rs1060500442
Positions:
Variant summary
Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1PM2PP5_Moderate
The NM_001267550.2(TTN):c.60621del(p.Tyr20207Ter) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Likely pathogenic (★). Synonymous variant affecting the same amino acid position (i.e. Y20207Y) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.
Frequency
Genomes: not found (cov: 32)
Consequence
TTN
NM_001267550.2 frameshift
NM_001267550.2 frameshift
Scores
Not classified
Clinical Significance
Conservation
PhyloP100: 0.997
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 12 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 2-178591103-TA-T is Pathogenic according to our data. Variant chr2-178591103-TA-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 404768.Status of the report is criteria_provided_single_submitter, 1 stars.
Transcripts
RefSeq
Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | MANE | UniProt |
---|---|---|---|---|---|---|---|
TTN | NM_001267550.2 | c.60621del | p.Tyr20207Ter | frameshift_variant | 304/363 | ENST00000589042.5 | |
TTN-AS1 | NR_038272.1 | n.3189-35del | intron_variant, non_coding_transcript_variant |
Ensembl
Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | TSL | MANE | Appris | UniProt |
---|---|---|---|---|---|---|---|---|---|
TTN | ENST00000589042.5 | c.60621del | p.Tyr20207Ter | frameshift_variant | 304/363 | 5 | NM_001267550.2 | P1 | |
TTN-AS1 | ENST00000659121.1 | n.417-6492del | intron_variant, non_coding_transcript_variant |
Frequencies
GnomAD3 genomes ? Cov.: 32
GnomAD3 genomes
?
Cov.:
32
GnomAD4 exome Cov.: 35
GnomAD4 exome
Cov.:
35
GnomAD4 genome ? Cov.: 32
GnomAD4 genome
?
Cov.:
32
ClinVar
Significance: Likely pathogenic
Submissions summary: Pathogenic:2
Revision: criteria provided, single submitter
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 | Nov 24, 2016 | For these reasons, this variant has been classified as Likely Pathogenic. This sequence change deletes 1 nucleotide from exon 304 of the TTN mRNA (c.60621delT), causing a frameshift at codon 20207. This creates a premature translational stop signal at codon 20207 of the TTN mRNA (p.Tyr20207*). While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the A-band of the TTN protein. This variant is found in the A-band of this gene. While this particular variant has not been reported in the literature, truncating variants in the A-band of TTN are significantly overrepresented in patients with dilated cardiomyopathy and are considered to be likely pathogenic for the disease (PMID: 25589632). - |
Dilated cardiomyopathy 1G Pathogenic:1
Likely pathogenic, criteria provided, single submitter | clinical testing | Invitae | Nov 24, 2016 | This sequence change deletes 1 nucleotide from exon 304 of the TTN mRNA (c.60621delT), causing a frameshift at codon 20207. This creates a premature translational stop signal at codon 20207 of the TTN mRNA (p.Tyr20207*). While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the A-band of the TTN protein. This variant is found in the A-band of this gene. While this particular variant has not been reported in the literature, truncating variants in the A-band of TTN are significantly overrepresented in patients with dilated cardiomyopathy and are considered to be likely pathogenic for the disease (PMID: 25589632). For these reasons, this variant has been classified as Likely Pathogenic. - |
Computational scores
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Calibrated prediction
Score
Prediction
Splicing
Name
Calibrated prediction
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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