 It was observed that a missense mutation in the "SCN9A" gene affected conserved residues in the pore-forming α subunit of the Nav1.7 channel.Multiple studies have found a dozen "SCN9A" mutations in multiple families as causing erythromelagia.All of the observed erythromelalgia mutations that are observed are missense mutations that change important and highly conserved amino acid residues of the Nav1.7 protein.