chr20-63407308-G-C

Position:

chr20-63407308-G-C

Variant summary

Our verdict is Likely benign. Variant got -4 ACMG points: 1P and 5B. PP2BP4BS2

The NM_172107.4(KCNQ2):c.1955C>G(p.Pro652Arg) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000689 in 1,595,920 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 33)

Exomes 𝑓: 0.0000055 ( 0 hom. )

Consequence

KCNQ2
NM_172107.4 missense

Scores

Clinical Significance

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

Conservation

PhyloP100: 2.09

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 Likely_benign. Variant got -4 ACMG points.

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.

BP4

Computational evidence support a benign effect (MetaRNN=0.3717454).

BS2

High AC in GnomAdExome4 at 8 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
KCNQ2	NM_172107.4 linkuse as main transcript	c.1955C>G	p.Pro652Arg	missense_variant	17/17	ENST00000359125.7	NP_742105.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
KCNQ2	ENST00000359125.7 linkuse as main transcript	c.1955C>G	p.Pro652Arg	missense_variant	17/17	1	NM_172107.4	ENSP00000352035	A1	O43526-1

Frequencies

GnomAD3 genomes

AF:

0.0000197

AC:

AN:

152238

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000723

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000212

AC:

AN:

236050

Hom.:

AF XY:

0.0000154

AC XY:

AN XY:

129554

show subpopulations

Gnomad AFR exome

AF:

0.000196

Gnomad AMR exome

AF:

0.0000291

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:

0.00000906

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000554

AC:

AN:

1443682

Hom.:

Cov.:

AF XY:

0.00000418

AC XY:

AN XY:

718028

show subpopulations

Gnomad4 AFR exome

AF:

0.000120

Gnomad4 AMR exome

AF:

0.0000448

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:

0.00000180

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000197

AC:

AN:

152238

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74372

show subpopulations

Gnomad4 AFR

AF:

0.0000723

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:

0.00

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.0000302

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

Nov 25, 2023

This sequence change replaces proline, which is neutral and non-polar, with arginine, which is basic and polar, at codon 652 of the KCNQ2 protein (p.Pro652Arg). This variant is present in population databases (rs770730662, gnomAD 0.02%). 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: 430045). 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 tolerated. 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. -

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Mar 12, 2018

A variant of uncertain significance has been identified in the KCNQ2 gene. The P652R variant has not been published as a pathogenic variant, nor has it been reported as a benign variant to our knowledge. The P652R variant is not observed at a significant frequency in large population cohorts (Lek et al., 2016; 1000 Genomes Consortium et al., 2015; Exome Variant Server). The P652R variant is a non-conservative amino acid substitution, which is likely to impact secondary protein structure as these residues differ in polarity, charge, size and/or other properties. This substitution occurs at a position that is conserved in mammals. In silico analysis is inconsistent in its predictions as to whether or not the variant is damaging to the protein structure/function. Therefore, based on the currently available information, it is unclear whether this variant is a pathogenic variant or a rare benign variant. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.14

BayesDel_addAF

Benign

-0.095

BayesDel_noAF

Benign

-0.090

CADD

Benign

DANN

Benign

0.96

DEOGEN2

Benign

0.27

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

Eigen

Benign

-0.29

Eigen_PC

Benign

-0.12

FATHMM_MKL

Uncertain

0.84

LIST_S2

Uncertain

0.91

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

M_CAP

Pathogenic

0.74

MetaRNN

Benign

0.37

T;T;T;T;T;T;T;T;T

MetaSVM

Pathogenic

1.0

MutationAssessor

Benign

1.4

.;.;.;.;.;L;.;.;.

MutationTaster

Benign

0.99

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

PrimateAI

Uncertain

0.57

PROVEAN

Benign

-1.3

.;.;.;N;.;N;.;N;.

REVEL

Uncertain

0.49

Sift

Benign

0.30

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

Sift4G

Benign

0.31

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

Polyphen

0.029

B;.;.;.;.;B;.;B;B

Vest4

0.059

MutPred

0.61

.;.;.;.;.;Loss of catalytic residue at P651 (P = 0.0099);.;.;.;

MVP

0.58

MPC

0.71

ClinPred

0.089

GERP RS

5.1

Varity_R

0.14

gMVP

0.39

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