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

Variant summary

Our verdict is Benign. Variant got -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

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 links:

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ACMG classification

Classification made for transcript

Verdict is Benign. Variant got -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 id is 754523.Status of the report is criteria_provided_single_submitter, 1 stars.

BS1

Variant frequency is greater than expected in population sas. gnomad4_exome 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 gnomad4_exome. There are 24 alleles in male gnomad4_exome subpopulation. Median coverage is 31. This position pass quality control queck.

BS2

High AC in GnomAdExome4 at 39 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNQ2	NM_172107.4 link	c.1301+8G>A		splice_region_variant, intron_variant	Intron 12 of 16	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.1301+8G>A		splice_region_variant, intron_variant	Intron 12 of 16	1	NM_172107.4	ENSP00000352035.2		O43526-1

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

GnomAD3 exomes

AF:

0.0000209

AC:

AN:

239480

Hom.:

AF XY:

0.0000386

AC XY:

AN XY:

129620

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 SAS exome

AF:

0.000172

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

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.000189

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000189

Gnomad4 OTH exome

AF:

0.0000332

GnomAD4 genome

AF:

0.0000131

AC:

AN:

152350

Hom.:

Cov.:

AF XY:

0.0000268

AC XY:

AN XY:

74510

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.000414

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

ClinVar

Significance: Likely benign

Submissions summary: Benign:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Early infantile epileptic encephalopathy with suppression bursts

Benign:1

Sep 26, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely 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

-0.26

CADD

Benign

DANN

Benign

0.94

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

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over