2-178597640-T-C
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Variant summary
Our verdict is Likely benign. Variant got -4 ACMG points: 1P and 5B. PP2BP4_StrongBP6
The NM_001267550.2(TTN):āc.57442A>Gā(p.Met19148Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000666 in 1,613,262 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. 14/19 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).
Frequency
Genomes: š 0.00039 ( 0 hom., cov: 32)
Exomes š: 0.00069 ( 1 hom. )
Consequence
TTN
NM_001267550.2 missense
NM_001267550.2 missense
Scores
3
14
Clinical Significance
Conservation
PhyloP100: 1.89
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]
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ACMG classification
Classification made for transcript
Verdict is Likely_benign. Variant got -4 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.
BP4
Computational evidence support a benign effect (MetaRNN=0.029392332).
BP6
Variant 2-178597640-T-C is Benign according to our data. Variant chr2-178597640-T-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 191935.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=4, Benign=2, Uncertain_significance=11}. Variant chr2-178597640-T-C is described in Lovd as [Likely_benign]. Variant chr2-178597640-T-C is described in Lovd as [Benign].
Transcripts
RefSeq
| Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | MANE | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|
| TTN | NM_001267550.2 | c.57442A>G | p.Met19148Val | missense_variant | 294/363 | ENST00000589042.5 | NP_001254479.2 | |
| TTN-AS1 | NR_038272.1 | n.3409T>C | non_coding_transcript_exon_variant | 13/17 |
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | TSL | MANE | Protein | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|---|
| TTN | ENST00000589042.5 | c.57442A>G | p.Met19148Val | missense_variant | 294/363 | 5 | NM_001267550.2 | ENSP00000467141 | P1 | |
| TTN-AS1 | ENST00000659121.1 | n.461T>C | non_coding_transcript_exon_variant | 2/13 |
Frequencies
GnomAD3 genomes 0.000395 AC: 60AN: 152048Hom.: 0 Cov.: 32
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GnomAD3 exomes AF: 0.000496 AC: 123AN: 248042Hom.: 1 AF XY: 0.000461 AC XY: 62AN XY: 134528
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GnomAD4 exome AF: 0.000695 AC: 1015AN: 1461096Hom.: 1 Cov.: 31 AF XY: 0.000643 AC XY: 467AN XY: 726834
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GnomAD4 genome 0.000394 AC: 60AN: 152166Hom.: 0 Cov.: 32 AF XY: 0.000242 AC XY: 18AN XY: 74392
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ClinVar
Significance: Conflicting classifications of pathogenicity
Submissions summary: Uncertain:11Benign:12
Revision: criteria provided, conflicting classifications
LINK: link
Submissions by phenotype
not provided Uncertain:5Benign:6
| Uncertain significance, criteria provided, single submitter | clinical testing | CeGaT Center for Human Genetics Tuebingen | Nov 30, 2016 | - - |
| Uncertain significance, criteria provided, single submitter | research | Biesecker Lab/Clinical Genomics Section, National Institutes of Health | Jun 24, 2013 | - - |
| Likely benign, no assertion criteria provided | clinical testing | Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center | - | - - |
| Uncertain significance, criteria provided, single submitter | clinical testing | ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories | Aug 24, 2023 | The TTN c.57442A>G; p.Met19148Val variant (rs188185141; ClinVar Variation ID: 191935) is rare in the general population (<0.2% allele frequency in the Genome Aggregation Database) and has been reported in individuals with hypertrophic cardiomyopathy and arrhythmogenic cardiomyopathy (Lopes 2013, Mates 2018). The clinical relevance of rare missense variants in this gene, which are identified on average once per individual sequenced in affected populations (Herman 2012), is not well understood. Yet, evidence suggests that the vast majority of such missense variants do not contribute to the clinical outcome of DCM (Begay 2015). Thus, the clinical significance of the p.Met19148Val variant cannot be determined with certainty. References: Lopes LR et al. Genetic complexity in hypertrophic cardiomyopathy revealed by high-throughput sequencing. J Med Genet. 2013 Apr;50(4):228-39. PMID: 23396983. Mates J et al. Role of copy number variants in sudden cardiac death and related diseases: genetic analysis and translation into clinical practice. Eur J Hum Genet. 2018 Jul;26(7):1014-1025. PMID: 29511324. Begay RL et al. Role of Titin Missense Variants in Dilated Cardiomyopathy. J Am Heart Assoc. 2015 Nov 13;4(11). PMID: 26567375. Herman DS et al. Truncations of titin causing dilated cardiomyopathy. N Engl J Med. 2012 Feb 16;366(7):619-28. PMID: 22335739. Linke WA and Hamdani N. Gigantic business: titin properties and function through thick and thin. Circ Res 2014; 114(6): 1052-1068. PMID: 24625729. - |
| Likely benign, criteria provided, single submitter | clinical testing | GeneDx | Apr 27, 2021 | - - |
| Likely benign, no assertion criteria provided | clinical testing | Laboratory of Diagnostic Genome Analysis, Leiden University Medical Center (LUMC) | - | - - |
