Carbamazepine, in particular, has been shown to partially normalize abnormal activation gating and reduce hyperexcitability in sensory neurons carrying gain-of-function Nav1.7 and Nav1.8 mutations linked to painful peripheral neuropathies and erythromelalgia, in line with the clinical responsiveness observed in affected individuals (28–31). The gene discussed is SCN9A; the disease is erythromelalgia.