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

Year 2023, , 263 - 275, 28.12.2023

Deniz Sünnetçi Akkoyunlu , Bülent Kara , Naci Çine , Seda Eren Keskin , Buket Doğruoğlu , Zeynep İlkay , Tolgahan Özer , Hakan Savlı

https://doi.org/10.26650/experimed.1380210

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.

Keywords

Intellectual disability, copy number variation, Turkish cohort, array CGH, deletion, duplication

Ethical Statement

Ethics Committee Approval: Ethical approval of the study was obtained from the Human Subjects Research Ethical Committee of the Kocaeli University (2009/102).

Supporting Institution

The authors declare that this study has received no financial support.

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