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Introduction: Autism spectrum disorder is a genetically and phenotypically heterogeneous group. Genetic studies carried out to date have suggested that both common and rare genetic variants play a role in the etiology of this disorder. In our study, we aimed to investigate the effect of FOXP2, GRIN2B, KATNAL2 and GABRA4 gene variants in the pathogenesis of autism spectrum disorder. Method: In our prospectively planned study, all exons and exon-intron junctions of FOXP2, GRIN2B, KATNAL2 and GABRA4 genes were screened by next generation sequencing analysis in 96 patients who diagnosed with autism spectrum disorder. Results: In our study, the average age was 10.1 and the male/female ratio was 75/21. Pathogenic or likely pathogenic variants were not detected in FOXP2, GRIN2B, KATNAL2 and GABRA4 genes, however, 69 intronic variants of unknown clinical significance were detected in 50 cases (52%). Among those, 26 were in the GABRA4 gene, 22 in the FOXP2 gene, 13 in the KATNAL2 gene, and 8 in the GRIN2B gene. Twenty three of these 69 variants were novel that were not previously reported in the literature. Conclusion: In our study, we could not identify a relationship between the autism spectrum disorder and FOXP2, GRIN2B, KATNAL2 and GABRA4 genes. Identifying genetic risk factors that play a role in the etiopathogenesis of autism spectrum disorder will contribute significantly to understanding the molecular mechanisms of the disease and the development of new treatment strategies. In this context, comprehensive molecular genetic studies such as whole exome or whole genome sequencing are required with higher number of cases in different populations. [ABSTRACT FROM AUTHOR]

Introduction: Aneuploids, copy number variations (CNVs), and single nucleotide variants in specific genes are the main genetic causes of developmental delay (DD) and intellectual disability disorder (IDD). These genetic changes can be detected using chromosome analysis, chromosomal microarray (CMA), and next-generation DNA sequencing techniques. Therefore; In this study, we aimed to investigate the importance of CMA in determining the genomic etiology of unexplained DD and IDD in 123 patients. Method: For 123 patients, chromosome analysis, DNA fragment analysis and microarray were performed. Conventional G-band karyotype analysis from peripheral blood was performed as part of the initial screening tests. FMR1 gene CGG repeat number and methylation analysis were carried out to exclude fragile X syndrome. Results: CMA analysis was performed in 123 unexplained IDD/DD patients with normal karyotypes and fragile X screening, which were evaluated by conventional cytogenetics. Forty-four CNVs were detected in 39 (39/123=31.7%) patients. Twelve CNV variant of unknown significance (VUS) (9.75%) patients and 7 CNV benign (5.69%) patients were reported. In 6 patients, one or more pathogenic CNVs were determined. Therefore, the diagnostic efficiency of CMA was found to be 31.7% (39/123). Conclusion: Today, genetic analysis is still not part of the routine in the evaluation of IDD patients who present to psychiatry clinics. A genetic diagnosis from CMA can eliminate genetic question marks and thus alter the clinical management of patients. Approximately one-third of the positive CMA findings are clinically intervenable. However, the emergence of CNVs as important risk factors for multiple disorders increases the need for individuals with comorbid neurodevelopmental conditions to be the priority where the CMA test is recommended. [ABSTRACT FROM AUTHOR]