The Role of Molecular Karyotyping in the Genetic Etiology of Autism

Abstract

The aim of this study was to investigate the deletions and duplications with a molecular karyotyping technique and to elucidate the etiology of autism. A total of 31 patients (20 boys and 11 girls) between 4 to 18 years old with normal chromosomal analysis and no Fragile X mutation were diagnosed in the Ege University Child and Adolescent Psychiatry Clinic with autism (according to DSM-IV-TR criteria) and were enrolled in the study. Symptom severity of the patients was evaluated with a Childhood Autism Rating Scale. Blood samples (EDTA collected) were obtained in order to extract DNA. Whole genome molecular karyotyping analyses were performed with Illumina IScan system by chips, which can scan 330.000 Single Nucleotid Polymorphisms (SNPs) to detect structural anomalies with a 10-kb resolution. All patients had copy number variations (CNV) that sized between 20-kb and 3-Mb. All detected CNVs were analyzed by the help of KaryoStudio software and DGV database. The ones which might be causal and pathogenic were selected. Pathogenic CNVs (7 deletions, 2 duplications) were detected in 9 patients (29%). As a result, this is the first study whereby a molecular karyotyping technique was successfully used in autism patients in Turkey. Moreover, an intermediate resolution of 330.000 SNP chips were proven to be efficient for molecular karyotyping analysis.