KCNA2

Chr 1AD

potassium voltage-gated channel subfamily A member 2

Also known as: DEE32, EIEE32, HBK5, HK4, HUKIV, KV1.2, MK2, NGK1

NCBI Gene: 3737 ENSG00000177301 UniProt: P16389

Potassium channels represent the most complex class of voltage-gated ion channels from both functional and structural standpoints. Their diverse functions include regulating neurotransmitter release, heart rate, insulin secretion, neuronal excitability, epithelial electrolyte transport, smooth muscle contraction, and cell volume. Four sequence-related potassium channel genes - shaker, shaw, shab, and shal - have been identified in Drosophila, and each has been shown to have human homolog(s). This gene encodes a member of the potassium channel, voltage-gated, shaker-related subfamily. This member contains six membrane-spanning domains with a shaker-type repeat in the fourth segment. It belongs to the delayed rectifier class, members of which allow nerve cells to efficiently repolarize following an action potential. The coding region of this gene is intronless, and the gene is clustered with genes KCNA3 and KCNA10 on chromosome 1. [provided by RefSeq, Jul 2008]

Primary Disease Associations & Inheritance

Developmental and epileptic encephalopathy 32MIM #616366

UniProtNizon-Isidor syndrome

590

ClinVar variants

Pathogenic / LP

0.91

pLI score· haploinsufficient

Active trials

Clinical Summary— KCNA2

🧬

Gene-Disease Validity (ClinGen)

developmental and epileptic encephalopathy · ADDefinitive

Definitive — sufficient evidence for diagnostic panels

⚡

Population Constraint (gnomAD)

Highly constrained gene — heterozygous loss-of-function variants are very rare in the population (pLI 0.91). One damaged copy is likely sufficient to cause disease.

📋

ClinVar Variants

81 Pathogenic / Likely Pathogenic· 302 VUS of 590 total submissions

💊

Clinical Trials

1 active or recruiting trial — potential therapeutic options may be available

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

gnomAD

Dual constrained — LoF & missense intolerant

LoF Constraint?LOEUF (Loss-of-function Observed/Expected Upper bound Fraction) is the upper bound of the 90% CI for LoF OE — the preferred gnomAD v4 metric. Lower = more intolerant to LoF. LOEUF < 0.35 = highly constrained.

0.38LOEUF

pLI 0.911

Z-score 3.32

OE 0.12 (0.05–0.38)

Highly constrained

More LoF-intolerant than ~75% of genes

Missense Constraint?Missense Z-score: standard deviations fewer missense variants observed vs. expected. Z > 3.09 (p < 0.001) = gene does not tolerate missense variation. OE missense < 0.6 is also considered constrained.

3.83Z-score

OE missense 0.35 (0.30–0.42)

99 obs / 279.1 exp

Constrained

Highly missense-constrained (top ~0.1%)

Observed / Expected Ratios?Shaded band = 90% confidence interval. Vertical tick = point estimate. Grey threshold line = gnomAD constraint cutoff for that variant class.

LoF OE?Ratio of observed to expected LoF variants. Upper CI bound (LOEUF) ≤ 0.35 = strong LoF constraint signal.0.12 (0.05–0.38)

0≤0.351.4

Missense OE?Ratio of observed to expected missense variants. OE ≤ 0.6 = fewer missense variants than expected by chance.0.35 (0.30–0.42)

0≤0.61.4

Synonymous OE?Control metric — synonymous variants are largely neutral and expected near OE = 1.0. Significant deviation may indicate annotation issues.1.00

0≤1.21.6

LoF obs/exp: 2 / 16.6Missense obs/exp: 99 / 279.1Syn Z: -0.03