Specifically, for BTN3A2, the most significantly pleiotropic associations with MDD were detected in two brain regions: caudate nucleus and spinal cord (β [SE] = 0.043 [0.008], P = 7.76 × 10−8; β [SE] = 0.042 [0.008], P = 1.72 × 10−7, respectively; Fig. 1). This evidence concerns the gene BTN3A2 and major depressive disorder.