rs138060032
Positions:
Variant summary
Our verdict is Uncertain significance. Variant got 0 ACMG points: 1P and 1B. PP2BP6
The NM_001267550.2(TTN):c.835C>T(p.Arg279Trp) variant causes a missense change. The variant allele was found at a frequency of 0.000397 in 1,614,026 control chromosomes in the GnomAD database, including 1 homozygotes. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. R279R) has been classified as Likely benign.
Frequency
Genomes: 𝑓 0.00028 ( 0 hom., cov: 32)
Exomes 𝑓: 0.00041 ( 1 hom. )
Consequence
TTN
NM_001267550.2 missense
NM_001267550.2 missense
Scores
5
9
3
Clinical Significance
Conservation
PhyloP100: 6.39
Genes affected
TTN (HGNC:12403): (titin) This gene encodes a large abundant protein of striated muscle. The product of this gene is divided into two regions, a N-terminal I-band and a C-terminal A-band. The I-band, which is the elastic part of the molecule, contains two regions of tandem immunoglobulin domains on either side of a PEVK region that is rich in proline, glutamate, valine and lysine. The A-band, which is thought to act as a protein-ruler, contains a mixture of immunoglobulin and fibronectin repeats, and possesses kinase activity. An N-terminal Z-disc region and a C-terminal M-line region bind to the Z-line and M-line of the sarcomere, respectively, so that a single titin molecule spans half the length of a sarcomere. Titin also contains binding sites for muscle associated proteins so it serves as an adhesion template for the assembly of contractile machinery in muscle cells. It has also been identified as a structural protein for chromosomes. Alternative splicing of this gene results in multiple transcript variants. Considerable variability exists in the I-band, the M-line and the Z-disc regions of titin. Variability in the I-band region contributes to the differences in elasticity of different titin isoforms and, therefore, to the differences in elasticity of different muscle types. Mutations in this gene are associated with familial hypertrophic cardiomyopathy 9, and autoantibodies to titin are produced in patients with the autoimmune disease scleroderma. [provided by RefSeq, Feb 2012]
Genome browser will be placed here
ACMG classification
Classification made for transcript
Verdict is Uncertain_significance. Variant got 0 ACMG points.
PP2
Missense variant in gene, where missense usually causes diseases (based on misZ statistic), TTN. . Gene score misZ -1.1021 (greater than the threshold 3.09). Trascript score misZ 6.9794 (greater than threshold 3.09). GenCC has associacion of gene with dilated cardiomyopathy, tibial muscular dystrophy, early-onset myopathy with fatal cardiomyopathy, autosomal recessive centronuclear myopathy, hypertrophic cardiomyopathy, hypertrophic cardiomyopathy 9, TTN-related myopathy, dilated cardiomyopathy 1G, arrhythmogenic right ventricular cardiomyopathy, myopathy, myofibrillar, 9, with early respiratory failure, familial isolated dilated cardiomyopathy, childhood-onset progressive contractures-limb-girdle weakness-muscle dystrophy syndrome, autosomal recessive limb-girdle muscular dystrophy type 2J.
BP6
Variant 2-178799566-G-A is Benign according to our data. Variant chr2-178799566-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 12659.We mark this variant Likely_benign, oryginal submissions are: {not_provided=1, Likely_benign=3, Uncertain_significance=11}.
