Abstract
Genetic diseases disrupt the functionality of an infant's genome during fetal-neonatal adaptation and represent a leading cause of neonatal and infant mortality in the United States. Due to disease acuity, gene locus and allelic heterogeneity, and overlapping and diverse clinical phenotypes, diagnostic genome sequencing in neonatal intensive care units has required the development of methods to shorten turnaround times and improve genomic interpretation. From 2012 to 2021, 31 clinical studies documented the diagnostic and clinical utility of first-tier rapid or ultrarapid whole-genome sequencing through cost-effective identification of pathogenic genomic variants that change medical management, suggest new therapeutic strategies, and refine prognoses. Genomic diagnosis also permits prediction of reproductive recurrence risk for parents and surviving probands. Using implementation science and quality improvement, deployment of a genomic learning healthcare system will contribute to a reduction of neonatal and infant mortality through the integration of genome sequencing into best-practice neonatal intensive care.