Specifically, GSK3-β (Benedetti et al. 2004) as well as CLOCK (Benedetti et al. 2003; Kripke et al. 2009), PER3 and ARNTL (Nievergelt et al. 2006), TIMELESS (Mansour et al. 2005), and NR1D1 ROR (Lai et al. 2015) genes all have demonstrated modest associations with BD, supporting a polygenetic heritability. Here, CLOCK is linked to Behcet disease.