2-178574139-C-T
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Variant summary
Our verdict is Benign. Variant got -19 ACMG points: 1P and 20B. PP2BP4_StrongBP6_Very_StrongBA1
The NM_001267550.2(TTN):c.71993G>A(p.Arg23998His) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.049 in 1,613,490 control chromosomes in the GnomAD database, including 3,832 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Benign (★★).
Frequency
Genomes: 𝑓 0.064 ( 519 hom., cov: 32)
Exomes 𝑓: 0.047 ( 3313 hom. )
Consequence
TTN
NM_001267550.2 missense
NM_001267550.2 missense
Scores
5
6
5
Clinical Significance
Conservation
PhyloP100: 7.86
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=0.001629144).
BP6
Variant 2-178574139-C-T is Benign according to our data. Variant chr2-178574139-C-T is described in ClinVar as [Benign]. Clinvar id is 47305.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr2-178574139-C-T is described in Lovd as [Benign].
BA1
GnomAd4 highest subpopulation (SAS) allele frequency at 95% confidence interval = 0.166 is higher than 0.05.
Transcripts
RefSeq
| Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | MANE | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|
| TTN | NM_001267550.2 | c.71993G>A | p.Arg23998His | missense_variant | 326/363 | ENST00000589042.5 | NP_001254479.2 | |
| TTN-AS1 | NR_038272.1 | n.2044-8433C>T | intron_variant, non_coding_transcript_variant |
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | TSL | MANE | Protein | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|---|
| TTN | ENST00000589042.5 | c.71993G>A | p.Arg23998His | missense_variant | 326/363 | 5 | NM_001267550.2 | ENSP00000467141 | P1 | |
| TTN-AS1 | ENST00000659121.1 | n.417-23457C>T | intron_variant, non_coding_transcript_variant |
Frequencies
GnomAD3 genomes 0.0636 AC: 9662AN: 152036Hom.: 506 Cov.: 32
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GnomAD3 exomes AF: 0.0795 AC: 19736AN: 248154Hom.: 1474 AF XY: 0.0785 AC XY: 10566AN XY: 134596
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GnomAD4 exome AF: 0.0474 AC: 69330AN: 1461336Hom.: 3313 Cov.: 39 AF XY: 0.0502 AC XY: 36508AN XY: 726956
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GnomAD4 genome 0.0638 AC: 9714AN: 152154Hom.: 519 Cov.: 32 AF XY: 0.0706 AC XY: 5250AN XY: 74360
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ClinVar
Significance: Benign
Submissions summary: Benign:22
Revision: criteria provided, multiple submitters, no conflicts
LINK: link
Submissions by phenotype
not specified Benign:10
| 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 | PreventionGenetics, part of Exact Sciences | - | - - |
| Benign, criteria provided, single submitter | research | Biesecker Lab/Clinical Genomics Section, National Institutes of Health | Jun 24, 2013 | - - |
| Benign, criteria provided, single submitter | clinical testing | GeneDx | Oct 18, 2012 | 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 | Eurofins Ntd Llc (ga) | Jun 04, 2014 | - - |
| Benign, criteria provided, single submitter | clinical testing | Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine | Sep 27, 2011 | - - |
| Likely benign, no assertion criteria provided | clinical testing | Genetic Services Laboratory, University of Chicago | - | Likely benign based on allele frequency in 1000 Genomes Project or ESP global frequency and its presence in a patient with a rare or unrelated disease phenotype. NOT Sanger confirmed. - |
| Benign, no assertion criteria provided | clinical testing | Clinical Genetics, Academic Medical Center | - | - - |
| Benign, criteria provided, single submitter | clinical testing | Women's Health and Genetics/Laboratory Corporation of America, LabCorp | Oct 30, 2019 | Variant summary: TTN c.64289G>A (p.Arg21430His) results in a non-conservative amino acid change located in the A-band of the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 0.08 in 248154 control chromosomes, predominantly at a frequency of 0.2 within the Latino subpopulation in the gnomAD database, including 713 homozygotes. The observed variant frequency within Latino control individuals in the gnomAD database is approximately 320-folds over 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 Latino origin. A ClinVar submission (evaluation after 2014) cites the variant as likely benign. Based on the evidence outlined above, the variant was classified as benign. - |
Autosomal recessive limb-girdle muscular dystrophy type 2J 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. - |
Early-onset myopathy with fatal cardiomyopathy 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. - |
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 | 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 | - - |
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 | Feb 01, 2024 | - - |
Dilated cardiomyopathy 1G 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. - |
not provided Benign:1
| Benign, criteria provided, single submitter | not provided | Breakthrough Genomics, Breakthrough Genomics | - | - - |
Cardiovascular phenotype Benign:1
| Benign, criteria provided, single submitter | clinical testing | Ambry Genetics | Jan 16, 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
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Name
Calibrated prediction
Score
Prediction
AlphaMissense
Uncertain
BayesDel_addAF
Benign
T
BayesDel_noAF
Uncertain
CADD
Uncertain
DANN
Benign
Eigen
Pathogenic
Eigen_PC
Pathogenic
FATHMM_MKL
Pathogenic
D
LIST_S2
Uncertain
D;D;D;.;D;D;D
MetaRNN
Benign
T;T;T;T;T;T;T
MetaSVM
Benign
T
MutationAssessor
Pathogenic
.;.;.;H;.;.;H
MutationTaster
Benign
D;D;D;D;D;D
PrimateAI
Uncertain
T
PROVEAN
Uncertain
D;D;.;.;D;D;.
REVEL
Uncertain
Sift
Pathogenic
D;D;.;.;D;D;.
Polyphen
1.0
.;.;.;D;.;.;D
Vest4
MPC
0.52
ClinPred
T
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