A novel mutation in the SCN4A responsible for cold-induced myotonia with normal electromyography findings on room temperature

One family is described with a novel SCN4A mutation, causing cold-aggravated myotonia without weakness. One affected family member had a normal needle electromyography at room temperature. Myotonic discharges were only discovered after cooling of the tested muscles. (C) 2011 Elsevier B.V. All rights reserved.