Reflection of a case misdiagnosed as trisomy 21 syndrome by G-banded chromosomal karyotyping analysis
10.3760/cma.j.issn.1003-9406.2019.10.021
- VernacularTitle: 染色体G显带核型分析误判一例21三体综合征及其思考
- Author:
Xue PEI
1
;
Mohan LIU
;
Yunqiang LIU
;
Yuan YANG
Author Information
1. Department of Medical Genetics, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
- Publication Type:Clinical Trail
- Keywords:
Chromosomal karyotype;
Small supernumerary marker chromosome;
Copy number variations;
16p11.2 microduplication
- From:
Chinese Journal of Medical Genetics
2019;36(10):1031-1034
- CountryChina
- Language:Chinese
-
Abstract:
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: 29 642 339-29 775 631 (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.
