Gain-of-function mutation p.Arg225Cys in SCN11A causes familial episodic pain and contributes to essential tremor.

Familial episodic pain is a rare autosomal-dominant disorder characterized by recurrent attacks of pain. The pathogenesis of familial episodic pain is not very clear so far. Essential tremor is the most common movement disorder, but the identification of essential tremor genes has remained elusive. We studied a four-generation Chinese family with early-onset familial episodic pain and adult onset familial essential tremor. All essential tremor diagnoses were confirmed based on a review of the questionnaires, videotaped neurological examinations and was then reconfirmed by a senior neurologist specializing in movement disorders using published criteria. SCN11A analysis was performed by whole-exome sequencing or Sanger sequencing. We confirmed the presence of the SCN11A (c.673C>T) mutation in family members with episodic pain and essential tremor. We identified a missense mutation of p.Arg225Cys in SCN11A in a four-generation Chinese family with early-onset familial episodic pain and adult onset familial essential tremor syndrome. This may belong to a rare hereditary syndrome that has not been reported up to now. For the first time, we associated the genetic variability of SCN11A with the development of essential tremor, and further confirmed essential tremor is one of the neurological channelopathies.