rs730882060

Variant names:

• chr20-63406653-G-GGGCCC
• rs118192246
• NM_172107.4:c.2605_2609dupGGGCC

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PVS1_Moderate PS3 PM2 PP5_Moderate

The NM_172107.4(KCNQ2):​c.2605_2609dupGGGCC​(p.Arg871GlyfsTer61) variant causes a frameshift change. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★). ClinVar reports functional evidence for this variant: "SCV005838025: Experimental studies have shown that this frameshift affects KCNQ2 function (PMID:14534157).".

• Frequency: Genomes: not found (cov: 34)
• Consequence: KCNQ2 NM_172107.4 frameshift
• Clinical Significance: Pathogenic criteria provided, single submitter P:2
• Conservation: PhyloP100: 3.60
• Publications: 3 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: G2P, Orphanet, Labcorp Genetics (formerly Invitae)
• 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
• undetermined early-onset epileptic encephalopathy

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• 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 10 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. Fraction of 0.00382 CDS is truncated, and there are 3 pathogenic variants in the truncated region.
• PS3: PS3 evidence extracted from ClinVar submissions: SCV005838025: Experimental studies have shown that this frameshift affects KCNQ2 function (PMID: 14534157).
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 20-63406653-G-GGGCCC is Pathogenic according to our data. Variant chr20-63406653-G-GGGCCC is described in ClinVar as Pathogenic. ClinVar VariationId is 21782.Status of the report is criteria_provided_single_submitter, 1 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_172107.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	KCNQ2	NM_172107.4	MANE Select	c.2605_2609dupGGGCC	p.Arg871GlyfsTer61	frameshift	Exon 17 of 17	NP_742105.1	O43526-1
	KCNQ2	NM_001382235.1		c.2659_2663dupGGGCC	p.Arg889GlyfsTer61	frameshift	Exon 17 of 17	NP_001369164.1	A0A9L9PXL0
	KCNQ2	NM_172106.3		c.2551_2555dupGGGCC	p.Arg853GlyfsTer61	frameshift	Exon 16 of 16	NP_742104.1	O43526-2

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	KCNQ2	ENST00000359125.7	TSL:1 MANE Select	c.2605_2609dupGGGCC	p.Arg871GlyfsTer61	frameshift	Exon 17 of 17	ENSP00000352035.2	O43526-1
	KCNQ2	ENST00000626839.2	TSL:1	c.2551_2555dupGGGCC	p.Arg853GlyfsTer61	frameshift	Exon 16 of 16	ENSP00000486706.1	O43526-2
	KCNQ2	ENST00000344462.8	TSL:1	c.2512_2516dupGGGCC	p.Arg840GlyfsTer61	frameshift	Exon 16 of 16	ENSP00000339611.4	O43526-4

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 34

ClinVar

ClinVar submissions

Significance: Pathogenic

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
1	-	-	Developmental and epileptic encephalopathy (1)
1	-	-	Seizures, benign familial neonatal, 1 (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		3.6
Mutation Taster		=0/200	disease causing (ClinVar)

Splicing

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs118192246; hg19: chr20-62038006;