rs118192203
Variant summary
Our verdict is Pathogenic. The variant received 19 ACMG points: 19P and 0B. PM1PM2PM5PP2PP3_StrongPP5_Very_Strong
The NM_172107.4(KCNQ2):c.637C>T(p.Arg213Trp) 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. 13/22 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R213L) has been classified as Likely pathogenic.
Frequency
Consequence
NM_172107.4 missense
Scores
Clinical Significance
Conservation
Publications
- complex neurodevelopmental disorderInheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
- developmental and epileptic encephalopathy, 7Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae), G2P
- neonatal encephalopathy with non-epileptic myoclonusInheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
- neonatal-onset developmental and epileptic encephalopathyInheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
- seizures, benign familial neonatal, 1Inheritance: AD Classification: DEFINITIVE Submitted by: G2P
- seizures, benign familial neonatal, 2Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
- benign familial infantile epilepsyInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- benign familial neonatal-infantile seizuresInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- benign neonatal seizuresInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- malignant migrating partial seizures of infancyInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
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ACMG classification
Our verdict: Pathogenic. The variant received 19 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes Cov.: 33
GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0AN: 1444802Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0AN XY: 716744
GnomAD4 genome Cov.: 33
ClinVar
Submissions by phenotype
not provided Pathogenic:3
Published functional studies demonstrate that R213W decreases the stability of the ion channel and decreases voltage sensitivity (Miceli et al., 2013); Not observed at significant frequency in large population cohorts (gnomAD); The majority of missense variants in this gene are considered pathogenic; In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 20437616, 24375629, 24318194, 22455920, 18353052, 29056246, 28038823, 27535030, 26993267, 25959266, 28717674, 27779742, 17765802, 22275249, 32139178, 31512412, 32917465, 32712949, 33726816, 31440721, 33659638, 31440733, 30440138, 23440208) -
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Developmental and epileptic encephalopathy, 7 Pathogenic:2Other:1
BFNE (benign familial neonatal epilepsy), EE (epileptic encephalopathy) -
This variant was identified as de novo (maternity and paternity confirmed). -
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Inborn genetic diseases Pathogenic:1
The p.R213W pathogenic mutation (also known as c.637C>T), located in coding exon 4 of the KCNQ2 gene, results from a C to T substitution at nucleotide position 637. The arginine at codon 213 is replaced by tryptophan, an amino acid with dissimilar properties. This mutation was detected in two siblings with BFNC (benign familial neonatal convulsions). Neither parent carried the mutation, and after parental relationships were confirmed, authors suspected germline mosaicism (Sadewa AH et al. Pediatr Int, 2008 Apr;50:167-71). In another study, this mutation was detected in an individual with EOEE (early onset epileptic encephalopathy) and was found to be mosaic in a parent (Milh M et al. Am. J. Med. Genet. A, 2015 Oct;167A:2314-8). In addition, this mutation has been detected in individuals with: non-specific epileptic encephalopathy, neonatal seizure disorder, congenital variant of Rett syndrome, and EIMFS (Epilepsy of Infancy with Migrating Focal Seizures) (Butler KM et al. Pediatr. Neurol., 2017 Dec;77:61-66; Zhang Q et al. Clin. Genet., 2017 May;91:717-724; Wang J et al. Mol Genet Genomic Med, 2019 Sep;:e968; Ware TL et al. Epilepsia Open, 2019 Sep;4:504-510). One functional study showed that this mutation destabilized the potassium ion channel and decreased voltage sensitivity (Miceli F et al. Proc. Natl. Acad. Sci. U.S.A., 2013 Mar;110:4386-91). In addition, a different alteration located at the same position, p.R213Q, has been detected in multiple individuals with epilepsy (Weckhuysen S et al. Ann. Neurol., 2012 Jan;71:15-25; Trump N et al. J. Med. Genet., 2016 May;53:310-7) and has been shown to result in a decrease in channel voltage sensitivity (Miceli F et al. Proc. Natl. Acad. Sci. U.S.A., 2013 Mar;110:4386-91; Orhan G et al. Ann. Neurol., 2014 Mar;75:382-94). Based on the supporting evidence, this alteration is interpreted as a disease-causing mutation. -
Developmental and epileptic encephalopathy Pathogenic:1
This sequence change replaces arginine, which is basic and polar, with tryptophan, which is neutral and slightly polar, at codon 213 of the KCNQ2 protein (p.Arg213Trp). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with benign familial neonatal seizures or early-onset epilepsy (PMID: 18353052, 27779742, 29056246). In at least one individual the variant was observed to be de novo. It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 21795). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is expected to disrupt KCNQ2 protein function with a positive predictive value of 95%. Experimental studies have shown that this missense change affects KCNQ2 function (PMID: 23440208). This variant disrupts the p.Arg213 amino acid residue in KCNQ2. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 22275249, 25982755). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -
Seizures, benign familial neonatal, 1 Pathogenic:1
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at