KCNC2

protein-coding

potassium voltage-gated channel subfamily C member 2, the group of Potassium voltage-gated channels

Gene summary

The Shaker gene family of Drosophila encodes components of voltage-gated potassium channels and is comprised of four subfamilies. Based on sequence similarity, this gene is similar to one of these subfamilies, namely the Shaw subfamily. The protein encoded by this gene belongs to the delayed rectifier class of channel proteins and is an integral membrane protein that mediates the voltage-dependent potassium ion permeability of excitable membranes. Several transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, May 2012]

MANE transcript

NM_139137.4

Inheritance

AD

ClinVar variants

P:19U:125B:18

Top phenotype

Developmental and epileptic encephalopathy 103

gnomAD constraint

pLI —, LoF o/e 0.25

Max pathogenic AF

—

Genomic locus

chr12:75,040,077-75,209,839

External References & Databases

Transcript & Mutation Effects

hg38 • Region Span ~169.8 kb
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GenCC Phenotypes & Disease Associations

Curated gene-disease validity assertions and inheritance patterns

developmental and epileptic encephalopathy 103STRONG

Inheritance Pattern: AD

Disease ID:MONDO:0030957

Submitter: PanelApp Australia

developmental and epileptic encephalopathy 103STRONG

Inheritance Pattern: AD

Disease ID:MONDO:0030957

Submitter: Labcorp Genetics (formerly Invitae)

genetic developmental and epileptic encephalopathyDEFINITIVE

Inheritance Pattern: AD

Disease ID:MONDO:0100062

Submitter: ClinGen

*KCNC2* was first reported in relation to developmental and epileptic encephalopathy in 2020 (Vetri L, et al, PMID: 31972370). Affected individuals present with seizures (varying types) in the first year of life, global developmental delay / intellectual disability, hypotonia, ataxia, and behavioral abnormalities. Fourteen variants (heterozygous missense) that have been reported in 14 probands in 6 publications (PMIDs: 31972370, 35314505, 35366058, 36090251, 36087422, 36035247) are included in this curation. More evidence is available in the literature, but the maximum score for genetic evidence (12 pts.) has been reached. The mechanism of pathogenicity is reported to be both gain and loss of function. One reported variant is suspected to have a dominant negative effect (PMID: 35314505). In addition to case-level evidence, the gene-disease relationship is supported by in vitro cell culture functional assays. (PMIDs: 35314505, 36090251, 36087422, 36035247). Depending on the variant, modified *KCNC2* channels showed both gain-of-function (a shift towards a hyperpolarized state with increased time to deactivation) and loss-of-function (reduced total current amplitude). A *KCNC2* knockout mouse model has also been published, however it was not scored given that the *KCNC2* variants seen in humans have been missense rather than truncating (PMID:11124984). In summary, there is definitive evidence supporting the relationship between *KCNC2* and autosomal dominant developmental and epileptic encephalopathy. This has been repeatedly demonstrated in both the research and clinical diagnostic settings, and has been upheld over time.This classification was approved by the ClinGen Intellectual Disability and Autism GCEP on the meeting date December 14, 2023 (SOP Version 10).

developmental and epileptic encephalopathy 103STRONG

Inheritance Pattern: AD

Disease ID:MONDO:0030957

Submitter: Ambry Genetics

Clinical Genomic Database (CGD)

Developmental and epileptic encephalopathy 103AD

Manifestation: Neurologic

Intervention: General

Rationale: Genetic knowledge may be beneficial related to issues such as selection of optimal supportive care, informed medical decision-making, prognostic considerations, and avoidance of unnecessary testing

Refs: 31972370; 32392612; 34448338; 35314505Source: CGD (NHGRI)

ClinVar Associated Diseases & Phenotypes

Reported disease conditions connected to KCNC2 variants in ClinVar

9 Conditions Cataloged
not providedTotal: 67
Inborn genetic diseasesTotal: 51
Developmental and epileptic encephalopathy 103Total: 31
KCNC2-related disorderTotal: 15
not specifiedTotal: 8
Developmental and epileptic encephalopathy, 9Total: 1
Developmental and epileptic encephalopathyTotal: 1
Neurodevelopmental delayTotal: 1

ClinVar Variants & Pathogenicity by Type

Statistics based on transcript NM_139137.4. Only rare variants are included.

We include only reliable ClinVar variants with their consequences to MANE Select, MANE Plus Clinical transcripts, or transcripts with TSL equal to 1. Click a count to filter the variants table below.

Slight differences between displayed counts and ClinVar may occur due to a different transcript/consequence chosen by our variant effect predictor, or because we classify Benign/Likely benign as Likely benign and Pathogenic/Likely pathogenic as Likely pathogenic.

EffectPLPVUSLBBSum
synonymous
2
clinvar
10
clinvar
1
clinvar
13
missense
8
clinvar
11
clinvar
117
clinvar
7
clinvar
143
nonsense
1
clinvar
1
start loss
0
frameshift
3
clinvar
3
splice donor/acceptor (+/-2bp)
2
clinvar
2
Total811125171162

Highest pathogenic variant AF is 0.0000012396935

Loading ClinVar variants...

