BDNF polymorphism rs6265 and hippocampal structure and memory performance in healthy control subjects.

Brain-derived neurotrophic factor (BDNF) is highly expressed in the hippocampus of many species, including humans. The single-nucleotide polymorphism rs6265 on the BDNF gene is thought to alter activity-dependent secretion of the protein, and previous research suggests that the Met allele is associated with smaller hippocampal volumes and poorer memory performance in human populations. For this study, we genotyped 154 healthy human subjects for the Val66Met polymorphism. The effects of genotype upon hippocampal volume, as assessed using high resolution magnetic resonance imaging and high-dimensional brain mapping, and upon memory performance, as assessed using a battery of neuropsychological tests, were determined. We found that genotype had no significant effect on hippocampal structure, nor did it have a significant effect on memory performance, covarying for age. Age, however, was significantly related to changes in whole brain volume and performance on memory tasks. We concluded that in a large cohort of healthy human subjects, the Met allele of rs6265 is not associated with hippocampal structure or memory performance.