GENE REFERENCE / HGNC:6296

KCNQ2

potassium voltage-gated channel subfamily Q member 2

protein-coding gene20q13.33Gene information

What does this gene do?

The KCNQ2 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 KCNQ2 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 KCNQ2 gene can form a channel. However, the KCNQ2 alpha subunits can also interact with alpha subunits produced from the KCNQ3 gene to form a functional potassium channel, and these channels transmit a much stronger M-current.

Source: MedlinePlus, National Library of Medicine. Source publication: 2020-08-18. Source review: 2013-04.

ClinGen reviews

ClinGen reviews the evidence linking a particular gene to a condition. Each rating below describes the strength of that link. It does not classify a variant in your DNA file.

Condition	Inheritance	Evidence
neonatal-onset developmental and epileptic encephalopathyMONDO:0100455 · Evaluated 2022-06-21	Autosomal dominant	DefinitiveEpilepsy Gene Curation Expert Panel
neonatal encephalopathy with non-epileptic myoclonusMONDO:0100456 · Evaluated 2022-02-15	Autosomal dominant	DefinitiveEpilepsy Gene Curation Expert Panel
complex neurodevelopmental disorderMONDO:0100038 · Evaluated 2021-11-15	Autosomal dominant	DefinitiveEpilepsy Gene Curation Expert Panel

ClinVar records

These numbers show what has been submitted to ClinVar. They cannot tell you how likely you are to have a condition.

Submitted alleles: 2,659
Submissions for variants in or overlapping this gene: 4,910
Submissions explicitly reporting this gene: 4,742
Alleles reported pathogenic / likely pathogenic: 867
VariationIDs with uncertain significance: 746
VariationIDs with conflicting classifications: 134

The rows count different things: alleles, submissions or VariationIDs. Their categories can overlap, so do not add them together. Pathogenic/likely pathogenic counts exclude structural variants that merely overlap a gene. A dash in the source means “not reported,” not zero.

NCBI produces the gene-summary file each week using counts recorded at the start of the month. The numbers may differ from those on the live ClinVar website. Read the field definitions ↗

View this gene in ClinVar ↗

YOUR DNA FILE

Can your DNA file tell you about KCNQ2?

From a DNA test kit (such as 23andMe, AncestryDNA or MyHeritage). These kits check a fixed list of about 600,000 to 700,000 positions across your whole genome. ClinVar lists 867 alleles in KCNQ2 reported as pathogenic or likely pathogenic. A kit checks only some of these positions, and often none of them.

From whole genome sequencing (a VCF file). Sequencing reads most of your genome. Your file lists the places where your DNA differs from the reference genome. Some regions are hard to sequence, including parts of some genes that have near-identical copies elsewhere, and a VCF file does not record which positions were read well.

If a variant is not in your file, that does not mean you don’t have it.

What BioDecode checks

BioDecode compares every variant in your file with ClinVar, on your own computer. For each match, it shows the ClinVar classification, the review status and the condition it was reported for. Your file is not uploaded.

A ClinVar classification applies to one particular variant and the condition it was reported for. It does not tell you about other variants in KCNQ2.

BioDecode cannot fill gaps in your test, diagnose a condition or replace clinical testing.

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