Transcripts
RefSeq
| Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | MANE | UniProt |
|---|---|---|---|---|---|---|---|
| TTN | NM_001267550.2 | c.835C>T | p.Arg279Trp | missense_variant | 6/363 | ENST00000589042.5 | |
| TTN | NM_133379.5 | c.835C>T | p.Arg279Trp | missense_variant | 6/46 | ENST00000360870.10 |
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | TSL | MANE | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|
| TTN | ENST00000589042.5 | c.835C>T | p.Arg279Trp | missense_variant | 6/363 | 5 | NM_001267550.2 | P1 | |
| TTN | ENST00000360870.10 | c.835C>T | p.Arg279Trp | missense_variant | 6/46 | 5 | NM_133379.5 |
Frequencies
GnomAD3 genomes 0.000276 AC: 42AN: 152176Hom.: 0 Cov.: 32
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GnomAD3 exomes AF: 0.000187 AC: 47AN: 251394Hom.: 0 AF XY: 0.000162 AC XY: 22AN XY: 135872
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GnomAD4 exome AF: 0.000409 AC: 598AN: 1461850Hom.: 1 Cov.: 31 AF XY: 0.000375 AC XY: 273AN XY: 727224
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GnomAD4 genome 0.000276 AC: 42AN: 152176Hom.: 0 Cov.: 32 AF XY: 0.000215 AC XY: 16AN XY: 74342
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ClinVar
Significance: Conflicting classifications of pathogenicity
Submissions summary: Pathogenic:1Uncertain:16Benign:3Other:1
Revision: criteria provided, conflicting classifications
LINK: link
Submissions by phenotype
not provided Uncertain:9Other:1
| Uncertain significance, no assertion criteria provided | clinical testing | Diagnostic Laboratory, Department of Genetics, University Medical Center Groningen | - | - - |
| Uncertain significance, criteria provided, single submitter | clinical testing | CeGaT Center for Human Genetics Tuebingen | Apr 01, 2017 | - - |
| Uncertain significance, criteria provided, single submitter | clinical testing | Athena Diagnostics | Sep 14, 2018 | - - |
| not provided, no classification provided | clinical testing | GeneDx | Sep 04, 2014 | - - |
| Uncertain significance, criteria provided, single submitter | research | Biesecker Lab/Clinical Genomics Section, National Institutes of Health | Jun 24, 2013 | - - |
| Uncertain significance, criteria provided, single submitter | clinical testing | Revvity Omics, Revvity | Oct 12, 2022 | - - |
| Uncertain significance, no assertion criteria provided | clinical testing | Laboratory of Diagnostic Genome Analysis, Leiden University Medical Center (LUMC) | - | - - |
| Uncertain significance, no assertion criteria provided | clinical testing | Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center | - | - - |
| Uncertain significance, no assertion criteria provided | clinical testing | Joint Genome Diagnostic Labs from Nijmegen and Maastricht, Radboudumc and MUMC+ | - | - - |
| Uncertain significance, no assertion criteria provided | clinical testing | Clinical Genetics, Academic Medical Center | - | - - |
Myopathy, myofibrillar, 9, with early respiratory failure Pathogenic:1Uncertain:1
| Uncertain significance, criteria provided, single submitter | clinical testing | Illumina Laboratory Services, Illumina | Apr 27, 2017 | 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). Publications were found based on this search. However, the evidence from the literature, in combination with allele frequency data from public databases where available, was not sufficient to rule this variant in or out of causing disease. Therefore, this variant is classified as a variant of unknown significance. - |
| Pathogenic, no assertion criteria provided | literature only | OMIM | Jun 10, 2005 | - - |
not specified Benign:2
| Likely benign, criteria provided, single submitter | clinical testing | Women's Health and Genetics/Laboratory Corporation of America, LabCorp | Jun 19, 2023 | Variant summary: TTN c.835C>T (p.Arg279Trp) results in a non-conservative amino acid change located in the Z-disk region 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 0.00019 in 282792 control chromosomes, predominantly at a frequency of 0.00036 within the Non-Finnish European subpopulation in the gnomAD database. This frequency is approximately equal to the estimated maximal expected allele frequency for a pathogenic variant in TTN causing Dilated Cardiomyopathy (0.00039), suggesting that the variant is a benign polymorphism found primarily in populations of Non-Finnish European origin. c.835C>T has been reported in the literature in multiple individuals affected with TTN-related conditions without