Referenced in: none

Automatically associated channels: ClC1 , ClC4

Title: Novel chloride channel mutations leading to mild myotonia among Chinese.

Authors: Jean-Marc Burgunder, Shang Huifang, Pascal Beguin, Roland Baur, Chew Soh Eng, Raymond C S Seet, Erle C H Lim, Benjamin K C Ong, Walter Hunziker, Erwin Sigel

Journal, date & volume: Neuromuscul. Disord., 2008 Aug , 18, 633-40

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/18579381

Abstract
We describe two Chinese families with a mild form of the myotonia congenita due to novel chloride channel (ClCN1) mutations. In one case, heterozygous I553F and H555N mutations were found. The patient shared the I553F mutation with his healthy father, and his mother had a history of mild myotonia when she was younger. In another family, autosomal dominant myotonia congenita was due to a L844F change. The physiological effects of the mutations were examined by using the two-electrode voltage-clamp technique after expression of the channels in Xenopus oocytes. All mutations drastically shifted the voltage required for half-maximal activation, more under conditions mimicking the homozygous situation, than under conditions mimicking the heterozygous situation. The larger effect was seen in the compound heterozygous situation combining the I553F and the H555N mutations. Our data suggest that myotonia congenita caused by CLCN1 mutations in Chinese have similar variable features to those found in the West.