SCN5A and familial dilated cardiomyopathy: In addition, Gosselin-Badaroudine and colleagues (Gosselin-Badaroudine et al., 2012) demonstrated that the R219H mutation in Nav1.5 causes a proton leak current, suggesting that this mutation induces intracellular acidification which may contribute to the DCM phenotype (Gosselin-Badaroudine et al., 2012).