Hsu W.-C.Huang Y.-C.Wang C.-W.Hsueh C.-H.LING-PING LAIYeh J.-H.2020-12-312020-12-3120060929-6646https://www.scopus.com/inward/record.uri?eid=2-s2.0-33745617091&doi=10.1016%2fS0929-6646%2809%2960191-1&partnerID=40&md5=85da162fddd8f149a44146c8db8187d7https://scholars.lib.ntu.edu.tw/handle/123456789/536704Paralysis periodica paramyotonica is an overlapping disease that shares the features of paramyotonia characteristic of paramyotonia congenita (PC) and periodic paralysis characteristic of hyperkalemic periodic paralysis. We report the case of a 23-year-old man with paralysis periodica paramyotonica. His father and a younger brother also exhibited a similar phenotype. A SCN4A Arg1448Cys mutation was detected in this family. The affected family members exhibited marked shifts in compound muscle action potential amplitudes on exercise test, and muscle weakness could be induced by potassium loading and cold exposure. This case demonstrates that SCN4A Arg1448Cys can produce paralysis periodica paramyotonica. Other genetic or environmental factors may modulate the manifestation of SCN4A Arg1448Cys mutation. ?2006 Elsevier & Formosan Medical Association.Exercise test; Hyperkalemic periodic paralysis; Paralysis periodica paramyotonica; Paramyotonia congenita; Sodium channelopathy[SDGs]SDG3arginine; cysteine; sodium channel; adult; article; case report; clinical feature; cold exposure; environmental factor; exercise test; family history; gene mutation; gene sequence; genetic analysis; human; hyperkalemia; male; medical examination; muscle action potential; muscle weakness; mutational analysis; nucleotide sequence; paralysis periodica paramyotonia; phenotype; polymerase chain reaction; sequence analysis; Thomsen diseasejournal article10.1016/S0929-6646(09)60191-1168010392-s2.0-33745617091