The results of CNVs analysis in patients with neurodevelopmental delay, dysmorphic features and congenital defects.

Array Comparative Genomic Hybridization (aCGH) enables genome-wide detection of copy number variants (CNVs), representing a major advance in diagnosing neurodevelopmental disorders and congenital anomalies. We performed aCGH in 1,468 patients referred for genetic evaluation due to neurodevelopmental delay, dysmorphic features, and congenital malformations. Pathogenic CNVs were detected in 24.5% of patients. The highest frequency of unbalanced aberrations occurred on chromosomes X, 15, 1, and 7. Most CNVs were small (< 10 Mbp), though entire-chromosome duplications (notably on 8, 9, and X) were also observed. The diagnostic yield and CNV distribution differed between prenatal and postnatal analyses, with deletions predominating in prenatal cases and a balanced ratio of deletions to duplications postnatally. The study confirms the high diagnostic utility of aCGH in patients with complex developmental phenotypes and highlights the importance of integrating cytogenetic analysis and periodic genomic data reinterpretation to refine diagnosis and counselling.