染色体G显带核型分析误判一例21三体综合征及其思考  

Reflection of a case misdiagnosed as trisomy 21 syndrome by G-banded chromosomal karyotyping analysis

作　　者：裴雪 刘默涵 刘运强[1] 杨元[1] Pei Xue;Liu Mohan;Liu Yunqiang;Yang Yuan(Department of Medical Genetics,West China Hospital,Sichuan University,Chengdu,Sichuan 610041,China)

机构地区：[1]四川大学华西医院医学遗传室,成都610041

出　　处：《中华医学遗传学杂志》2019年第10期1031-1034,共4页Chinese Journal of Medical Genetics

基　　金：国家自然科学基金(81370748).

摘　　要：目的对1例染色体核型与表型严重不符的21三体综合征患儿进行基因组拷贝数变异(copy number variations,CNVs)分析,探讨对额外小标记染色体(small supernumerary marker chromosome,sSMC)的携带者进行CNVs检测的临床意义.方法患儿主要表现为肥胖以及身材矮小,染色体G显带核型分析提示其为21三体综合征.因其核型与表型不符,使用高通量测序技术对患儿进行全基因组CNVs检测,并用定量PCR方法对结果进行验证.结果CNVs检测显示患儿16p11.2区29642339-29775631存在微重复,重复片段长约133.292 kb.对重复区域内的OMIM基因QPRT和SPN进行的定量PCR检测,显示患儿拷贝数约为正常对照的1.5倍,与测序结果一致.患者父母未携带上述重复.结论患儿16p11.2区微重复为新发的基因组结构变异,但与其临床表现缺乏关联.以染色体微阵列或高通量测序为基础的基因组CNVs检测可以准确判断sSMC的来源,降低临床误诊的风险.Objective To emphasize the clinical significance of copy number variations(CNVs)detection by describing a case misdiagnosed as trisomy 21 syndrome by G-banded chromosomal karyotype analysis.Methods A girl with obesity and short stature was diagnosed as trisomy 21 syndrome by G-banded chromosomal karyotype analysis.Considering the discrepancy of her karyotype with her phenotype,genomic CNVs was detected by next-generation sequencing and the result was verified by quantitative PCR(qPCR).Results A microduplication of 16p11.2:29642339-29775631(133.292 kb)was detected.qPCR assay for QPRT and SPN located in the duplicated region confirmed the finding of CNVs assay.Meanwhile,her parents did not present similar duplication in 16p11.2.Conclusion The 16p11.2 microduplication was a novel genomic structural variation in the girl,though it may not be associated with her clinical manifestations.Chromosomal microarray or next-generation sequencing-based CNVs detection can accurately determine the origin of small supernumerary marker chromosome and reduce the chance of misdiagnosis.

关 键 词：染色体核型 额外小标记染色体 拷贝数变异 16p11.2微重复 

分 类 号：R72[医药卫生—儿科]