Objective To investigate the detection of pathogenic and likely pathogenic copy number variations (CNVs) in 120 children with intellectual disability (ID)/developmental delay (DD) in Anhui province, and to analyze the clinical phenotype of the children, so as to clarify the genetic etiology of ID/DD children. Methods A total of 120 children with unexplained ID/DD who were treated in the Department of Pediatric Rehabilitation of Anhui Children′s Hospital from May 2019 to June 2020 were selected and tested for the presence of pathogenic and likely pathogenic CNVs by chromosome microarray analysis (CMA).The clinical phenotype and characteristics of pathogenic and likely pathogenic CNVs were analyzed. Results Among 120 children with ID/DD, pathogenic CNVs were detected in 18 cases (15.00%), likely pathogenic CNVs in 2 cases (1.67%), variation of uncertain significance CNVs in 39 cases (32.50%), and likely benign and benign CNVs in 61 cases (50.83%). Among 20 children with pathogenic and likely pathogenic CNVs, 5 had congenital malformations/special faces, and 14 had one or more other diseases. There were 3 cases, 12 cases and 5 cases with mild, moderate and severe mental retardation, respectively. There were 21 pathogenic and likely pathogenic CNVs in 20 children with ID/DD, including 13 microdeletion fragments (61.90%) and 8 microduplication fragments (38.10%) with a ratio of 1.63∶1. The average fragment size was 6.34 Mb. Twenty one pathogenic and possibly pathogenic CNVs were detected most on chromosomes 2 and 22 (3 locations).Among the 20 children with ID/DD, 10 cases (50.00%) had known syndromes, and 10 cases (50.00%) had still undefined syndromes or disease areas in the database. Conclusion For children with unexplained ID/DD, CMA detection can clarify the genetic etiology, which is of great significance for the treatment of children and guidance for their parents to reproduce.
Key words
intellectual disability /
developmental delay /
chromosome microarray analysis /
copy number variation /
clinical phenotype
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