Genes in the SCN family provide instructions for making sodium channels. These channels transport positively charged sodium atoms (sodium ions) into cells. Sodium channels play key roles in a cell's ability to generate and transmit electrical signals.
Sodium channels are made up of several protein components (subunits), each of which is produced from a particular gene. The α (alpha) subunit is the largest and most important component of each sodium channel. It forms the hole (pore) through which sodium ions can flow. The α subunit interacts with one or more smaller β (beta) subunits, which help regulate the channel's function and interact with various other proteins inside and outside the cell.
Sodium channels have critical functions in several different tissues. For example, these channels are abundant in heart (cardiac) muscle, where they play a major role in maintaining a normal heart rhythm. Sodium channels are also found in muscles used for movement (skeletal muscles), where they help control muscle tensing (contraction) and relaxation. Additionally, sodium channels are essential for the normal function of the nervous system. These channels help transmit electrical signals within and between nerve cells in the brain and throughout the body.
Mutations in genes in the SCN family cause disorders affecting the heart, skeletal muscles, and nervous system. In the heart, abnormal sodium channel function causes several diseases characterized by abnormal heart rhythms (arrhythmias). Changes in sodium channels in skeletal muscle cells are responsible for disorders that cause muscle weakness and episodes of paralysis. Altered sodium channel function in the nervous system can lead to several types of childhood epilepsy, a rare familial form of migraines, and pain disorders.
Several medications work by targeting sodium channels. These medications include certain drugs used to block the sensation of pain (anesthetics), anti-seizure drugs, and drugs used to treat abnormal heartbeats (antiarrhythmics).
The HUGO Gene Nomenclature Committee (HGNC) provides a list of genes in the SCN family.
Genetics Home Reference provides additional information about these members of the SCN gene family: SCN1A, SCN4A, SCN5A, and SCN9A.
Genetics Home Reference includes these conditions related to genes in the SCN gene family:
You may find the following resources about the SCN gene family helpful.
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