rs759258191

Variant summary

Our verdict is Benign. Variant got -12 ACMG points: 1P and 13B. PP2BP4_StrongBP6BS1BS2

The NM_172107.4(KCNQ2):c.2312C>T(p.Thr771Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000824 in 1,577,554 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. T771T) has been classified as Likely benign.

Frequency

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

Exomes 𝑓: 0.0000070 ( 0 hom. )

Consequence

KCNQ2
NM_172107.4 missense

Scores

Clinical Significance

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

Conservation

PhyloP100: 1.18

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 Benign. Variant got -12 ACMG points.

PP2

Missense variant where missense usually causes diseases, KCNQ2

BP4

Computational evidence support a benign effect (MetaRNN=0.020989537).

BP6

Variant 20-63406951-G-A is Benign according to our data. Variant chr20-63406951-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 461417.We mark this variant Likely_benign, oryginal submissions are: {not_provided=1, Uncertain_significance=2, Likely_benign=1}.

BS1

Variant frequency is greater than expected in population eas. gnomad4 allele frequency = 0.0000197 (3/152210) while in subpopulation EAS AF= 0.000578 (3/5190). AF 95% confidence interval is 0.000157. There are 0 homozygotes in gnomad4. There are 3 alleles in male gnomad4 subpopulation. This position pass quality control queck.

BS2

High AC in GnomAdExome at 9 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KCNQ2	NM_172107.4 linkuse as main transcript	c.2312C>T	p.Thr771Ile	missense_variant	17/17	ENST00000359125.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KCNQ2	ENST00000359125.7 linkuse as main transcript	c.2312C>T	p.Thr771Ile	missense_variant	17/17	1	NM_172107.4	A1	O43526-1

Frequencies

GnomAD3 genomes

AF:

0.0000197

AC:

AN:

152210

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:

0.000578

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:

0.0000494

AC:

AN:

182270

Hom.:

AF XY:

0.0000298

AC XY:

AN XY:

100680

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.000556

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.000205

GnomAD4 exome

AF:

0.00000702

AC:

AN:

1425344

Hom.:

Cov.:

AF XY:

0.00000566

AC XY:

AN XY:

706676

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.000210

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00

Gnomad4 OTH exome

AF:

0.0000338

GnomAD4 genome

AF:

0.0000197

AC:

AN:

152210

Hom.:

Cov.:

AF XY:

0.0000403

AC XY:

AN XY:

74362

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.000578

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.0000491

ExAC

AF:

0.0000254

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

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

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Early infantile epileptic encephalopathy with suppression bursts

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Dec 13, 2023

This sequence change replaces threonine, which is neutral and polar, with isoleucine, which is neutral and non-polar, at codon 771 of the KCNQ2 protein (p.Thr771Ile). This variant is present in population databases (rs759258191, gnomAD 0.07%), and has an allele count higher than expected for a pathogenic variant. This missense change has been observed in individual(s) with pyridoxine-responsive epileptic encephalopathy (PMID: 35906921). ClinVar contains an entry for this variant (Variation ID: 461417). 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. Experimental studies have shown that this missense change affects KCNQ2 function (PMID: 35104249). 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. -

Developmental and epileptic encephalopathy, 7

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Pediatrics, West China Second University Hospital, Sichuan University

Dec 31, 2019

- -

not provided

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

GeneDx

Sep 14, 2020

In silico analysis supports that this missense variant does not alter protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -

Complex neurodevelopmental disorder

Other:1

not provided, no classification provided

literature only

Channelopathy-Associated Epilepsy Research Center

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.076

BayesDel_addAF

Benign

-0.57

BayesDel_noAF

Benign

-0.69

Cadd

Benign

6.5

Dann

Benign

0.85

Eigen

Benign

-1.0

Eigen_PC

Benign

-1.0

FATHMM_MKL

Benign

0.076

LIST_S2

Benign

0.71

T;T;T;T;T;T

M_CAP

Benign

0.050

MetaRNN

Benign

0.021

T;T;T;T;T;T

MetaSVM

Benign

-1.0

MutationTaster

Benign

1.0

N;N;N;N;N;N;N;N;N

PrimateAI

Uncertain

0.56

Sift4G

Benign

0.18

T;.;T;T;T;T

Polyphen

0.0

B;.;B;.;B;B

Vest4

0.041

MutPred

0.16

.;.;Loss of phosphorylation at T771 (P = 0.0034);.;.;.;

MVP

0.18

MPC

0.67

ClinPred

0.014

GERP RS

0.68

Varity_R

0.046

gMVP

0.12

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