18号染色体短臂缺失1例的实验室诊断

Laboratory diagnosis of chromosome 18 short arm deletion in one case

目的:对1例羊水标本疑似18号染色体短臂缺失进行实验室诊断,探讨染色体畸变检测在产前诊断中的应用价值。方法:孕妇于21周抽取羊水进行羊水细胞培养,染色体核型分析,同时留取羊水5mL,离心,留取细胞提取DNA,经高通量DNA测序进行进一步鉴定,明确断裂点位置,片段大小,是否有致病性拷贝数变异等。结果:羊水细胞染色体核型分析疑似18号短臂部分缺失,结果拟报告为46,XN,del(18)(p11.32);全基因组拷贝数变异分析(CNVs)检测结果显示胎儿18号染色体p11.32-p11.31处缺失5.16Mb区域。结论:CNVs畸变检测在产前诊断中具有极大的应用价值,能够检测出具有明确临床意义的染色体微结构异常。

Objective: To assess the value of prenatal detection of chromosomal aberration through laboratory diagnosis of suspected deletion of short arm of chromosome 18 in amniotic fluid in one case. Methods :Amniotic fluid was obtained from one pregnant woman at 21st gestational week,and subjected to cell culturing for karyotype analysis.Then,5 mL of amniotic fluid was collected and centrifugated.DNA was extracted from the cells and undergone high-throughput DNA sequencing to determine the location of breakpoints,fragment size and pathogenic copy number variation. Results :Chromosome karyotype analysis of amniotic fluid cells indicated suspected partial deletion of short arm of chromosome 18.The results were reported to be 46,XN,del (18)(p11.32).Copy number variations (CNVs) results revealed that 5.16 Mb region was deleted at chromosome p11.32-p11.31 of fetus No.18. Conclusion :CNVs aberration detection is clinically valuable in prenatal diagnosis of fetal development,because it can detect the micro-structural abnormalities of chromosome.