[Hypokalemic periodic paralysis: new advances]

We present a 56-year-old man with an episode of hypokalemic periodic paralysis. There are several interesting aspects of this rare disease, such as the suggestive history and clinical signs (sudden onset, symmetrical paralysis mainly of the lower extremities, "walking-off" phenomenon, no symptoms or signs between attacks) or the unexplained episodic character of the attacks. It belongs to the recently recognized ion channel diseases, a group of disorders in which mutations of genes encoding the channel protein are responsible for defective channel function. Molecular studies of mutated channels or channel subunits should provide insight into channel functioning and help to develop effective drug treatment. Once diagnosis of hypokalemic periodic paralysis is established, treatment and regular follow-up are necessary to prevent the development of permanent muscle weakness. The increasing mobility of the world's population will add to the frequency of thyrotoxic hypokalemic periodic paralysis (which is relatively frequent in Asian populations) even in Western countries.