8-132170353-C-T

Variant names:

Variant summary

Our verdict is Benign. Variant got -7 ACMG points: 0P and 7B. BP4_ModerateBP6BS2

The NM_004519.4(KCNQ3):c.1216G>A(p.Val406Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000044 in 1,613,612 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).

Frequency

Genomes: 𝑓 0.000039 ( 0 hom., cov: 31)

Exomes 𝑓: 0.000044 ( 0 hom. )

Consequence

KCNQ3
NM_004519.4 missense

Scores

Clinical Significance

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

Conservation

PhyloP100: 2.16

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 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Benign. Variant got -7 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.23720983).

BP6

Variant 8-132170353-C-T is Benign according to our data. Variant chr8-132170353-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 205969.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=2, Uncertain_significance=2, not_provided=1}.

BS2

High AC in GnomAd4 at 6 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNQ3	NM_004519.4 link	c.1216G>A	p.Val406Ile	missense_variant	Exon 8 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.1216G>A	p.Val406Ile	missense_variant	Exon 8 of 15	1	NM_004519.4	ENSP00000373648.3		O43525-1

Frequencies

GnomAD3 genomes

AF:

0.0000395

AC:

AN:

152038

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:

0.0000882

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000520

AC:

AN:

250190

Hom.:

AF XY:

0.0000665

AC XY:

AN XY:

135380

show subpopulations

Gnomad AFR exome

AF:

0.0000621

Gnomad AMR exome

AF:

0.0000579

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000545

Gnomad SAS exome

AF:

0.000164

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000354

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000445

AC:

AN:

1461456

Hom.:

Cov.:

AF XY:

0.0000509

AC XY:

AN XY:

727022

show subpopulations

Gnomad4 AFR exome

AF:

0.0000299

Gnomad4 AMR exome

AF:

0.0000447

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000252

Gnomad4 SAS exome

AF:

0.000185

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000378

Gnomad4 OTH exome

AF:

0.0000497

GnomAD4 genome

AF:

0.0000394

AC:

AN:

152156

Hom.:

Cov.:

AF XY:

0.0000672

AC XY:

AN XY:

74366

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:

0.0000882

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.0000453

ESP6500AA

AF:

0.000227

AC:

ESP6500EA

AF:

0.00

AC:

ExAC

AF:

0.0000165

AC:

EpiCase

AF:

0.0000545

EpiControl

AF:

0.0000593

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:2Benign:2Other:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Seizures, benign familial neonatal, 2

Uncertain:1Other:1

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

GenomeConnect - Invitae Patient Insights Network

Significance: not provided

Review Status: no classification provided

Collection Method: phenotyping only

Variant interpreted as Uncertain significance and reported on 12-31-2020 by Lab Invitae. GenomeConnect-Invitae Patient Insights Network assertions are reported exactly as they appear on the patient-provided report from the testing laboratory. Registry team members make no attempt to reinterpret the clinical significance of the variant. Phenotypic details are available under supporting information. -

Benign neonatal seizures

Uncertain:1

Jan 02, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces valine, which is neutral and non-polar, with isoleucine, which is neutral and non-polar, at codon 406 of the KCNQ3 protein (p.Val406Ile). This variant is present in population databases (rs144474368, gnomAD 0.02%). 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: 205969). 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 95%. 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. -

Inborn genetic diseases

Benign:1

Mar 17, 2023

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. -

not provided

Benign:1

Nov 08, 2018

GeneDx

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.094

BayesDel_addAF

Benign

-0.18

BayesDel_noAF

Benign

-0.24

CADD

Benign

DANN

Uncertain

0.99

DEOGEN2

Benign

0.23

T;.;.;.;.

Eigen

Benign

-0.084

Eigen_PC

Benign

0.098

FATHMM_MKL

Uncertain

0.90

LIST_S2

Uncertain

0.89

D;D;D;D;D

M_CAP

Uncertain

0.095

MetaRNN

Benign

0.24

T;T;T;T;T

MetaSVM

Pathogenic

0.83

PrimateAI

Uncertain

0.52

PROVEAN

Benign

-0.11

N;.;N;N;.

REVEL

Uncertain

0.43

Sift

Benign

0.19

T;.;T;T;.

Sift4G

Benign

0.38

T;T;T;T;.

Polyphen

0.27

B;.;.;B;.

Vest4

0.14

MVP

0.60

MPC

0.74

ClinPred

0.32

GERP RS

5.8

Varity_R

0.22

gMVP

0.34

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.090

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