Truncating CLCN1 mutations in myotonia congenita: variable patterns of inheritance.

Journal Article (Journal Article)

INTRODUCTION: Myotonia congenita due to protein truncating CLCN1 mutations is associated with variable patterns of inheritance. METHODS: Three family kindreds are described, all of whom possess protein truncating mutations (Y33X, fs503X, R894X). One lineage also has coexistent R894X, A313T, and A320V mutations. RESULTS: The Y33X mutation kinship has autosomal recessive inheritance and a severe phenotype when homozygous. The fs503X family has autosomal dominant inheritance and a moderate-to-severe phenotype. The A313T mutation kindred also has autosomal dominant inheritance but expresses a mild phenotype, except for the more severely affected compound heterozygotes. CONCLUSIONS: Early truncating mutations precluding dimerization are expected to be autosomal recessive and express a severe phenotype, while later mutations may be variable. The pedigrees presented here demonstrate that intrafamilial phenotypic variability may result from a dosage effect of an additional mutation, not necessarily variable expressivity. Mutations that have unexpected patterns of inheritance may represent allelic variability.

Full Text

Duke Authors

Cited Authors

  • Richardson, RC; Tarleton, JC; Bird, TD; Gospe, SM

Published Date

  • April 2014

Published In

Volume / Issue

  • 49 / 4

Start / End Page

  • 593 - 600

PubMed ID

  • 23893571

Electronic International Standard Serial Number (EISSN)

  • 1097-4598

Digital Object Identifier (DOI)

  • 10.1002/mus.23976


  • eng

Conference Location

  • United States