chr20-63442465-C-T

Position:

• chr20-63442465-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM1 PM2 PP2 PP5_Moderate

The NM_172107.4(KCNQ2):​c.757G>A​(p.Ala253Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Likely pathogenic (★).

• Frequency: Genomes: not found (cov: 29)
• Consequence: KCNQ2 NM_172107.4 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1 O:1
• Conservation: PhyloP100: 7.73

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 (HGNC:):

ACMG classification

Verdict is Likely_pathogenic. Variant got 7 ACMG points.

• PM1: In a region_of_interest Mediates interaction with SLC5A3 (size 101) in uniprot entity KCNQ2_HUMAN there are 33 pathogenic changes around while only 0 benign (100%) in NM_172107.4
• 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.
• PP5: Variant 20-63442465-C-T is Pathogenic according to our data. Variant chr20-63442465-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 369761.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
KCNQ2	NM_172107.4	c.757G>A	p.Ala253Thr	missense_variant	5/17	ENST00000359125.7	NP_742105.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
KCNQ2	ENST00000359125.7	c.757G>A	p.Ala253Thr	missense_variant	5/17	1	NM_172107.4	ENSP00000352035.2

Frequencies

GnomAD3 genomes Cov.: 29

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 29

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1 Other:1

Revision: criteria provided, single submitter

Submissions by phenotype

Developmental and epileptic encephalopathy, 7 Pathogenic:1 Other:1

Likely pathogenic, criteria provided, single submitter	clinical testing	Institute of Human Genetics, University of Leipzig Medical Center	Dec 23, 2022	_x000D_ Criteria applied: PM5_STR, PM1, PS4_SUP, PM2_SUP, PP3 -
not provided, no classification provided	literature only	GeneReviews	-	Uncertain severity -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.69
BayesDel_addAF	Pathogenic	0.23	D
BayesDel_noAF	Uncertain	0.090
CADD	Pathogenic	26
DANN	Uncertain	1.0
DEOGEN2	Benign	0.35	.;.;T;T;D;T;D;T;.;.;.;.
Eigen	Benign	0.10
Eigen_PC	Benign	0.17
FATHMM_MKL	Uncertain	0.94	D
LIST_S2	Uncertain	0.96	D;D;D;D;D;D;D;D;D;D;D;D
M_CAP	Pathogenic	0.51	D
MetaRNN	Uncertain	0.69	D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Uncertain	2.8	M;.;.;.;.;.;M;.;M;M;M;.
PrimateAI	Uncertain	0.78	T
PROVEAN	Benign	-1.8	.;.;.;.;N;.;N;.;N;N;N;.
REVEL	Pathogenic	0.68
Sift	Uncertain	0.023	.;.;.;.;D;.;D;.;D;D;D;.
Sift4G	Benign	0.091	T;T;T;T;T;.;T;T;T;T;T;T
Polyphen		0.23	B;.;.;.;.;.;B;.;B;B;.;.
Vest4		0.86
MutPred		0.50		Gain of methylation at K255 (P = 0.0975);Gain of methylation at K255 (P = 0.0975);Gain of methylation at K255 (P = 0.0975);Gain of methylation at K255 (P = 0.0975);Gain of methylation at K255 (P = 0.0975);.;Gain of methylation at K255 (P = 0.0975);.;Gain of methylation at K255 (P = 0.0975);Gain of methylation at K255 (P = 0.0975);Gain of methylation at K255 (P = 0.0975);.;
MVP		0.92
MPC		2.0
ClinPred		0.97	D
GERP RS		3.4
Varity_R		0.37
gMVP		0.98

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.050		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: rs1057516093; hg19: chr20-62073818;