Channelopathy: A disease involving dysfunction of an ion channel. Channelopathies are known that involve the ion channels for potassium, sodium, chloride and calcium. There are also channelopathies involving the acetylcholine receptor, the glycine receptor, and other receptors. Each channelopathy can play a role in a number of different diseases. For example, the calcium channelopathies include familial hemiplegic migraine, malignant hyperthermia (a rare but often fatal genetic condition during anesthesia), episodic ataxia type 2, spinocerebellar ataxia type 6, hypokalemic periodic paralysis type I, central core disease (a cause of the floppy baby syndrome), congenital night blindness and stationary night blindness. Abnormalities of cardiac rhythm can also be caused by channelopathies. These include Brugada syndrome, among others. See also: Ion channel.