一例胎儿羊水15号染色体两个额外小标记片段重复分析

Analysis of Small Supernumerary Marker Chromosomes Repeated in Two Fragments of 15q in A Fetal Amniotic Fluid Case

应用传统G显带技术对1例胎儿羊水细胞及其父母外周血进行染色体核型分析,进一步用染色体拷贝数变异(copy number variant,CNV)技术明确胎儿额外小标记染色体(small supernumerary marker chromosome,sSMC)的来源。胎儿羊水染色体G显带核型分析结果为47,XY,+mar;羊水CNV-seq显示dup(15)(q11.2q13.2)区域重复和dup(15)(q13.2q13.3)区域重复,片段大小分别为7.64 Mb和1.58 Mb,为致病性。胎儿父亲未检出染色体非整倍体,母亲3号染色体q13.13处缺失0.28 Mb区域,临床意义未明确。通过CNV技术可以确定sSMC的来源,可作为传统核型分析的补充,为临床产前诊断和遗传咨询提供可靠的依据。

By using the conventional G-banding technique to analyze the chromosome karyotype of one fetal amniotic fluid cell and peripheral blood of the fetal′ s parents,and furtherly the clinical value of chromosome copy number variation(CNV) technique was used to identify the source of fetal small supernumerary marker chromosome(sSMC).The G-banding karyotype of fetal amniotic fluid was 47,XY,+mar;Fetal amniotic fluid CNV-seq showed dup(15)(q11.2q13.2) region repeats and dup(15)(q13.2q13.3) region repeats with fragment sizes of 7.64 Mb and 1.58 Mb respectively,pathogenicity.Chromosome aneuploidy was not detected from the fetal′s father,the mother had a deletion of a 0.28 Mb region of chromosome 3 at q13.13,the clinical significance was unclear.The source of sSMC could be identified by CNV technique which could be used as a supplement to traditional karyotype analysis and provide a reliable basis for clinical prenatal diagnosis and genetic counseling.