Hypokalemic periodic paralysis: an autosomal dominant muscle disorder caused by mutations in a voltage-gated calcium channel.
Hypokalemic periodic paralysis (hypoPP) is an autosomal dominant disorder characterized by acute attacks of muscle weakness concomitant to a drop in blood potassium levels. Recent molecular work has shown that hypoPP is due to mutations in a skeletal muscle voltage-gated calcium channel: the dihydropyridine receptor (DHP receptor). Mutations affect segments S4 of domains II and IV, changing an arginine in position 528 and 1239 into an histidine, or an histidine or a glycine respectively. Surprisingly, expressing in vitro mutants channels in a non-muscular environment resulted in functional calcium channels with minor modifications in electrophysiological properties. Expressing mutant channels in a muscular environment or transgenic mice might help to bridge the gap between the knowledge of the molecular defect and the understanding of the pathophysiology of the disease.
Lapie
P
P
INSERM CJF96108, Hôpital de la Salpêtrière, Paris, France.
Lory
P
P
Fontaine
B
B
D000818:Animals; D015220:Calcium Channels / Q000235:genetics*; D005799:Genes, Dominant; D006801:Humans; D007008:Hypokalemia / Q000235:genetics*; D015640:Ion Channel Gating / Q000235:genetics*; D008564:Membrane Potentials / Q000502:physiology; D009154:Mutation; D010243:Paralysis / Q000235:genetics*; D010507:Periodicity
D015220:Calcium Channels