Abstract
OBJECTIVE: This study aims to analyze the diagnostic yield of aCGH in pediatric patients with suspected rare diseases, focusing on its diagnostic value and effectiveness depending on different clinical symptoms. METHODS: This observational study analyzed 600 aCGH tests performed in a pediatric unit (2018-2022) for patients with suspected rare diseases. DNA was extracted from peripheral blood; aCGH resolution was adjusted to clinical features. CNVs were classified per international guidelines. Forty sociodemographic, clinical, and genetic variables were analyzed using IBM SPSS v.26. RESULTS: Of the 600 patients analyzed, 543 were included in the final study. The median age was 4.7 years (IQR: 6.36 years), and 66.3% were male. Most referrals came from pediatric neurology (84.3%), and the most common clinical manifestations were altered phenotype (38.6%), autism spectrum disorder (ASD) (38.6%), dysmorphia (28.2%), global developmental delay (GDD) (27.1%), and intellectual disability (21.0%). Among 543 patients, 30.4% presented CNVs, with 12.4% identified as pathogenic and 18.1% as variants of uncertain significance. Diagnostic yield was 12.2%, with 66 conclusive results - 90.9% of which were pathogenic. CNVs were most frequently detected on chromosomes 15 and 16. The highest yield was observed in clinical features such as coordination problems (35.7%), learning disorders (28.6%), and microcephaly (22.6%). CONCLUSION: The diagnostic yield of aCGH in this study was 12.2%. The test demonstrated higher diagnostic value in patients with multiple clinical manifestations, highlighting the importance of aCGH as a first-line diagnostic tool for rare diseases. This technique enables earlier diagnosis, improves clinical management, and provides better counseling for affected families.