Genetic Variant KCNQ2:p.Ile592Ile (chr20-63408524-G-A) – ACMG Classification: Benign (-9 pts)

Variant summary

Our verdict is Benign. The variant received -9 ACMG points: 0P and 9B. BP4_ModerateBP6_ModerateBP7BS2

The NM_172107.4(KCNQ2):c.1776C>T(p.Ile592Ile) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000807 in 1,610,666 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 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000082 ( 0 hom. )

Consequence

KCNQ2
NM_172107.4 synonymous

Scores

Clinical Significance

Likely benign criteria provided, single submitter B:1

Conservation

PhyloP100: -0.682

Publications

4 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 -9 ACMG points.

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.45).

BP6

Variant 20-63408524-G-A is Benign according to our data. Variant chr20-63408524-G-A is described in ClinVar as Likely_benign. ClinVar VariationId is 413250.Status of the report is criteria_provided_single_submitter, 1 stars.

BP7

Synonymous conserved (PhyloP=-0.682 with no splicing effect.

BS2

High AC in GnomAdExome4 at 12 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.1776C>T	p.Ile592Ile	synonymous	Exon 16 of 17	NP_742105.1
KCNQ2	NM_001382235.1		c.1830C>T	p.Ile610Ile	synonymous	Exon 16 of 17	NP_001369164.1
KCNQ2	NM_172106.3		c.1722C>T	p.Ile574Ile	synonymous	Exon 15 of 16	NP_742104.1

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
KCNQ2	ENST00000359125.7	TSL:1 MANE Select	c.1776C>T	p.Ile592Ile	synonymous	Exon 16 of 17	ENSP00000352035.2
KCNQ2	ENST00000626839.2	TSL:1	c.1722C>T	p.Ile574Ile	synonymous	Exon 15 of 16	ENSP00000486706.1
KCNQ2	ENST00000344462.8	TSL:1	c.1683C>T	p.Ile561Ile	synonymous	Exon 15 of 16	ENSP00000339611.4

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152134

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

GnomAD2 exomes

AF:

0.0000164

AC:

AN:

243464

AF XY:

0.0000151

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000293

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000183

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000823

AC:

AN:

1458414

Hom.:

Cov.:

AF XY:

0.00000827

AC XY:

AN XY:

725416

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33462

American (AMR)

AF:

0.0000225

AC:

AN:

44520

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26062

East Asian (EAS)

AF:

0.00

AC:

AN:

39646

South Asian (SAS)

AF:

0.0000349

AC:

AN:

85876

European-Finnish (FIN)

AF:

0.0000194

AC:

AN:

51560

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5762

European-Non Finnish (NFE)

AF:

0.00000630

AC:

AN:

1111252

Other (OTH)

AF:

0.00

AC:

AN:

60274

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.467

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:

0.00000657

AC:

AN:

152252

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74440

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41544

American (AMR)

AF:

0.00

AC:

AN:

15306

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5166

South Asian (SAS)

AF:

0.00

AC:

AN:

4824

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10620

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68000

Other (OTH)

AF:

0.00

AC:

AN:

2114

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.475

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.0000113

ClinVar

Significance: Likely benign

Submissions summary: Benign:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Developmental and epileptic encephalopathy

Benign:1

Apr 19, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.45

CADD

Benign

(source)

DANN

Benign

0.86

PhyloP100

-0.68

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

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over