rs1240338507

Positions:

chr20-63428368-T-C

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2PP2

The NM_172107.4(KCNQ2):c.1216A>G(p.Arg406Gly) variant causes a missense, splice region change. The variant allele was found at a frequency of 0.000000707 in 1,414,500 control chromosomes in the GnomAD database, with no homozygous occurrence. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★★).

Frequency

Genomes: not found (cov: 33)

Exomes 𝑓: 7.1e-7 ( 0 hom. )

Consequence

KCNQ2
NM_172107.4 missense, splice_region

Scores

Splicing: ADA: 0.9989

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:2

Conservation

PhyloP100: 6.16

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:

KCNQ2 (HGNC:):

KCNQ2 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 3 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PP2

Missense variant in gene, where missense usually causes diseases (based on misZ statistic), KCNQ2. . Gene score misZ 4.0411 (greater than the threshold 3.09). Trascript score misZ 3.6968 (greater than threshold 3.09). GenCC has associacion of gene with seizures, benign familial neonatal, 1, neonatal-onset developmental and epileptic encephalopathy, benign familial neonatal-infantile seizures, benign neonatal seizures, malignant migrating partial seizures of infancy, neonatal encephalopathy with non-epileptic myoclonus, complex neurodevelopmental disorder, seizures, benign familial neonatal, 2, developmental and epileptic encephalopathy, 7, benign familial infantile epilepsy.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
KCNQ2	NM_172107.4 linkuse as main transcript	c.1216A>G	p.Arg406Gly	missense_variant, splice_region_variant	10/17	ENST00000359125.7	NP_742105.1	O43526-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
KCNQ2	ENST00000359125.7 linkuse as main transcript	c.1216A>G	p.Arg406Gly	missense_variant, splice_region_variant	10/17	1	NM_172107.4	ENSP00000352035.2		O43526-1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD3 exomes

AF:

0.00000559

AC:

AN:

179036

Hom.:

AF XY:

0.0000105

AC XY:

AN XY:

94822

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000382

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS 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:

7.07e-7

AC:

AN:

1414500

Hom.:

Cov.:

AF XY:

0.00000143

AC XY:

AN XY:

698824

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.0000270

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

Cov.:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Early infantile epileptic encephalopathy with suppression bursts

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jul 12, 2022

This sequence change replaces arginine, which is basic and polar, with glycine, which is neutral and non-polar, at codon 406 of the KCNQ2 protein (p.Arg406Gly). In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive. ClinVar contains an entry for this variant (Variation ID: 452880). This variant has not been reported in the literature in individuals affected with KCNQ2-related conditions. The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. -

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Mar 29, 2024

In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; In silico analysis supports a deleterious effect on splicing; Has not been previously published as pathogenic or benign to our knowledge -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.39

BayesDel_addAF

Pathogenic

0.38

BayesDel_noAF

Pathogenic

0.31

CADD

Pathogenic

DANN

Uncertain

1.0

DEOGEN2

Benign

0.39

.;.;T;T;T;T;D;T;.;.

Eigen

Benign

0.15

Eigen_PC

Benign

0.15

FATHMM_MKL

Pathogenic

0.97

LIST_S2

Pathogenic

0.98

D;D;D;D;D;D;D;D;D;D

M_CAP

Pathogenic

0.68

MetaRNN

Uncertain

0.58

D;D;D;D;D;D;D;D;D;D

MetaSVM

Pathogenic

1.0

MutationAssessor

Uncertain

2.5

M;.;.;.;.;.;M;.;.;M

PrimateAI

Uncertain

0.59

PROVEAN

Uncertain

-3.6

.;.;.;.;D;.;D;.;D;.

REVEL

Pathogenic

0.74

Sift

Uncertain

0.0010

.;.;.;.;D;.;D;.;D;.

Sift4G

Uncertain

0.025

D;T;D;T;T;.;D;T;D;D

Polyphen

0.90

P;.;.;.;.;.;P;.;P;P

Vest4

0.77

MutPred

0.26

Gain of ubiquitination at K407 (P = 0.0268);.;.;.;.;.;Gain of ubiquitination at K407 (P = 0.0268);.;.;Gain of ubiquitination at K407 (P = 0.0268);

MVP

0.98

MPC

1.5

ClinPred

0.95

GERP RS

4.3

Varity_R

0.25

gMVP

0.79

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Pathogenic

0.98

SpliceAI score (max)

0.65

Details are displayed if max score is > 0.2

DS_DL_spliceai

0.65

Position offset: -1

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