Karyotype and molecular cytogenetic analysis among sample of Iraqi children with idiopathic intellectual disability

Abstract

Background: Most children with uncertain etiology have moderate ID, which accounts for 48.8% of all intellectual impairments. Genetic testing allows early etiologic diagnosis, medical comorbidity monitoring, and genetic counselling for families. Aim of the study: To study the clinical features of Intellectual disabilities, determine the yield of karyotyping in children with idiopathic intellectual disability. Patients and Methods: A retrospective and prospective observational study were conducted on seventy-two Pediatric patients with intellectual disabilities who visited child welfare teaching hospital outpatient clinic for Pediatric neurological diseases. The data records were collected from the beginning of January 2018 to the end of July 2022, children aged 5 up to 14 years who were diagnosed clinically to have intellectual disability were included. Raven’s IQ test, Brain MRI were performed in all patients with intellectual disability. GTG banding karyotype, florescence in situ hybridization and PCR were the materials used. Results: The male-to-female ratio was ≈ (4:1). Speech difficulty and Behavioral abnormalities were significantly higher among males (P=0.042), (P=0.017) respectively. The majority of children were with normal MRI 45 (62.5%), while the highest proportion of abnormal MRI findings was brain atrophy reported in 16 (22.2%) of cases. Epilepsy was among only 22 (30.6%). Conclusion: In this study, Individuals with intellectual disabilities including speech delays and/or learning disabilities, with or without behavior problems, are more likely to have chromosome abnormalities, in form of deletion, duplication, and fragile X, and particularly del (22) (22q 11.2)], [del (5) (p15.1- p 15.2)..Most of the cases with duplication had mild levels of intellectual disability and positive history of parental consanguinity.