NM_004974.4:c.890G>A
Variant summary
Our verdict is Pathogenic. Variant got 19 ACMG points: 19P and 0B. PM1PM2PM5PP2PP3_StrongPP5_Very_Strong
The NM_004974.4(KCNA2):c.890G>A(p.Arg297Gln) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 12/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R297W) has been classified as Pathogenic.
Frequency
Consequence
NM_004974.4 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Pathogenic. Variant got 19 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes Cov.: 32
GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0AN: 1461890Hom.: 0 Cov.: 34 AF XY: 0.00 AC XY: 0AN XY: 727246
GnomAD4 genome Cov.: 32
ClinVar
Submissions by phenotype
Developmental and epileptic encephalopathy, 32 Pathogenic:5
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This sequence change replaces arginine, which is basic and polar, with glutamine, which is neutral and polar, at codon 297 of the KCNA2 protein (p.Arg297Gln). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with autosomal dominant epileptic encephalopathy (PMID: 25477152, 25751627, 27733563). In at least one individual the variant was observed to be de novo. ClinVar contains an entry for this variant (Variation ID: 190328). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt KCNA2 protein function with a positive predictive value of 80%. Experimental studies have shown that this missense change affects KCNA2 function (PMID: 25751627). For these reasons, this variant has been classified as Pathogenic. -
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The variant is not observed in the gnomAD v2.1.1 dataset. Predicted Consequence/Location: Missense changes are a common disease-causing mechanism. In silico tool predictions suggest damaging effect of the variant on gene or gene product [REVEL: 0.74 (>=0.6, sensitivity 0.68 and specificity 0.92); 3Cnet: 0.72 (>=0.6, sensitivity 0.72 and precision 0.9)]. Same nucleotide change resulting in same amino acid change has been previously reported as pathogenic/likely pathogenic with strong evidence (ClinVar ID: VCV000585073 /PMID: 31278393).The variant has been previously reported as de novo in a similarly affected individual (PMID: 31278393, 31278393).The variant has been observed in multiple (>3) similarly affected unrelated individuals (PMID: 31278393).Different missense changes at the same codon (p.Val1002Gly, p.Val1002Leu) have been reported to be associated with TRPM3 related disorder (PMID: 36648066). Therefore, this variant is classified as Pathogenic according to the recommendation of ACMG/AMP guideline. -
not provided Pathogenic:2
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Functional studies indicate a gain-of-function effect that disrupts normal function of the Kv1.2 potassium channel (Syrbe et al., 2015); Not observed in large population cohorts (Lek et al., 2016); In silico analysis, which includes protein predictors and evolutionary conservation, supports a deleterious effect; This variant is associated with the following publications: (PMID: 33802230, 31628766, 31692161, 30660924, 27535533, 31075689, 31487502, 31054490, 30283815, 29050392, 27733563, 25751627, 25477152) -
Developmental and epileptic encephalopathy, 1 Pathogenic:1Other:1
Variant interpreted as Pathogenic and reported on 12-31-2019 by Lab Invitae. GenomeConnect-Invitae Patient Insights Network assertions are reported exactly as they appear on the patient-provided report from the testing laboratory. Registry team members make no attempt to reinterpret the clinical significance of the variant. Phenotypic details are available under supporting information. -
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Inborn genetic diseases Pathogenic:1
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Neurodevelopmental disorder Pathogenic:1
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at