protein
Potassium voltage-gated channel subfamily KQT member 3
Gene
KCNQ3
Organism
Homo sapiens(9606)
Length
872 aa
Mass
96,742 Da
KCNQ3 encodes the pore-forming subunit of voltage-gated potassium M-channels, which regulate the M-current—a slowly activating and deactivating potassium conductance critical for controlling neuronal excitability and synaptic responsiveness (UniProt: O43525). The channel assembles as heterotetramers with KCNQ2 and can also associate with KCNQ5 to form functional channels in the brain. M-channel activity is suppressed by activation of M1 muscarinic acetylcholine receptors, and the channel exhibits selective ion permeability with preference for K+ over other cations (UniProt: O43525).
KCNQ3 mutations cause benign familial neonatal seizures (BFNS2), characterized by seizure clusters occurring in the first days of life, typically with spontaneous remission by 12 months and normal psychomotor development (UniProt: O43525). The channel's role in neuronal excitability regulation makes it functionally relevant to seizure pathophysiology.
KCNQ3 has been classified as syndromic autism-risk relevant (SFARI Cat 2), indicating a potential association with autism spectrum disorder alongside its established link to neonatal seizure disorders. However, the specific neurodevelopmental mechanisms connecting KCNQ3 dysfunction to autism phenotypes are not detailed in the provided data.
Generated from the curated entity record below. May contain errors — verify against source links.
Genetic Evidence · ASD
Strong candidate — functional studies support ASD association
Source: SFARI Gene database · gene.sfari.org
Related Publications
Browse all →Inherited and De Novo Genetic Risk for Autism Impacts Shared Networks.
Ruzzo Elizabeth K et al.Cell2019PMID 31398340Inherited and multiple de novo mutations in autism/developmental delay risk genes suggest a multifactorial model.
Guo Hui et al.Molecular autism2018PMID 30564305Whole genome sequencing resource identifies 18 new candidate genes for autism spectrum disorder.
C Yuen Ryan K et al.Nature neuroscience2017PMID 28263302Identification of common genetic risk variants for autism spectrum disorder.
Grove Jakob et al.Nature genetics2019PMID 30804558Synaptic, transcriptional and chromatin genes disrupted in autism.
De Rubeis Silvia et al.Nature2014PMID 25363760
Function
Pore-forming subunit of the voltage-gated potassium (Kv) M-channel which is responsible for the M-current, a key controller of neuronal excitability (PubMed:16319223, PubMed:27564677, PubMed:28793216, PubMed:9872318). M-channel is composed of pore-forming subunits KCNQ2 and KCNQ3 assembled as heterotetramers (PubMed:14534157, PubMed:16319223, PubMed:27564677, PubMed:9872318). The native M-current has a slowly activating and deactivating potassium conductance which plays a critical role in determining the subthreshold electrical excitability of neurons as well as the responsiveness to synaptic inputs (PubMed:14534157, PubMed:16319223, PubMed:28793216). M-channel is selectively permeable in vitro to other cations besides potassium, in decreasing order of affinity K(+) > Rb(+) > Cs(+) > Na(+) (PubMed:28793216). M-channel association with SLC5A3/SMIT1 alters channel ion selectivity, increasing Na(+) and Cs(+) permeation relative to K(+) (PubMed:28793216). Suppressed by activation of M1 muscarinic acetylcholine receptors (PubMed:10713961). KCNQ3 also associates with KCNQ5 to form a functional channel in vitro and may also contribute to the M-current in brain (PubMed:11159685)
Disease associations
Seizures, benign familial neonatal 2BFNS2
A disorder characterized by clusters of seizures occurring in the first days of life. Most patients have spontaneous remission by 12 months of age and show normal psychomotor development. The disorder is distinguished from benign familial infantile seizures by an earlier age at onset.
Sources
Last updated 5/6/2026, 5:24:04 AM