SCN4A and Myalgia: The coexistence of the p.Met485Val with mutations on the SCN4A gene has previously been reported by Furby et al. (20) who described a young man harboring p.Gly1306Glu/p.Met485Val, affected from birth, and sharing eye lid myotonia, abundant myotonic discharges in his legs, muscle hypertrophy normalized with age, stiffness, and myalgia with the case studied herein.