Copy Number Variations in a Turkish Cohort of Children with Intellectual Disability*


SÜNNETÇİ AKKOYUNLU D., KARA B., ÇİNE N., EREN KESKİN S., Dogruoglu B., Ilkay Z., ...More

Experimed, vol.13, no.3, pp.263-275, 2023 (Scopus) identifier

  • Publication Type: Article / Article
  • Volume: 13 Issue: 3
  • Publication Date: 2023
  • Doi Number: 10.26650/experimed.1380210
  • Journal Name: Experimed
  • Journal Indexes: Scopus
  • Page Numbers: pp.263-275
  • Keywords: array CGH, copy number variation, deletion, duplication, Intellectual disability, Turkish cohort
  • Kocaeli University Affiliated: Yes

Abstract

Objective: Intellectual disability (ID) is a complex, variable, and clinically heterogeneous neurodevelopmental disorder that affects 1% – 3% of the global population. Copy number variations (CNVs) contribute to approximately 15%–20% of ID cases. Array comparative genomic hybridization (aCGH) is the first-line test for diagnosing patients with ID with/without multiple congenital anomalies (MCAs). This study aimed to present CNVs identified in a retrospective aCGH cohort of Turkish patients with ID with/without other medical conditions. Materials and Methods: The study population consisted of 210 patients (139 male, 71 female) aged 2–18 years. aCGH analysis was performed using oligo and bacterial artificial chromosome (BAC)-based microarray platforms. CNVs were interpreted using public databases and literature mining and categorized according to international guidelines. Results: Forty-five CNVs were detected in 38 (18%) patients. Among these CNVs, 21 (46.6%) were pathogenic, 4 (8.8%) were likely pathogenic, and 8 (17.7%) were variants of uncertain clinical significance (VUS). Nineteen CNVs corresponded to rare microdeletion/ microduplication syndromes. Conclusions: This study reports rare CNVs or syndromes among Turkish patients with ID with/without other medical conditions. Data revealed an overall diagnostic rate of 11.43%, which confirms aCGH as the first-line technology allowing geneticists to diagnose complex phenotypes, identify candidate genes involved in ID, and explore novel CNV effects.