Recently, a (NAT) was reported to be a potential candidate gene for patients with inherited (primary erythromelalgia, paroxysmal extreme pain disorder, and painful small fiber neuropathy) or acquired chronic pain disorders linked to the SCN9A locus, taking into account that the sense gene must not contain mutations which lead to sense gene-NAT pairing. The gene discussed is SCN9A; the disease is primary erythermalgia.