rs397517589
Positions:
Variant summary
Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong
The NM_001267550.2(TTN):c.47506C>T(p.Gln15836Ter) variant causes a stop gained change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Variant results in nonsense mediated mRNA decay.
Frequency
Genomes: not found (cov: 32)
Consequence
TTN
NM_001267550.2 stop_gained
NM_001267550.2 stop_gained
Scores
4
2
1
Clinical Significance
Conservation
PhyloP100: 5.89
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 Pathogenic. Variant got 18 ACMG points.
PVS1
?
Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
PM2
?
Very rare variant in population databases, with high coverage;
PP5
?
Variant 2-178617845-G-A is Pathogenic according to our data. Variant chr2-178617845-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 47012.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
Transcripts
RefSeq
Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | MANE | UniProt |
---|---|---|---|---|---|---|---|
TTN | NM_001267550.2 | c.47506C>T | p.Gln15836Ter | stop_gained | 253/363 | ENST00000589042.5 |
Ensembl
Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | TSL | MANE | Appris | UniProt |
---|---|---|---|---|---|---|---|---|---|
TTN | ENST00000589042.5 | c.47506C>T | p.Gln15836Ter | stop_gained | 253/363 | 5 | NM_001267550.2 | P1 | |
TTN-AS1 | ENST00000659121.1 | n.502+20164G>A | intron_variant, non_coding_transcript_variant |
Frequencies
GnomAD3 genomes ? Cov.: 32
GnomAD3 genomes
?
Cov.:
32
GnomAD4 exome Cov.: 32
GnomAD4 exome
Cov.:
32
GnomAD4 genome ? Cov.: 32
GnomAD4 genome
?
Cov.:
32
ClinVar
Significance: Likely pathogenic
Submissions summary: Pathogenic:2
Revision: criteria provided, multiple submitters, no conflicts
LINK: link
Submissions by phenotype
Autosomal recessive limb-girdle muscular dystrophy type 2J;C1858763:Dilated cardiomyopathy 1G Pathogenic:1
Likely pathogenic, criteria provided, single submitter | clinical testing | Invitae | Oct 07, 2021 | This variant is located in the A band of TTN (PMID: 25589632). Truncating variants in this region are significantly overrepresented in patients affected with dilated cardiomyopathy (PMID: 25589632). Truncating variants in this region have also been reported in individuals affected with autosomal recessive centronuclear myopathy (PMID: 23975875). This sequence change creates a premature translational stop signal (p.Gln15836*) in the TTN gene. While this is not anticipated to result in nonsense mediated decay, it is expected to create a truncated TTN protein. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. ClinVar contains an entry for this variant (Variation ID: 47012). This variant has not been reported in the literature in individuals affected with TTN-related conditions. This variant is not present in population databases (ExAC no frequency). - |
Primary dilated cardiomyopathy Pathogenic:1
Likely pathogenic, criteria provided, single submitter | clinical testing | Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine | Jan 16, 2013 | The Gln13268X variant in TTN has not been reported in the literature nor previou sly identified by our laboratory. This variant has not been identified in large European American and African American populations by the NHLBI Exome Sequencing Project (http://evs.gs.washington.edu/EVS/), which increases the likelihood tha t it is pathogenic. However, we cannot exclude that it may be common in other po pulations. This nonsense variant leads to a premature termination codon at posit ion 13268, which is predicted to lead to a truncated or absent protein. Frameshi ft and other truncating variants are strongly associated with DCM and the majori ty occur in the A-band (Herman 2012, LMM unpublished data), where this variant i s located. In summary, the available data supports that the Gln13268X variant is likely to be pathogenic, though additional studies are needed to fully establis h its clinical significance. - |
Computational scores
Source:
Name
Calibrated prediction
Score
Prediction
BayesDel_addAF
Pathogenic
D
BayesDel_noAF
Pathogenic
CADD
Pathogenic
DANN
Uncertain
Eigen
Pathogenic
Eigen_PC
Pathogenic
FATHMM_MKL
Uncertain
D
MutationTaster
Benign
A;A;A;A;A;A
Vest4
GERP RS
Splicing
Name
Calibrated prediction
Score
Prediction
SpliceAI score (max)
Details are displayed if max score is > 0.2
Find out detailed SpliceAI scores and Pangolin per-transcript scores at