Evidence of genetic heterogeneity among the nondystrophic myotonias.
Recent in vitro electrophysiologic studies have demonstrated abnormal sodium channel gating in muscle from patients with Thomsen's disease and have called the chloride hypothesis into question. Abnormal sodium channel function, like myotonia, is a feature common to Thomsen's disease and several myotonias that are genetically linked to a chromosome-17q sodium channel locus. We present a pedigree segregating an allele for Thomsen's disease that is unlinked to this sodium channel locus, thus constituting evidence of genetic heterogeneity among the nondystrophic myotonias.
Ptacek
L J
LJ
Department of Neurology, University of Utah School of Medicine, Salt Lake City.
Ziter
F A
FA
Roberts
J W
JW
Leppert
M F
MF
D002648:Child; D002675:Child, Preschool; D002874:Chromosome Mapping; D002886:Chromosomes, Human, Pair 17; D004247:DNA / Q000032:analysis; D005260:Female; D008040:Genetic Linkage; D006801:Humans; D008126:Lod Score; D008297:Male; D009224:Myotonia Congenita / Q000235:genetics*; D010375:Pedigree; D015222:Sodium Channels / Q000235:genetics
D015222:Sodium Channels; D004247:DNA