基于社区水平的珠海市大人群地中海贫血的遗传筛查和产前诊断

目的 阐述在广东省珠海市开展基于社区的控制重型α和β地中海贫血(简称地贫)的预防模式.方法 构建由6家医院组成的二级地贫遗传服务网络,以珠海市婚前医学或产前检查人群作为筛查对象,采用常规杂合子筛查策略,以标准的血液学分析流程进行α和β地贫特征的筛查.对所有地贫疑诊对象进行随访和遗传咨询,并采用基于PCR的分子诊断技术对高风险夫妇进行确诊.在知情同意和选择的情况下,对高风险妊娠实施产前基因诊断并通过选择性引产淘汰受累的重型地贫胎儿.结果 从1998年1月至2005年12月,共筛查了85522例拟婚育龄青年和10439例孕妇,婚检地贫筛查覆盖率达到71.38%.在6563例地贫筛查阳性的病例中,α和β地贫分别为4312例(4.5%)和2251例(2.3%);总计发现148对有生育重型地贫儿可能的高风险夫妇(α地贫103对,β地贫45对),其中有142对(95.9%)高风险夫妇进行了产前诊断(α地贫98例,β地贫44例).本项目启动后共减少了41例重型地贫患儿的出生,其中包括Hb Barts水肿胎23例、Hb H病4例和重型β-地贫14例.结论 这是我国首次基于社区水平的、在拥有129万人口的珠海市实施的前瞻性α和β地贫预防监控计划.这一预防模式对我国其他地贫高发区和其他发展中国家开展地贫和其他血红蛋白病的预防有着重要的借鉴意义.

A community-based genetic screening of large-scale population and prenatal diagnosis for alpha and beta thalassemia in Zhuhai city of Guangdong province

OBJECTIVE: To describe a community-based model for prevention and control of severe alpha and beta thalassemias in Zhuhai city of Guangdong province. METHODS: Couples for premarital medical examination or regular healthcare examination in pregnancy were enrolled in this prospective screening program, which was supported by the two-level network composed of 6 local hospitals for testing thalassemias and follow-up for genetic counseling. A conventional heterozygote screening strategy was used to determine alpha and beta thalassemia traits in women and their partners according to the standard procedures of hematological phenotype analysis. Then confirmative diagnosis of alpha and beta thalassemia was performed on those couples suspected at-risk for severe thalassemia by using the PCR-based molecular diagnostic assays. The couples at-risk for severe thalassemia were counseled and offered prenatal diagnosis and termination of pregnancy in case of an affected fetus. RESULTS: During the period between January 1998 and December 2005, the screened records included 85522 young females and their partners for premarital screening and 10439 pregnant women for prenatal screening, with 71.38% coverage of total population recorded in this city for premarital screening. Six thousands five hundreds and sixty-three individuals in total were found to be the carriers of thalassemias, with 4312 for alpha thalassemia (4.5%) and 2251 for beta thalassemia (2.3%), respectively. One hundred and forty-eight couples were diagnosed to be at-risk for thalassemias, including 103 for alpha thalassemia and 45 for beta thalassemia, respectively. Successful prenatal diagnosis was made for 142 (98 for alpha thalassemia and 44 for beta thalassemia) out of 148 (95.9%) pregnancies at-risk for severe thalassemias. Twenty-three cases of hydrops fetalis, 4 of Hb H diseases and 14 of beta thalassemia were identified. All 41 pregnancies with affected fetuses were voluntarily terminated. Thus, this has led to a marked decrease of severe thalassemia syndrome since the program started. CONCLUSION: We presented the first community-based prospective screening program in China for control of alpha and beta thalassemia in Zhuhai city with a population of 1.29 million through premarital or prenatal screening. This model could be used for control of thalassemias and other hemoglobinopathies in other regions of China and also in other developing countries.