关键词: 全面性发育延迟, 病因, 常规染色体核型, 染色体微阵列, 基因组拷贝数变异

Abstract: Objective To explore the clinical and genetic etiology in children with global developmental delay(GDD),and to provide theoretical basis for the genetic counseling,recurrence risk assessment of sibling and prenatal diagnosis. Methods A total of 92 cases of unexplained GDD were selected and analyzed by routine G banding karyotype analysis.If the result of routine G banding karyotype analysis was normal,further lines of chromosomal microarray analysis(CMA) for genome-wide copy number variations (CNVs) detection,analysis of pathogenesis of copy number variation would be conducted.And the correlation between CNVs and GDD was analyzed. Results In this study,there were 18 cases (19.6%) with abnormal chromosomal results of 92 patients with unexplained GDD.Among them,11 cases (12.0%) showed abnormal karyotype analysis results by routine G banding.Seven cases (7.6%) of abnormality in chromosome microarray analysis were detected.7 pCNVs were found in these 7 cases including 4 known syndromes like 1p36 deletion comprehensive syndrome,2q37 microdeletion syndrome,18q deletion syndrome,and lq21.1 microdeletion syndrome. Conclusions Gene CNVs related microdeletion/repetition is one of the main genetic causes of unknown GDD patients.Routine G banding karyotype analysis combined with CMA for patients with unexplained GDD will be helpful for the etiology diagnosis,thereby providing evidence for genetic counseling of their families,recurrence risk assessment and prenatal diagnosis.

Key words: global developmental delay, pathogeny, routine G banding karyotype analysis, chromosomal microarray analysis, copy number variations