rs145974930
Variant summary
Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM5
The NM_000218.3(KCNQ1):c.1553G>A(p.Arg518Gln) variant causes a missense change. The variant allele was found at a frequency of 0.000126 in 1,613,918 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R518G) has been classified as Pathogenic.
Frequency
Consequence
NM_000218.3 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Uncertain_significance. Variant got 2 ACMG points.
Transcripts
RefSeq
Ensembl
Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
---|---|---|---|---|---|---|---|---|---|---|
KCNQ1 | ENST00000155840.12 | c.1553G>A | p.Arg518Gln | missense_variant | Exon 12 of 16 | 1 | NM_000218.3 | ENSP00000155840.2 | ||
KCNQ1 | ENST00000335475.6 | c.1172G>A | p.Arg391Gln | missense_variant | Exon 12 of 16 | 1 | ENSP00000334497.5 | |||
KCNQ1 | ENST00000496887.7 | c.1196G>A | p.Arg399Gln | missense_variant | Exon 12 of 16 | 5 | ENSP00000434560.2 | |||
KCNQ1 | ENST00000646564.2 | c.1013G>A | p.Arg338Gln | missense_variant | Exon 7 of 11 | ENSP00000495806.2 |
Frequencies
GnomAD3 genomes AF: 0.0000460 AC: 7AN: 152072Hom.: 0 Cov.: 32
GnomAD3 exomes AF: 0.0000318 AC: 8AN: 251410Hom.: 0 AF XY: 0.0000368 AC XY: 5AN XY: 135892
GnomAD4 exome AF: 0.000135 AC: 197AN: 1461846Hom.: 0 Cov.: 31 AF XY: 0.000132 AC XY: 96AN XY: 727214
GnomAD4 genome AF: 0.0000460 AC: 7AN: 152072Hom.: 0 Cov.: 32 AF XY: 0.0000404 AC XY: 3AN XY: 74258
ClinVar
Submissions by phenotype
Long QT syndrome Uncertain:3
This missense variant replaces arginine with glutamine at codon 518 of the KCNQ1 protein. Computational prediction suggests that this variant may have deleterious impact on protein structure and function (internally defined REVEL score threshold >= 0.7, PMID: 27666373). Functional studies have shown that this variant does not affect the ability of KCNQ1 protein to regulate renal ciliogenesis (PMID: 19716085, 26546361). This variant has been reported in an individual affected with sudden infant death syndrome (PMID: 29544605) and in several individuals referred for long QT syndrome genetic testing (PMID: 19716085, 26159999). Mean QTc interval of the carriers was not significantly different from that of non-carriers (PMID: 26159999). This variant has also been reported in one individual affected with cardiac arrest; however, the sibling who also carried the variant was asymptomatic (PMID: 31994352). This variant has been identified in 9/282772 chromosomes in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -
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This sequence change replaces arginine, which is basic and polar, with glutamine, which is neutral and polar, at codon 518 of the KCNQ1 protein (p.Arg518Gln). This variant is present in population databases (rs145974930, gnomAD 0.005%). This missense change has been observed in individual(s) with sudden infant death syndrome and in individuals with QT intervals in the normal range (PMID: 26159999, 29544605). ClinVar contains an entry for this variant (Variation ID: 67036). 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 not expected to disrupt KCNQ1 protein function with a negative predictive value of 80%. Experimental studies have shown that this missense change does not substantially affect KCNQ1 function (PMID: 26546361). This variant disrupts the p.Arg518 amino acid residue in KCNQ1. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 16414944, 21511995, 24363352; internal data). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. 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. -
not specified Uncertain:1
Variant summary: KCNQ1 c.1553G>A (p.Arg518Gln) results in a conservative amino acid change located in the Potassium channel, voltage dependent, KCNQ, C-terminal domain (IPR013821) of the encoded protein sequence. Three of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 3.2e-05 in 251410 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.1553G>A has been reported in the literature in individuals affected with Long QT syndrome, sudden infant death, epilepsy and hypertrophic cardiomyopathy (examples: Kapplinger_2009, Costa_2012, Lieve_2013, Ghouse_2015, Ruwald_2016, Tester_2018, Li_2019, Dai_2021). In addition, the variant was found to co-occur with a pathogenic RYR2 variant (c.527G>T, p.Arg176Leu) in a female affected with cardiac arrest and her brother exhibiting catecholaminergic polymorphic ventricular tachycardia (CPVT) phenotype. Their mother who was also affected with cardiac arrest was found to only carry the RYR2 variant, as were multiple symptomatic members from the maternal side of the family. The authors concluded that the RYR2 variant was predisposing to low penetrant CPVT in this family (Tung_2020). These reports do not provide unequivocal conclusions about association of the variant with Arrhythmia. At least one publication reports experimental evidence evaluating an impact on protein function. Slaats_2015 demonstrated that KCNQ1-p.R518Q variant could rescue ciliogenecis defect to the same levels as wild-type. Three clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 and all laboratories classified the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance. -
Beckwith-Wiedemann syndrome;C1837014:Atrial fibrillation, familial, 3;C1865019:Short QT syndrome type 2;C4551509:Jervell and Lange-Nielsen syndrome 1;C4551647:Long QT syndrome 1 Uncertain:1
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not provided Uncertain:1
Observed in individuals with Long QT syndrome and sudden infant death syndrome in the published literature (Kapplinger et al., 2009; Ghouse et al., 2015; Tester et al., 2018); Published functional studies demonstrate the R518Q variant retains function and have suggested this is a benign variant (Slaats et al., 2015); 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: 22581653, 25637381, 25854863, 26159999, 32048431, 29544605, 19716085, 31994352, Rida2023[review], 26546361, 26318259, 34333030, 31696929, 38014677) -
Cardiovascular phenotype Uncertain:1
The c.1553G>A (p.R518Q) alteration is located in exon 12 (coding exon 12) of the KCNQ1 gene. This alteration results from a G to A substitution at nucleotide position 1553, causing the arginine (R) at amino acid position 518 to be replaced by a glutamine (Q). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -
Cardiac arrhythmia Uncertain:1
This missense variant replaces arginine with glutamine at codon 518 of the KCNQ1 protein. Computational prediction tools indicate that this variant has a deleterious impact on protein structure and function. This variant is found within a highly conserved C-terminus region (a.a. 509-575). Rare non-truncating variants in this region have been shown to be significantly overrepresented in individuals with long QT syndrome (PMID: 32893267). Functional studies have shown that this variant does not affect the ability of KCNQ1 protein to regulate renal ciliogenesis (PMID: 19716085, 26546361). This variant has been reported in an individual affected with sudden infant death syndrome (PMID: 29544605) and in several individuals referred for long QT syndrome genetic testing (PMID: 19716085, 26159999). Mean QTc interval of the carriers was not significantly different from that of non-carriers (PMID: 26159999). This variant has also been reported in one individual affected with cardiac arrest; however, the sibling who also carried the variant was asymptomatic (PMID: 31994352). This variant has been identified in 9/282772 chromosomes in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -
Congenital long QT syndrome Other:1
This variant has been reported as associated with Long QT syndrome in the following publications (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