An Arg528His Mutation of the CACNL1A3 Gene in a Korean Family with Hypokalemic Periodic Paralysis / 대한소아신경학회지

Familial hypokalemic periodic paralysis (HOPP) is an autosomal dominant disorder characterized by episodic attacks of muscle weakness with concomitant hypokalemia (<3.5 mEq/L). The onset of HOPP usually occurs within the first and second decade of life. Mutations in the skeletal muscle calcium (CACNL1A3) and sodium channel (SCN4A) genes have been reported to be responsible for familial HOPP. Voltage-sensitive ion channels mediate action potentials in electrically excitable cells and play important roles in signal transduction in other cell types. Therefore, abnormalities in a channel's function lead to disarray of signal transduction and thus various neurological symptoms. Those are called channel diseases, which include familial HOPP. We report a 14-year-old boy with HOPP from a family in which two members of two generations are affected. Genetic examination identified a mutation causing a codon change from arginine to histidine at the amino acid portion #528 (R528H) in the calcium channel gene CACNL1A3.

An Arg1239His mutation of the CACNL1A3 gene in a Korean family with hypokalemic periodic paralysis / 소아과

Familial hypokalemic periodic paralysis (hypoPP) is a rare inherited channelopathy that often presents with episodic weakness accompanied by hypokalemia. Thus far, mutations in the gene encoding two ion channels (CACNL1A3, L-type calcium channel alpha-1 subunit and SCN4A, a sodium channel type IV alpha subunit) have been identified. Several cases of familial hypoPP in children have been reported in Koreans, but there are only a few cases with identified mutations. We report a 12-year-old boy and his affected mother with hypoPP who has a heterozygous G to A substitution at codon 1239 in exon 30 of the CACNL1A3 gene that causes a change from arginine to histidine (Arg1239His, CACNL1A3). This mutation is common among Caucasians; however, it has not yet been reported in Koreans. The patients were treated with oral acetazolamide and potassium replacement and were instructed to avoid precipitating factors. After the medication and lifestyle modification, the paralytic attacks significantly decreased.