Hyperkalemic periodic paralysis with cardiac dysrhythmia: a novel sodium channel mutation?

A patient is presented with hyperkalemic periodic paralysis (HyperPP) and a cardiac dysrhythmia. An amino acid substitution (Val783Ile) in the adult skeletal muscle sodium channel gene was detected. Although lack of available family members precluded rigorous genetic tests, the sodium channel change may be responsible for HyperPP in this patient and could also be responsible for the associated cardiac dysrhythmia.