Genomic testing in the neonatal intensive care unit: a 5-year retrospective single-centre study from a tertiary care hospital in Bengaluru, India

Genetic disorders contribute significantly to morbidity and mortality in neonatal intensive care units (NICUs), yet data from low- and middle-income settings remain limited. This study evaluated the diagnostic yield and clinical utility of genetic testing in a tertiary care NICU. This retrospective observational study included neonates and young infants who underwent genetic testing in a tertiary NICU in Bengaluru, India, over 67 months (January 2019–July 2024). Genetic variants were classified using American College of Medical Genetics and Genomics criteria. Diagnostic yield and its distribution across clinical phenotypes and inheritance patterns were analysed descriptively. Seventy infants underwent genetic evaluation, with an overall diagnostic yield of 24.3% (17/70). Variants of uncertain significance were identified in 35.7% of cases. Diagnostic yield varied by phenotype, with the highest yield in metabolic/endocrine presentations (50%) and the lowest in non-specific presentations (7.7%). Among confirmed diagnoses, autosomal recessive disorders predominated (47%), followed by autosomal dominant (29%) and X-linked (24%) inheritance. Genetic testing appeared to influence clinical management and family counselling in selected cases, including targeted therapy, treatment modification, and definitive interventions. One infant (1.4%) with an HRAS variant highlighted the evolving clinical relevance of variants of uncertain significance.

Conclusion: Genetic testing may provide clinically meaningful diagnoses in a subset of NICU infants, particularly in well-defined clinical phenotypes. A phenotype-driven approach, along with cautious interpretation and follow-up, may help optimise the clinical utility of genomic testing in resource-limited settings.