rs120074183
Variant summary
Our verdict is Pathogenic. The variant received 19 ACMG points: 19P and 0B. PM1PM2PM5PP2PP3_StrongPP5_Very_Strong
The NM_000218.3(KCNQ1):c.1034G>A(p.Gly345Glu) variant causes a missense, splice region change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000186 in 1,613,830 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 14/25 in silico tools predict a damaging outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G345V) has been classified as Likely pathogenic.
Frequency
Consequence
NM_000218.3 missense, splice_region
Scores
Clinical Significance
Conservation
Publications
- long QT syndromeInheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
- long QT syndrome 1Inheritance: AD, AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P
- Jervell and Lange-Nielsen syndromeInheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
- Jervell and Lange-Nielsen syndrome 1Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: PanelApp Australia, Labcorp Genetics (formerly Invitae), G2P
- atrial fibrillation, familial, 3Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
- short QT syndromeInheritance: AD Classification: STRONG, SUPPORTIVE Submitted by: ClinGen, Orphanet
- short QT syndrome type 2Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P
- familial atrial fibrillationInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- Jervell and Lange-Nielsen syndromeInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
- hypertrophic cardiomyopathyInheritance: AD Classification: NO_KNOWN Submitted by: ClinGen
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ACMG classification
Our verdict: Pathogenic. The variant received 19 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000131 AC: 2AN: 152224Hom.: 0 Cov.: 33 show subpopulations
GnomAD4 exome AF: 6.84e-7 AC: 1AN: 1461606Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0AN XY: 727096 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.0000131 AC: 2AN: 152224Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0AN XY: 74368 show subpopulations
ClinVar
Submissions by phenotype
Long QT syndrome 1 Pathogenic:1
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not provided Pathogenic:1
Not observed at significant frequency in large population cohorts (gnomAD); Published functional studies demonstrate a damaging effect through dominant-negative suppression of potassium channel current (PMID: 10376919); 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: 31589614, 10376919, 15840476, 8528244) -
Long QT syndrome Pathogenic:1
This sequence change replaces glycine, which is neutral and non-polar, with glutamic acid, which is acidic and polar, at codon 345 of the KCNQ1 protein (p.Gly345Glu). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with long QT syndrome (PMID: 8528244). It has also been observed to segregate with disease in related individuals. This variant is also known as G216E. ClinVar contains an entry for this variant (Variation ID: 3122). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. Experimental studies have shown that this missense change affects KCNQ1 function (PMID: 10376919). For these reasons, this variant has been classified as Pathogenic. -
Cardiac arrhythmia Pathogenic:1
This missense variant replaces glycine with glutamic acid at codon 345 of the KCNQ1 protein. This variant is found within the highly conserved transmembrane domain S6 (a.a. 328-348). 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 causes a reduction of potassium channel current when expressed in xenopus oocytes (PMID: 10376919) and results in prolonged action potential duration in edited cardiomyocytes derived from induced human pluripotent stem cells (PMID: 25082577). This variant has been reported to segregate with long QT syndrome in at least 11 related carriers from a family (PMID: 8528244, 10376919). This variant has also been reported in another individual suspected of having long QT syndrome (PMID: 15840476). This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). A different missense variant occurring at the same codon, p.Gly345Arg, is known to be disease-causing (Clinvar variation ID 200837), indicating that glycine at this position is a clinically important residue. Based on the available evidence, this variant is classified as Likely Pathogenic. -
Congenital long QT syndrome Other:1
This variant has been reported as associated with Long QT syndrome in the following publications (PMID:8528244;PMID:10376919;PMID:15840476). 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