假肥大型肌营养不良症产前基因诊断的临床应用

Clinical application of prenatal gene diagnosis of Duchenne and Becker muscular dystrophy

目的 建立规范的假肥大型肌营养不良症 (DMD/BMD)产前基因诊断程序。方法 利用DMD基因内 18个缺失热点的PCR引物 ,6个DMD基因内 (CA)n短重复序列 (STR)引物以及性别决定基因SRY引物 ,多重聚合酶链反应检测羊水胎儿脱落细胞、先证者和双亲外周血有核细胞基因组DMD基因 ,通过胎儿性别确定、基因缺失检测和基因连锁分析确定胎儿DMD基因状态。结果 在 4例先证者基因缺失家系的产前诊断中 ,2例男胎DMD基因缺失与先证者相同 ,1例女胎为基因缺失携带者 ,1例男胎未发现缺失 ;在 4例有 2个或 2个以上患者且先证者未检出缺失的家系产前诊断中 ,发现获得风险染色体的男胎与女胎各 1例 ,余1例女胎和 1例男胎均未携带风险染色体。检测结果的可靠性经流产胚胎和已出生胎儿DNA分析、DMD临床症状监测得到部分证实。结论 胎儿性别基因诊断、DMD基因缺失检测结合基因连锁分析的方法 ,在严格控制检测范围、规范的检测程序和有效的质量控制下 ,能准确地对DMD/BMD进行产前基因诊断 。

Objective To establish a normative procedure for clinical prenatal gene diagnosis of Duchenne and Becker muscular dystrophy(DMD/BMD).Methods Fetus DMD gene status was confirmed by sexual determination,detection of gene deletion and analysis for gene linkage, which were performed using multiplex polymerase chain reaction with 25 primers which were for 18 dystrophin exons,6 intragenic short tandem repeat(STR) and SRY gene.Results Probands deletions were determined in 4 DMD pedigrees in which 2 male fetus deletions were the same as the probands, 1 female fetus was carrier of DMD gene deletion,and 1 male fetus was normal.In other 4 DMD pedigrees,in whom more than two patients were found but no probands deletion was found.one male and one female fetus carried inherited risk chromosome but the other one male and female fetus were normal.The reliability of the test was confirmed partly by the second test for the DNA of aborted embryos and neonates and monitoring for the clinical symptoms of DMD.Conclusion With strict control for detection range,normative detection procedure and effective quality control,the detection for deletion combined with sexual determination and gene linkage analysis is the most effective laboratory test up to now in the clinical prenatal gene diagnosis for the risk fetus of DMD/BMD.