2-178549293-G-C
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Variant summary
Our verdict is Likely benign. Variant got -2 ACMG points: 1P and 3B. PP2BP4_ModerateBP6
The NM_001267550.2(TTN):āc.92333C>Gā(p.Thr30778Arg) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000229 in 1,613,768 control chromosomes in the GnomAD database, with no homozygous occurrence. 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 0.00012 ( 0 hom., cov: 33)
Exomes š: 0.00024 ( 0 hom. )
Consequence
TTN
NM_001267550.2 missense
NM_001267550.2 missense
Scores
4
13
Clinical Significance
Conservation
PhyloP100: 3.28
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 -2 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=0.21055174).
BP6
Variant 2-178549293-G-C is Benign according to our data. Variant chr2-178549293-G-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 47522.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=4, Uncertain_significance=9}. Variant chr2-178549293-G-C is described in Lovd as [Likely_benign].
Transcripts
RefSeq
| Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | MANE | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|
| TTN | NM_001267550.2 | c.92333C>G | p.Thr30778Arg | missense_variant | 339/363 | ENST00000589042.5 | NP_001254479.2 |
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | TSL | MANE | Protein | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|---|
| TTN | ENST00000589042.5 | c.92333C>G | p.Thr30778Arg | missense_variant | 339/363 | 5 | NM_001267550.2 | ENSP00000467141.1 |
Frequencies
GnomAD3 genomes 0.000118 AC: 18AN: 152146Hom.: 0 Cov.: 33
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GnomAD3 exomes AF: 0.0000803 AC: 20AN: 249176Hom.: 0 AF XY: 0.0000814 AC XY: 11AN XY: 135182
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GnomAD4 exome AF: 0.000241 AC: 352AN: 1461622Hom.: 0 Cov.: 34 AF XY: 0.000215 AC XY: 156AN XY: 727098
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GnomAD4 genome 0.000118 AC: 18AN: 152146Hom.: 0 Cov.: 33 AF XY: 0.0000673 AC XY: 5AN XY: 74312
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ClinVar
Significance: Conflicting classifications of pathogenicity
Submissions summary: Uncertain:9Benign:4
Revision: criteria provided, conflicting classifications
LINK: link
Submissions by phenotype
not provided Uncertain:3Benign:1
| Uncertain significance, criteria provided, single submitter | clinical testing | Eurofins Ntd Llc (ga) | Jun 01, 2018 | - - |
| Uncertain significance, criteria provided, single submitter | clinical testing | Mayo Clinic Laboratories, Mayo Clinic | Mar 11, 2020 | - - |
| Likely benign, criteria provided, single submitter | clinical testing | GeneDx | Oct 15, 2020 | - - |
| Uncertain significance, criteria provided, single submitter | clinical testing | Revvity Omics, Revvity | Nov 26, 2021 | - - |
not specified Uncertain:1
| Uncertain significance, criteria provided, single submitter | clinical testing | Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine | Feb 17, 2015 | 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 | 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. - |
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 | Nov 16, 2017 | - - |
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 | Nov 11, 2019 | The p.T21713R variant (also known as c.65138C>G), located in coding exon 166 of the TTN gene, results from a C to G substitution at nucleotide position 65138. The threonine at codon 21713 is replaced by arginine, an amino acid with similar properties. This amino acid position is not well conserved in available vertebrate species. In addition, this alteration is predicted to be tolerated by in silico analysis. 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 | Nov 01, 2022 | - - |
Myopathy, myofibrillar, 9, with early respiratory failure 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. - |
Tibial muscular dystrophy 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. - |
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;.;D;D;D
M_CAP
Benign
D
MetaRNN
Benign
T;T;T;T;T;T;T
MetaSVM
Benign
T
MutationAssessor
Benign
.;.;.;L;.;.;L
MutationTaster
Benign
D;D;D;D;D;D
PrimateAI
Uncertain
T
PROVEAN
Uncertain
D;D;.;.;D;D;.
REVEL
Benign
Sift
Benign
T;T;.;.;T;T;.
Polyphen
0.81
.;.;.;P;.;.;P
Vest4
MVP
MPC
0.24
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