Thomsen or Becker myotonia? A novel autosomal recessive nonsense mutation in the CLCN1 gene associated with a mild phenotype.

Centro de Estudos do Genoma Humano-IB-USP, Biosciences Institute, University of São Paulo, R. do Matão, 277, Sala 220, CEP 05508-900 São Paulo, Brazil.
Muscle & Nerve (Impact Factor: 2.31). 02/2012; 45(2):279-83. DOI: 10.1002/mus.22252
Source: PubMed

ABSTRACT We describe a large Brazilian consanguineous kindred with 3 clinically affected patients with a Thomsen myotonia phenotype. They carry a novel homozygous nonsense mutation in the CLCN1 gene (K248X). None of the 6 heterozygote carriers show any sign of myotonia on clinical evaluation or electromyography. These findings confirm the autosomal recessive inheritance of the novel mutation in this family, as well as the occurrence of phenotypic variability in the autosomal recessive forms of myotonia.

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May 30, 2014