NTRK2 and alcohol drinking: Importantly, we are the first to report SNPs associated with unequal age-of-onset distributions for susceptible cases to alcoholism [rs172677 on GRIN2B (p = 0.013), rs1439047 on NTRK2 (p = 0.005), rs63319 on ALDH1A1 (p = 0.033), and rs1079597 on DRD2 (p = 0.028)].