rs774002673

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -3 ACMG points: 3P and 6B. PM5PP2BP4BS1_SupportingBS2

The NM_172107.4(KCNQ2):c.2252C>T(p.Ser751Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000952 in 1,533,154 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 Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. S751A) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.000099 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000095 ( 0 hom. )

Consequence

KCNQ2
NM_172107.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:2

Conservation

PhyloP100: 9.27

Publications

1 publications found

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 Gene-Disease associations (from GenCC):

complex neurodevelopmental disorder
Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
developmental and epileptic encephalopathy, 7
Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae), G2P
neonatal encephalopathy with non-epileptic myoclonus
Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
neonatal-onset developmental and epileptic encephalopathy
Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
seizures, benign familial neonatal, 1
Inheritance: AD Classification: DEFINITIVE Submitted by: G2P
seizures, benign familial neonatal, 2
Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
benign familial infantile epilepsy
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
benign familial neonatal-infantile seizures
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
benign neonatal seizures
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
malignant migrating partial seizures of infancy
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

KCNQ2 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -3 ACMG points.

PM5

Other missense variant is known to change same aminoacid residue: Variant chr20-63407012-A-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 3248555.Status of the report is no_assertion_criteria_provided, 0 stars.

PP2

Missense variant in the KCNQ2 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 319 curated pathogenic missense variants (we use a threshold of 10). The gene has 78 curated benign missense variants. Gene score misZ: 4.0411 (above the threshold of 3.09). Trascript score misZ: 3.6968 (above the threshold of 3.09). GenCC associations: The gene is linked to benign familial infantile epilepsy, malignant migrating partial seizures of infancy, developmental and epileptic encephalopathy, 7, benign familial neonatal-infantile seizures, benign neonatal seizures, neonatal-onset developmental and epileptic encephalopathy, complex neurodevelopmental disorder, seizures, benign familial neonatal, 2, seizures, benign familial neonatal, 1, neonatal encephalopathy with non-epileptic myoclonus.

BP4

Computational evidence support a benign effect (MetaRNN=0.41681403).

BS1

Variant frequency is greater than expected in population amr. GnomAd4 allele frequency = 0.0000985 (15/152224) while in subpopulation AMR AF = 0.000262 (4/15292). AF 95% confidence interval is 0.0000887. There are 0 homozygotes in GnomAd4. There are 5 alleles in the male GnomAd4 subpopulation. Median coverage is 33. This position passed quality control check. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

BS2

High AC in GnomAd4 at 15 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNQ2	NM_172107.4 link	c.2252C>T	p.Ser751Leu	missense_variant	Exon 17 of 17	ENST00000359125.7	NP_742105.1	O43526-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCNQ2	ENST00000359125.7 link	c.2252C>T	p.Ser751Leu	missense_variant	Exon 17 of 17	1	NM_172107.4	ENSP00000352035.2		O43526-1

Frequencies

GnomAD3 genomes

AF:

0.0000985

AC:

AN:

152224

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000482

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:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.000118

Gnomad OTH

AF:

0.000478

GnomAD2 exomes

AF:

0.0000652

AC:

AN:

138110

AF XY:

0.0000656

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.000368

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:

0.00

GnomAD4 exome

AF:

0.0000949

AC:

131

AN:

1380930

Hom.:

Cov.:

AF XY:

0.0000985

AC XY:

AN XY:

680422

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

31598

American (AMR)

AF:

0.000308

AC:

AN:

35686

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

24576

East Asian (EAS)

AF:

0.00

AC:

AN:

36182

South Asian (SAS)

AF:

0.00

AC:

AN:

79278

European-Finnish (FIN)

AF:

0.00

AC:

AN:

36012

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5418

European-Non Finnish (NFE)

AF:

0.000107

AC:

115

AN:

1074746

Other (OTH)

AF:

0.0000871

AC:

AN:

57434

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.478

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:

0.0000985

AC:

AN:

152224

Hom.:

Cov.:

AF XY:

0.0000672

AC XY:

AN XY:

74358

show subpopulations

African (AFR)

AF:

0.0000482

AC:

AN:

41470

American (AMR)

AF:

0.000262

AC:

AN:

15292

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5188

South Asian (SAS)

AF:

0.00

AC:

AN:

4838

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10628

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.000118

AC:

AN:

68016

Other (OTH)

AF:

0.000478

AC:

AN:

2094

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.508

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:

0.0000712

Hom.:

Bravo

AF:

0.0000982

ExAC

AF:

0.0000182

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Developmental and epileptic encephalopathy

Uncertain:1

Nov 27, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces serine, which is neutral and polar, with leucine, which is neutral and non-polar, at codon 751 of the KCNQ2 protein (p.Ser751Leu). This variant is present in population databases (rs774002673, gnomAD 0.04%), and has an allele count higher than expected for a pathogenic variant. This variant has not been reported in the literature in individuals affected with KCNQ2-related conditions. ClinVar contains an entry for this variant (Variation ID: 339329). 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) has been performed for this missense variant. However, the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on KCNQ2 protein function. 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

Jul 03, 2020

New York Genome Center

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.17

BayesDel_addAF

Uncertain

0.040

BayesDel_noAF

Uncertain

0.13

CADD

Uncertain

(source)

DANN

Uncertain

0.99

DEOGEN2

Benign

0.041

.;T;T;T;.;.

Eigen

Benign

0.18

Eigen_PC

Uncertain

0.25

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Uncertain

0.97

D;D;D;D;D;D

M_CAP

Pathogenic

0.56

MetaRNN

Benign

0.42

T;T;T;T;T;T

MetaSVM

Pathogenic

0.93

MutationAssessor

Uncertain

2.0

.;.;M;.;.;.

PhyloP100

9.3

PrimateAI

Uncertain

0.74

PROVEAN

Benign

-1.9

.;.;N;.;N;.

REVEL

Uncertain

0.55

Sift

Benign

0.26

.;.;T;.;T;.

Sift4G

Benign

0.28

T;.;T;T;T;T

Polyphen

0.91

P;.;P;.;P;P

Vest4

0.50

MutPred

0.27

.;.;Loss of sheet (P = 0.0142);.;.;.;

MVP

0.72

MPC

0.72

ClinPred

0.21

GERP RS

5.2

Varity_R

0.17

gMVP

0.41

Mutation Taster

=79/21

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

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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