Finally, homocysteine, which is raised in hypertension and diabetes, causes EEC dysfunction and apoptosis (Miller et al., 2000; Wei et al., 2010), suppression of superoxide dismutase and activation of matrix metalloproteinases (MMPs) in the plasma membrane, causing Cx43 disruption (Rosenberger et al., 2006). Here, GJA1 is linked to diabetes mellitus.