rs199473362
Variant summary
Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PP3_ModeratePP5
The NM_000219.6(KCNE1):c.292C>T(p.Arg98Trp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000434 in 1,588,590 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R98L) has been classified as Uncertain significance.
Frequency
Consequence
NM_000219.6 missense
Scores
Clinical Significance
Conservation
Publications
- long QT syndrome 5Inheritance: AD Classification: DEFINITIVE, STRONG, LIMITED Submitted by: ClinGen, G2P, Labcorp Genetics (formerly Invitae), Ambry Genetics
- Jervell and Lange-Nielsen syndrome 2Inheritance: AR Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P, PanelApp Australia
- Jervell and Lange-Nielsen syndromeInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
- atrial fibrillationInheritance: AD Classification: LIMITED Submitted by: Ambry Genetics
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ACMG classification
Our verdict: Uncertain_significance. The variant received 3 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.00000708 AC: 1AN: 141302Hom.: 0 Cov.: 17 show subpopulations
GnomAD2 exomes AF: 0.0000318 AC: 8AN: 251432 AF XY: 0.0000515 show subpopulations
GnomAD4 exome AF: 0.0000470 AC: 68AN: 1447288Hom.: 0 Cov.: 29 AF XY: 0.0000555 AC XY: 40AN XY: 720798 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.00000708 AC: 1AN: 141302Hom.: 0 Cov.: 17 AF XY: 0.00 AC XY: 0AN XY: 68446 show subpopulations
ClinVar
Submissions by phenotype
not provided Pathogenic:1Uncertain:1
In vitro functional studies show a reduction in potassium channel current and abnormal KCNQ1 protein trafficking; however additional studies are needed to validate the functional effect of this variant in vivo (PMID: 19907016, 17341399, 38816749); 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: 24710009, 24606995, 10973849, 19862833, 16684966, 23861362, 21070882, 17341399, 16945797, 31447099, 30461122, 30123799, 19907016, 38565666, 38816749, 32058015, 31941373, 29672598, 30530868, 16922724, 29766885, 33077954, 34930020, 29261713) -
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Long QT syndrome Pathogenic:1Uncertain:1
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This sequence change replaces arginine, which is basic and polar, with tryptophan, which is neutral and slightly polar, at codon 98 of the KCNE1 protein (p.Arg98Trp). This variant is present in population databases (rs199473362, gnomAD 0.005%). This missense change has been observed in individuals with long QT syndrome or sudden unexpected death (PMID: 10973849, 16922724, 17341399, 21070882, 30530868, 32058015, 34930020). ClinVar contains an entry for this variant (Variation ID: 132676). 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) has been performed for this missense variant. However, the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on KCNE1 protein function. Experimental studies have shown that this missense change affects KCNE1 function (PMID: 17341399, 19907016). In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -
Long QT syndrome 5 Pathogenic:1
This c.292C>T (p.Arg98Trp) variant in the KCNE1 gene has been reported in 6 individuals and one family from a cohort of 262 patients with long QT [PMID 10973849] and additional patients [PMID 16922724, 17341399]. Segregation of the variant with the disorder was observed in one additional family of 7 individuals, 2 of which were carrier for this variant [PMID 21070882]. Functional assays showed a modest effect of the variant on trafficking and current density [PMID 17341399]. This variant was reported in 2 heterozygous individuals from Europe and East-Asia (http://exac.broadinstitute.org/variant/21-35821641-G-A). Arginine at amino acid position 98 of the KCNE1 protein is highly conserved in mammals. While not validated for clinical use, computer-based algorithms SIFT and Polyphen-2 predict this p.Arg98Trp change to be deleterious. This variant thus classified as pathogenic. -
Cardiovascular phenotype Pathogenic:1
The p.R98W variant (also known as c.292C>T), located in coding exon 1 of the KCNE1 gene, results from a C to T substitution at nucleotide position 292. The arginine at codon 98 is replaced by tryptophan, an amino acid with dissimilar properties. In long QT syndrome (LQTS) cohorts, this variant has been described in asymptomatic patients, patients with QT interval prolongation, repolarization abnormalities and/or syncope, aborted cardiac arrest, or sudden death on exertion (Splawski I et al. Circulation. 2000;102(10):1178-85; Millat G et al. Clin Genet. 2006;70(3):214-27; Ohno S et al. Heart Rhythm. 2007;4(3):332-40; Skinner JR et al. Heart Rhythm. 2011;8(3):412-9; Garmany R et al. Heart Rhythm. 2020 06;17(6):937-944Roberts JD et al. Circulation. 2020 02;141(6):429-439). In one family with epilepsy and LQTS, this variant did not segregate with disease while a KCNQ1 exon 2 deletion did segregate with disease (Coll M et al. PLoS ONE, 2017 Dec;12:e0189618). In studies using in vitro functional analyses, this variant adversely affected the voltage-gated potassium ion channel, resulting in decreased current amplitude, a positive shift of the voltage dependence of activation threshold, and accelerated channel deactivation (Ohno S et al. Heart Rhythm. 2007;4(3):332-40; Harmer SC et al. Am J Physiol.,Cell Physiol. 2010;298(2):C263-73). This amino acid position is well conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Based on the majority of available evidence to date, this variant is likely to be pathogenic. However, pathogenic and likely pathogenic KCNE1 variants typically exhibit low penetrance in the heterozygous state and may represent risk factors that manifest clinically only in the presence of additional genetic or environmental factors (Roberts JD et al. Circulation. 2020 02;141(6):429-439). -
Congenital long QT syndrome Other:1
This variant has been reported as associated with Long QT syndrome in the following publications (PMID:10973849;PMID:16922724;PMID:19907016). This is a literature report, and does not necessarily reflect the clinical interpretation of the Imperial College / Royal Brompton Cardiovascular Genetics laboratory. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at