Genetic Variant KCNQ2:p.Arg871Ser (chr20-63406650-C-A) – ACMG Classification: Benign (-17 pts)

Variant summary

Our verdict is Benign. The variant received -17 ACMG points: 1P and 18B. PP2BP4_ModerateBP6_Very_StrongBS1BS2

The NM_172107.4(KCNQ2):c.2613G>T(p.Arg871Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000054 in 1,591,312 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 Likely benign (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R871G) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000072 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000052 ( 0 hom. )

Consequence

KCNQ2
NM_172107.4 missense

Scores

Clinical Significance

Benign/Likely benign criteria provided, multiple submitters, no conflicts B:6O:1

Conservation

PhyloP100: 0.867

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: Benign. The variant received -17 ACMG points.

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=0.19921276).

BP6

Variant 20-63406650-C-A is Benign according to our data. Variant chr20-63406650-C-A is described in ClinVar as Benign/Likely_benign. ClinVar VariationId is 129343.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

BS1

Variant frequency is greater than expected in population nfe. GnomAd4 allele frequency = 0.0000723 (11/152178) while in subpopulation NFE AF = 0.000162 (11/68016). AF 95% confidence interval is 0.0000905. There are 0 homozygotes in GnomAd4. There are 4 alleles in the male GnomAd4 subpopulation. Median coverage is 33. This position passed quality control check.

BS2

High AC in GnomAd4 at 11 AD gene.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_172107.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
KCNQ2	NM_172107.4	MANE Select	c.2613G>T	p.Arg871Ser	missense	Exon 17 of 17	NP_742105.1
KCNQ2	NM_001382235.1		c.2667G>T	p.Arg889Ser	missense	Exon 17 of 17	NP_001369164.1
KCNQ2	NM_172106.3		c.2559G>T	p.Arg853Ser	missense	Exon 16 of 16	NP_742104.1

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
KCNQ2	ENST00000359125.7	TSL:1 MANE Select	c.2613G>T	p.Arg871Ser	missense	Exon 17 of 17	ENSP00000352035.2
KCNQ2	ENST00000626839.2	TSL:1	c.2559G>T	p.Arg853Ser	missense	Exon 16 of 16	ENSP00000486706.1
KCNQ2	ENST00000344462.8	TSL:1	c.2520G>T	p.Arg840Ser	missense	Exon 16 of 16	ENSP00000339611.4

Frequencies

GnomAD3 genomes

AF:

0.0000723

AC:

AN:

152178

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:

0.000162

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.000104

AC:

AN:

212392

AF XY:

0.000127

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 FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000200

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000521

AC:

AN:

1439134

Hom.:

Cov.:

AF XY:

0.0000448

AC XY:

AN XY:

714902

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33146

American (AMR)

AF:

0.00

AC:

AN:

43382

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

25748

East Asian (EAS)

AF:

0.00

AC:

AN:

39168

South Asian (SAS)

AF:

0.0000707

AC:

AN:

84868

European-Finnish (FIN)

AF:

0.00

AC:

AN:

42014

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5726

European-Non Finnish (NFE)

AF:

0.0000588

AC:

AN:

1105448

Other (OTH)

AF:

0.0000671

AC:

AN:

59634

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.493

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:

0.0000723

AC:

AN:

152178

Hom.:

Cov.:

AF XY:

0.0000538

AC XY:

AN XY:

74340

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41452

American (AMR)

AF:

0.00

AC:

AN:

15276

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5186

South Asian (SAS)

AF:

0.00

AC:

AN:

4826

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10628

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.000162

AC:

AN:

68016

Other (OTH)

AF:

0.00

AC:

AN:

2094

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.516

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:

0.000142

Hom.:

Bravo

AF:

0.0000604

ExAC

AF:

0.000170

AC:

ClinVar

Significance: Benign/Likely benign

Submissions summary: Benign:6Other:1

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not specified

Benign:3

Mar 31, 2014

Genetic Services Laboratory, University of Chicago

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Nov 24, 2015

Eurofins Ntd Llc (ga)

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Feb 17, 2016

GeneDx

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease.

Developmental and epileptic encephalopathy

Benign:1

Jan 07, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Seizures, benign familial neonatal, 1

Benign:1

May 28, 2019

Mendelics

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

not provided

Benign:1

Breakthrough Genomics, Breakthrough Genomics

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:not provided

Developmental and epileptic encephalopathy, 7

Other:1

GeneReviews

Significance:not provided

Review Status:no classification provided

Collection Method:literature only

EE (epileptic encephalopathy)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.26

BayesDel_addAF

Benign

-0.067

BayesDel_noAF

Uncertain

-0.050

CADD

Benign

(source)

DANN

Uncertain

0.99

DEOGEN2

Benign

0.0094

Eigen

Benign

-0.14

Eigen_PC

Benign

0.0039

FATHMM_MKL

Uncertain

0.96

LIST_S2

Uncertain

0.92

M_CAP

Uncertain

0.29

MetaRNN

Benign

0.20

MetaSVM

Uncertain

0.73

MutationAssessor

Benign

0.34

PhyloP100

0.87

PrimateAI

Uncertain

0.71

PROVEAN

Benign

-0.83

REVEL

Uncertain

0.55

Sift

Uncertain

0.013

Sift4G

Benign

0.49

Polyphen

0.55

Vest4

0.36

MutPred

0.26

Loss of MoRF binding (P = 0.0189)

MVP

0.78

MPC

0.96

ClinPred

0.093

GERP RS

3.8

Varity_R

0.16

gMVP

0.34

Mutation Taster

=1/99

disease causing

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.010

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

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