Monday 29 September 2003
Definition: Channelopathies are diseases caused by inherited mutations of ion channels. Mutations of ion channels can thus theoretically alter the activation, ion selectivity, or inactivation of the corresponding mutated channel. Channelopathies can be classified according to the abnormal channel or affected organ (muscle or brain).
One characteristic of the channelopathies is a significant phenotypic overlap in clinical presentation, pathophysiology, and treatment. For example, patients with episodic ataxia type 2 have episodes of ataxia, but can alternatively have migraines and epilepsy.
Electrophysiologic investigations (electromyogram, electroencephalogram, and electrocardiogram) are useful in this group of diseases for demonstrating cellular hyperexcitability and correctly orient a specific diagnosis.
Most of these diseases have similar precipitants (stress, fatigue, and dietary factors), and are treated with medications selectively acting on specific ion channels (i.e., channel blockers).
Different mutations in the same gene can cause different diseases (e.g., mutations in the same voltage-dependent sodium channel in skeletal muscle can result in hyperkalemic periodic paralysis, hypokalemic periodic paralysis, potassium-aggravated myotonia, and paramyotonia congenita).
Mutations in different genes can result in the same apparent disease phenotype (e.g., hyperkalemic periodic paralysis is caused by mutations in different genes coding for the skeletal muscle sodium channel).
According to channel types
According to the localization
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