[Mutation analysis of the CACNL1A3 gene in Japanese hypokalemic periodic paralysis families].

Recent genetic research has revealed that hereditary periodic paralysis is an ion channel disorder. Genetic linkage analysis has mapped the autosomal dominant hypokalemic periodic paralysis (HypoPP) locus to chromosome 1q31-32, where the dihydropyridine sensitive calcium channel alpha 1 subunit (CACNL1A3) is located. Subsequently, two predominant missense point mutations were found in the CNCNL1A3 gene. Both mutations substitute arginine to histidine (Arg528His and Arg1239His). The Arg528His mutation is characterized by incomplete penetrance in females, whereas Arg1239His is not. We analyzed Japanese hypokalemic periodic paralysis patients (familial, sporadic and thyrotoxic), and detected the Arg528His mutation in one HypoPP family. This family shows more severe symptoms in successive generations, and the severity of the symptoms is higher in males than in females within the same family.