rs201552546

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -1 ACMG points: 0P and 1B. BP6

The NM_004519.4(KCNQ3):c.1471G>A(p.Gly491Arg) variant causes a missense change. The variant allele was found at a frequency of 0.0000471 in 1,612,706 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G491E) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000026 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000049 ( 0 hom. )

Consequence

KCNQ3
NM_004519.4 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:2B:1

Conservation

PhyloP100: 4.55

Publications

2 publications found

Variant links:

Genes affected

KCNQ3 (HGNC:6297): (potassium voltage-gated channel subfamily Q member 3) This gene encodes a protein that functions in the regulation of neuronal excitability. The encoded protein forms an M-channel by associating with the products of the related KCNQ2 or KCNQ5 genes, which both encode integral membrane proteins. M-channel currents are inhibited by M1 muscarinic acetylcholine receptors and are activated by retigabine, a novel anti-convulsant drug. Defects in this gene are a cause of benign familial neonatal convulsions type 2 (BFNC2), also known as epilepsy, benign neonatal type 2 (EBN2). Alternative splicing of this gene results in multiple transcript variants. [provided by RefSeq, May 2014]

KCNQ3 Gene-Disease associations (from GenCC):

seizures, benign familial neonatal, 2
Inheritance: AD Classification: STRONG, MODERATE Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)
benign familial infantile epilepsy
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
benign neonatal seizures
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
genetic developmental and epileptic encephalopathy
Inheritance: AR Classification: LIMITED Submitted by: Ambry Genetics

KCNQ3 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -1 ACMG points.

BP6

Variant 8-132140173-C-T is Benign according to our data. Variant chr8-132140173-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 279818.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNQ3	NM_004519.4 link	c.1471G>A	p.Gly491Arg	missense_variant	Exon 11 of 15	ENST00000388996.10	NP_004510.1	O43525-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCNQ3	ENST00000388996.10 link	c.1471G>A	p.Gly491Arg	missense_variant	Exon 11 of 15	1	NM_004519.4	ENSP00000373648.3		O43525-1

Frequencies

GnomAD3 genomes

AF:

0.0000263

AC:

AN:

152056

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000242

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:

0.0000441

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000565

AC:

AN:

247714

AF XY:

0.0000597

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000290

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000117

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000493

AC:

AN:

1460650

Hom.:

Cov.:

AF XY:

0.0000537

AC XY:

AN XY:

726588

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33462

American (AMR)

AF:

0.0000224

AC:

AN:

44710

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26124

East Asian (EAS)

AF:

0.000202

AC:

AN:

39684

South Asian (SAS)

AF:

0.00

AC:

AN:

86204

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53088

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5650

European-Non Finnish (NFE)

AF:

0.0000540

AC:

AN:

1111360

Other (OTH)

AF:

0.0000497

AC:

AN:

60368

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.447

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.0000263

AC:

AN:

152056

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74274

show subpopulations

African (AFR)

AF:

0.0000242

AC:

AN:

41396

American (AMR)

AF:

0.00

AC:

AN:

15276

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5186

South Asian (SAS)

AF:

0.00

AC:

AN:

4812

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10608

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000441

AC:

AN:

67992

Other (OTH)

AF:

0.00

AC:

AN:

2086

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.488

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.0000988

Hom.:

Bravo

AF:

0.0000189

ExAC

AF:

0.0000988

AC:

EpiCase

AF:

0.0000545

EpiControl

AF:

0.0000593

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:2Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Benign neonatal seizures

Uncertain:1

Dec 30, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces glycine, which is neutral and non-polar, with arginine, which is basic and polar, at codon 491 of the KCNQ3 protein (p.Gly491Arg). This variant is present in population databases (rs201552546, gnomAD 0.01%). This variant has not been reported in the literature in individuals affected with KCNQ3-related conditions. ClinVar contains an entry for this variant (Variation ID: 279818). 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 not expected to disrupt KCNQ3 protein function with a negative predictive value of 80%. 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

Sep 15, 2017

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

A variant of uncertain significance has been identified in the KCNQ3 gene. The G491R variant has not been published as a pathogenic variant, nor has it been reported as a benign variant to our knowledge. The G491R variant is observed in 12/64,692 (0.02%) alleles from individuals of European background in large population cohorts (Lek et al., 2016). This 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, and in silico analysis predicts this variant is probably damaging to the protein structure/function. However, missense variants in nearby residues have not been reported in the Human Gene Mutation Database in association with KCNQ3-related disorders (Stenson et al., 2014). Therefore, based on the currently available information, it is unclear whether this variant is a pathogenic variant or a rare benign variant. -

Inborn genetic diseases

Benign:1

Jan 22, 2020

Ambry Genetics

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.65

BayesDel_addAF

Uncertain

0.12

BayesDel_noAF

Pathogenic

0.18

CADD

Pathogenic

(source)

DANN

Pathogenic

1.0

DEOGEN2

Uncertain

0.79

D;.;.;.;.

Eigen

Uncertain

0.56

Eigen_PC

Uncertain

0.61

FATHMM_MKL

Uncertain

0.91

LIST_S2

Uncertain

0.91

D;D;D;D;D

M_CAP

Uncertain

0.18

MetaRNN

Uncertain

0.64

D;D;D;D;D

MetaSVM

Pathogenic

1.1

MutationAssessor

Uncertain

2.4

M;.;.;.;.

PhyloP100

4.6

PrimateAI

Uncertain

0.72

PROVEAN

Uncertain

-2.5

D;.;D;D;.

REVEL

Pathogenic

0.66

Sift

Benign

0.038

D;.;D;D;.

Sift4G

Benign

0.18

T;T;T;T;.

Polyphen

1.0

D;.;.;D;.

Vest4

0.41

MutPred

0.59

Gain of MoRF binding (P = 0.062);.;.;Gain of MoRF binding (P = 0.062);.;

MVP

0.86

MPC

2.2

ClinPred

0.45

GERP RS

5.9

Varity_R

0.30

gMVP

0.69

Mutation Taster

=59/41

polymorphism

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.020

Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over