rs199473634
Variant summary
Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM1PP3_Moderate
The NM_001099404.2(SCN5A):c.5336C>T(p.Thr1779Met) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000533 in 1,614,044 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). Synonymous variant affecting the same amino acid position (i.e. T1779T) has been classified as Likely benign.
Frequency
Consequence
NM_001099404.2 missense
Scores
Clinical Significance
Conservation
Publications
- Brugada syndromeInheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: ClinGen, Orphanet
- Brugada syndrome 1Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, Laboratory for Molecular Medicine, G2P, Genomics England PanelApp, Labcorp Genetics (formerly Invitae)
- dilated cardiomyopathyInheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
- dilated cardiomyopathy 1EInheritance: AD Classification: DEFINITIVE, STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae), Ambry Genetics
- familial long QT syndromeInheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
- long QT syndrome 3Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae), G2P
- sick sinus syndrome 1Inheritance: AD, AR Classification: STRONG, LIMITED Submitted by: Labcorp Genetics (formerly Invitae)
- progressive familial heart block, type 1AInheritance: SD, AD Classification: STRONG, MODERATE Submitted by: Ambry Genetics, Genomics England PanelApp
- atrial standstillInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- familial atrial fibrillationInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- familial isolated dilated cardiomyopathyInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- familial sick sinus syndromeInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- paroxysmal familial ventricular fibrillationInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- progressive familial heart blockInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- arrhythmogenic right ventricular cardiomyopathyInheritance: AD Classification: LIMITED Submitted by: ClinGen
- catecholaminergic polymorphic ventricular tachycardiaInheritance: AD Classification: NO_KNOWN Submitted by: ClinGen
- short QT syndromeInheritance: AD Classification: NO_KNOWN Submitted by: ClinGen
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ACMG classification
Our verdict: Uncertain_significance. The variant received 4 ACMG points.
Transcripts
RefSeq
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|
| SCN5A | NM_001099404.2 | c.5336C>T | p.Thr1779Met | missense_variant | Exon 28 of 28 | ENST00000413689.6 | NP_001092874.1 | |
| SCN5A | NM_000335.5 | c.5333C>T | p.Thr1778Met | missense_variant | Exon 28 of 28 | ENST00000423572.7 | NP_000326.2 |
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|---|
| SCN5A | ENST00000413689.6 | c.5336C>T | p.Thr1779Met | missense_variant | Exon 28 of 28 | 5 | NM_001099404.2 | ENSP00000410257.1 | ||
| SCN5A | ENST00000423572.7 | c.5333C>T | p.Thr1778Met | missense_variant | Exon 28 of 28 | 1 | NM_000335.5 | ENSP00000398266.2 |
Frequencies
GnomAD3 genomes AF: 0.0000724 AC: 11AN: 152036Hom.: 0 Cov.: 31 show subpopulations
GnomAD2 exomes AF: 0.0000398 AC: 10AN: 251190 AF XY: 0.0000221 show subpopulations
GnomAD4 exome AF: 0.0000493 AC: 72AN: 1461890Hom.: 0 Cov.: 35 AF XY: 0.0000523 AC XY: 38AN XY: 727244 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.0000920 AC: 14AN: 152154Hom.: 0 Cov.: 31 AF XY: 0.000121 AC XY: 9AN XY: 74382 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
not provided Uncertain:6
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Reported in association with various phenotypes, including LQTS, Brugada syndrome, hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM), atrial fibrillation, and cardiac arrest (PMID: 15840476, 20129283, 25351510, 28416588, 31638414, 36964972); In vitro functional studies suggested that the p.(T1779M) variant demonstrates channel function similar to wild-type (PMID: 25904541); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Also known as p.(T1778M) due to the use of an alternate transcript; This variant is associated with the following publications: (PMID: 25637381, 24055113, 19862833, 22378279, 20129283, 25351510, 25904541, 28150151, 26986070, 19716085, 19841300, 28416588, 28567303, 27566755, 31638414, 34426522, 30203441, 15840476, 36964972, 34643236) -
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This sequence change replaces threonine, which is neutral and polar, with methionine, which is neutral and non-polar, at codon 1779 of the SCN5A protein (p.Thr1779Met). This variant is present in population databases (rs199473634, gnomAD 0.006%). This missense change has been observed in individual(s) with long QT syndrome (PMID: 15840476, 19716085, 19841300, 20129283, 27566755, 28416588). ClinVar contains an entry for this variant (Variation ID: 67985). 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 does not substantially affect SCN5A function (PMID: 25904541). 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. -
