2-178800696-A-G
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Variant summary
Our verdict is Likely benign. Variant got -5 ACMG points: 0P and 5B. BP4_StrongBP6
The NM_001267550.2(TTN):c.296-14T>C variant causes a splice polypyrimidine tract, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000721 in 1,601,676 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).
Frequency
Genomes: 𝑓 0.00058 ( 0 hom., cov: 32)
Exomes 𝑓: 0.00074 ( 1 hom. )
Consequence
TTN
NM_001267550.2 splice_polypyrimidine_tract, intron
NM_001267550.2 splice_polypyrimidine_tract, intron
Scores
2
Clinical Significance
Conservation
PhyloP100: 1.04
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 -5 ACMG points.
BP4
Computational evidence support a benign effect (BayesDel_noAF=-0.77).
BP6
Variant 2-178800696-A-G is Benign according to our data. Variant chr2-178800696-A-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 137836.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=2, Benign=4, Uncertain_significance=5}. Variant chr2-178800696-A-G is described in Lovd as [Benign]. Variant chr2-178800696-A-G is described in Lovd as [Likely_benign].
Transcripts
RefSeq
Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | MANE | Protein | UniProt |
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TTN | NM_001267550.2 | c.296-14T>C | splice_polypyrimidine_tract_variant, intron_variant | ENST00000589042.5 | NP_001254479.2 | |||
TTN | NM_133379.5 | c.296-14T>C | splice_polypyrimidine_tract_variant, intron_variant | ENST00000360870.10 | NP_596870.2 |
Ensembl
Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | TSL | MANE | Protein | Appris | UniProt |
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TTN | ENST00000360870.10 | c.296-14T>C | splice_polypyrimidine_tract_variant, intron_variant | 5 | NM_133379.5 | ENSP00000354117 | ||||
TTN | ENST00000589042.5 | c.296-14T>C | splice_polypyrimidine_tract_variant, intron_variant | 5 | NM_001267550.2 | ENSP00000467141 | P1 |
Frequencies
GnomAD3 genomes AF: 0.000578 AC: 88AN: 152184Hom.: 0 Cov.: 32
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GnomAD3 exomes AF: 0.000518 AC: 124AN: 239192Hom.: 0 AF XY: 0.000535 AC XY: 69AN XY: 129026
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GnomAD4 exome AF: 0.000736 AC: 1067AN: 1449374Hom.: 1 Cov.: 31 AF XY: 0.000739 AC XY: 532AN XY: 719814
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GnomAD4 genome AF: 0.000578 AC: 88AN: 152302Hom.: 0 Cov.: 32 AF XY: 0.000564 AC XY: 42AN XY: 74478
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ClinVar
Significance: Conflicting classifications of pathogenicity
Submissions summary: Uncertain:5Benign:13
Revision: criteria provided, conflicting classifications
LINK: link
Submissions by phenotype
not specified Uncertain:1Benign:6
Benign, criteria provided, single submitter | clinical testing | GeneDx | Aug 19, 2013 | This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease. - |
Benign, no assertion criteria provided | clinical testing | Clinical Genetics, Academic Medical Center | - | - - |
Uncertain significance, criteria provided, single submitter | clinical testing | Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine | Aug 02, 2013 | Variant classified as Uncertain Significance - Favor Benign. The 296-14T>C varia nt in TTN has not been reported in individuals with cardiomyopathy, but has been identified in 0.1% (12/8600) of European American chromosomes by the NHLBI Exom e Sequencing Project (http://evs.gs.washington.edu/EVS/; dbSNP rs199951296). Thi s variant is located in the 3' splice region. Computational tools do not suggest a strong impact on splicing, though this information is not predictive enough t o rule out pathogenicity. While the frequency of this variant suggests that it i s more likely to be benign, it is too low to confidently rule out a disease caus ing role. At this time, additional information is needed to fully assess its cli nical significance. - |
Benign, no assertion criteria provided | clinical testing | Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center | - | - - |
Benign, no assertion criteria provided | clinical testing | Joint Genome Diagnostic Labs from Nijmegen and Maastricht, Radboudumc and MUMC+ | - | - - |
