SCN4A and familial periodic paralysis: Mutations of Nav1.4 are related with various neuromuscular disorders including PMC (paramyotonia congenita of von Eulenburg), HOKPP2 (periodic paralysis hypokalemic 2), HYPP (periodic paralysis hyperkalemic), NKPP (periodic paralysis normokalemic), MYOSCN4A (myotonia SCN4A-related), and CMS16 (myasthenic syndrome, congenital, 16) (Fig. 3D and Table 5).