Non-dystrophic myotonias and periodic paralyses. A European Neuromuscular Center Workshop held 4-6 October 1992, Ulm, Germany.

Our understanding of the pathology of the nondystrophic myotonias and the periodic paralyses has profited immensely from the use of modern electrophysiology (three microelectrode voltage clamp, patch-clamp techniques) and molecular biology (candidate gene approaches in contrast to reverse genetics in other neuromuscular diseases). In the past few years it has become clear that--apart from the not yet understood pathomechanism of myotonia in myotonic dystrophy--there are two clearly distinct pathomechanisms discernible for the non-dystrophic myotonic disorders: with a mutation in either the gene encoding the skeletal muscle C1channel (CHLCNI) or the gene encoding the ~-subunit of the adult skeletal muscle Na ÷ 'channel (SCN4A). Several mutations exist in each gene. As a consequence of this new knowledge the terms of skeletal muscle CIchannel diseases (chloride channelopathies) and skeletal muscle Na ÷ channel diseases (sodium channelopathies) were coined [1, 2] and the workshop (organized by Frank Lehmann-Horn and Reinhardt Rfidel) was structured accordingly. The participants of the workshop approved of this classification and suggested that the Editor of Neuromuscular Disorders be asked to adopt it for his Table of Gene Locations.