20-63444665-G-T

Position:

chr20-63444665-G-T

Variant summary

Our verdict is Pathogenic. Variant got 13 ACMG points: 13P and 0B. PM1PM2PM5PP2PP3_StrongPP5_Moderate

The NM_172107.4(KCNQ2):c.684C>A(p.His228Gln) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. H228R) has been classified as Uncertain significance.

Frequency

Genomes: not found (cov: 33)

Exomes 𝑓: 0.0 ( 0 hom. )

Failed GnomAD Quality Control

Consequence

KCNQ2
NM_172107.4 missense

Scores

Clinical Significance

Pathogenic criteria provided, single submitter P:1O:2

Conservation

PhyloP100: 2.45

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 Pathogenic. Variant got 13 ACMG points.

PM1

In a hotspot region, there are 13 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 5 uncertain in NM_172107.4

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr20-63444667-G-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 2857655.Status of the report is criteria_provided_single_submitter, 1 stars.

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.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.984

PP5

Variant 20-63444665-G-T is Pathogenic according to our data. Variant chr20-63444665-G-T is described in ClinVar as [Pathogenic]. Clinvar id is 21797.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KCNQ2	NM_172107.4 linkuse as main transcript	c.684C>A	p.His228Gln	missense_variant	4/17	ENST00000359125.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KCNQ2	ENST00000359125.7 linkuse as main transcript	c.684C>A	p.His228Gln	missense_variant	4/17	1	NM_172107.4	A1	O43526-1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

Data not reliable, filtered out with message: AC0

AF:

0.00

AC:

AN:

1405038

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

691712

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:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

Cov.:

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1Other:2

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Early infantile epileptic encephalopathy with suppression bursts

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Invitae

Sep 22, 2023

This sequence change replaces histidine, which is basic and polar, with glutamine, which is neutral and polar, at codon 228 of the KCNQ2 protein (p.His228Gln). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individuals with benign familial neonatal seizures (PMID: 4055306, 14534157; Invitae). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 21797). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt KCNQ2 protein function. For these reasons, this variant has been classified as Pathogenic. -

Seizures, benign familial neonatal, 1

Other:1

not provided, no classification provided

literature only

GeneReviews

BFNE (benign familial neonatal epilepsy) -

Complex neurodevelopmental disorder

Other:1

not provided, no classification provided

literature only

Channelopathy-Associated Epilepsy Research Center

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

1.0

BayesDel_addAF

Pathogenic

0.51

BayesDel_noAF

Pathogenic

0.49

CADD

Uncertain

DANN

Uncertain

0.99

DEOGEN2

Uncertain

0.47

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

Eigen

Benign

0.18

Eigen_PC

Benign

0.10

FATHMM_MKL

Uncertain

0.97

LIST_S2

Uncertain

0.95

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

M_CAP

Pathogenic

0.84

MetaRNN

Pathogenic

0.98

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

MetaSVM

Pathogenic

0.97

MutationAssessor

Uncertain

2.1

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

MutationTaster

Benign

1.0

A;A;A;A;A;A;A;A;A;A;A;A

PrimateAI

Pathogenic

0.89

PROVEAN

Pathogenic

-7.2

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

REVEL

Pathogenic

0.84

Sift

Pathogenic

0.0

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

Sift4G

Pathogenic

0.0010

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

Polyphen

1.0

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

Vest4

0.98

MutPred

0.91

Gain of methylation at K230 (P = 0.111);Gain of methylation at K230 (P = 0.111);Gain of methylation at K230 (P = 0.111);Gain of methylation at K230 (P = 0.111);Gain of methylation at K230 (P = 0.111);.;Gain of methylation at K230 (P = 0.111);.;Gain of methylation at K230 (P = 0.111);Gain of methylation at K230 (P = 0.111);Gain of methylation at K230 (P = 0.111);.;

MVP

1.0

MPC

2.8

ClinPred

1.0

GERP RS

0.71

Varity_R

0.98

gMVP

0.98

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

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