散发型DMD／BMD家系突变分析及产前诊断研究

Mutation analysis and prenatal diagnosis of sporadic DMD/BMD families

目的分析散发型DMD／BMD家系中患者的致病突变，为部分家系的胎儿进行产前基因诊断，明确该类家庭中女性成员是否致病突变携带者，分析该类家系新发突变的比例。方法共收集30个散发DMD／BMD家系，应用传统mPCR方法分析DMD基因缺失热区中的18个外显子；应用MLPA方法，对家系中的30例患者及23个家系中的28位女性成员，进行DMD基因全部79个外显子的定量分析，并为其中19个家系进行20例产前诊断。结果mPCR检测到19例缺失突变；MLPA检测到21例缺失突变和3例重复突变，并明确缺失突变范围。在检测到突变的家系中，10例母亲为缺失突变携带者，2例为重复突变携带者，9例母亲不是携带者，新发突变比例为37．5％。7例患者的姐妹中5例为携带者（3例缺失，2例重复），2例不是携带者。经产前诊断，12例男性胎儿中5例为患者，8例女性胎儿中2例为携带者。结论MLPA方法可全面检测DMD基因缺失及重复突变、明确女性携带者，为产前诊断提供准确信息。

Objective To analyze the pathogenic mutation of sporadic patients in Duchenne/ Becker muscular dystrophy （DMD/BMD） families and to perform prenatal diagnosis, identify the female carriers and evaluate the ratio of de novo mutation in these pedigrees. Methods A total of 30 sporadic DMD/BMD families were included. Traditional multiplex PCR was used to detect the 18 exons in the deletion hot area of DMD gene. MLPA was used to detect the deletion or duplication mutations of DMD gene for 30 patients and 28 females from 23 families. Prenatal diagnosis was performed in 19 families. Results Deletion mutation was detected in 19 patients through mPCR. Twenty-one deletions and 3 duplication mutations were detected by MLPA. Among 21 mothers, 10 mothers were carriers of deletion mutation and two duplication mutation carriers. The other 9 mothers were non-carriers, the mutations in these families were de novo and the ratio was 37.5%. Among seven sisters, five were arriers and two non-carriers. In the prenatal diagnosis families, 2 of 8 female fetuses were carriers and 5 of 12 male fetus patients. Conclusion The MLPA technique has proved to he an accurate and reliahle tool not only for the deletion and duplication mutations of DMD patients, but also for the prenatal diagnosis and the female carriers in these families.