多重探针连接依赖式扩增快速检测染色体非整倍体异常

目的评价多重探针连接依赖式扩增（multiplex ligation-dependent probe amplification，MLPA）在常见染色体非整倍体异常及其在产前诊断中的应用价值。方法收集经染色体核型分析证实的12例21三体、1例（45，X）、1例（47，XYY）患者，8名正常健康人外周血标本和4例21三体胎儿脐带血标本及1例21三体胎儿羊水、7例核型正常胎儿羊水，共计34份样本。提取外周血或脐带血基因组DNA，羊水标本蛋白酶K消化获得细胞裂解液，采用MLPA技术检测34份标本13、18、21、X和Y染色体拷贝数的变化。结果48h内即可完成样本分析。除1份离心后含大量红细胞的羊水标本经MLPA分析后提示（69，XXY）或母血污染外，其余33份外周血、脐带血或羊水标本报告均与染色体核型分析结果一致，临床符合率97．1％。正常二倍体标本Ratio值除Y染色体相对拷贝数变异略大外，其余均接近于1．0。经单因素方差分析，21三体和正常二倍体标本的Ratio均值间差异有统计学意义（F=298．906，P=0．000）。结论高灵敏度MLPA技术结合计算机辅助数据分析方法操作简便、快速、可自动化，是诊断常见染色体非整倍体异常的可靠方法。

Rapid detection of chromosomal aneuploidies by multiplex ligation-dependent probe amplification

Objective To test whether multiplex ligation-dependent probe amplification(MLPA)could be used for the prenatal detection of the most common aneuploidies of chromosomes 13,18,21,X,and Y.Methods 34 cases including 22 blood samples(12 with trisomy 21,1 with monosomy X,one male witll extra Y and 8 healthy persons),4 cord blood samples with Down syndrome and 8 amniotic fluid samples ( 1 with trisomy 21 and 7 normal fetuses)were recruited into this study.All samples were confirmed by karvotype analysis. DNA was extracted from blood and amniotic lysate was incubated with proteinase K.MLPA was used to determine the relative copy numbers.Results The resuhs were available within 48 h and were concordant with karyotype analysis in all but one case of amniotic fluid that was suggested to be triploid sample 69,XXY by MLPA or contaminated by maternal blood.This sample actually was found containing a number of red blood cells after centfifugation in test. In total,the concordance rate with clinical characteristics was 97.1%.The Ratio values of 13,18,21,X in normal samples were approaching 1.0 except chromosome Y having slightly higher variation in relative copy number.The difference of ratio means between the normal and trisomy 21 samples was statistically significant by one-way ANOVA(F=298.906.P=0.000).Conclusion Computer assisted MLPA with high sensitivity is a rapid,simple,automatic and reliable method for detection of common chromosomal aneuploidies.