| Likely benign, no assertion criteria provided | clinical testing | Diagnostic Laboratory, Department of Genetics, University Medical Center Groningen | - | - - |
| Uncertain significance, criteria provided, single submitter | clinical testing | Eurofins Ntd Llc (ga) | Sep 06, 2017 | - - |
| Uncertain significance, criteria provided, single submitter | clinical testing | Revvity Omics, Revvity | Apr 25, 2022 | - - |
| Likely benign, no assertion criteria provided | clinical testing | Clinical Genetics, Academic Medical Center | - | - - |
| Likely benign, no assertion criteria provided | clinical testing | Genome Diagnostics Laboratory, University Medical Center Utrecht | - | - - |
not specified Uncertain:1Benign:2
| Likely benign, criteria provided, single submitter | clinical testing | Women's Health and Genetics/Laboratory Corporation of America, LabCorp | May 15, 2023 | Variant summary: TTN c.49738A>G (p.Met16580Val) results in a conservative amino acid change located in the A-band region of the encoded protein sequence. Three of four in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 0.0005 in 248042 control chromosomes, predominantly at a frequency of 0.0009 within the Non-Finnish European subpopulation in the gnomAD database, including 1 homozygotes. The observed variant frequency within Non-Finnish European control individuals in the gnomAD database is approximately 2 fold of the estimated maximal expected allele frequency for a pathogenic variant in TTN causing Dilated Cardiomyopathy phenotype (0.00039), strongly suggesting that the variant is a benign polymorphism found primarily in populations of Non-Finnish European origin. c.49738A>G has been reported in the literature in individuals affected with Dilated Cardiomyopathy without strong evidence for causality. These reports do not provide unequivocal conclusions about association of the variant with Dilated Cardiomyopathy. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publication have been ascertained in the context of this evaluation (PMID: 35207729). Multiple clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. Multiple laboratories reported the variant with conflicting assessments: Benign (n=1), Likely Benign (n=3) and VUS (n=7). Based on the evidence outlined above, the variant was classified as likely benign. - |
| Uncertain significance, criteria provided, single submitter | clinical testing | Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine | Oct 10, 2017 | proposed classification - variant undergoing re-assessment, contact laboratory - |
| Benign, no assertion criteria provided | clinical testing | Joint Genome Diagnostic Labs from Nijmegen and Maastricht, Radboudumc and MUMC+ | - | - - |
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 | Dec 14, 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. - |
Autosomal recessive limb-girdle muscular dystrophy type 2J;C1838244:Tibial muscular dystrophy;C1858763:Dilated cardiomyopathy 1G;C1861065:Hypertrophic cardiomyopathy 9;C1863599:Myopathy, myofibrillar, 9, with early respiratory failure;C2673677:Early-onset myopathy with fatal cardiomyopathy Uncertain:1
| Uncertain significance, criteria provided, single submitter | clinical testing | Fulgent Genetics, Fulgent Genetics | Oct 31, 2018 | - - |
Cardiomyopathy Benign:1
| Likely benign, criteria provided, single submitter | clinical testing | CHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern Ontario | Jan 03, 2020 | - - |
Myopathy, myofibrillar, 9, with early respiratory failure Benign:1
| Benign, criteria provided, single submitter | clinical testing | Illumina Laboratory Services, Illumina | Jul 18, 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 was too high to be consistent with this variant causing disease. Therefore, this variant is classified as benign. - |
Tibial muscular dystrophy Benign:1
| Benign, criteria provided, single submitter | clinical testing | Illumina Laboratory Services, Illumina | Jul 18, 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 was too high to be consistent with this variant causing disease. Therefore, this variant is classified as benign. - |
Cardiovascular phenotype Benign:1
| Likely benign, criteria provided, single submitter | clinical testing | Ambry Genetics | May 06, 2020 | This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. - |
Computational scores
Source:
Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
BayesDel_addAF
Benign
T
BayesDel_noAF
Benign
CADD
Benign
DANN
Benign
Eigen
Benign
Eigen_PC
Benign
FATHMM_MKL
Uncertain
D
LIST_S2
Uncertain
D;D;D;.;T;D;T
M_CAP
Benign
T
MetaRNN
Benign
T;T;T;T;T;T;T
MetaSVM
Benign
T
MutationAssessor
Benign
.;.;.;N;.;.;N
MutationTaster
Benign
D;D;D;D;D;D
PrimateAI
Benign
T
PROVEAN
Uncertain
N;D;.;.;D;D;.
REVEL
Benign
Sift
Benign
T;D;.;.;D;D;.
Polyphen
0.065
.;.;.;B;.;.;B
Vest4
MVP
MPC
0.086
ClinPred
T
GERP RS
RBP_binding_hub_radar
RBP_regulation_power_radar
Splicing
Name
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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