rs794727134

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 5P and 4B. PM1PP2PP3PP5BS2

The NM_172107.4(KCNQ2):c.1627G>A(p.Val543Met) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000013 in 1,612,582 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000014 ( 0 hom. )

Consequence

KCNQ2
NM_172107.4 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:4U:4

Conservation

PhyloP100: 2.91

Publications

8 publications found

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 Gene-Disease associations (from GenCC):

complex neurodevelopmental disorder
Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
developmental and epileptic encephalopathy, 7
Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae), G2P
neonatal encephalopathy with non-epileptic myoclonus
Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
neonatal-onset developmental and epileptic encephalopathy
Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
seizures, benign familial neonatal, 1
Inheritance: AD Classification: DEFINITIVE Submitted by: G2P
seizures, benign familial neonatal, 2
Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
benign familial infantile epilepsy
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
benign familial neonatal-infantile seizures
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
benign neonatal seizures
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
malignant migrating partial seizures of infancy
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

KCNQ2 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 1 ACMG points.

PM1

In a hotspot region, there are 13 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 15 uncertain in NM_172107.4

PP2

Missense variant in the KCNQ2 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 319 curated pathogenic missense variants (we use a threshold of 10). The gene has 78 curated benign missense variants. Gene score misZ: 4.0411 (above the threshold of 3.09). Trascript score misZ: 3.6968 (above the threshold of 3.09). GenCC associations: The gene is linked to benign familial infantile epilepsy, malignant migrating partial seizures of infancy, developmental and epileptic encephalopathy, 7, benign familial neonatal-infantile seizures, benign neonatal seizures, neonatal-onset developmental and epileptic encephalopathy, complex neurodevelopmental disorder, seizures, benign familial neonatal, 2, seizures, benign familial neonatal, 1, neonatal encephalopathy with non-epileptic myoclonus.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.796

PP5

Variant 20-63414092-C-T is Pathogenic according to our data. Variant chr20-63414092-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 194446.

BS2

High AC in GnomAdExome4 at 20 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNQ2	NM_172107.4 link	c.1627G>A	p.Val543Met	missense_variant	Exon 14 of 17	ENST00000359125.7	NP_742105.1	O43526-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCNQ2	ENST00000359125.7 link	c.1627G>A	p.Val543Met	missense_variant	Exon 14 of 17	1	NM_172107.4	ENSP00000352035.2		O43526-1

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152180

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000655

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.00000404

AC:

AN:

247742

AF XY:

0.00

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 FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000906

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000137

AC:

AN:

1460402

Hom.:

Cov.:

AF XY:

0.0000110

AC XY:

AN XY:

726604

show subpopulations

African (AFR)

AF:

0.0000299

AC:

AN:

33472

American (AMR)

AF:

0.00

AC:

AN:

44720

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26126

East Asian (EAS)

AF:

0.00

AC:

AN:

39694

South Asian (SAS)

AF:

0.00

AC:

AN:

86246

European-Finnish (FIN)

AF:

0.00

AC:

AN:

52788

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5766

European-Non Finnish (NFE)

AF:

0.0000153

AC:

AN:

1111246

Other (OTH)

AF:

0.0000331

AC:

AN:

60344

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.455

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152180

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74338

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41448

American (AMR)

AF:

0.0000655

AC:

AN:

15278

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5196

South Asian (SAS)

AF:

0.00

AC:

AN:

4826

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10614

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68026

Other (OTH)

AF:

0.00

AC:

AN:

2094

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.525

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.0000264

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:4Uncertain:4

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:3

Jun 25, 2018

Eurofins Ntd Llc (ga)

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Mar 12, 2018

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The V543M variant has been previously reported in an individual with benign familial neonatal seizures; the variant was also identified in the affected father and 2 paternal aunts (Lee et al., 2017). Functional studies demonstrate the V543M variant causes a mild electrophysiological change in channel function compared to wild type (Lee et al., 2017). Missense variants in nearby residues have been reported in the Human Gene Mutation Database in individuals with with KCNQ2-related disorders (Stenson et al., 2014). The V543M variant is observed in 1/108796 (0.001%) alleles from individuals of European background (Lek et al., 2016). However, the V543M variant is a conservative amino acid substitution, which is not likely to impact secondary protein structure as these residues share similar properties. In-silico analyses, including protein predictors and evolutionary conservation, support that this variant does not alter protein structure/function. Therefore, based on the currently available information, it is unclear whether this variant is a pathogenic variant or a rare benign variant. -

Jun 01, 2025

CeGaT Center for Human Genetics Tuebingen

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

KCNQ2: PP3 -

Inborn genetic diseases

Pathogenic:1

Mar 01, 2017

Ambry Genetics

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The p.V543M variant (also known as c.1627G>A), located in coding exon 14 of the KCNQ2 gene, results from a G to A substitution at nucleotide position 1627. The valine at codon 543 is replaced by methionine, an amino acid with highly similar properties. This variant has been determined to be the result of a de novo mutation or germline mosaicism in one family with an isolated case of KCNQ2-related seizure disorder. This amino acid position is well conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Based on the majority of available evidence to date, this variant is likely to be pathogenic. -

Developmental and epileptic encephalopathy

Pathogenic:1

Jan 05, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces valine, which is neutral and non-polar, with methionine, which is neutral and non-polar, at codon 543 of the KCNQ2 protein (p.Val543Met). This variant is present in population databases (rs794727134, gnomAD 0.0009%). This missense change has been observed in individuals with clinical features of benign familial neonatal-infantile seizures or early infantile epileptic encephalopathy (PMID: 28399683, 29056246, 31199083; internal data). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 194446). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is expected to disrupt KCNQ2 protein function with a positive predictive value of 95%. Experimental studies have shown that this missense change affects KCNQ2 function (PMID: 28399683). For these reasons, this variant has been classified as Pathogenic. -

Seizures, benign familial neonatal, 1

Pathogenic:1

Nov 15, 2016

Clinical Molecular Genetics Laboratory, Johns Hopkins All Children's Hospital

Significance:Likely pathogenic

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Developmental and epileptic encephalopathy, 7

Pathogenic:1

Jan 01, 2020

Centre de Biologie Pathologie Génétique, Centre Hospitalier Universitaire de Lille

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

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

Uncertain:1

Oct 31, 2018

Fulgent Genetics, Fulgent Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.28

BayesDel_addAF

Pathogenic

0.28

BayesDel_noAF

Pathogenic

0.16

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

DEOGEN2

Benign

0.40

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

Eigen

Uncertain

0.55

Eigen_PC

Uncertain

0.51

FATHMM_MKL

Uncertain

0.87

LIST_S2

Uncertain

0.96

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

M_CAP

Pathogenic

0.83

MetaRNN

Pathogenic

0.80

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

MetaSVM

Pathogenic

1.0

MutationAssessor

Uncertain

2.8

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

PhyloP100

2.9

PrimateAI

Pathogenic

0.81

PROVEAN

Benign

-2.3

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

REVEL

Pathogenic

0.77

Sift

Uncertain

0.0010

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

Sift4G

Uncertain

0.0030

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

Polyphen

1.0

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

Vest4

0.68

MutPred

0.69

.;.;.;.;.;.;Gain of sheet (P = 0.039);.;.;.;.;

MVP

0.91

MPC

1.6

ClinPred

0.94

GERP RS

4.4

Varity_R

0.70

gMVP

0.83

Mutation Taster

=2/98

disease causing (ClinVar)

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.020

Details are displayed if max score is > 0.2

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over