Structural Biochemistry/Channelopathies

Overview

Channelopathies are genetic diseases due to alterations in ion channel genes. Examples:

Familial Hemiplegic migraines (FHM). These have been shown to occur due to mutations in the Ca²+ channel in the brain. Mutations in pore-forming region of this channel result in FHM characterized by uncontrolled muscle movement. This and other examples suggest a correlation between mutations in the gene for this ion channel and specific implications of FHM symptoms. While this relation is evidenced, the original cause of the migraine is unknown.

Episodic ataxia type 2, or EA2. These mutations cause Ca²+ channels to be cut off, leading to abnormal composition of the channel. Symptoms include uncontrolled muscle movement, vertigo, nausea and headaches.

CSNB (congenital stationary night blindness) is caused by similar mutations as EA2 and leads to abnormal retinal function. It results in numerous affects on vision, including night blindness and lack of acuity.

(GEFS) Epilepsy results from a defect in the Na+ channel. These mutations slow the channel activation, which may explain the hyperexcitability phenoma characteristic of epilepsy occurring here.

(BFNC) seizures occur from mutations in the gene for the K+ channel, leading to hyperexcitability that causes abrupt seizures in the first few weeks-months of life.

Reference

Purves, Dave, et all. Neuroscience, Fourth Edition. Sunderland, MA: C. 2008, Sinauer Associates, Inc. Text.