Association between the common functional FKBP5 variant (rs1360780) and brain structure in a non-clinical population.

FK506 binding protein 5 (FKBP5) is induced by stress and regulates glucocorticoid receptor sensitivity. The T allele of the single nucleotide polymorphism (SNP) FKBP5 rs1360780 (C/T) is associated with an increased risk of post-traumatic stress disorder (PTSD) and reduced hippocampal volume in traumatized or depressed subjects. To examine whether this SNP affects brain structures that regulate stress response, we obtained magnetic resonance imaging data of the brain in 162 healthy subjects using a 1.5 T system. Gray matter volumes and diffusion tensor imaging data were compared between individuals with and without the T allele, using optimized voxel-based morphometry. We found that the dorsal anterior cingulate cortex (dACC) volume was smaller in T carriers than in non-T carriers (P < 0.001). T carriers also showed significantly higher mean diffusivity values in the dACC and posterior cingulate cortex (PCC) compared with non-T carriers (P < 0.001). Our results suggest that carrying the T allele of FKBP5 rs1360780 is associated with smaller gray matter volumes in the dACC and altered white matter integrity in the dACC and PCC in the non-clinical population, which might constitute the structural basis of stress-related psychiatric disorders including PTSD.