For example, analogous to the Nav1.4 R1469 residue, the R1642C mutation (in Nav1.3) leads to developmental epileptic encephalopathy (Zaman et al., 2018), and R1644C/H mutations in Nav1.5 (analogous to R1469 in Nav1.4) cause cardiac arrythmias, characterized by accelerated rates of channel recovery from inactivation (Frustaci et al., 2005). This evidence concerns the gene SCN5A and developmental and epileptic encephalopathy.