NM_004974.4:c.890G>A

Variant names:

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

Genomes: not found (cov: 32)

Exomes 𝑓: 0.0 ( 0 hom. )

Failed GnomAD Quality Control

Consequence

KCNA2
NM_004974.4 missense

Scores

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:10O:1

Conservation

PhyloP100: 7.91

Variant links:

Genes affected

KCNA2 (HGNC:6220): (potassium voltage-gated channel subfamily A member 2) 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]

KCNA2 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 19 ACMG points.

PM1

In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 3 uncertain in NM_004974.4

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr1-110603894-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 986989.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

PP2

Missense variant in the KCNA2 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 37 curated pathogenic missense variants (we use a threshold of 10). The gene has 14 curated benign missense variants. Gene score misZ: 3.831 (above the threshold of 3.09). Trascript score misZ: 5.1665 (above the threshold of 3.09). GenCC associations: The gene is linked to undetermined early-onset epileptic encephalopathy, developmental and epileptic encephalopathy, developmental and epileptic encephalopathy, 32.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.969

PP5

Variant 1-110603893-C-T is Pathogenic according to our data. Variant chr1-110603893-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 190328.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr1-110603893-C-T is described in Lovd as [Pathogenic]. Variant chr1-110603893-C-T is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNA2	NM_004974.4 link	c.890G>A	p.Arg297Gln	missense_variant	Exon 3 of 3	ENST00000316361.10	NP_004965.1	P16389-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCNA2	ENST00000316361.10 link	c.890G>A	p.Arg297Gln	missense_variant	Exon 3 of 3	2	NM_004974.4	ENSP00000314520.4		P16389-1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

Data not reliable, filtered out with message: AC0

AF:

0.00

AC:

AN:

1461890

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

727246

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

Cov.:

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:10Other:1

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Developmental and epileptic encephalopathy, 32

Pathogenic:5

Apr 01, 2015

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

Jan 04, 2021

Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, IRCCS Fondazione Stella Maris

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: research

- -

Oct 02, 2021

3billion, Medical Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Same nucleotide change resulting in same amino acid change has been previously reported multiple times as de novoo in similarly affected unrelated individuals (PMID:25477152, 25751627, 27733563, PS2, PS4). It is not observed in the gnomAD v2.1.1 dataset (PM2). A different missense change at the same codon (p.Glu545Lys) has been reported as pathogenic (VCV000013655.18 PM5). In silico tool predictions suggest damaging effect of the variant on gene or gene product (REVEL: 0.982, 3Cnet: 0.967, PP3). Therefore, this variant is classified as pathogenic according to the recommendation of ACMG/AMP guideline. -

Sep 08, 2002

Center of Excellence for Medical Genomics, Chulalongkorn University

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: research

- -

Jan 22, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. -

not provided

Pathogenic:2

Jun 21, 2021

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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) -

Jan 01, 2017

CeGaT Center for Human Genetics Tuebingen

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Developmental and epileptic encephalopathy, 1

Pathogenic:1Other:1

Jan 01, 2019

Centre de Biologie Pathologie Génétique, Centre Hospitalier Universitaire de Lille

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

GenomeConnect - Invitae Patient Insights Network

Significance: not provided

Review Status: no classification provided

Collection Method: phenotyping only

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. -

Inborn genetic diseases

Pathogenic:1

Apr 26, 2016

Ambry Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Neurodevelopmental disorder

Pathogenic:1

Feb 18, 2020

Laboratory of Molecular Genetics (Pr. Bezieau's lab), CHU de Nantes

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.99

BayesDel_addAF

Pathogenic

0.57

BayesDel_noAF

Pathogenic

0.58

CADD

Pathogenic

DANN

Pathogenic

1.0

DEOGEN2

Pathogenic

0.98

D;.;.;.;.;.;D;D;D;D;.

Eigen

Pathogenic

1.0

Eigen_PC

Pathogenic

0.99

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Pathogenic

1.0

.;D;D;D;D;T;.;.;.;D;D

M_CAP

Pathogenic

0.80

MetaRNN

Pathogenic

0.97

D;D;D;D;D;D;D;D;D;D;D

MetaSVM

Pathogenic

1.0

MutationAssessor

Pathogenic

3.8

H;H;.;.;.;.;H;H;H;H;.

PrimateAI

Pathogenic

0.83

PROVEAN

Uncertain

-3.8

.;D;.;.;.;.;.;D;.;D;.

REVEL

Pathogenic

0.98

Sift

Pathogenic

0.0

.;D;.;.;.;.;.;D;.;D;.

Sift4G

Pathogenic

0.0010

D;D;.;.;.;.;.;D;.;D;.

Polyphen

1.0

D;.;.;.;.;.;D;D;D;D;.

Vest4

0.93

MutPred

0.84

Loss of helix (P = 0.0304);Loss of helix (P = 0.0304);.;.;.;.;Loss of helix (P = 0.0304);Loss of helix (P = 0.0304);Loss of helix (P = 0.0304);Loss of helix (P = 0.0304);.;

MVP

0.99

MPC

2.5

ClinPred

1.0

GERP RS

5.9

Varity_R

0.94

gMVP

0.99

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.12

Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over