Pathogenic copy number variation and clinical phenotype in children with neurodevelopment disorders

Objective To analyze the microdeletion and microduplication characteristics of pathogenic copy number variations (pCNVs) and clinical phenotypes in children with neurodevelopmental disorders, and to clarify the genetic pathogenic cause of children with neurodevelopmental disorders. Methods Children who were identified as neurodevelopment disorders such as global developmental delay and mental disorder, by next generation sequencing-based whole genomic copy number variation testing from January 2017 to November 2019 at the First Affiliated Hospital of Anhui Medical University were enrolled, and the clinical phenotypes and pCNVs were reviewed analyzed. Results There were 36 pCNVs in total 31 children, consisting of 24 microdeletion segments (66.67%)and 12 microduplication segments (33.33%), with sizes ranging from 320.00 kb to 93.26 Mb (mean 11.33 Mb). pCNVs frequently occurred in chromosome 15 , chromosome 8 and chromosome X, there were 9 children with 9 pCNVs in chromosome 15(25.00%), 3 children with 5 pCNVs in chromosome 8(13.89%)and 3 children with 4 pCNVs in chromosome X(11.11%) .The mainly clinical manifestations were motor disorder (30 children, 96.77%), mental disorder (22 children, 70.97%), speech development delay(22 children, 70.97% )accompanied by the malformation(11 children, 35.48%), abnormal face(11 children, 35.48%) and epilepsy(8 children, 25.81%), multisystem abnormalities generally exist in one individual. Conclusion This study demonstrates the clinical utility of whole genome CNVs testing in the genetic diagnosis of children with neurodevelopment disorders.Genetic pathogenesis of children with neurodevelopmental disorders can be revealed by the analysis of pCNVs. Key words: Neurodevelopmental disorder; Pathogenic copy number variation; Child