疑似Prader-Willi综合征患儿的细胞遗传学和基因组拷贝数变异检测

Cytogenetics and genome-wide copy number variation analysis of a suspect patient with Prader-Willi syndrome

目的对1个疑似Prader-Willi综合征患儿进行基因组拷贝数变异检测，确诊其病因。方法收集临床诊断疑似Prader—Willi综合征患儿及其父母外周血，常规G显带和高分辨染色体检查并提取患儿基因组DNA行全基因组拷贝数变异检测。结果患儿及其父母高分辨染色体技术结果未见异常，但全基因组拷贝数检测患儿结果提示染色体15q11．2-13．1区域杂合缺失5Mb；患儿定期做Baylay、Gesell发育量表检查提示智商为60～70分，符合Prader—Willi综合征的临床特征。结论染色体15q11．2-13．1区域杂合缺失是该家系Prader—Willi综合征的病因。当Prader-Willi综合征患者在细胞遗传学未发现异常时，应进一步分子遗传学检查可弥补细胞遗传学方法的不足。

Objective To definite the etiopathogenisis by carrying out the genome-wide copy number variation analysis for a suspect patient with Prader-Willi syndrome. Methods The peripheral blood was collected from the patient who was diagnosed as having Prader-Willi syndrome, as well as his parents for conventional cytogenetic G-banding and high resolution chromosome assay. Genomic DNA of the child patient was extracted from the blood to perform the genome-wide copy number variation analysis. Results There was a heterozygosis deletion of a 5Mb region in chromosome 15q11. 2-q13.1 by the genome-wide copy number variation analysis, but no abnormality was observed in high resolution chromosome assay in the child patient and his parents, Baylay and Gesell developmental scale was assessed regularly; the results suggested that the IQ of the child patient was 60-70, according with the clinical feature of Prader-Willi syndrome. Conclusion The heteroaygosis deletion in chromosome 15q11.2-q13.1 is the cause of Prader-Willi syndrome in this family. Further molecular genetics detection can make up for the insufficiency in cytogenetics methods, when no abnormality is observed at the level of cytogenetics in patients with Prader-Willi syndrome.