In addition, if the effect of rs1801260 on susceptibility to MDD is also population specific, the lack of association in Asian populations may not be generalizable to other continental populations.35 Our discovery of a functional impact of this SNP on luciferase activity when expressed in human cells (Figure 1) encouraged us to re-evaluate previous association reports and include this marker in our association analyses, leading to the identification of a significant association by χ2 analysis between rs1801260 in hClock and MDD in male study participants (Table 1). Here, CLOCK is linked to major depressive disorder.