Late Onset Painful Cold-Aggravated Myotonia: Three Families With Scn4a L1436p Mutation

We describe three Belgian families with a L1436P mutation in the SCN4A gene, causing a sodium channel myotonia with an atypical clinical presentation, characterized by late onset painful cold-aggravated myotonia. These families represent a distinct phenotype within the spectrum of sodium channel myotonia. (C) 2011 Elsevier B.V. All rights reserved.