rs118192215

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 19 ACMG points: 19P and 0B. PM1PM2PM5PP2PP3_StrongPP5_Very_Strong

The NM_172107.4(KCNQ2):c.997C>T(p.Arg333Trp) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic 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. R333Q) has been classified as Pathogenic.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 0.0 ( 0 hom. )

Failed GnomAD Quality Control

Consequence

KCNQ2
NM_172107.4 missense

Scores

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:6O:1

Conservation

PhyloP100: 3.74

Publications

21 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: Pathogenic. The variant received 19 ACMG points.

PM1

In a hotspot region, there are 18 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 3 uncertain in NM_172107.4

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr20-63438650-C-T is described in ClinVar as Pathogenic. ClinVar VariationId is 21810.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

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, 0.982

PP5

Variant 20-63438651-G-A is Pathogenic according to our data. Variant chr20-63438651-G-A is described in ClinVar as Pathogenic. ClinVar VariationId is 21809.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNQ2	NM_172107.4 link	c.997C>T	p.Arg333Trp	missense_variant	Exon 7 of 17	ENST00000359125.7	NP_742105.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCNQ2	ENST00000359125.7 link	c.997C>T	p.Arg333Trp	missense_variant	Exon 7 of 17	1	NM_172107.4	ENSP00000352035.2

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

Data not reliable, filtered out with message: AC0

AF:

0.00

AC:

AN:

1461482

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

727020

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.00

AC:

AN:

44720

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26132

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.00

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53072

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1111970

Other (OTH)

AF:

0.00

AC:

AN:

60382

GnomAD4 genome

Cov.:

Alfa

AF:

0.00

Hom.:

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:6Other:1

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Pathogenic:3

Sep 09, 2024

GeneDx

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 23621294, 20437616, 32593896, 23692823, 16039833, 28135719, 28867141, 28191890, 30182498, 31069529, 35104249, 33811133, 31785789, 31440721, 38259611, 30008368, 27602407, 33057194, 35982159) -

Genome Diagnostics Laboratory, University Medical Center Utrecht

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Joint Genome Diagnostic Labs from Nijmegen and Maastricht, Radboudumc and MUMC+

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

KCNQ2-related disorder

Pathogenic:1

Rady Children's Institute for Genomic Medicine, Rady Children's Hospital San Diego

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.997C>T (p.Arg333Trp) variant affects a highly conserved amino acid and is predicted by multiple in silico tools to have a deleterious effect on protein function. This variant has been previously reported as a de novo and heterozygous change in patients with early onset epileptic encephalopathies (PMID: 16039833, 23621294, 23692823, 30182498, 31440721, 32593896). The c.997C>T (p.Arg333Trp) variant is located in a mutational hotspot for pathogenic variations associated with KCNQ2-related disorders (PMID: 30008368). A different amino acid change at the same residue, KCNQ2 c.998G>A (p.Arg333Gln), has been previously reported in individuals with benign neonatal seizures (PMID: 14534157, 29215089, 31152295, 31832524, 33897753). Functional studies indicate that the p.Arg333Trp variant reduced axonal surface expression of potassium voltage-gated channels, reduced the sensitivity of the channels to phosphatidylinositol-4,5-bisphosphate (PIP2) stimulation, and disrupted the ability to inhibit excitability in hippocampal neurons (PMID: 30008368). The c.997C>T (p.Arg333Trp) variant is absent from the gnomAD population database and thus is presumed to be rare. Analysis of the parental samples was negative for the variant, indicating this variant likely occurred as a de novo event. Based on the available evidence, c.997C>T (p.Arg333Trp) is classified as Pathogenic. -

Developmental and epileptic encephalopathy

Pathogenic:1

Feb 24, 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 tryptophan, which is neutral and slightly polar, at codon 333 of the KCNQ2 protein (p.Arg333Trp). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with neonatal seizures (PMID: 16039833, 23621294, 23692823). In at least one individual the variant was observed to be de novo. ClinVar contains an entry for this variant (Variation ID: 21809). 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 KCNQ2 protein function with a positive predictive value of 95%. For these reasons, this variant has been classified as Pathogenic. -

Seizure

Pathogenic:1

Oct 11, 2024

Génétique des Maladies du Développement, Hospices Civils de Lyon

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Developmental and epileptic encephalopathy, 7

Other:1

GeneReviews

Significance:not provided

Review Status:no classification provided

Collection Method:literature only

EE (epileptic encephalopathy) -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

1.0

BayesDel_addAF

Pathogenic

0.53

BayesDel_noAF

Pathogenic

0.52

CADD

Pathogenic

(source)

DANN

Pathogenic

1.0

DEOGEN2

Uncertain

0.58

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

Eigen

Uncertain

0.58

Eigen_PC

Uncertain

0.50

FATHMM_MKL

Uncertain

0.91

LIST_S2

Pathogenic

1.0

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

M_CAP

Pathogenic

0.84

MetaRNN

Pathogenic

0.98

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

MetaSVM

Pathogenic

1.1

MutationAssessor

Uncertain

2.7

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

PhyloP100

3.7

PrimateAI

Pathogenic

0.93

PROVEAN

Pathogenic

-7.3

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

REVEL

Pathogenic

0.94

Sift

Uncertain

0.0010

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

Sift4G

Pathogenic

0.0010

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

Polyphen

1.0

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

Vest4

0.93

MutPred

0.85

Loss of disorder (P = 0.005);Loss of disorder (P = 0.005);Loss of disorder (P = 0.005);Loss of disorder (P = 0.005);Loss of disorder (P = 0.005);.;Loss of disorder (P = 0.005);.;Loss of disorder (P = 0.005);Loss of disorder (P = 0.005);Loss of disorder (P = 0.005);

MVP

1.0

MPC

2.8

ClinPred

1.0

GERP RS

4.3

Varity_R

0.77

gMVP

0.98

Mutation Taster

=0/100

disease causing (ClinVar)

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.010

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

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over