CLOCK and Behcet disease: Gene association studies, including GWAS, identified gene variants for clock and clock controlled molecules associated with BD and lithium responsiveness (Nievergelt et al., 2006; Mansour et al., 2009; Sjoholm et al., 2010; Soria et al., 2010; McCarthy et al., 2012; McCarthy and Welsh, 2012; Pandey et al., 2012; Rybakowski, 2014; Bollettini et al., 2017; Suzuki et al., 2017).