rs118192203

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.637C>T​(p.Arg213Trp) 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. 13/22 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. R213L) has been classified as Likely pathogenic.

Frequency

Genomes: not found (cov: 33)
Exomes 𝑓: 0.0 ( 0 hom. )
Failed GnomAD Quality Control

Consequence

KCNQ2
NM_172107.4 missense

Scores

16
2
1

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:8O:1

Conservation

PhyloP100: 6.65

Publications

36 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

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 30 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 6 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 chr20-63444711-C-A is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 1685899.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, 0.99
PP5
Variant 20-63444712-G-A is Pathogenic according to our data. Variant chr20-63444712-G-A is described in ClinVar as Pathogenic. ClinVar VariationId is 21795.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
KCNQ2NM_172107.4 linkc.637C>T p.Arg213Trp missense_variant Exon 4 of 17 ENST00000359125.7 NP_742105.1 O43526-1

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
KCNQ2ENST00000359125.7 linkc.637C>T p.Arg213Trp missense_variant Exon 4 of 17 1 NM_172107.4 ENSP00000352035.2 O43526-1

Frequencies

GnomAD3 genomes
Cov.:
33
GnomAD4 exome
Data not reliable, filtered out with message: AC0
AF:
0.00
AC:
0
AN:
1444802
Hom.:
0
Cov.:
32
AF XY:
0.00
AC XY:
0
AN XY:
716744
African (AFR)
AF:
0.00
AC:
0
AN:
33318
American (AMR)
AF:
0.00
AC:
0
AN:
42156
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
25768
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39058
South Asian (SAS)
AF:
0.00
AC:
0
AN:
83542
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
51054
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5746
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
1104380
Other (OTH)
AF:
0.00
AC:
0
AN:
59780
GnomAD4 genome
Cov.:
33
Alfa
AF:
0.00000619
Hom.:
0

ClinVar

Significance: Pathogenic
Submissions summary: Pathogenic:8Other:1
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

not provided Pathogenic:3
Mar 25, 2023
GeneDx
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Published functional studies demonstrate that R213W decreases the stability of the ion channel and decreases voltage sensitivity (Miceli et al., 2013); Not observed at significant frequency in large population cohorts (gnomAD); The majority of missense variants in this gene are considered pathogenic; 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: 20437616, 24375629, 24318194, 22455920, 18353052, 29056246, 28038823, 27535030, 26993267, 25959266, 28717674, 27779742, 17765802, 22275249, 32139178, 31512412, 32917465, 32712949, 33726816, 31440721, 33659638, 31440733, 30440138, 23440208) -

Nov 01, 2018
CeGaT Center for Human Genetics Tuebingen
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Feb 18, 2015
Eurofins Ntd Llc (ga)
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Developmental and epileptic encephalopathy, 7 Pathogenic:2Other:1
-
GeneReviews
Significance:not provided
Review Status:no classification provided
Collection Method:literature only

BFNE (benign familial neonatal epilepsy), EE (epileptic encephalopathy) -

Oct 19, 2020
Institute of Human Genetics, University of Leipzig Medical Center
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This variant was identified as de novo (maternity and paternity confirmed). -

