20-63406653-G-GGGCCC

Position:

• chr20-63406653-G-GGGCCC

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM2 PM4 PP5

The NM_172107.4(KCNQ2):​c.2609_2610insGGGCC​(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 (no stars).

• Frequency: Genomes: not found (cov: 34)
• Consequence: KCNQ2 NM_172107.4 frameshift
• Clinical Significance: Pathogenic no assertion criteria provided P:1
• Conservation: PhyloP100: 3.60

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 Uncertain_significance. Variant got 5 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM4: Frameshift in the end of transcript resulting in stoplost. Downstream stopcodon found after 873 codons.
• PP5: Variant 20-63406653-G-GGGCCC is Pathogenic according to our data. Variant chr20-63406653-G-GGGCCC is described in ClinVar as [Pathogenic]. Clinvar id is 21782.Status of the report is no_assertion_criteria_provided, 0 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KCNQ2	NM_172107.4	c.2609_2610insGGGCC	p.Arg871GlyfsTer61	frameshift_variant	17/17	ENST00000359125.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KCNQ2	ENST00000359125.7	c.2609_2610insGGGCC	p.Arg871GlyfsTer61	frameshift_variant	17/17	1	NM_172107.4	A1

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 34

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: no assertion criteria provided

Submissions by phenotype

Seizures, benign familial neonatal, 1 Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

GeneReviews

Mar 31, 2016

BFNE (benign familial neonatal epilepsy). 3/12 seizures continued until age 2, 3, 7 years. -

Computational scores

Source: dbNSFP v4.3

Splicing

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

Publications

LitVar

Other links and lift over

dbSNP: rs118192246; hg19: chr20-62038006;