rs769414365

Positions:

chr20-63414938-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 5P and 4B. PM2PP2PP3_ModerateBS2

The NM_172107.4(KCNQ2):c.1490G>A(p.Arg497His) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000342 in 1,460,596 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 Uncertain significance (★★).

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 0.0000034 ( 0 hom. )

Consequence

KCNQ2
NM_172107.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:2

Conservation

PhyloP100: 1.79

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 Uncertain_significance. Variant got 1 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

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, 0.857

BS2

High AC in GnomAdExome4 at 5 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
KCNQ2	NM_172107.4 linkuse as main transcript	c.1490G>A	p.Arg497His	missense_variant	13/17	ENST00000359125.7	NP_742105.1	O43526-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
KCNQ2	ENST00000359125.7 linkuse as main transcript	c.1490G>A	p.Arg497His	missense_variant	13/17	1	NM_172107.4	ENSP00000352035.2		O43526-1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD3 exomes

AF:

0.00000403

AC:

AN:

248190

Hom.:

AF XY:

0.00

AC XY:

AN XY:

134636

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:

0.00000902

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000342

AC:

AN:

1460596

Hom.:

Cov.:

AF XY:

0.00000275

AC XY:

AN XY:

726658

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:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000450

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

Cov.:

Alfa

AF:

0.0000282

Hom.:

Bravo

AF:

0.00000378

ExAC

AF:

0.0000165

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Early infantile epileptic encephalopathy with suppression bursts

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Oct 19, 2022

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. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). ClinVar contains an entry for this variant (Variation ID: 530434). This variant has not been reported in the literature in individuals affected with KCNQ2-related conditions. This variant is present in population databases (rs769414365, gnomAD 0.0009%). This sequence change replaces arginine, which is basic and polar, with histidine, which is basic and polar, at codon 497 of the KCNQ2 protein (p.Arg497His). -

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Aug 23, 2019

The majority of missense variants in this gene are considered pathogenic (Stenson et al., 2014); In silico analysis, which includes protein predictors and evolutionary conservation, supports a deleterious effect; Has not been previously published as pathogenic or benign to our knowledge; This substitution is predicted to be within the C-terminal cytoplasmic domain -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.26

BayesDel_addAF

Pathogenic

0.24

BayesDel_noAF

Uncertain

0.10

CADD

Pathogenic

DANN

Pathogenic

1.0

DEOGEN2

Benign

0.39

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

Eigen

Uncertain

0.54

Eigen_PC

Uncertain

0.50

FATHMM_MKL

Uncertain

0.86

LIST_S2

Uncertain

0.97

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

M_CAP

Pathogenic

0.83

MetaRNN

Pathogenic

0.86

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

MetaSVM

Pathogenic

1.0

MutationAssessor

Uncertain

2.6

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

PrimateAI

Uncertain

0.71

PROVEAN

Uncertain

-4.4

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

REVEL

Pathogenic

0.76

Sift

Uncertain

0.0010

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

Sift4G

Uncertain

0.0050

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

Polyphen

1.0

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

Vest4

0.45

MutPred

0.69

.;.;.;.;.;.;Loss of MoRF binding (P = 0.0262);.;.;.;.;

MVP

0.90

MPC

1.8

ClinPred

0.99

GERP RS

5.2

Varity_R

0.65

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