The study group comprised 45 depressed patients and 45 age- and gender-matched control subjects. High angular resolution diffusion images were obtained and analyzed using tract-based spatial statistics. Analysis of a single nucleotide polymorphism in the BDNF (rs6265/Valine66Methionine) and NTRK2 (rs11140714) genes was performed.
An interactive effect was found between NTRK2 and depression diagnosis maximally affecting the cingulum. Depressed patients homozygous for the A allele of NTRK2 showed significantly reduced fractional anisotropy compared with depressed patients with at least one copy of the G allele or control subjects with either the A/A or G carrier genotypes in the left and right corona radiata, left uncinate fasciculus, left inferior fronto-occipital fasciculus, left cerebral peduncle, posterior thalamic radiation, and middle cerebral peduncle. Significantly smaller gray matter volume was seen in frontal lobe regions in patients homozygous for the A allele.
Polymorphisms in NTRK2 gene increase risk of architectural changes in several brain regions involved in emotional regulation.