SCN4A

SCN4A is a gene that encodes the alpha subunit of the voltage-gated sodium channel, Nav1.4. This channel is primarily expressed in skeletal muscle cells and is responsible for the initiation and propagation of action potentials in these cells. Mutations in the SCN4A gene are associated with several neuromuscular disorders, including Paramyotonia congenita, Hyperkalemic periodic paralysis, and Hypokalemic periodic paralysis.

Function

The SCN4A gene encodes the alpha subunit of the voltage-gated sodium channel, Nav1.4. This channel is responsible for the initiation and propagation of action potentials in skeletal muscle cells. The alpha subunit is the main component of the channel and is responsible for its voltage sensitivity and ion selectivity.

Clinical significance

Mutations in the SCN4A gene are associated with several neuromuscular disorders. These include:

• Paramyotonia congenita: This is a disorder characterized by exercise-induced muscle stiffness and weakness. It is caused by mutations in the SCN4A gene that result in a gain of function of the Nav1.4 channel.

• Hyperkalemic periodic paralysis: This is a disorder characterized by episodes of muscle weakness or paralysis associated with high levels of potassium in the blood. It is caused by mutations in the SCN4A gene that result in a gain of function of the Nav1.4 channel.

• Hypokalemic periodic paralysis: This is a disorder characterized by episodes of muscle weakness or paralysis associated with low levels of potassium in the blood. It is caused by mutations in the SCN4A gene that result in a loss of function of the Nav1.4 channel.

See also

• Voltage-gated sodium channel
• Sodium channelopathy

References

SCN4A Resources
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