rs536974988
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Variant summary
Our verdict is Likely benign. Variant got -1 ACMG points: 1P and 2B. PP2BP4_Moderate
The NM_001267550.2(TTN):āc.26744C>Gā(p.Ala8915Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000223 in 1,613,288 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/18 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (ā ā ).
Frequency
Genomes: š 0.000079 ( 0 hom., cov: 33)
Exomes š: 0.000016 ( 0 hom. )
Consequence
TTN
NM_001267550.2 missense
NM_001267550.2 missense
Scores
1
2
13
Clinical Significance
Conservation
PhyloP100: 3.33
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 -1 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=0.16473329).
Transcripts
RefSeq
| Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | MANE | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|
| TTN | NM_001267550.2 | c.26744C>G | p.Ala8915Gly | missense_variant | 92/363 | ENST00000589042.5 | NP_001254479.2 | |
| LOC124906100 | XR_007087318.1 | n.2346G>C | non_coding_transcript_exon_variant | 2/2 |
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | TSL | MANE | Protein | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|---|
| TTN | ENST00000589042.5 | c.26744C>G | p.Ala8915Gly | missense_variant | 92/363 | 5 | NM_001267550.2 | ENSP00000467141 | P1 | |
| TTN-AS1 | ENST00000659121.1 | n.503-20590G>C | intron_variant, non_coding_transcript_variant |
Frequencies
GnomAD3 genomes 0.0000329 AC: 5AN: 152162Hom.: 0 Cov.: 33
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GnomAD3 exomes AF: 0.0000201 AC: 5AN: 248246Hom.: 0 AF XY: 0.00000743 AC XY: 1AN XY: 134680
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GnomAD4 exome AF: 0.0000164 AC: 24AN: 1461008Hom.: 0 Cov.: 31 AF XY: 0.0000138 AC XY: 10AN XY: 726738
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GnomAD4 genome 0.0000788 AC: 12AN: 152280Hom.: 0 Cov.: 33 AF XY: 0.0000403 AC XY: 3AN XY: 74442
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ClinVar
Significance: Uncertain significance
Submissions summary: Uncertain:12
Revision: criteria provided, multiple submitters, no conflicts
LINK: link
Submissions by phenotype
not provided Uncertain:3
| Uncertain significance, criteria provided, single submitter | clinical testing | ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories | Mar 20, 2018 | The TTN c.23012C>G; p.Ala7671Gly variant is rare in the general population (<1% allele frequency in the Genome Aggregation Database) and has not been reported in the medical literature in association with dilated cardiomyopathy (DCM) or other TTN-related disease. 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. While the clinical significance of such variants is considered uncertain, evidence suggests that the vast majority of missense variants do not contribute to the clinical outcome of DCM (Begay 2015). Given the available evidence, the clinical significance of the p.Ala7671Gly variant cannot be determined with certainty. - |
| Uncertain significance, criteria provided, single submitter | clinical testing | Revvity Omics, Revvity | Sep 13, 2023 | - - |
| Uncertain significance, criteria provided, single submitter | clinical testing | Athena Diagnostics | Sep 12, 2017 | - - |
not specified Uncertain:2
| Uncertain significance, criteria provided, single submitter | clinical testing | GeneDx | May 07, 2015 | Missense variants in the TTN gene are considered 'unclassified' if they are not previously reported in the literature and do not have >1% frequency in the population to be considered a polymorphism. Research indicates that truncating mutations in the TTN gene are expected to account for approximately 25% of familial and 18% of sporadic idiopathic DCM; however, truncating variants in the TTN gene have been reported in approximately 3% of reported control alleles. There has been little investigation into non-truncating variants. (Herman D et al. Truncations of titin causing dilated cardiomyopathy. N Eng J Med 366:619-628, 2012) The variant is found in DCM panel(s). - |
| Uncertain significance, criteria provided, single submitter | clinical testing | Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine | Nov 11, 2015 | The p.Ala7671Gly variant in TTN has not been previously reported in patients wit h cardiomyopathy, but has been identified in 1/8440 East Asian chromosomes by th e Exome Aggregation Consortium (ExAC, http://exac.broadinstitute.org; dbSNP rs53 6974988). Computational prediction tools and conservation analysis suggest that this variant may not impact the protein, though this information is not predicti ve enough to rule out pathogenicity. In summary, the clinical significance of th e p.Ala7671Gly variant is uncertain. - |
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 | Jan 02, 2018 | - - |
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. - |
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 | Jul 26, 2021 | - - |
Tibial muscular dystrophy 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. - |
Myopathy, myofibrillar, 9, with early respiratory failure 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. - |
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
Pathogenic
D
LIST_S2
Benign
T;T;.;T
M_CAP
Benign
D
MetaRNN
Benign
T;T;T;T
MetaSVM
Benign
T
MutationTaster
Benign
D;D;D;N;N;N
PrimateAI
Benign
T
PROVEAN
Uncertain
D;.;.;.
REVEL
Benign
Sift
Uncertain
D;.;.;.
Polyphen
0.12
.;.;B;B
Vest4
MutPred
0.60
.;.;Gain of methylation at K8593 (P = 0.0676);Gain of methylation at K8593 (P = 0.0676);
MVP
MPC
0.12
ClinPred
T
GERP RS
Splicing
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Score
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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