KCN gene family

Genes in the KCN family provide instructions for making potassium channels. These channels transport positively charged potassium atoms (potassium ions) into and out of cells. Potassium channels play key roles in a cell's ability to generate and transmit electrical signals.

Potassium channels are made up of several protein components (subunits), each of which is produced from a particular gene. Each channel includes four α (alpha) subunits, which are usually identical, and several β (beta) subunits. The α subunits form the hole (pore) through which potassium ions can flow. The β subunits help regulate the channel's function and interact with various proteins inside and outside the cell.

Potassium channels are the most diverse of all the body's ion channels. They have critical functions in many different tissues. In the nervous system, these channels help determine the electrical charge of nerve cells (neurons) and play important roles in communication between these cells. Potassium channels in the inner ear maintain a balance of ions necessary for hearing. In heart (cardiac) muscle, potassium channels are involved in recharging the muscle after each contraction to maintain a regular heartbeat. In muscles used for movement (skeletal muscles), potassium channels play a role in the pattern of muscle tensing (contraction) and relaxation that allows the body to move.

Mutations in KCN genes are associated with several disorders affecting the nervous system, heart, and muscles. Altered potassium channel function in the nervous system can lead to episodic ataxia (a condition characterized by episodes of poor coordination and balance), a muscle disorder called myokymia, and rare forms of epilepsy. Changes in potassium channels in the inner ear likely contribute to hearing loss. In the heart, abnormal potassium channel function causes several diseases characterized by abnormal heart rhythms (arrhythmias). Changes in potassium channels in skeletal muscle cells are associated with episodes of paralysis as part of a condition called Andersen-Tawil syndrome.