2-178727218-A-T
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Variant summary
Our verdict is Benign. Variant got -19 ACMG points: 1P and 20B. PP2BP4_StrongBP6_Very_StrongBS1BS2
The NM_001267550.2(TTN):c.20147T>A(p.Met6716Lys) variant causes a missense change. The variant allele was found at a frequency of 0.00105 in 1,613,246 control chromosomes in the GnomAD database, including 16 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★).
Frequency
Genomes: 𝑓 0.0058 ( 7 hom., cov: 33)
Exomes 𝑓: 0.00056 ( 9 hom. )
Consequence
TTN
NM_001267550.2 missense
NM_001267550.2 missense
Scores
7
8
Clinical Significance
Conservation
PhyloP100: 3.97
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 Benign. Variant got -19 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=0.010240138).
BP6
Variant 2-178727218-A-T is Benign according to our data. Variant chr2-178727218-A-T is described in ClinVar as [Likely_benign]. Clinvar id is 46666.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr2-178727218-A-T is described in Lovd as [Benign]. Variant chr2-178727218-A-T is described in Lovd as [Likely_benign].
BS1
Variant frequency is greater than expected in population afr. gnomad4 allele frequency = 0.00579 (881/152192) while in subpopulation AFR AF= 0.0205 (850/41560). AF 95% confidence interval is 0.0193. There are 7 homozygotes in gnomad4. There are 417 alleles in male gnomad4 subpopulation. Median coverage is 33. This position pass quality control queck.
BS2
High Homozygotes in GnomAd4 at 7 AD,AR gene
Transcripts
RefSeq
| Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | MANE | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|
| TTN | NM_001267550.2 | c.20147T>A | p.Met6716Lys | missense_variant | 69/363 | ENST00000589042.5 | NP_001254479.2 |
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | TSL | MANE | Protein | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|---|
| TTN | ENST00000589042.5 | c.20147T>A | p.Met6716Lys | missense_variant | 69/363 | 5 | NM_001267550.2 | ENSP00000467141.1 |
Frequencies
GnomAD3 genomes 0.00579 AC: 881AN: 152074Hom.: 7 Cov.: 33
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GnomAD3 exomes AF: 0.00134 AC: 334AN: 248332Hom.: 3 AF XY: 0.000958 AC XY: 129AN XY: 134718
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GnomAD4 exome AF: 0.000561 AC: 820AN: 1461054Hom.: 9 Cov.: 31 AF XY: 0.000491 AC XY: 357AN XY: 726782
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GnomAD4 genome 0.00579 AC: 881AN: 152192Hom.: 7 Cov.: 33 AF XY: 0.00560 AC XY: 417AN XY: 74406
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ClinVar
Significance: Benign/Likely benign
Submissions summary: Benign:21
Revision: criteria provided, multiple submitters, no conflicts
LINK: link
Submissions by phenotype
not specified Benign:6
| Benign, criteria provided, single submitter | clinical testing | Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine | Mar 15, 2012 | Met5472Lys in exon 66 of TTN: This variant is not expected to have clinical sign ificance because it has been identified in 1.7% (55/3150) of African American ch romosomes from a broad population by the NHLBI Exome Sequencing Project (http:// evs.gs.washington.edu/EVS; dbSNP rs28626194). - |
| Likely benign, criteria provided, single submitter | clinical testing | Women's Health and Genetics/Laboratory Corporation of America, LabCorp | Apr 15, 2021 | - - |
| Benign, criteria provided, single submitter | clinical testing | GeneDx | Jun 23, 2014 | 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, criteria provided, single submitter | clinical testing | Athena Diagnostics | Sep 15, 2020 | - - |
| Benign, criteria provided, single submitter | clinical testing | Genetic Services Laboratory, University of Chicago | Jun 08, 2016 | - - |
| Benign, no assertion criteria provided | clinical testing | Clinical Genetics, Academic Medical Center | - | - - |
not provided Benign:3
| Benign, criteria provided, single submitter | clinical testing | ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories | Nov 11, 2019 | - - |
| Likely benign, no assertion criteria provided | clinical testing | Laboratory of Diagnostic Genome Analysis, Leiden University Medical Center (LUMC) | - | - - |
| Likely benign, criteria provided, single submitter | not provided | Breakthrough Genomics, Breakthrough Genomics | - | - - |
Autosomal recessive limb-girdle muscular dystrophy type 2J Benign:2
| Benign, criteria provided, single submitter | clinical testing | Genome-Nilou Lab | Sep 10, 2021 | - - |
| Likely 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 likely benign is not then subjected to further curation. The score for this variant resulted in a classification of likely benign for this disease. - |
Early-onset myopathy with fatal cardiomyopathy Benign:2
| Likely 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 likely benign is not then subjected to further curation. The score for this variant resulted in a classification of likely benign for this disease. - |
| Benign, criteria provided, single submitter | clinical testing | Genome-Nilou Lab | Sep 10, 2021 | - - |
Tibial muscular dystrophy Benign:2
| 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. - |
| Benign, criteria provided, single submitter | clinical testing | Genome-Nilou Lab | Sep 10, 2021 | - - |
Myopathy, myofibrillar, 9, with early respiratory failure Benign:2
| Benign, criteria provided, single submitter | clinical testing | Genome-Nilou Lab | Sep 10, 2021 | - - |
| 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. - |
Autosomal recessive limb-girdle muscular dystrophy type 2J;C1858763:Dilated cardiomyopathy 1G Benign:1
| Benign, criteria provided, single submitter | clinical testing | Labcorp Genetics (formerly Invitae), Labcorp | Jan 31, 2024 | - - |
Cardiomyopathy Benign:1
| Benign, criteria provided, single submitter | clinical testing | CHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern Ontario | May 16, 2023 | - - |
Dilated cardiomyopathy 1G Benign:1
| Likely 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 likely benign is not then subjected to further curation. The score for this variant resulted in a classification of likely benign for this disease. - |
Cardiovascular phenotype Benign:1
| Benign, criteria provided, single submitter | clinical testing | Ambry Genetics | Sep 18, 2013 | This alteration is classified as benign based on a combination of the following: 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
Uncertain
BayesDel_addAF
Benign
T
BayesDel_noAF
Benign
CADD
Benign
DANN
Benign
Eigen
Uncertain
Eigen_PC
Uncertain
FATHMM_MKL
Uncertain
D
LIST_S2
Benign
T;T;.;T
MetaRNN
Benign
T;T;T;T
MetaSVM
Benign
T
PrimateAI
Uncertain
T
PROVEAN
Uncertain
D;.;.;.
REVEL
Uncertain
Sift
Benign
T;.;.;.
Polyphen
0.79
.;.;P;P
Vest4
MVP
MPC
0.26
ClinPred
T
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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