应用微阵列比较基因组杂交技术对胎儿额外小标记染色体及染色体大片段重复进行产前诊断

Application of Array Comparative Genome Hybridization Technology to Prenatal Diagnosis of Small Supernumerary Marker Chromosome and Chromosome Fragment Repetition

目的对产前羊水细胞培养染色体核型分析,检测出来源不明染色体片段的胎儿应用基于芯片的微阵列比较基因组杂交(aCGH)技术检测,以明确其遗传物质的变异,探讨aCGH技术在检测胎儿来源不明染色体片段致病性中的临床价值。方法通过胎儿羊水细胞培养,染色体G显带核型分析,诊断出2例胎儿染色体异常(来源不明片段),核型分别为47,XY,+Mar及46,XY,add(16)(p13.1)。对此2例标本进行aCGH分析,通过多位点高分辨率扫描确定未知片段的来源及大小。结果 aCGH扫描检测出其中一个胎儿染色体在15q11.1-q12.1区带存在3.2 Mb的重复,另一个胎儿染色体在13q22.2-q33.3区带存在35.1 Mb的重复。结论利用aCGH技术可以方便快速地鉴定和分析染色体的重复变异,也能高效地对染色体重复片段进行定位,结合传统的核型分析技术,可以为判断额外染色体片段的遗传学效应和产前诊断提供帮助。

Objective To explore the clinical application of array comparative genomic hybridization（aCGH）and karyotype analysis in the prenatal evaluation of fetal with small supernumerary marker chromosome（sSMC）and large chromosome fragment repetition.Methods Two fetuses were diagnosed as having abnormal chromosomes by G-banding analysis of amniocytes.One fetus had a karyotype of 47,XY,＋Mar,and the other had a karyotype of 46,XY,add（16）（p13.1）.aCGH was used to examine the precise location and size of the unknown chromosome fragment by multi-site high resolution scanning.ResultsaCGH revealed that there was 3.2Mb duplication in 15q11.1-q12.1in the first fetus,35.1Mb duplication in 13q22.2-q33.3in the second fetus.Conclusion The technology of aCGH can be used for convenient and rapid identification and analysis of chromosome fragment repetition,and also for locating the loci of the chromosome fragment repetition.Combined with the karyotype analysis,it can be applied to genetics analysis and prenatal diagnosis.