MLPA技术用于假性肥大型肌营养不良症产前基因诊断的价值

摘要

目的 探讨多重连接探针扩增(MLPA)技术用于假性肥大型肌营养不良症(DMD)先证者家系中高风险孕妇产前DMD基因诊断的价值.方法 收集2005年至2012年广州医学院第三附属医院、南方医科大学南方医院等4家医院的155例有DMD先证者家系的高风险孕妇,其中7例孕早期孕妇取绒毛标本,148例孕中期孕妇取羊水样本,对绒毛标本和血性羊水标本排除母体DNA污染后,采用MLPA技术对绒毛和羊水样本行胎儿DMD基因检测；计算155个家系中DMD基因外显子突变发生次数.结果 (1)155例孕妇中共检出DMD胎儿27例、胎儿DMD基因携带者28例、正常胎儿100例.155例胎儿中,男胎72例,其中27例为DMD胎儿(38％)；女胎83例,其中28例胎儿为DMD基因携带者(34％).(2)27例DMD胎儿中,DMD外显子缺失突变22例(14.2％,22/155)；外显子重复突变5例,(3.2％,5/155)；28例DMD基因携带者中,DMD外显子杂合缺失突变25例(16.1％,25/155),外显子杂合重复突变3例(1.9％,3/155).155个家系中,DMD基因突变的发生主要分布在外显子45 ～ 52之间,其中外显子49突变发生次数最高,共22次.(3)7例早孕期孕妇的绒毛组织DMD基因诊断结果中,有两例胎儿DMD基因型分别与先证者、孕妇的DMD基因型一致,其中1例为患儿、1例为DMD基因携带者,分别给予终止妊娠和继续妊娠的处理.结论 MLPA技术用于DMD产前基因诊断,能准确区分DMD基因突变是属于缺失型、重复型突变还是杂合性缺失等,对DMD先证者家系的高危孕妇有较高的产前诊断价值,临床结果可靠；绒毛膜活检可用于产前DMD早期基因诊断.%Objective To investigate the clinical value of multiplex ligation-dependent probe amplification (MLPA) in the prenatal gene diagnosis of high risk pregnant women from Duchenne muscular dystrophy (DMD) families.Methods The 155 high risk pregnant women from DMD families were recruited from 2005 to 2012 in 4 hospitals in Guangzhou,such as Southern Hospital of Southern Medical University and the Third Affiliated Hospital of Guangzhou Medical University.Among all the samples,7 were chorionic villus samples taken from early-stage pregnancy and 148 were amniotic fluid samples from mid-stage pregnancy.After the maternal contamination was eliminated,the fetal DMD gene screening was carried out by using MLPA.The mutation rates in DMD exons were calculated in all the 155 families.Results (1) Among the 155 fetuses of the DMD high risk pregnant women,there were 72 male fetuses and 83 female fetuses.In the male fetuses,there were 27 sufferers(38％).In the female fetuses,there were 28 carriers(34％).And there were 100 normal fetuses.(2) Among the 27 DMD sufferers,22 cases were DMD exon homozygous deletions (14.2％,22/155) and 5 cases were DMD exon duplications (3.2％,5/155).Among the 28 carriers,25 cases were gene heterozygous deletions (16.1％,25/155) and 3 cases were gene heterozygous duplications (1.9％,3/155).In the 155 families,the DMD mutations mainly occurred in exons 45-52,and the exon 49 had the highest mutation rates of 22 times.(3) Among the 7 cases of prenatal gene diagnosis using chorionic villus samples,2 fetuses had the identical DMD genotypes with their mothers and probands.One was a DMD sufferer and the other was a carrier.Termination or continuation of pregnancy was suggested based on the genotype of the fetus.Conclusions MLPA provides an accurate method in the prenatal diagnosis of DMD.It could be used to distinguish DMD gene homozygous deletions from heterozygous deletions and duplications.Therefore,it is valuable for DMD prenatal diagnosis in high-risk women.Chorionic villus sampling can be applied to the early prenatal diagnosis for DMD disease.