatal diagnosis and termination of pregnancy in case of an affected fetus in the rights of consent and of option voluntarily.From January 1998 to December 2010, 85 522 brides and grooms-to-be for premarital screening and 41 503 pregnant women in addition to 14 141 partners for prenatal screening were recorded, the covering rates of premarital screening and prenatal screening in the city were 92.698% (from 1998 to 2003) and 27.667% (from 2004 to 2010), respectively. Totally 10 726 cases were found to be the carriers of thalassemias, with 7393 for α-thalassemia (5.237%, 7 393/141 166) and 3333 for β-thalassemia (2.361%, 3 333/141 166). A total of 257 couples at-risk for severe thalassemias were detected including 190 for α-thalassemia and 67 for β-thalassemia. Among them, 251 (97.7%, 251/257) couples were performed prenatal diagnosis. During the preventive control program, a total of 72 fetuses with severe thalassemias including hemoglobin H disease were voluntarily terminated. In Zhuhai City, the average annual birth rate of fetuses with severe thalassemia was declined by 32.9% (49/149).This study has reduced effectively birth rate of perinatal infants with severe thalassemias in Zhuhai City by genetic screening and prenatal diagnosis of thalassemia in the large population of 13 years. Our summary comes out of technical proposals for prenatal screening and diagnosis, which could be take example by preventative control of thalassemia in other regions of China where are prevalent.