Paroxysmal itch caused by gain-of-function Nav1.7 mutation

Grazia Devigili, Roberto Eleopra, Tiziana Pierro, Raffaella Lombardi, Sara Rinaldo, Christian Lettieri, Catharina G. Faber, Ingemar S J Merkies, Stephen G. Waxman, Giuseppe Lauria

Research output: Contribution to journalArticlepeer-review

Abstract

Itch is a common experience. It can occur in the course of systemic diseases and can be a manifestation of allergies or a consequence of diseases affecting the somatosensory pathway. We describe a kindred characterized by paroxysmal itch caused by a variant in SCN9A gene encoding for the Nav1.7 sodium channel. Patients underwent clinical and somatosensory profile assessment by quantitative sensory testing, nerve conduction study, autonomic cardiovascular reflex, and sympathetic skin response examination, skin biopsy with quantification of intraepidermal nerve fiber density, and SCN9A mutational analysis. The index patient, her mother, and a sister presented with a stereotypical clinical picture characterized by paroxysmal itch attacks involving the shoulders, upper back, and upper limbs, followed by transient burning pain, and triggered by environmental warmth, hot drinks, and spicy food. Somatosensory profile assessment demonstrated a remarkably identical pattern of increased cold and pain thresholds and paradoxical heat sensation. Autonomic tests were negative, whereas skin biopsy revealed decreased intraepidermal nerve fiber density in 2 of the 3 patients. All affected members harbored the 2215A>G I739V substitution in exon 13 of SCN9A gene. Pregabalin treatment reduced itch intensity and attack frequency in all patients. The co-segregation of the I739V variant in the affected members of the family provides evidence, for the first time, that paroxysmal itch can be related to a mutation in sodium channel gene.

Original languageEnglish
Pages (from-to)1702-1707
Number of pages6
JournalPain
Volume155
Issue number9
DOIs
Publication statusPublished - 2014

Keywords

  • Burning pain
  • Itch
  • Neuropathic pain
  • Paroxysmal
  • SCN9A
  • Small nerve fiber
  • Sodium channels

ASJC Scopus subject areas

  • Clinical Neurology
  • Anesthesiology and Pain Medicine
  • Neurology
  • Pharmacology
  • Medicine(all)

Fingerprint

Dive into the research topics of 'Paroxysmal itch caused by gain-of-function Nav1.7 mutation'. Together they form a unique fingerprint.

Cite this