Genetic analysis of a child with small supernumerary marker chromosomes by chromosomal microarray analysis

doi:10.3969/j.issn.1673-8640.2025.02.005

Abstract

Abstract:

Objective To analyze the origin of small supernumerary marker chromosomes（sSMC） of a mental decline and developmental delay child，and to investigate its mechanism and provide a reference for clinical genetic counseling. Methods Peripheral blood of the child and her parents was analyzed with conventional G-banding. Chromosomal microarray analysis（CMA） was performed to analyze the whole-genome copy number variations（CNV） in order to identify the origin，region and size of sSMC. Results The karyotype of the parents was normal，and the karyotype was 47，XX，+mar. CMA showed that the child had a duplication of 9.7 Mb in chr15q11.2q13.3（copy number was 4），which was clinical pathogenic CNV correlating with dup（15） syndrome. Conclusions Because of the diversity of the origin of sSMC，it is necessary to combine CMA with traditional chromosome karyotype analysis to identify the origin，region and size of sSMC，so as to provide a reference for the diagnosis，treatment and clinical genetic counseling for children.

Key words: Small supernumerary marker chromosome, Conventional G-banding, Chromosomal microarray analysis, Whole-genome copy number variation

CLC Number:

R446.1

ZHANG Xia, YIN Yanjun, FU Zhixuan, KE Jiangwei. Genetic analysis of a child with small supernumerary marker chromosomes by chromosomal microarray analysis[J]. Laboratory Medicine, 2025, 40(2): 131-134.

Figures/Tables 2

References 26

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