GJA5 and atrial fibrillation: In human clinical studies, both somatic and germline GJA5 gene (encoding Cx40) mutations as well as other genetic variants in the regulatory regions of GJA5 were found to associate with AF (Firouzi et al., 2004; Gollob et al., 2006; Juang et al., 2007; Yang et al., 2010b; Yang et al., 2010a; Wirka et al., 2011; Sun et al., 2013).