Clinical and Genetic Profile of Down Syndrome: Insights from 10 Years of Experience at a Tertiary Care Center

Background & Aim: Down Syndrome (DS) is a genetic disorder characterized by distinct clinical features, predominantly caused by trisomy chromosome 21. This study aimed to conduct a retrospective analysis of clinical features, genetic profiles, and karyotype findings in Down Syndrome patients. Materials and Methods: We performed a retrospective analysis of cases referred to the Genetic Clinic in the Department of Pediatrics at Maulana Azad Medical College (MAMC) and Lok Nayak Hospital over a ten-year period (2014-2024). Existing case proformas of patients with Down Syndrome phenotype, who underwent cytogenetic evaluation, were systematically reviewed. Results: Analysis included 688 patients with DS, with 375 males and 313 females (M: F ratio 1.2:1). The average age at presentation was 19.4 months (range: 1 day to 26 years). Distinct craniofacial features were present in 97.8% of cases, including mongoloid slant (97.8%), flat facial profile (97%), and protruding tongue (91.7%) and epicanthic folds (62.7%). Cytogenetic findings revealed free trisomy in 95.93%, translocations in 3.05%, mosaics in 0.72%, and rare findings in 0.29%. Among the Robertsonian translocations, 52.4% were t (14;21), 9.5% t (15;21), and 38.1% t (21;21). Conclusion: The findings emphasize the importance of early detection and comprehensive evaluation of Down Syndrome. Understanding the mechanisms of nondisjunction and its implications is vital for genetic counseling and assessing recurrence risks in families. Key words: Down Syndrome, Nondisjunction, translocation, Robertsonian, Mosaic syndrome.