Brain-derived neurotrophic factor Val66Met variant on brain volumes in infants.

The brain-derived neurotrophic factor (BDNF) has many important roles in neurogenesis and neuronal health. BDNF is also involved in learning and memory. Individuals with BDNF-Val66Met variant (Met +) are at higher risk for neuropsychiatric disorders and have smaller hippocampi and amgydalae compared to those without this variant (Met -). Whether these smaller brain volumes are already present at birth is unknown and were evaluated. 66 newborn infants were genotyped for BDNF-rs6265 and had brain MRI scans. The T1-weighted images were automatically parcellated for hippocampus and amygdala, as well as the intracranial volume (ICV), total brain volume, total gray and white matter, using a multi-atlas label fusion method implemented in the MRICloud ( https://braingps.anatomyworks.org ). The segmented brain volumes were normalized to the ICV for group comparisons. The two infant groups were not different in their demographics and birth characteristics. However, compared to Met - infants, the Met + infants had smaller hippocampi (p = 0.013), smaller amygdalae (p = 0.041), and less steep age-related declines in total brain volume and % white matter volume. The smaller relative hippocampal and amygdala volumes in Met + infants suggest that the Met + genotype affected prenatal developmental processes. In addition, the slower age-dependent declines in the relative total brain and white matter volumes of the Met + group in this cross-sectional dataset suggest the BDNF-Val66Met variant might have an ongoing negative influence on the postnatal developmental processes.