rs1057519536

chr20-63442424-A-T

Variant summary

Our verdict is Pathogenic. Variant got 13 ACMG points: 13P and 0B. PS1_Moderate PM1 PM2 PM5 PP2 PP3_Moderate PP5_Moderate

The NM_172107.4(KCNQ2):c.798T>A(p.Asp266Glu) 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 nucleotide change resulting in same amino acid change has been previously reported as Likely pathogenicin UniProt. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. D266G) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 29)
• Consequence: KCNQ2 NM_172107.4 missense
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: -0.560

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]

ACMG classification

Verdict is Pathogenic. Variant got 13 ACMG points.

• PS1: Transcript NM_172107.4 (KCNQ2) is affected with MISSENSE_VARIANT having same AA change as one Pathogenic present in UniProt
• PM1: In a hotspot region, there are 15 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 8 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 chr20-63442425-T-C is described in ClinVar as [Pathogenic]. Clinvar id is 852899.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP2: Missense variant where missense usually causes diseases, KCNQ2
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.843
• PP5: Variant 20-63442424-A-T is Pathogenic according to our data. Variant chr20-63442424-A-T is described in ClinVar as [Pathogenic]. Clinvar id is 375518.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	c.798T>A	p.Asp266Glu	missense_variant	5/17	ENST00000359125.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KCNQ2	ENST00000359125.7	c.798T>A	p.Asp266Glu	missense_variant	5/17	1	NM_172107.4	A1

Frequencies

GnomAD3 genomes Cov.: 29

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 29

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Epileptic encephalopathy Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Neurogenetics Laboratory - MEYER, AOU Meyer

Nov 16, 2016

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Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.98
BayesDel_addAF	Pathogenic	0.33	D
BayesDel_noAF	Pathogenic	0.23
Cadd	Benign	5.8
Dann	Uncertain	0.98
Eigen	Benign	-0.93
Eigen_PC	Benign	-1.2
FATHMM_MKL	Benign	0.26	N
LIST_S2	Uncertain	0.97	D;D;D;D;D;D;D;D;D;D;D;D
M_CAP	Pathogenic	0.57	D
MetaRNN	Pathogenic	0.84	D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	0.92	D
MutationAssessor	Uncertain	2.4	M;.;.;.;.;.;M;.;M;M;M;.
MutationTaster	Benign	1.0	D;D;D;D;D;D;D;D;D;D;D;D
PrimateAI	Pathogenic	0.88	D
Sift4G	Uncertain	0.034	D;D;D;D;D;.;D;D;D;D;D;D
Polyphen		0.96	P;.;.;.;.;.;D;.;D;D;.;.
Vest4		0.94
MutPred		0.68		Loss of helix (P = 0.2271);Loss of helix (P = 0.2271);Loss of helix (P = 0.2271);Loss of helix (P = 0.2271);Loss of helix (P = 0.2271);.;Loss of helix (P = 0.2271);.;Loss of helix (P = 0.2271);Loss of helix (P = 0.2271);Loss of helix (P = 0.2271);.;
MVP		0.99
MPC		2.0
ClinPred		0.97	D
GERP RS		-6.8
Varity_R		0.71
gMVP		0.99

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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

Other links and lift over

dbSNP: rs1057519536; hg19: chr20-62073777;