Genetic Variant KCNQ2:c.1301+8G>A (chr20-63419611-C-T) – ACMG Classification: Benign (-12 pts)

Variant summary

Our verdict is Benign. The variant received -12 ACMG points: 0P and 12B. BP4_ModerateBP6_ModerateBS1BS2

The NM_172107.4(KCNQ2):c.1301+8G>A variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000255 in 1,608,312 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Likely benign (★).

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000027 ( 0 hom. )

Consequence

KCNQ2
NM_172107.4 splice_region, intron

Scores

Splicing: ADA: 0.001107

Clinical Significance

Likely benign criteria provided, single submitter B:1

Conservation

PhyloP100: 0.641

Publications

0 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 -12 ACMG points.

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.26).

BP6

Variant 20-63419611-C-T is Benign according to our data. Variant chr20-63419611-C-T is described in ClinVar as Likely_benign. ClinVar VariationId is 754523.Status of the report is criteria_provided_single_submitter, 1 stars.

BS1

Variant frequency is greater than expected in population sas. GnomAdExome4 allele frequency = 0.0000268 (39/1455962) while in subpopulation SAS AF = 0.000189 (16/84832). AF 95% confidence interval is 0.000117. There are 0 homozygotes in GnomAdExome4. There are 24 alleles in the male GnomAdExome4 subpopulation. Median coverage is 31. This position passed quality control check.

BS2

High AC in GnomAdExome4 at 39 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	Effect	Exon Rank	Protein
KCNQ2	NM_172107.4	MANE Select	c.1301+8G>A	splice_region intron	N/A	NP_742105.1
KCNQ2	NM_001382235.1		c.1248-4485G>A	intron	N/A	NP_001369164.1
KCNQ2	NM_172106.3		c.1248-4485G>A	intron	N/A	NP_742104.1

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	Effect	Exon Rank	Protein
KCNQ2	ENST00000359125.7	TSL:1 MANE Select	c.1301+8G>A	splice_region intron	N/A	ENSP00000352035.2
KCNQ2	ENST00000626839.2	TSL:1	c.1248-4485G>A	intron	N/A	ENSP00000486706.1
KCNQ2	ENST00000344462.8	TSL:1	c.1248-4521G>A	intron	N/A	ENSP00000339611.4

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152232

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:

0.000414

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000209

AC:

AN:

239480

AF XY:

0.0000386

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:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000268

AC:

AN:

1455962

Hom.:

Cov.:

AF XY:

0.0000332

AC XY:

AN XY:

723698

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33462

American (AMR)

AF:

0.00

AC:

AN:

44058

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

25958

East Asian (EAS)

AF:

0.00

AC:

AN:

39464

South Asian (SAS)

AF:

0.000189

AC:

AN:

84832

European-Finnish (FIN)

AF:

0.00

AC:

AN:

52066

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5548

European-Non Finnish (NFE)

AF:

0.0000189

AC:

AN:

1110404

Other (OTH)

AF:

0.0000332

AC:

AN:

60170

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.463

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:

0.0000131

AC:

AN:

152350

Hom.:

Cov.:

AF XY:

0.0000268

AC XY:

AN XY:

74510

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41588

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:

5176

South Asian (SAS)

AF:

0.000414

AC:

AN:

4830

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10628

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68028

Other (OTH)

AF:

0.00

AC:

AN:

2116

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.550

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:

0.00

Hom.:

ClinVar

ClinVar submissions as Germline

Significance:Likely benign

Revision:criteria provided, single submitter

View on ClinVar

Pathogenic

VUS

Benign

Condition

Developmental and epileptic encephalopathy (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.26

CADD

Benign

(source)

DANN

Benign

0.94

PhyloP100

0.64

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Benign

0.0011

dbscSNV1_RF

Benign

0.052

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

You must be logged in to view publications. This limit was set because tens of millions (!) of queries from AI bots are generated daily.

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

Computational scores

Splicing

Publications

Other links and lift over