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The official name of this gene is “potassium voltage-gated channel, KQT-like subfamily, member 3.”
KCNQ3 is the gene's official symbol. The KCNQ3 gene is also known by other names, listed below.
The KCNQ3 gene belongs to a large family of genes that provide instructions for making potassium channels. These channels, which transport positively charged atoms (ions) of potassium 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. Channels made with the KCNQ3 protein are active in nerve cells (neurons) in the brain, where they transport potassium ions out of cells. These channels transmit a particular type of electrical signal called the M-current, which prevents the neuron from continuing to send signals to other neurons. The M-current ensures that the neuron is not constantly active, or excitable.
Potassium channels are made up of several protein components (subunits). Each channel contains four alpha subunits that form the hole (pore) through which potassium ions move. Four alpha subunits from the KCNQ3 gene can form a channel. However, the KCNQ3 alpha subunits can also interact with alpha subunits from the KCNQ2 gene to form a functional potassium channel, and these channels transmit a much stronger M-current.
The KCNQ3 gene belongs to a family of genes called KCN (potassium channels).
A gene family is a group of genes that share important characteristics. Classifying individual genes into families helps researchers describe how genes are related to each other. For more information, see What are gene families? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genefamilies) in the Handbook.
A mutation in the KCNQ3 gene has been identified in some people with benign familial neonatal seizures (BFNS), a condition characterized by recurrent seizures in newborn babies. The seizures begin around day 3 of life and usually go away within 1 to 4 months. At least three mutations have been identified in people with this condition, and these mutations change single protein building blocks (amino acids) in the KCNQ3 protein. As a result of these mutations, the M-current is reduced. Researchers believe that a reduction of the current by 25 percent is enough to cause BFNS. A reduced M-current leads to excessive excitability of neurons, which is known to cause seizures. It is unclear why the seizures stop around the age of 4 months. It has been suggested that potassium channels formed from the KCNQ2 and KCNQ3 proteins play a major role in preventing excessive excitability of neurons in newborns, but other mechanisms develop during infancy.
Cytogenetic Location: 8q24
Molecular Location on chromosome 8: base pairs 133,133,104 to 133,493,003
The KCNQ3 gene is located on the long (q) arm of chromosome 8 at position 24.
More precisely, the KCNQ3 gene is located from base pair 133,133,104 to base pair 133,493,003 on chromosome 8.
See How do geneticists indicate the location of a gene? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genelocation) in the Handbook.
You and your healthcare professional may find the following resources about KCNQ3 helpful.
You may also be interested in these resources, which are designed for genetics professionals and researchers.
See How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.
acids ; benign ; cell ; channel ; familial ; gene ; ions ; mutation ; neonatal ; neuron ; potassium ; protein ; subunit ; voltage
You may find definitions for these and many other terms in the Genetics Home Reference Glossary (http://www.ghr.nlm.nih.gov/glossary).
The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.