目的 明确1例不明原因生长发育迟缓患儿染色体异常的性质及来源，分析其与表型的相关性。 方法 选择2019年7月9日就诊于郑州大学附属儿童医院的1例患儿作为研究对象。用G显带染色体核型分析及单核苷酸多态性微阵列芯片技术(SNP array)对患儿及其父母进行检测。 结果 G显带核型分析结合SNP array技术提示患儿染色体核型为：46，XX，dup(7)(q34q36.3)，其父母核型均未见异常。SNP array检测提示患儿染色体7q34q36.3区存在20.6 Mb重复，具体为arr[hg19]7q34q36.3(138335828_158923941)×3，其父母均未查见染色体拷贝数异常。 结论 患儿为罕见的7q部分重复且为新发变异，其基因型与表型的相关性有助于临床诊疗及遗传咨询。 Objective To define the nature and origin of a chromosomal aberration in a child with unexplained growth and development retardation, and to analyze its genotype-phenotype correlation. Methods A child who had presented at the Affiliated Children′s Hospital of Zhengzhou University on July 9, 2019 was selected as the study subject. Chromosomal karyotypes of the child and her parents were determined with routine G-banding analysis. Their genomic DNA was also analyzed with single nucleotide polymorphism array (SNP array). Results Karyotyping analysis combined with SNP array suggested that the chromosomal karyotype of the child was 46, XX, dup(7)(q34q36.3), whilst no karyotypic abnormality was found in either of her parents. SNP array has identified a de novo 20.6 Mb duplication at 7q34q36.3 [arr[hg19]7q34q36.3(138335828_158923941)×3] in the child. Conclusion The partial trisomy 7q carried by the child was rated as a de novo pathogenic variant. SNP array can clarify the nature and origin of chromosomal aberrations. Analysis of the correlation between genotype and phenotype can facilitate the clinical diagnosis and genetic counseling.
Abstract
Objective To define the nature and origin of a chromosomal aberration in a child with unexplained growth and development retardation, and to analyze its genotype-phenotype correlation. Methods A child who had presented at the Affiliated Children′s Hospital of Zhengzhou University on July 9, 2019 was selected as the study subject. Chromosomal karyotypes of the child and her parents were determined with routine G-banding analysis. Their genomic DNA was also analyzed with single nucleotide polymorphism array (SNP array). Results Karyotyping analysis combined with SNP array suggested that the chromosomal karyotype of the child was 46, XX, dup(7)(q34q36.3), whilst no karyotypic abnormality was found in either of her parents. SNP array has identified a de novo 20.6 Mb duplication at 7q34q36.3 [arr[hg19]7q34q36.3(138335828_158923941)×3] in the child. Conclusion The partial trisomy 7q carried by the child was rated as a de novo pathogenic variant. SNP array can clarify the nature and origin of chromosomal aberrations. Analysis of the correlation between genotype and phenotype can facilitate the clinical diagnosis and genetic counseling.
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