Transcript Catalog

Annotated transcript isoforms across RefSeq and Ensembl databases

Showing 4 of 49 transcripts
Transcript IDSourceProtein IDCoding ExonsMANE Status
NM_139137.4RefSeqNP_631875.14MANE Select
ENST00000549446.6EnsemblENSP00000449253.24MANE Select
NM_001260497.2RefSeqNP_001247426.14Standard
NM_001260498.2RefSeqNP_001247427.14Standard

Gene Ontology (GO) Annotations & Pathways

Biological processes, molecular functions, cellular components and pathways

Pathways ConsensusPathDB

  • Neuronal System
  • Voltage gated Potassium channels
  • Potassium Channels

Biological Process

  • response to light intensity
  • response to organic cyclic compound
  • response to amine
  • globus pallidus development
  • response to magnesium ion

Molecular Function

  • voltage-gated potassium channel activity
  • delayed rectifier potassium channel activity
  • ion channel binding
  • voltage-gated ion channel activity involved in regulation of presynaptic membrane potential

Cellular Component

  • plasma membrane
  • integral component of plasma membrane
  • voltage-gated potassium channel complex
  • membrane
  • integral component of membrane

gnomAD Constraint

Source: gnomAD

Gene type
protein_coding
Transcript type
protein_coding
Transcript
ENST00000549446
Coding exons
4
Length
169792
Individuals with no LoFs
125738
Homozygous LoFs
0
Heterozygous LoFs
10
Defined
125748
p
0.0000398
Z-ScoreObservedExpectedObserved/ExpectedMutation RateTotal Possible
Missense2.982043640.5610.00001864095
Missense (PolyPhen)36156.630.229841837
Synonymous-2.011891571.200.000008801354
Loss of Function3.07519.70.2540.00000105240

Population LoF Frequency

PopulationCAFp-valueStatus
African00.0absent
Latino/Admixed American0.0000310.000029rare
Ashkenazi Jewish00.0absent
East Asian00.0absent
Finnish00.0absent
European (Non-Finnish)0.0000530.000053rare
South Asian0.0000980.000098rare
Other00.0absent

dbNSFP Gene Annotations

Source: dbNSFP

Function
FUNCTION: Voltage-gated potassium channel that mediates transmembrane potassium transport in excitable membranes, primarily in the brain. Contributes to the regulation of the fast action potential repolarization and in sustained high-frequency firing in neurons of the central nervous system. Homotetramer channels mediate delayed-rectifier voltage-dependent potassium currents that activate rapidly at high-threshold voltages and inactivate slowly. Forms tetrameric channels through which potassium ions pass in accordance with their electrochemical gradient. The channel alternates between opened and closed conformations in response to the voltage difference across the membrane (PubMed:15709110). Can form functional homotetrameric and heterotetrameric channels that contain variable proportions of KCNC1, and possibly other family members as well; channel properties depend on the type of alpha subunits that are part of the channel. Channel properties may be modulated either by the association with ancillary subunits, such as KCNE1, KCNE2 or KCNE3 or indirectly by nitric oxide (NO) through a cGMP- and PKG- mediated signaling cascade, slowing channel activation and deactivation of delayed rectifier potassium channels (By similarity). Contributes to fire sustained trains of very brief action potentials at high frequency in retinal ganglion cells, thalamocortical and suprachiasmatic nucleus (SCN) neurons and in hippocampal and neocortical interneurons (PubMed:15709110). Sustained maximal action potential firing frequency in inhibitory hippocampal interneurons is negatively modulated by histamine H2 receptor activation in a cAMP- and protein kinase (PKA) phosphorylation-dependent manner. Plays a role in maintaining the fidelity of synaptic transmission in neocortical GABAergic interneurons by generating action potential (AP) repolarization at nerve terminals, thus reducing spike-evoked calcium influx and GABA neurotransmitter release. Required for long-range synchronization of gamma oscillations over distance in the neocortex. Contributes to the modulation of the circadian rhythm of spontaneous action potential firing in suprachiasmatic nucleus (SCN) neurons in a light-dependent manner (By similarity). {ECO:0000250|UniProtKB:P22462, ECO:0000250|UniProtKB:Q14B80, ECO:0000269|PubMed:15709110, ECO:0000305|PubMed:10414303, ECO:0000305|PubMed:11506885}.;
Disease
DISEASE: Note=A chromosomal aberration involving KCNC2 has been found in a mother and her two children with varying degrees of neurodevelopmental delay and cerebellar ataxia. One child also exhibits episodes of unresponsiveness suggestive of absence seizures and facial dysmorphism. Deletion at 12q21.1 deletes exons 3-5 of KCNC2. {ECO:0000269|PubMed:23475819}.;

Recessive Scores

pRec
0.0978

Intolerance Scores

LoFtool
0.0257
RVIS EVS
-0.82
RVIS percentile EVS
11.68

Essentials

Essential (CRISPR)
N
Essential (CRISPR2)
N
Essential (gene trap)
N
Indispensability pred.
E
Indispensability score
0.920

Gene Damage Prediction

AllRecessiveDominant
MendelianMediumMediumMedium
Primary ImmunodeficiencyMediumMediumMedium
CancerMediumMediumMedium
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