Referenced in: none

Automatically associated channels: Nav1.4

Title: Temperature-sensitive mutations in the III-IV cytoplasmic loop region of the skeletal muscle sodium channel gene in paramyotonia congenita.

Authors: A I McClatchey, P Van den Bergh, M A Pericak-Vance, W Raskind, C Verellen, D McKenna-Yasek, K Rao, J L Haines, T Bird, R H Brown

Journal, date & volume: Cell, 1992 Feb 21 , 68, 769-74

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/1310898

Abstract
Paramyotonia congenita (PMC), a dominant disorder featuring cold-induced myotonia (muscle stiffness), has recently been genetically linked to a candidate gene, the skeletal muscle sodium channel gene SCN4A. We have now established that SCN4A is the disease gene in PMC by identifying two different single-base coding sequence alterations in PMC families. Both mutations affect highly conserved residues in the III-IV cytoplasmic loop, a portion of the sodium channel thought to pivot in response to membrane depolarization, thereby blocking and inactivating the channel. Abnormal function of this cytoplasmic loop therefore appears to produce the Na+ current abnormality and the unique temperature-sensitive clinical phenotype in this disorder.