rs199472710
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.704T>A(p.Ile235Asn) 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. Variant has been reported in ClinVar as Pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. I235L) has been classified as Likely pathogenic.
Frequency
Consequence
NM_000218.3 missense
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 Cov.: 33
GnomAD4 exome Cov.: 31
GnomAD4 genome Cov.: 33
ClinVar
Submissions by phenotype
Long QT syndrome Pathogenic:1
For these reasons, this variant has been classified as Pathogenic. Experimental studies have shown that this missense change affects KCNQ1 function (PMID: 19590188, 24269949). Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive. ClinVar contains an entry for this variant (Variation ID: 53088). This missense change has been observed in individuals with long QT syndrome (PMID: 18452873, 22949429, 24269949). It has also been observed to segregate with disease in related individuals. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces isoleucine, which is neutral and non-polar, with asparagine, which is neutral and polar, at codon 235 of the KCNQ1 protein (p.Ile235Asn). -
Cardiac arrhythmia Pathogenic:1
Variant summary: KCNQ1 c.704T>A (p.Ile235Asn) results in a non-conservative amino acid change located in the Ion transport domain (IPR005821; voltage sensor transmembrane domain S4 in Henrion_2009) of the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant was absent in 248876 control chromosomes (gnomAD). c.704T>A has been reported in the literature in multiple individuals affected with Long QT Syndrome as well as ten individuals with concealed LQT1 in one family (Choi_2004, Johnson_2008, Bartos_2013). These data indicate that the variant is very likely to be associated with disease. Functional studies report experimental evidence evaluating an impact on protein function and this variant effect results in reducing KCNQ1 channel currents in a dominant-negative manner and impaired Protein Kinase A response of slow delayed rectifier potassium channels. One ClinVar submitter (evaluation after 2014) cites the variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -
Congenital long QT syndrome Other:1
This variant has been reported as associated with Long QT syndrome in the following publications (PMID:15466642;PMID:15840476;PMID:19590188;PMID:19716085;PMID:19841300). 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