KCNA1

Chr 12AD

potassium voltage-gated channel subfamily A member 1

This protein forms a voltage-gated delayed rectifier potassium channel that controls neuronal excitability through tetrameric complexes in cell membranes. Mutations cause episodic ataxia with myokymia syndrome through an autosomal dominant inheritance pattern. The pathogenic mechanism involves gain-of-function effects that disrupt normal potassium channel activity.

OMIMResearchSummary from RefSeq, OMIM, UniProt, Mechanism
MultiplemechanismADLOEUF 0.731 OMIM phenotype
Clinical SummaryKCNA1
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Gene-Disease Validity (ClinGen)
episodic ataxia type 1 · ADDefinitive

Definitive — sufficient evidence for diagnostic panels

Population Constraint (gnomAD)
Constrained for loss-of-function variants (OE-LoF 0.32) despite low pLI — interpret in context.
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Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

Missense constrained — critical functional residues
LoF Constraint
0.73LOEUF
pLI 0.076
Z-score 2.23
OE 0.32 (0.160.73)
Tolerant

Typical tolerance to LoF variation

Missense Constraint
3.33Z-score
OE missense 0.47 (0.410.54)
148 obs / 313.8 exp
Constrained

Highly missense-constrained (top ~0.1%)

Observed / Expected Ratios
LoF OE0.32 (0.160.73)
00.351.4
Missense OE0.47 (0.410.54)
00.61.4
Synonymous OE1.10
01.21.6
LoF obs/exp: 4 / 12.5Missense obs/exp: 148 / 313.8Syn Z: -0.95
Curated Mechanism (G2P)Gene2Phenotype (DDG2P) ↗
limitedKCNA1-related epileptic encephalopathyOTHERAD
limitedKCNA1-related epileptic encephalopathyOTHERAR
DN
0.81top 10%
GOF
0.86top 5%
LOF
0.2289th %ile

This gene has evidence for multiple mechanisms of pathogenicity (gain-of-function and dominant-negative). Both the Badonyi & Marsh prediction and the broader genomic evidence point to gain-of-function as the predominant mechanism. Different variants in this gene may act through different mechanisms — interpret in context of the specific variant.

GOFprediction above median · 1 literature citation
DNprediction above median · 1 literature citation

Note: In-silico variant effect predictors (SIFT, PolyPhen, REVEL, CADD) may underestimate pathogenicity of missense variants in genes with GOF or DN mechanisms. Consider functional evidence and clinical context.

Literature Evidence

DNDominant-negative mutation p.Arg324Thr in KCNA1 impairs Kv1.1 channel function in episodic ataxia.PMID:27477325
GOFThe excellent clinical response to carbamazepine observed in the patients carrying the A261T variant suggests an exquisite sensitivity of KCNA1 GoF to sodium channel inhibition that should be further explored.PMID:34778950

Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312.

ClinVar Variant Classifications

0 submitted variants in ClinVar

Protein Context — Lollipop Plot

KCNA1 · protein map & ClinVar variants

Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.

3D Protein StructureAlphaFold

Clinical Trials

Active and recruiting trials from ClinicalTrials.gov

No active trials found for this gene.

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Clinical Literature
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