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    Topic review

    KCNQ3 Gene

    Subjects: Genetics
    View times: 4
    Submitted by: Dean Liu
    (This entry belongs to Entry Collection "MedlinePlus ")

    Definition

    Potassium voltage-gated channel subfamily Q member 3

    1. Introduction

    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.

    2. Health Conditions Related to Genetic Changes

    2.1. Benign Familial Neonatal Seizures

    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.

    3. Other Names for This Gene

    • BFNC2

    • EBN2

    • KCNQ3_HUMAN

    • KV7.3

    • potassium channel subunit alpha KvLQT3

    • potassium channel, voltage gated KQT-like subfamily Q, member 3

    • potassium channel, voltage-gated, subfamily Q, member 3

    • potassium voltage-gated channel subfamily KQT member 3

    • potassium voltage-gated channel, KQT-like subfamily, member 3

    • voltage-gated potassium channel subunit Kv7.3

    The entry is from https://medlineplus.gov/genetics/gene/kcnq3

    References

    1. Chung HJ, Jan YN, Jan LY. Polarized axonal surface expression of neuronal KCNQchannels is mediated by multiple signals in the KCNQ2 and KCNQ3 C-terminaldomains. Proc Natl Acad Sci U S A. 2006 Jun 6;103(23):8870-5.
    2. Rogawski MA. KCNQ2/KCNQ3 K+ channels and the molecular pathogenesis ofepilepsy: implications for therapy. Trends Neurosci. 2000 Sep;23(9):393-8.Review.
    3. Schroeder BC, Kubisch C, Stein V, Jentsch TJ. Moderate loss of function ofcyclic-AMP-modulated KCNQ2/KCNQ3 K+ channels causes epilepsy. Nature. 1998 Dec17;396(6712):687-90.
    4. Singh NA, Westenskow P, Charlier C, Pappas C, Leslie J, Dillon J, Anderson VE,Sanguinetti MC, Leppert MF; BFNC Physician Consortium. KCNQ2 and KCNQ3 potassium channel genes in benign familial neonatal convulsions: expansion of thefunctional and mutation spectrum. Brain. 2003 Dec;126(Pt 12):2726-37.
    5. Soldovieri MV, Miceli F, Bellini G, Coppola G, Pascotto A, Taglialatela M.Correlating the clinical and genetic features of benign familial neonatalseizures (BFNS) with the functional consequences of underlying mutations.Channels (Austin). 2007 Jul-Aug;1(4):228-33.
    6. Wang HS, Pan Z, Shi W, Brown BS, Wymore RS, Cohen IS, Dixon JE, McKinnon D.KCNQ2 and KCNQ3 potassium channel subunits: molecular correlates of theM-channel. Science. 1998 Dec 4;282(5395):1890-3.
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