chr20-63406728-G-C

Variant names:

Variant summary

Our verdict is Benign. The variant received -20 ACMG points: 0P and 20B. BP4_StrongBP6_Very_StrongBS1BS2

The NM_172107.4(KCNQ2):c.2535C>G(p.Leu845Leu) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000597 in 1,609,036 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 (★★).

Frequency

Genomes: 𝑓 0.00032 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000032 ( 0 hom. )

Consequence

KCNQ2
NM_172107.4 synonymous

Scores

Clinical Significance

Benign/Likely benign criteria provided, multiple submitters, no conflicts B:4

Conservation

PhyloP100: 0.344

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 -20 ACMG points.

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.59).

BP6

Variant 20-63406728-G-C is Benign according to our data. Variant chr20-63406728-G-C is described in ClinVar as Benign/Likely_benign. ClinVar VariationId is 205852.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

BS1

Variant frequency is greater than expected in population afr. GnomAd4 allele frequency = 0.000322 (49/152370) while in subpopulation AFR AF = 0.00111 (46/41590). AF 95% confidence interval is 0.000852. There are 0 homozygotes in GnomAd4. There are 23 alleles in the male GnomAd4 subpopulation. Median coverage is 33. This position passed quality control check.

BS2

High AC in GnomAd4 at 49 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNQ2	NM_172107.4 link	c.2535C>G	p.Leu845Leu	synonymous_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.2535C>G	p.Leu845Leu	synonymous_variant	Exon 17 of 17	1	NM_172107.4	ENSP00000352035.2		O43526-1

Frequencies

GnomAD3 genomes

AF:

0.000328

AC:

AN:

152252

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00113

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000654

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:

0.00

Gnomad OTH

AF:

0.000955

GnomAD2 exomes

AF:

0.000113

AC:

AN:

238842

AF XY:

0.0000765

show subpopulations

Gnomad AFR exome

AF:

0.00174

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:

0.00000936

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000323

AC:

AN:

1456666

Hom.:

Cov.:

AF XY:

0.0000290

AC XY:

AN XY:

724464

show subpopulations

African (AFR)

AF:

0.00123

AC:

AN:

33422

American (AMR)

AF:

0.0000225

AC:

AN:

44364

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

25990

East Asian (EAS)

AF:

0.00

AC:

AN:

39500

South Asian (SAS)

AF:

0.00

AC:

AN:

85854

European-Finnish (FIN)

AF:

0.00

AC:

AN:

50976

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5762

European-Non Finnish (NFE)

AF:

9.00e-7

AC:

AN:

1110666

Other (OTH)

AF:

0.0000665

AC:

AN:

60132

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.497

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:

0.000322

AC:

AN:

152370

Hom.:

Cov.:

AF XY:

0.000309

AC XY:

AN XY:

74508

show subpopulations

African (AFR)

AF:

0.00111

AC:

AN:

41590

American (AMR)

AF:

0.0000653

AC:

AN:

15314

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5180

South Asian (SAS)

AF:

0.00

AC:

AN:

4834

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10630

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68028

Other (OTH)

AF:

0.000945

AC:

AN:

2116

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.502

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:

0.0000854

Hom.:

Bravo

AF:

0.000351

Asia WGS

AF:

0.000289

AC:

AN:

3478

ClinVar

Significance: Benign/Likely benign

Submissions summary: Benign:4

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not specified

Benign:1

Oct 13, 2014

GeneDx

Significance: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. -

KCNQ2-related disorder

Benign:1

Jul 11, 2024

PreventionGenetics, part of Exact Sciences

Significance:Likely benign

Review Status:no assertion criteria provided

Collection Method:clinical testing

This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -

Inborn genetic diseases

Benign:1

Aug 23, 2019

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. -

Developmental and epileptic encephalopathy

Benign:1

Feb 02, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.59

CADD

Benign

0.88

(source)

DANN

Benign

0.50

PhyloP100

0.34

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