rs199473348
Variant summary
Our verdict is Likely benign. Variant got -6 ACMG points: 0P and 6B. BP4_ModerateBS2
The NM_000219.6(KCNE1):c.23C>T(p.Ala8Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. In-silico tool predicts a benign outcome for this variant. 13/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).
Frequency
Consequence
NM_000219.6 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Likely_benign. Variant got -6 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000969 AC: 9AN: 92872Hom.: 0 Cov.: 13
GnomAD3 exomes AF: 0.000104 AC: 26AN: 251178Hom.: 0 AF XY: 0.000140 AC XY: 19AN XY: 135844
GnomAD4 exome AF: 0.000102 AC: 81AN: 795706Hom.: 7 Cov.: 11 AF XY: 0.000103 AC XY: 42AN XY: 409650
GnomAD4 genome AF: 0.0000968 AC: 9AN: 92948Hom.: 0 Cov.: 13 AF XY: 0.000134 AC XY: 6AN XY: 44890
ClinVar
Submissions by phenotype
not specified Uncertain:2
Variant summary: KCNE1 c.23C>T (p.Ala8Val) results in a non-conservative amino acid change in the encoded protein sequence. Four of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 0.00011 in 251512 control chromosomes, predominantly at a frequency of 0.00049 within the East Asian subpopulation in the gnomAD database. c.23C>T has been reported in the literature in multiple individuals affected with arrhythmia (e.g. Ohno_2007, Sale_2008, Kapplinger_2009, Fedida_2017, Bennett_2019, Li_2019), including three individuals from one family in which the variant segregated with a Long QT Syndrome (LQTS) phenotype (Li_2019). These data indicate that the variant may be associated with disease. At least four publications report experimental evidence evaluating the functional effects of the variant and suggest it may alter channel kinetics or cell surface expression, however the biological consequences of these findings are not clear (e.g. Ohno_2007, Sale, 2008, Du_2013, Muhammad_2024). The following publications have been ascertained in the context of this evaluation (PMID: 31535183, 31521807, 30461122, 30123799, 28988457, 28767663, 26926294, 26715165, 26410412, 25650408, 24400172, 20541041, 19862833, 19716085, 19695459, 18776039, 17341399, 38816749). ClinVar contains an entry for this variant (Variation ID: 132670). Based on the evidence outlined above, the variant was classified as VUS-possibly pathogenic. -
The p.Ala8Val variant in KCNE1 has been reported in the heterozygous state in on e individual with paroxysmal atrial fibrillation and sick sinus syndrome and one individual with Long QT syndrome (Ohno 2007, Sale 2008, Kapplinger 2009). This variant has been identified in 11/18860 East Asian chromosomes by the Genome Agg regation Database (gnomAD, http://gnomad.broadinstitute.org/) and is reported in ClinVar (Variation ID: 132670). In vitro functional studies provide some eviden ce that the p.Ala8Val variant may impact protein function (Ohno 2007, Sale 2008, Du 2013). However, these types of assays may not accurately represent biologica l function. Alanine (Ala) at position 8 is not conserved in mammals or evolution arily distant species and 4 mammals carry a Valine (Val) at this position, raisi ng the possibility that this change may be tolerated. Additional computational p rediction tools suggest that the p.Ala8Val variant may not impact the protein, t hough this information is not predictive enough to rule out pathogenicity. In su mmary, the clinical significance of the p.Ala8Val variant is uncertain. ACMG/AMP Criteria applied: PS3_Supporting, PS4_Supporting, BP4_Strong. -
Long QT syndrome Uncertain:2
This sequence change replaces alanine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 8 of the KCNE1 protein (p.Ala8Val). This variant is present in population databases (rs199473348, gnomAD 0.06%). This missense change has been observed in individual(s) with long QT syndrome or clinical suspicion of long QT syndrome (PMID: 17341399, 19716085, 31521807, 31535183, 34403091). ClinVar contains an entry for this variant (Variation ID: 132670). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt KCNE1 protein function with a negative predictive value of 95%. Experimental studies have shown that this missense change affects KCNE1 function (PMID: 17341399, 18776039, 24400172). In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -
Low GERP score may suggest that this variant may belong in a lower pathogenicity class -
Long QT syndrome 5 Uncertain:1Other:1
This variant is interpreted as a Uncertain Significance - Conflicting Evidence, for Long QT syndrome 5, in Autosomal Dominant manner. The following ACMG Tag(s) were applied: BS1 => Allele frequency is greater than expected for disorder. PS3-Moderate => PS3 downgraded in strength to Moderate (PMID:18776039). -
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Long QT syndrome 5;C2676723:Jervell and Lange-Nielsen syndrome 2 Uncertain:1
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Cardiovascular phenotype Uncertain:1
The c.23C>T (p.A8V) alteration is located in exon 3 (coding exon 1) of the KCNE1 gene. This alteration results from a C to T substitution at nucleotide position 23, causing the alanine (A) at amino acid position 8 to be replaced by a valine (V). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -
Congenital long QT syndrome Other:1
This variant has been reported as associated with Long QT syndrome in the following publications (PMID:17341399;PMID:19716085). 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