20-63408430-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PP2PP3

The NM_172107.4(KCNQ2):c.1870G>A(p.Gly624Arg) variant causes a missense change. The variant allele was found at a frequency of 0.00000684 in 1,608,654 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 (★★). Another nucleotide change resulting in same amino acid change has been previously reported as Uncertain significancein ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G624W) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 33)

Exomes 𝑓: 0.0000069 ( 0 hom. )

Consequence

KCNQ2
NM_172107.4 missense

Scores

Clinical Significance

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

Conservation

PhyloP100: 4.72

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 2 ACMG points.

PP2

Missense variant where missense usually causes diseases, KCNQ2

PP3

MetaRNN computational evidence supports a deleterious effect, 0.791

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KCNQ2	NM_172107.4 linkuse as main transcript	c.1870G>A	p.Gly624Arg	missense_variant	16/17	ENST00000359125.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KCNQ2	ENST00000359125.7 linkuse as main transcript	c.1870G>A	p.Gly624Arg	missense_variant	16/17	1	NM_172107.4	A1	O43526-1

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152190

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

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:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000125

AC:

AN:

239708

Hom.:

AF XY:

0.00000764

AC XY:

AN XY:

130848

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000293

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:

0.00000926

Gnomad OTH exome

AF:

0.000170

GnomAD4 exome

AF:

0.00000687

AC:

AN:

1456464

Hom.:

Cov.:

AF XY:

0.00000414

AC XY:

AN XY:

724474

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.0000449

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000117

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000630

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152190

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74334

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000147

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.0000264

ExAC

AF:

0.00000829

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

KCNQ2-related disorder

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

PreventionGenetics, part of Exact Sciences

Sep 11, 2023

The KCNQ2 c.1870G>A variant is predicted to result in the amino acid substitution p.Gly624Arg. This variant was reported in an individual with alternating hemiplegia of childhood; however, this individual carried additional candidate variants of uncertain significance, and the KCNQ2 variant was inherited from an unaffected father and absent from an affected sibling (Pavone et al. 2022. PubMed ID: 35177115). This variant is reported in 0.0029% of alleles in individuals of Latino descent in gnomAD (http://gnomad.broadinstitute.org/variant/20-62039783-C-T). At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -

Early infantile epileptic encephalopathy with suppression bursts

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Nov 10, 2023

This sequence change replaces glycine, which is neutral and non-polar, with arginine, which is basic and polar, at codon 624 of the KCNQ2 protein (p.Gly624Arg). This variant is present in population databases (rs771211103, gnomAD 0.003%). This variant has not been reported in the literature in individuals affected with KCNQ2-related conditions. ClinVar contains an entry for this variant (Variation ID: 580776). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. 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. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.83

BayesDel_addAF

Uncertain

0.15

BayesDel_noAF

Uncertain

0.080

Cadd

Pathogenic

Dann

Pathogenic

1.0

Eigen

Uncertain

0.46

Eigen_PC

Uncertain

0.44

FATHMM_MKL

Uncertain

0.94

LIST_S2

Uncertain

0.97

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

M_CAP

Pathogenic

0.94

MetaRNN

Pathogenic

0.79

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

MetaSVM

Pathogenic

1.1

MutationTaster

Benign

1.0

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

PrimateAI

Pathogenic

0.82

Sift4G

Benign

0.20

T;T;T;T;.;T;T;T;T

Polyphen

1.0

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

Vest4

0.84

MutPred

0.59

.;.;.;.;.;Loss of ubiquitination at K628 (P = 0.0224);.;.;.;

MVP

0.83

MPC

1.8

ClinPred

0.87

GERP RS

4.9

Varity_R

0.78

gMVP

0.92

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.060

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