Utility of Chromosomal Microarray in Children with Unexplained Developmental Delay/Intellectual Disability

ObjectiveTo evaluate the chromosomal microarray (CMA) yield among children who presented with global developmental delay/intellectual disability (GDD/ID) with/without co-occurring conditions. Methods: The pathogenic copy number variation (pCNVs) findings on CMA of all children who presented with unexplained GDD/ID were categorized based on the clinical features. The karyotype results were compared with CMA. Results: The overall pCNV yield in children presenting with GDD/ID with or without comorbid conditions constituted 20.9%. Among the 17 pCNVs, 13 were losses and four were gains. Cardiac defect was the only co-morbidity in our study that demonstrated statistically significant prediction for pCNV (odds ratio 6.13, p value- 0.031). Six children who were karyotyped prior to CMA testing showed a structural abnormality. Conclusions: In our study, 20.9% of children with GDD/ID showed pCNVs on CMA. Cardiac defect alongside GDD/ID, emerged as the single strongest phenotype associated with pCNVs. CMA also provided vital information in previously karyotyped patients.