rs28939684

Positions:

chr20-63444709-G-A

Variant summary

Our verdict is Pathogenic. Variant got 19 ACMG points: 19P and 0B. PM1PM2PM5PP2PP3_StrongPP5_Very_Strong

The NM_172107.4(KCNQ2):c.640C>T(p.Arg214Trp) variant causes a missense change involving the alteration of a non-conserved nucleotide. 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 Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R214Q) has been classified as Pathogenic.

Frequency

Genomes: not found (cov: 33)

Exomes 𝑓: 0.0 ( 0 hom. )

Failed GnomAD Quality Control

Consequence

KCNQ2
NM_172107.4 missense

Scores

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:5O:2

Conservation

PhyloP100: 1.78

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 Pathogenic. Variant got 19 ACMG points.

PM1

In a hotspot region, there are 15 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 chr20-63444708-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 578032.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

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.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.958

PP5

Variant 20-63444709-G-A is Pathogenic according to our data. Variant chr20-63444709-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 7385.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KCNQ2	NM_172107.4 linkuse as main transcript	c.640C>T	p.Arg214Trp	missense_variant	4/17	ENST00000359125.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KCNQ2	ENST00000359125.7 linkuse as main transcript	c.640C>T	p.Arg214Trp	missense_variant	4/17	1	NM_172107.4	A1	O43526-1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

Data not reliable, filtered out with message: AC0

AF:

0.00

AC:

AN:

1440890

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

714432

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/Likely pathogenic

Submissions summary: Pathogenic:5Other:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Pathogenic:3

Likely pathogenic, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	May 27, 2015	- -
Pathogenic, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Nov 01, 2019	- -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Aug 12, 2022	Published functional studies demonstrate a damaging effect: significantly altered channel voltage-dependent gating in homomeric and heteromeric configurations with Q3 by reducing the opening and increasing the closing kinetics and decreasing voltage sensitivity (Castaldo et al., 2002); 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; Missense variants in this gene are often considered pathogenic (HGMD); This variant is associated with the following publications: (PMID: 12015163, 16916607, 28488083, 19818940, 14534157, 17475800, 19380078, 18238816, 18353052, 18698150, 11690625, 21687499, 11572947, 28372301, 11784811, 11175290, 29056246, 16686649, 35642783) -

Seizures, benign familial neonatal, 1

Pathogenic:1Other:1

Pathogenic, no assertion criteria provided	literature only	OMIM	Dec 01, 2000	- -
not provided, no classification provided	literature only	GeneReviews	-	BFNE (benign familial neonatal epilepsy) -

Early infantile epileptic encephalopathy with suppression bursts

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Aug 03, 2023

For these reasons, this variant has been classified as Pathogenic. This variant disrupts the p.Arg214 amino acid residue in KCNQ2. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 31152295). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. Experimental studies have shown that this missense change affects KCNQ2 function (PMID: 11784811). 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. ClinVar contains an entry for this variant (Variation ID: 7385). This missense change has been observed in individual(s) with KCNQ2-related conditions (PMID: 11175290). It has also been observed to segregate with disease in related individuals. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces arginine, which is basic and polar, with tryptophan, which is neutral and slightly polar, at codon 214 of the KCNQ2 protein (p.Arg214Trp). -

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

Pathogenic

1.0

BayesDel_addAF

Pathogenic

0.52

BayesDel_noAF

Pathogenic

0.51

CADD

Uncertain

DANN

Uncertain

1.0

DEOGEN2

Uncertain

0.56

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

Eigen

Benign

-0.056

Eigen_PC

Benign

-0.25

FATHMM_MKL

Uncertain

0.82

LIST_S2

Pathogenic

0.99

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

M_CAP

Pathogenic

0.92

MetaRNN

Pathogenic

0.96

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

MetaSVM

Pathogenic

1.1

MutationAssessor

Pathogenic

3.6

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

MutationTaster

Benign

1.0

A;A;A;A;A;A;A;A;A;A;A;A

PrimateAI

Pathogenic

0.94

PROVEAN

Pathogenic

-7.2

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

REVEL

Pathogenic

0.84

Sift

Pathogenic

0.0

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

Sift4G

Pathogenic

0.0

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

Polyphen

1.0

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

Vest4

0.95

MVP

1.0

MPC

2.8

ClinPred

1.0

GERP RS

0.17

Varity_R

0.74

gMVP

0.97

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