rs1555850590
Positions:
Variant summary
Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PVS1_StrongPM2PP5_Moderate
The NM_172107.4(KCNQ2):c.2278del(p.Arg760AlafsTer170) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★). Synonymous variant affecting the same amino acid position (i.e. R760R) has been classified as Likely benign.
Frequency
Genomes: not found (cov: 34)
Consequence
KCNQ2
NM_172107.4 frameshift
NM_172107.4 frameshift
Scores
Not classified
Clinical Significance
Conservation
PhyloP100: 0.0260
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]
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ACMG classification
Classification made for transcript
Verdict is Likely_pathogenic. Variant got 8 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. There are 12 pathogenic variants in the truncated region.
PM2
Very rare variant in population databases, with high coverage;
PP5
Variant 20-63406984-CG-C is Pathogenic according to our data. Variant chr20-63406984-CG-C is described in ClinVar as [Pathogenic]. Clinvar id is 461416.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.2278del | p.Arg760AlafsTer170 | frameshift_variant | 17/17 | ENST00000359125.7 |
Ensembl
Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | TSL | MANE | Appris | UniProt |
---|---|---|---|---|---|---|---|---|---|
KCNQ2 | ENST00000359125.7 | c.2278del | p.Arg760AlafsTer170 | frameshift_variant | 17/17 | 1 | NM_172107.4 | A1 |
Frequencies
GnomAD3 genomes Cov.: 34
GnomAD3 genomes
Cov.:
34
GnomAD4 exome Cov.: 36
GnomAD4 exome
Cov.:
36
GnomAD4 genome Cov.: 34
GnomAD4 genome
Cov.:
34
ClinVar
Significance: Pathogenic
Submissions summary: Pathogenic:1
Revision: criteria provided, single submitter
LINK: link
Submissions by phenotype
Early infantile epileptic encephalopathy with suppression bursts Pathogenic:1
Pathogenic, criteria provided, single submitter | clinical testing | Invitae | Sep 01, 2022 | This variant results in an extension of the KCNQ2 protein. Other variant(s) that result in a similarly extended protein product (p.Gly866Alafs*64) have been determined to be pathogenic (PMID: 10482260, 21937445). This suggests that these extensions are likely to be disease-causing. ClinVar contains an entry for this variant (Variation ID: 461416). This variant has not been reported in the literature in individuals affected with KCNQ2-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change results in a frameshift in the KCNQ2 gene (p.Arg760Alafs*170). While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 113 amino acid(s) of the KCNQ2 protein and extend the protein by 56 additional amino acid residues. For these reasons, this variant has been classified as Pathogenic. - |
Computational scores
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Splicing
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SpliceAI score (max)
Details are displayed if max score is > 0.2
Find out detailed SpliceAI scores and Pangolin per-transcript scores at