rs375264483

Positions:

chr20-63414923-G-A

Variant summary

Our verdict is Likely benign. Variant got -3 ACMG points: 1P and 4B. PP2BS2

The ENST00000359125.7(KCNQ2):c.1505C>T(p.Ala502Val) variant causes a missense change. The variant allele was found at a frequency of 0.0000589 in 1,612,570 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A502T) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000063 ( 0 hom. )

Consequence

KCNQ2
ENST00000359125.7 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:4B:1O:1

Conservation

PhyloP100: 5.45

Variant links:

Genes affected

KCNQ2 (HGNC:6296): (potassium voltage-gated channel subfamily Q member 2) The M channel is a slowly activating and deactivating potassium channel that plays a critical role in the regulation of neuronal excitability. The M channel is formed by the association of the protein encoded by this gene and a related protein encoded by the KCNQ3 gene, both integral membrane proteins. M channel currents are inhibited by M1 muscarinic acetylcholine receptors and activated by retigabine, a novel anti-convulsant drug. Defects in this gene are a cause of benign familial neonatal convulsions type 1 (BFNC), also known as epilepsy, benign neonatal type 1 (EBN1). At least five transcript variants encoding five different isoforms have been found for this gene. [provided by RefSeq, Jul 2008]

KCNQ2 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -3 ACMG points.

PP2

Missense variant in gene, where missense usually causes diseases (based on misZ statistic), KCNQ2. . Gene score misZ 4.0411 (greater than the threshold 3.09). Trascript score misZ 3.6968 (greater than threshold 3.09). GenCC has associacion of gene with seizures, benign familial neonatal, 1, neonatal-onset developmental and epileptic encephalopathy, benign familial neonatal-infantile seizures, benign neonatal seizures, malignant migrating partial seizures of infancy, neonatal encephalopathy with non-epileptic myoclonus, complex neurodevelopmental disorder, seizures, benign familial neonatal, 2, developmental and epileptic encephalopathy, 7, benign familial infantile epilepsy.

BS2

High AC in GnomAdExome4 at 92 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
KCNQ2	NM_172107.4 linkuse as main transcript	c.1505C>T	p.Ala502Val	missense_variant	13/17	ENST00000359125.7	NP_742105.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
KCNQ2	ENST00000359125.7 linkuse as main transcript	c.1505C>T	p.Ala502Val	missense_variant	13/17	1	NM_172107.4	ENSP00000352035	A1	O43526-1

Frequencies

GnomAD3 genomes

AF:

0.0000197

AC:

AN:

151974

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000441

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000363

AC:

AN:

248212

Hom.:

AF XY:

0.0000520

AC XY:

AN XY:

134652

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000812

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000630

AC:

AN:

1460596

Hom.:

Cov.:

AF XY:

0.0000523

AC XY:

AN XY:

726644

show subpopulations

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:

0.0000116

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000818

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000197

AC:

AN:

151974

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74206

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000441

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000847

Hom.:

Bravo

AF:

0.0000151

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000116

AC:

ExAC

AF:

0.00000824

AC:

EpiCase

AF:

0.00

EpiControl

AF:

0.000119

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:4Benign:1Other:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:2Benign:1

Uncertain significance, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Oct 09, 2019	- -
Likely benign, criteria provided, single submitter	clinical testing	GeneDx	Aug 31, 2020	- -
Uncertain significance, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Sep 01, 2019	- -

Early infantile epileptic encephalopathy with suppression bursts

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Nov 24, 2023

This sequence change replaces alanine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 502 of the KCNQ2 protein (p.Ala502Val). This variant is present in population databases (rs375264483, gnomAD 0.007%). This missense change has been observed in individual(s) with clinical features of benign familial neonatal-infantile seizures (Invitae). ClinVar contains an entry for this variant (Variation ID: 205906). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant¬†is likely to be tolerated. Experimental studies have shown that this missense change does not substantially affect KCNQ2 function (PMID: 35104249). In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Seizures, benign familial neonatal, 1;C3150986:Developmental and epileptic encephalopathy, 7

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Oct 31, 2018

- -

Complex neurodevelopmental disorder

Other:1

not provided, no classification provided

literature only

Channelopathy-Associated Epilepsy Research Center

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.13

BayesDel_addAF

Uncertain

0.082

BayesDel_noAF

Uncertain

0.070

CADD

Uncertain

DANN

Uncertain

1.0

DEOGEN2

Benign

0.32

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

Eigen

Benign

0.050

Eigen_PC

Benign

0.049

FATHMM_MKL

Uncertain

0.81

LIST_S2

Uncertain

0.95

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

M_CAP

Pathogenic

0.37

MetaRNN

Uncertain

0.51

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

MetaSVM

Pathogenic

1.2

MutationAssessor

Uncertain

2.2

.;.;.;.;.;.;M;.;.;.;.

MutationTaster

Benign

0.74

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

PrimateAI

Uncertain

0.55

PROVEAN

Benign

-1.9

.;.;.;.;N;.;N;.;N;.;.

REVEL

Uncertain

0.63

Sift

Benign

0.081

.;.;.;.;T;.;T;.;T;.;.

Sift4G

Benign

0.41

T;T;T;T;T;.;T;T;T;T;T

Polyphen

0.82

P;.;.;.;.;.;P;.;P;P;.

Vest4

0.50

MVP

0.94

MPC

0.70

ClinPred

0.25

GERP RS

5.2

Varity_R

0.19

gMVP

0.64

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.0

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