一例胎儿羊水15号染色体两个额外小标记片段重复分析

doi:10.12280/gjfckx.20240047

摘要/Abstract

摘要：

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。

关键词: 额外小标记染色体, 染色体畸变, DNA拷贝数变异, 遗传标记, 产前诊断

Abstract:

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.

Key words: Small supernumerary marker chromosome, Chromosome aberrations, DNA copy number variations, Genetic markers, Prenatal diagnosis

童飞, 黄卫彤, 刘开敏, 周朔安, 卢秀华. 一例胎儿羊水15号染色体两个额外小标记片段重复分析[J]. 国际妇产科学杂志, 2024, 51(4): 473-476.

TONG Fei, HUANG Wei-tong, LIU Kai-min, ZHOU Shuo-an, LU Xiu-hua. Analysis of Small Supernumerary Marker Chromosomes Repeated in Two Fragments of 15q in A Fetal Amniotic Fluid Case[J]. Journal of International Obstetrics and Gynecology, 2024, 51(4): 473-476.

图/表 5

图1 胎儿羊水G显带核型分析图注：胎儿羊水染色体G显带核型分析结果为47,XY,+mar。

图2 胎儿CNV-seq分析图注：胎儿羊水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（拷贝数为4）和1.58 Mb（拷贝数为3），为致病性。

图3 胎儿父亲CNV-seq分析图注：胎儿父亲CNV-seq显示未检出染色体非整倍体。

图4 胎儿母亲CNV-seq分析图注：胎儿母亲CNV-seq显示3号染色体q13.13处缺失0.28 Mb区域，临床意义未明确。

图5 胎儿B超图注：宫内中孕，单活胎（相当于23+周）。红色箭头所示为胎儿右足呈内翻姿势。

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