Erythermalgia is an inherited painful neuropathy. Inherited erythermalgia (also termed erythromelalgia) is characterized by severe pain in the limbs in response to mild thermal stimuli or exercise.
Etiology
primary erythermalgia can be caused by mutation in the SCN9A gene (MIM.603415), encoding a voltage-gated sodium channel Na(v)1.7
- SCN9A is selectively expressed within nociceptive dorsal root ganglion and sympathetic ganglion neurons.
- Shifts in activation and deactivation, and enhanced responses to small stimuli in SCN9A mutant channels, decrease the threshold for single impulses and high-frequency trains of impulses in pain-sensing neurons.
References
Waxman SG, Dib-Hajj S. Erythermalgia: molecular basis for an inherited pain syndrome. Trends Mol Med. 2005 Dec;11(12):555-62. PMID: 16278094