Hyperkalemic periodic paralysis
From SNPedia
Hyperkalemic periodic paralysis (HYPP, hyperKPP) is a genetic disorder that occurs in humans and horses, where it is also known as Impressive syndrome. It is an inherited autosomal dominant disorder that affects sodium channels in muscle cells and the ability to regulate potassium levels in the blood. It is most commonly associated with horses, but when it occurs in humans, it may also be called Gamstorp episodic adynamy. It is characterized by muscle hyperexcitability or weakness which, exacerbated by potassium or cold, can lead to uncontrolled shaking followed by paralysis. Onset in humans usually occurs in early childhood.Wikipedia