rs1057516098

Variant names:

• chr20-63439657-C-A
• rs1057516098
• NM_172107.4:c.868G>T

Your query was ambiguous. Multiple possible variants found:

• chr20-63439657-C-A
• chr20-63439657-C-T

Variant summary

Our verdict is Pathogenic. The variant received 19 ACMG points: 19P and 0B. PM1 PM2 PM5 PP2 PP3_Strong PP5_Very_Strong

The NM_172107.4(KCNQ2):​c.868G>T​(p.Gly290Cys) variant causes a missense change. 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 Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G290S) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 33)
• Consequence: KCNQ2 NM_172107.4 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 5.98
• Publications: 0 publications found

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 Gene-Disease associations (from GenCC):

• complex neurodevelopmental disorder

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• developmental and epileptic encephalopathy, 7

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae), G2P
• neonatal encephalopathy with non-epileptic myoclonus

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• neonatal-onset developmental and epileptic encephalopathy

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• seizures, benign familial neonatal, 1

  Inheritance: AD Classification: DEFINITIVE Submitted by: G2P
• seizures, benign familial neonatal, 2

  Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
• benign familial infantile epilepsy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• benign familial neonatal-infantile seizures

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• benign neonatal seizures

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• malignant migrating partial seizures of infancy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Pathogenic. The variant received 19 ACMG points.

• PM1: In a hotspot region, there are 27 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 10 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 chr20-63439657-C-T is described in ClinVar as Pathogenic. ClinVar VariationId is 369768.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP2: Missense variant in the KCNQ2 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 319 curated pathogenic missense variants (we use a threshold of 10). The gene has 78 curated benign missense variants. Gene score misZ: 4.0411 (above the threshold of 3.09). Trascript score misZ: 3.6968 (above the threshold of 3.09). GenCC associations: The gene is linked to benign familial infantile epilepsy, malignant migrating partial seizures of infancy, developmental and epileptic encephalopathy, 7, benign familial neonatal-infantile seizures, benign neonatal seizures, neonatal-onset developmental and epileptic encephalopathy, complex neurodevelopmental disorder, seizures, benign familial neonatal, 2, seizures, benign familial neonatal, 1, neonatal encephalopathy with non-epileptic myoclonus.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.988
• PP5: Variant 20-63439657-C-A is Pathogenic according to our data. Variant chr20-63439657-C-A is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 1803794.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNQ2	NM_172107.4	c.868G>T	p.Gly290Cys	missense_variant	Exon 6 of 17	ENST00000359125.7	NP_742105.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCNQ2	ENST00000359125.7	c.868G>T	p.Gly290Cys	missense_variant	Exon 6 of 17	1	NM_172107.4	ENSP00000352035.2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Developmental and epileptic encephalopathy, 7 Pathogenic:2

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Neuberg Centre For Genomic Medicine, NCGM

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The missense variant p.G290C in KCNQ2 (NM_172107.3) causes a change at the same amino acid residue as a previously established pathogenic variant (G290D). The p.G290C variant is novel (not in any individuals) in gnomAD Exomes and is novel (not in any individuals) in 1000 Genomes. There is a large physicochemical difference between glycine and cysteine, which is likely to impact secondary protein structure as these residues differ in polarity, charge, size and/or other properties. The gene KCNQ2 contains 114 pathogenic missense variants, indicating that missense variants are a common mechanism of disease in this gene. The p.G290C missense variant is predicted to be damaging by both SIFT and PolyPhen2. The glycine residue at codon 290 of KCNQ2 is conserved in all mammalian species. The nucleotide c.868 in KCNQ2 is predicted conserved by GERP++ and PhyloP across 100 vertebrates. For these reasons, this variant has been classified as Likely Pathogenic. -

Aug 18, 2020

Foundation for Research in Genetics and Endocrinology, FRIGE's Institute of Human Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: research

A heterozygous de novo missense variation in exon 6 of the KCNQ2 gene that results in the amino acid substitution of Cysteine for Glycine at codon 290 was detected. The observed variant c.868G>T (p.Gly290Cys) has not been reported in the 1000 genomes and ExAC databases. The in silico prediction of the variant are possibly damaging by PolyPhen-2 (HumDiv) and damaging by SIFT, LRT and MutationTaster2. The reference codon is conserved across species. In summary, the variant meets our criteria to be classified as pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.56	D
BayesDel_noAF	Pathogenic	0.57
CADD	Pathogenic	28
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.66	.;.;D;D;D;D;D;D;.;.;.
Eigen	Pathogenic	0.79
Eigen_PC	Uncertain	0.61
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Pathogenic	1.0	D;D;D;D;D;D;D;D;D;D;D
M_CAP	Pathogenic	0.97	D
MetaRNN	Pathogenic	0.99	D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	4.8	H;.;.;.;.;.;H;.;H;H;H
PhyloP100		6.0
PrimateAI	Pathogenic	0.84	D
PROVEAN	Pathogenic	-8.3	.;.;.;.;D;.;D;.;D;D;D
REVEL	Pathogenic	0.97
Sift	Pathogenic	0.0	.;.;.;.;D;.;D;.;D;D;D
Sift4G	Pathogenic	0.0	D;D;D;D;D;.;D;D;D;D;D
Polyphen		1.0	D;.;.;.;.;.;D;.;D;D;.
Vest4		0.98
MutPred		0.87		Loss of sheet (P = 0.0457);Loss of sheet (P = 0.0457);Loss of sheet (P = 0.0457);Loss of sheet (P = 0.0457);Loss of sheet (P = 0.0457);.;Loss of sheet (P = 0.0457);.;Loss of sheet (P = 0.0457);Loss of sheet (P = 0.0457);Loss of sheet (P = 0.0457);
MVP		1.0
MPC		2.9
ClinPred		1.0	D
GERP RS		4.0
PromoterAI		-0.033	Neutral
Varity_R		0.99
gMVP		1.0
Mutation Taster		=0/100	disease causing

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

Other links and lift over

dbSNP: rs1057516098; hg19: chr20-62071010;