Utility of clinical exome sequencing in the evaluation of neonates with suspected genetic condition – An observational study from tertiary neonatal care unit in South India

To study the utility of clinical exome sequencing (CES) using next generation sequencing (NGS) in evaluating neonates with suspected genetic conditions. This is an observational study conducted in a tertiary care neonatal unit. We included neonates with suspected genetic conditions, for whom CES were done either by direct sampling or from stored DNA. Data was collected from the Sri Ramachandra centre of excellence in perinatal health (SCOPE) case records of 2016–2019. Yield of CES, percentage of pathogenic, non-pathogenic and variant of uncertain significance (VUS) and associated disorders were studied. CES was done in 36 neonates. Variants were detected in 78% (28/36). However, significant variants with clinical correlation were present in 20 (56%) babies. Test was carried out from the stored sample in 10 (28%) babies. Mean turn-around time was 39 ± 7 days. Specialist was involved in 1 and treatment changes were done in 5 neonates. Five out of 8 VUS were clinically correlating. Inborn errors of metabolism were the commonest (60%). Two VUS were ascertained as likely pathogenic after parental segregation analysis. CES has a definite role in evaluation of suspected genetic conditions for diagnosis and prognostication. It also helps scientific society to build in additional evidence so that the “VUS” could be asserted as “likely pathogenic” . Our experience reiterates the importance of storing and archiving DNA of the affected child.