strong evidence for causality (e.g., Lange_2005, Campuzan_2015, Sanchez_2016, van Spaendonck-Zwart_2014). At-least two co-occurrences with other pathogenic variant(s) have been reported in cis with this variant (TTN c.87491C>T, p.Pro29164Leu, Lange_2005; c.69086_69095del10, p.Arg23029ThrfsX9, van Spaendonck-Zwart_2014), providing supporting evidence for a benign role. Two publications report experimental evidence evaluating an impact on protein function, demonstrating reduced binding to nbd1 in mutant cells (Lange_2005, Chaveau_2014). However, neither study provides quantitative data indicating the strength of the effect. The following publications have been ascertained in the context of this evaluation (PMID: 26516846, 24105469, 24569025, 24578547, 27930701, 20708934, 24558114, 15802564, 24271327, 24231549). Eight submitters have cited clinical-significance assessments for this variant to ClinVar after 2014. Six submitters classified the variant as a variant of uncertain significance, and two classified it as likely benign. Based on the evidence outlined above, the variant was classified as likely benign. - |
| Likely benign, criteria provided, single submitter | clinical testing | Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine | Apr 09, 2018 | proposed classification - variant undergoing re-assessment, contact laboratory - |
Autosomal recessive limb-girdle muscular dystrophy type 2J Uncertain:1
| Uncertain significance, criteria provided, single submitter | clinical testing | Illumina Laboratory Services, Illumina | Apr 27, 2017 | 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. - |
Autosomal recessive limb-girdle muscular dystrophy type 2J;C1858763:Dilated cardiomyopathy 1G Uncertain:1
| Uncertain significance, criteria provided, single submitter | clinical testing | Labcorp Genetics (formerly Invitae), Labcorp | May 08, 2017 | - - |
Dilated cardiomyopathy 1G Uncertain:1
| Uncertain significance, criteria provided, single submitter | clinical testing | Illumina Laboratory Services, Illumina | Apr 27, 2017 | 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. - |
Early-onset myopathy with fatal cardiomyopathy Uncertain:1
| Uncertain significance, criteria provided, single submitter | clinical testing | Illumina Laboratory Services, Illumina | Apr 27, 2017 | 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. - |
Tibial muscular dystrophy Uncertain:1
| Uncertain significance, criteria provided, single submitter | clinical testing | Illumina Laboratory Services, Illumina | Apr 27, 2017 | 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:1
| Uncertain significance, criteria provided, single submitter | clinical testing | Ambry Genetics | Nov 13, 2018 | The p.R279W variant (also known as c.835C>T), located in coding exon 5 of the TTN gene, results from a C to T substitution at nucleotide position 835. The arginine at codon 279 is replaced by tryptophan, an amino acid with dissimilar properties. This variant was reported in cis with a truncating TTN alteration in a family with both dilated cardiomyopathy and peripartum cardiomyopathy (van Spaendonck-Zwarts KY et al. Eur Heart J. 2014;35:2165-73). This alteration has also been reported as a secondary cardiac variant in an exome cohort, and was detected in a sudden unexplained death case with variants in other cardiac-related genes (Ng D et al. Circ Cardiovasc Genet. 2013;6:337-46; Sanchez O et al. PLoS ONE. 2016;11(12):e0167358). This amino acid position is highly conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. - |
Cardiomyopathy Benign:1
| Likely benign, criteria provided, single submitter | clinical testing | CHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern Ontario | Dec 10, 2020 | - - |
Computational scores
Source:
Name
Calibrated prediction
Score
Prediction
AlphaMissense
Pathogenic
BayesDel_addAF
Benign
T
BayesDel_noAF
Uncertain
CADD
Uncertain
DANN
Uncertain
Eigen
Uncertain
Eigen_PC
Uncertain
FATHMM_MKL
Pathogenic
D
LIST_S2
Uncertain
D;D;D;.;D;D;D;D
M_CAP
Benign
D
MetaRNN
Uncertain
T;T;T;T;T;T;T;T
MetaSVM
Uncertain
D
MutationTaster
Benign
A;A;A;A;A;A;A
PrimateAI
Uncertain
T
PROVEAN
Pathogenic
D;D;.;.;D;D;.;D
REVEL
Uncertain
Sift
Pathogenic
D;D;.;.;D;D;.;D
Sift4G
Pathogenic
.;.;.;.;.;.;.;D
Polyphen
1.0
.;.;.;D;.;.;D;D
Vest4
MVP
MPC
0.47
ClinPred
D
GERP RS
Splicing
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SpliceAI score (max)
Details are displayed if max score is > 0.2
Find out detailed SpliceAI scores and Pangolin per-transcript scores at