KCNE1

The KCNE1 gene provides instructions for making a protein that regulates the activity of potassium channels. These channels, which transport positively charged potassium atoms (ions) into and out of cells, play a key role in a cell's ability to generate and transmit electrical signals.

The specific function of a potassium channel depends on its protein components and its location in the body. The KCNE1 protein regulates a channel made up of proteins produced by the KCNQ1 gene. Four alpha subunits, each made from the KCNQ1 gene, form the structure of each channel. One beta subunit, produced from the KCNE1 gene, binds to the channel and regulates its activity.

These channels are active in the inner ear and in heart (cardiac) muscle, where they transport potassium ions out of cells. In the inner ear, the channels play a role in maintaining the proper ion balance needed for normal hearing. In cardiac muscle, the channels are involved in recharging the muscle after each contraction to maintain a regular heartbeat. The KCNE1 protein is also produced in the kidneys, testes, and uterus, where it probably regulates the activity of other channels.

Jervell and Lange-Nielsen syndrome - caused by mutations in the KCNE1 gene

Several mutations in the KCNE1 gene have been identified in people with Jervell and Lange-Nielsen syndrome. Affected people typically have mutations in both copies of the KCNE1 gene in each cell. These mutations change a single protein building block (amino acid) in the KCNE1 protein, which disrupts the protein's normal structure. An altered KCNE1 protein cannot regulate the flow of potassium ions through channels in the inner ear and cardiac muscle. This loss of channel function leads to the profound hearing loss and abnormal heart rhythm (arrhythmia) characteristic of Jervell and Lange-Nielsen syndrome.

Romano-Ward syndrome - caused by mutations in the KCNE1 gene

More than 30 KCNE1 mutations are known to cause Romano-Ward syndrome. Usually, people with this condition have a mutation in only one copy of the KCNE1 gene in each cell. These mutations change a single amino acid in the KCNE1 protein, which alters the protein's ability to regulate potassium channels in cardiac muscle cells. A disruption in the flow of potassium ions out of these cells causes the irregular heartbeat found in Romano-Ward syndrome.

other disorders - associated with the KCNE1 gene

Certain drugs, including medications used to treat arrhythmias, infections, seizures, and psychotic disorders, can lead to an abnormal heart rhythm in some people. This drug-induced heart condition, which is known as acquired long QT syndrome, increases the risk of cardiac arrest and sudden death. A small percentage of cases of acquired long QT syndrome occur in people who have an underlying mutation in the KCNE1 gene.