Identification of copy number variants in children and adolescents with autism spectrum disorder: a study from Turkey

Abstract

Background: Copy number variants (CNVs) play a key role in the etiology of autism spectrum disorder (ASD). Therefore, recent guidelines recommend chromosomal microarrays (CMAs) as first-tier genetic tests. This study's first aim was to determine the clinical usefulness of CMAs in children diagnosed with ASD in a Turkish population. The second aim was to describe the CNVs and clinical phenotypes of children with ASD.

Methods and results: This was a single-center retrospective cross-sectional study. Data were obtained from the medical records of children with ASD followed at Gazi University Hospital, (Ankara, Turkey). The sample consisted of 47 ASD cases (mean age: 60.34 ± 25.60 months; 82.9% boys). The diagnostic yield of the CMAs was 8.5%. Four pathogenic CNVs were identified: 9p24.3p24.2 deletion, 15q11-q13 duplication, 16p11.2 deletion, and 22q13.3 deletion. Also, four variants were found at 2q36.3, 10p11.21, 15q11.2, and Xp11.22, which were classified as variants of uncertain significance (VUS).

Conclusions: The TRAP12 and PARD3 genes in CNVs classified as VUS may be worth investigating for autism. The initial identification of both clinical and biological markers can facilitate monitoring, early intervention, or prevention and advance our understanding of the neurobiology underlying ASD.

Keywords: Array comparative genomic hybridization; Autism spectrum disorder; Copy number variant; Turkish children.