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Long QT syndrome 3 Uncertain:3
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This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases did not allow this variant to be ruled in or out of causing disease. Therefore, this variant is classified as a variant of unknown significance. -
Cardiovascular phenotype Uncertain:2
The p.T1779M variant (also known as c.5336C>T), located in coding exon 27 of the SCN5A gene, results from a C to T substitution at nucleotide position 5336. The threonine at codon 1779 is replaced by methionine, an amino acid with similar properties. This alteration has been reported in long QT syndrome and hypertrophic cardiomyopathy cohorts; however, clinical details were limited (Tester DJ et al. Heart Rhythm, 2005 May;2:507-17; Kapa S et al. Circulation, 2009 Nov;120:1752-60; Kapplinger JD et al. Heart Rhythm, 2009 Sep;6:1297-303; Lopes LR et al. Heart, 2015 Feb;101:294-301). Additionally, this alteration has been detected in a dilated cardiomyopathy cohort and an atrial fibrillation cohort (Dal Ferro M et al. Heart, 2017 11;103:1704-1710; Goodyer WR et al. Circ Genom Precis Med, 2019 11;12:e002713). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -
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Brugada syndrome 1 Uncertain:1
This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases did not allow this variant to be ruled in or out of causing disease. Therefore, this variant is classified as a variant of unknown significance. -
Ventricular fibrillation, paroxysmal familial, type 1 Uncertain:1
This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases did not allow this variant to be ruled in or out of causing disease. Therefore, this variant is classified as a variant of unknown significance. -
Dilated cardiomyopathy 1E Uncertain:1
This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases did not allow this variant to be ruled in or out of causing disease. Therefore, this variant is classified as a variant of unknown significance. -
Progressive familial heart block, type 1A Uncertain:1
This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases did not allow this variant to be ruled in or out of causing disease. Therefore, this variant is classified as a variant of unknown significance. -
Long QT syndrome Uncertain:1
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Cardiac arrhythmia Uncertain:1
This missense variant replaces threonine with methionine at codon 1779 of the SCN5A protein. Computational prediction suggests that this variant may have deleterious impact on protein structure and function. A functional study has shown that this variant does not impair sodium channel function (PMID: 25904541). This variant has been reported in six individuals affected with long QT syndrome (PMID: 19841300, 27566755), in three individuals referred for long QT syndrome (PMID: 15840476, 19716085), in one individual referred for Brugada syndrome testing (PMID: 20129283), in one individual affected with very early onset atrial fibrillation (PMID: 31638414), and in a control subject (PMID: 25904541). This variant has also been identified in 12/282546 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. -
not specified Benign:1
Variant summary: SCN5A c.5336C>T (p.Thr1779Met) results in a non-conservative amino acid change located in the Ion transport domain (IPR005821) of the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 4e-05 in 271740 control chromosomes. The observed variant frequency is approximately 1.62 fold of the estimated maximal expected allele frequency for a pathogenic variant in SCN5A causing Cardiomyopathy phenotype (2.5e-05). c.5336C>T has been reported in the literature in individuals affected with long QT syndrome, dilated cardiomyopathy and Brugada syndrome (ie. Tester_2005, Kapplinger_2009, Kapa_2009, Stavropoulos_2016, Dal Ferro_2017, Verheul_2023). These reports do not provide unequivocal conclusions about association of the variant with Cardiomyopathy. At least one functional study reports this variant has no impact on protein function (Kapplinger_2016). The following publications have been ascertained in the context of this evaluation (PMID: 28416588, 19841300, 19716085, 25904541, 23174487, 22378279, 28567303, 15840476, 37967257). ClinVar contains an entry for this variant (Variation ID: 67985). Based on the evidence outlined above, the variant was classified as likely benign. -
Sick sinus syndrome 1 Benign:1
This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases allowed determination this variant is unlikely to cause disease. Therefore, this variant is classified as likely benign. -
Congenital long QT syndrome Other:1
This variant has been reported as associated with Long QT syndrome in the following publications (PMID:15840476;PMID:19716085;PMID:19841300;PMID:22378279). 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