Association between mitochondrial DNA copy number and neurodevelopmental outcomes among black and white preterm infants up to two years of age.

Abstract

Objectives: Mitochondrial DNA copy number (mtDNAcn) is associated with mitochondrial function, with abnormal copy numbers having been linked to various disease states. Our study aims to understand the association between infant mtDNAcn and infant neurodevelopment, as well as the association with racial disparities.

Methods: A longitudinal study was conducted with 55 preterm infants from whom a single blood sample was collected during their Neonatal intensive care unit (NICU) stay and used to analyze mtDNAcn. In addition, the NICU Network Neurobehavioral Scale at 36-38 postmenstrual age (PMA) and the Bayley Scale of Infant and Toddler Development (Bayley) Edition III at 1 and 2 years of corrected age were both conducted. Linear regression models were performed to investigate the relationship between infant clinical characteristics, infant neurobehavioral outcomes, and mtDNAcn.

Results: The majority of infants studied were white (72.73%), non-Hispanic (70.91%), males (54.55%), delivered through C-section (72.73%), and without preterm premature rupture of membrane (76.36%). Increased mtDNAcn was associated with younger birth gestational age (<30.57 wk, P < 0.001). In addition, the opposite associations between mtDNAcn and neurodevelopmental outcomes were observed between white and black infants up to 1 year of gestational age.

Conclusions: Increased mtDNAcn in white infants, and decreased mtDNAcn in black infants may be considered significant predictors of poor early-life neurodevelopmental outcomes in infants. A better understanding of the underlying mechanisms contributing to infant disparity in mtDNAcn and how low or high copy number impacts infant outcomes is essential.