Feb 02, 2017
Equipe Genetique des Anomalies du Developpement, Université de Bourgogne
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Inborn genetic diseases Pathogenic:1
Nov 06, 2019
Ambry Genetics
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The p.R213W pathogenic mutation (also known as c.637C>T), located in coding exon 4 of the KCNQ2 gene, results from a C to T substitution at nucleotide position 637. The arginine at codon 213 is replaced by tryptophan, an amino acid with dissimilar properties. This mutation was detected in two siblings with BFNC (benign familial neonatal convulsions). Neither parent carried the mutation, and after parental relationships were confirmed, authors suspected germline mosaicism (Sadewa AH et al. Pediatr Int, 2008 Apr;50:167-71). In another study, this mutation was detected in an individual with EOEE (early onset epileptic encephalopathy) and was found to be mosaic in a parent (Milh M et al. Am. J. Med. Genet. A, 2015 Oct;167A:2314-8). In addition, this mutation has been detected in individuals with: non-specific epileptic encephalopathy, neonatal seizure disorder, congenital variant of Rett syndrome, and EIMFS (Epilepsy of Infancy with Migrating Focal Seizures) (Butler KM et al. Pediatr. Neurol., 2017 Dec;77:61-66; Zhang Q et al. Clin. Genet., 2017 May;91:717-724; Wang J et al. Mol Genet Genomic Med, 2019 Sep;:e968; Ware TL et al. Epilepsia Open, 2019 Sep;4:504-510). One functional study showed that this mutation destabilized the potassium ion channel and decreased voltage sensitivity (Miceli F et al. Proc. Natl. Acad. Sci. U.S.A., 2013 Mar;110:4386-91). In addition, a different alteration located at the same position, p.R213Q, has been detected in multiple individuals with epilepsy (Weckhuysen S et al. Ann. Neurol., 2012 Jan;71:15-25; Trump N et al. J. Med. Genet., 2016 May;53:310-7) and has been shown to result in a decrease in channel voltage sensitivity (Miceli F et al. Proc. Natl. Acad. Sci. U.S.A., 2013 Mar;110:4386-91; Orhan G et al. Ann. Neurol., 2014 Mar;75:382-94). Based on the supporting evidence, this alteration is interpreted as a disease-causing mutation. -

Developmental and epileptic encephalopathy Pathogenic:1
Oct 16, 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 213 of the KCNQ2 protein (p.Arg213Trp). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with benign familial neonatal seizures or early-onset epilepsy (PMID: 18353052, 27779742, 29056246). In at least one individual the variant was observed to be de novo. It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 21795). 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: 23440208). This variant disrupts the p.Arg213 amino acid residue in KCNQ2. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 22275249, 25982755). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -

Seizures, benign familial neonatal, 1 Pathogenic:1
May 28, 2019
Mendelics
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
1.0
BayesDel_addAF
Pathogenic
0.57
D
BayesDel_noAF
Pathogenic
0.58
CADD
Pathogenic
34
DANN
Pathogenic
1.0
DEOGEN2
Uncertain
0.65
.;.;D;D;D;T;D;D;.;.;.;.
Eigen
Pathogenic
0.77
Eigen_PC
Uncertain
0.65
FATHMM_MKL
Pathogenic
0.98
D
LIST_S2
Pathogenic
1.0
D;D;D;D;D;D;D;D;D;D;D;D
M_CAP
Pathogenic
0.91
D
MetaRNN
Pathogenic
0.99
D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM
Pathogenic
1.1
D
MutationAssessor
Pathogenic
4.3
H;.;.;.;.;.;H;.;H;H;H;.
PhyloP100
6.7
PrimateAI
Pathogenic
0.93
D
PROVEAN
Pathogenic
-7.2
.;.;.;.;D;.;D;.;D;D;D;.
REVEL
Pathogenic
0.97
Sift
Pathogenic
0.0
.;.;.;.;D;.;D;.;D;D;D;.
Sift4G
Pathogenic
0.0010
D;D;D;D;D;.;D;D;D;D;D;D
Polyphen
1.0
D;.;.;.;.;.;D;.;D;D;.;.
Vest4
0.98
MutPred
0.94
Loss of solvent accessibility (P = 0.086);Loss of solvent accessibility (P = 0.086);Loss of solvent accessibility (P = 0.086);Loss of solvent accessibility (P = 0.086);Loss of solvent accessibility (P = 0.086);.;Loss of solvent accessibility (P = 0.086);.;Loss of solvent accessibility (P = 0.086);Loss of solvent accessibility (P = 0.086);Loss of solvent accessibility (P = 0.086);.;
MVP
0.98
MPC
2.8
ClinPred
1.0
D
GERP RS
4.0
PromoterAI
-0.010
Neutral
Varity_R
0.87
gMVP
0.98
Mutation Taster
=0/100
disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs118192203; hg19: chr20-62076065; API