rs796052675

Positions:

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 16P and 4B. PVS1PP5_Very_StrongBS2

The NM_004519.4(KCNQ3):c.679C>T(p.Arg227Ter) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000372 in 1,614,038 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 Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000034 ( 0 hom. )

Consequence

KCNQ3
NM_004519.4 stop_gained

Scores

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:2

Conservation

PhyloP100: 1.12

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 Pathogenic. Variant got 12 ACMG points.

PVS1

Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.

PP5

Variant 8-132180255-G-A is Pathogenic according to our data. Variant chr8-132180255-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 205961.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr8-132180255-G-A is described in Lovd as [Pathogenic].

BS2

High AC in GnomAdExome4 at 5 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
KCNQ3	NM_004519.4 linkuse as main transcript	c.679C>T	p.Arg227Ter	stop_gained	4/15	ENST00000388996.10	NP_004510.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
KCNQ3	ENST00000388996.10 linkuse as main transcript	c.679C>T	p.Arg227Ter	stop_gained	4/15	1	NM_004519.4	ENSP00000373648	P1	O43525-1

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152236

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:

0.00000398

AC:

AN:

251132

Hom.:

AF XY:

0.00

AC XY:

AN XY:

135736

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.0000463

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000342

AC:

AN:

1461802

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

727194

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.0000187

Gnomad4 NFE exome

AF:

0.00000270

Gnomad4 OTH exome

AF:

0.0000166

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152236

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74386

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:

0.00000756

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Benign neonatal seizures

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Oct 26, 2019

For these reasons, this variant has been classified as Pathogenic. Loss-of-function variants in KCNQ3 are known to be pathogenic (PMID: 29383681, 29852413). This variant has not been reported in the literature in individuals with KCNQ3-related conditions. ClinVar contains an entry for this variant (Variation ID: 205961). This variant is not present in population databases (ExAC no frequency). This sequence change creates a premature translational stop signal (p.Arg227*) in the KCNQ3 gene. It is expected to result in an absent or disrupted protein product. -

not provided

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Mar 03, 2014

p.Arg227Stop (CGA>TGA): c.679 C>T in exon 4 of the KCNQ3 gene (NM_004519.2) The Arg227Stop nonsense mutation in the KCNQ3 gene is predicted to cause loss of normal protein function either through protein truncation or nonsense-mediated mRNA decay. It was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. This mutation has not been reported previously to our knowledge. The variant is found in INFANT-EPI panel(s). -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.63

BayesDel_noAF

Pathogenic

0.56

CADD

Pathogenic

DANN

Uncertain

1.0

Eigen

Uncertain

0.52

Eigen_PC

Uncertain

0.35

FATHMM_MKL

Uncertain

0.83

MutationTaster

Benign

1.0

A;A;A

Vest4

0.98

GERP RS

2.6

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.030

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