chr8-132129390-G-A

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -5 ACMG points: 0P and 5B. BP4_StrongBP6

The NM_004519.4(KCNQ3):c.2491C>T(p.Arg831Trp) variant causes a missense change. The variant allele was found at a frequency of 0.000018 in 1,614,170 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 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. R831Q) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.000039 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000016 ( 0 hom. )

Consequence

KCNQ3
NM_004519.4 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1B:3

Conservation

PhyloP100: 3.65

Publications

1 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 -5 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.06149566).

BP6

Variant 8-132129390-G-A is Benign according to our data. Variant chr8-132129390-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 205954.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_004519.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	KCNQ3	NM_004519.4	MANE Select	c.2491C>T	p.Arg831Trp	missense	Exon 15 of 15	NP_004510.1
	KCNQ3	NM_001204824.2		c.2131C>T	p.Arg711Trp	missense	Exon 15 of 15	NP_001191753.1

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
KCNQ3	ENST00000388996.10	TSL:1 MANE Select	c.2491C>T	p.Arg831Trp	missense	Exon 15 of 15	ENSP00000373648.3
KCNQ3	ENST00000519445.5	TSL:5	c.2455C>T	p.Arg819Trp	missense	Exon 15 of 15	ENSP00000428790.1
KCNQ3	ENST00000521134.6	TSL:2	c.2131C>T	p.Arg711Trp	missense	Exon 15 of 15	ENSP00000429799.1

Frequencies

GnomAD3 genomes

AF:

0.0000394

AC:

AN:

152164

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000262

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.0000942

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000597

AC:

AN:

251400

AF XY:

0.0000589

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.000376

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.000326

GnomAD4 exome

AF:

0.0000157

AC:

AN:

1461888

Hom.:

Cov.:

AF XY:

0.0000179

AC XY:

AN XY:

727244

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.000335

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.00

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53420

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5766

European-Non Finnish (NFE)

AF:

0.00000450

AC:

AN:

1112008

Other (OTH)

AF:

0.0000497

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.477

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:

0.0000394

AC:

AN:

152282

Hom.:

Cov.:

AF XY:

0.0000403

AC XY:

AN XY:

74470

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41566

American (AMR)

AF:

0.000261

AC:

AN:

15300

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5170

South Asian (SAS)

AF:

0.00

AC:

AN:

4820

European-Finnish (FIN)

AF:

0.0000942

AC:

AN:

10618

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68020

Other (OTH)

AF:

0.00

AC:

AN:

2110

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.517

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:

0.0000187

Hom.:

Bravo

AF:

0.0000529

ExAC

AF:

0.0000741

AC:

Asia WGS

AF:

0.000289

AC:

AN:

3478

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1Benign:3

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Jul 19, 2017

Athena Diagnostics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Inborn genetic diseases

Benign:1

Aug 27, 2025

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.

Benign neonatal seizures

Benign:1

Oct 23, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

not provided

Benign:1

Apr 30, 2019

GeneDx

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.21

BayesDel_addAF

Benign

-0.22

BayesDel_noAF

Benign

-0.24

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

DEOGEN2

Uncertain

0.43

Eigen

Uncertain

0.20

Eigen_PC

Benign

0.19

FATHMM_MKL

Uncertain

0.94

LIST_S2

Uncertain

0.95

M_CAP

Benign

0.043

MetaRNN

Benign

0.061

MetaSVM

Benign

-0.68

MutationAssessor

Benign

1.2

PhyloP100

3.7

PrimateAI

Uncertain

0.67

PROVEAN

Benign

-1.9

REVEL

Uncertain

0.32

Sift

Uncertain

0.016

Sift4G

Uncertain

0.041

Polyphen

1.0

Vest4

0.38

MVP

0.37

MPC

0.51

ClinPred

0.24

GERP RS

2.6

Varity_R

0.089

gMVP

0.23

Mutation Taster

=54/46

polymorphism

(source)

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

You must be logged in to view publications. This limit was set because tens of millions (!) of queries from AI bots are generated daily.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over