Benign, criteria provided, single submitter | clinical testing | Women's Health and Genetics/Laboratory Corporation of America, LabCorp | Aug 19, 2019 | Variant summary: TTN c.296-14T>C alters a non-conserved nucleotide located close to a canonical splice site and therefore could affect mRNA splicing, leading to a significantly altered protein sequence. 4/4 computational tools predict no significant impact on normal splicing. However, these predictions have yet to be confirmed by functional studies. The variant allele was found at a frequency of 0.00052 in 239192 control chromosomes, predominantly at a frequency of 0.00098 within the Non-Finnish European subpopulation in the gnomAD database. The observed variant frequency within Non-Finnish European control individuals in the gnomAD database is approximately 1.6 fold of the estimated maximal expected allele frequency for a pathogenic variant in TTN causing Cardiomyopathy phenotype (0.00063), strongly suggesting that the variant is a benign polymorphism found primarily in populations of Non-Finnish European origin. To our knowledge, no occurrence of c.296-14T>C in individuals affected with Cardiomyopathy and no experimental evidence demonstrating its impact on protein function have been reported. One clinical diagnostic laboratory has submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation and classified the variant as uncertain significance. Two laboratories have submitted clinical-significance assessments for this variant to ClinVar before 2014 without evidence for independent evaluation (benign =1, VUS =1). Based on the evidence outlined above, the variant was classified as benign. - |
Benign, no assertion criteria provided | clinical testing | Genome Diagnostics Laboratory, University Medical Center Utrecht | - | - - |
not provided Benign:3
Likely benign, no assertion criteria provided | clinical testing | Diagnostic Laboratory, Department of Genetics, University Medical Center Groningen | - | - - |
Likely benign, no assertion criteria provided | clinical testing | Laboratory of Diagnostic Genome Analysis, Leiden University Medical Center (LUMC) | - | - - |
Likely benign, criteria provided, single submitter | clinical testing | ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories | Nov 09, 2021 | - - |
Autosomal recessive limb-girdle muscular dystrophy type 2J Uncertain:1
Uncertain significance, criteria provided, single submitter | clinical testing | Illumina Laboratory Services, Illumina | Jan 13, 2018 | This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. - |
Dilated cardiomyopathy 1G Uncertain:1
Uncertain significance, criteria provided, single submitter | clinical testing | Illumina Laboratory Services, Illumina | Jan 13, 2018 | This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. - |
Early-onset myopathy with fatal cardiomyopathy Uncertain:1
Uncertain significance, criteria provided, single submitter | clinical testing | Illumina Laboratory Services, Illumina | Jan 13, 2018 | This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. - |
Cardiovascular phenotype Uncertain:1
Uncertain significance, criteria provided, single submitter | clinical testing | Ambry Genetics | Sep 06, 2015 | The c.296-14T>C intronic alteration consists of a T to C substitution 14 nucleotides before coding exon 3 in the TTN gene. Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. - |
TTN-related disorder Benign:1
Likely benign, no assertion criteria provided | clinical testing | PreventionGenetics, part of Exact Sciences | Apr 11, 2022 | This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). - |
Autosomal recessive limb-girdle muscular dystrophy type 2J;C1858763:Dilated cardiomyopathy 1G Benign:1
Likely benign, criteria provided, single submitter | clinical testing | Labcorp Genetics (formerly Invitae), Labcorp | Jan 31, 2024 | - - |
Myopathy, myofibrillar, 9, with early respiratory failure Benign:1
Benign, criteria provided, single submitter | clinical testing | Illumina Laboratory Services, Illumina | Jan 13, 2018 | This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. - |
Tibial muscular dystrophy Benign:1
Benign, criteria provided, single submitter | clinical testing | Illumina Laboratory Services, Illumina | Jan 13, 2018 | This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. - |
Computational scores
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Details are displayed if max score is > 0.2
Find out detailed SpliceAI scores and Pangolin per-transcript scores at