rs370069759
Variant summary
Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2BP4_Moderate
The NM_001267550.2(TTN):c.97192+4A>G variant causes a splice donor region, intron change. The variant allele was found at a frequency of 0.0000131 in 152,212 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).
Frequency
Genomes: 𝑓 0.000013 ( 0 hom., cov: 32)
Consequence
TTN
NM_001267550.2 splice_donor_region, intron
NM_001267550.2 splice_donor_region, intron
Scores
2
Splicing: ADA: 0.9716
1
1
Clinical Significance
Conservation
PhyloP100: 4.08
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 Uncertain_significance. Variant got 0 ACMG points.
PM2
?
Very rare variant in population databases, with high coverage;
BP4
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Computational evidence support a benign effect (BayesDel_noAF=-0.43).
Transcripts
RefSeq
Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | MANE | UniProt |
---|---|---|---|---|---|---|---|
TTN | NM_001267550.2 | c.97192+4A>G | splice_donor_region_variant, intron_variant | ENST00000589042.5 | |||
TTN-AS1 | NR_038272.1 | n.2043+297T>C | intron_variant, non_coding_transcript_variant |
Ensembl
Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | TSL | MANE | Appris | UniProt |
---|---|---|---|---|---|---|---|---|---|
TTN | ENST00000589042.5 | c.97192+4A>G | splice_donor_region_variant, intron_variant | 5 | NM_001267550.2 | P1 | |||
TTN-AS1 | ENST00000659121.1 | n.416+19022T>C | intron_variant, non_coding_transcript_variant |
Frequencies
GnomAD3 genomes ? AF: 0.0000131 AC: 2AN: 152212Hom.: 0 Cov.: 32
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GnomAD3 exomes AF: 0.00000403 AC: 1AN: 247968Hom.: 0 AF XY: 0.00000743 AC XY: 1AN XY: 134540
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GnomAD4 genome ? AF: 0.0000131 AC: 2AN: 152212Hom.: 0 Cov.: 32 AF XY: 0.0000269 AC XY: 2AN XY: 74354
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ClinVar
Significance: Uncertain significance
Submissions summary: Uncertain:3
Revision: criteria provided, multiple submitters, no conflicts
LINK: link
Submissions by phenotype
Autosomal recessive limb-girdle muscular dystrophy type 2J;C1858763:Dilated cardiomyopathy 1G Uncertain:1
Uncertain significance, criteria provided, single submitter | clinical testing | Invitae | Jul 14, 2022 | In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. This variant is located in the A band of TTN (PMID: 25589632). Variants in this region may be relevant for cardiac or neuromuscular disorders (PMID: 25589632, 23975875). Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant is not likely to affect RNA splicing. ClinVar contains an entry for this variant (Variation ID: 223355). This variant has not been reported in the literature in individuals affected with TTN-related conditions. This variant is present in population databases (rs370069759, gnomAD 0.008%). This sequence change falls in intron 348 of the TTN gene. It does not directly change the encoded amino acid sequence of the TTN protein. It affects a nucleotide within the consensus splice site. - |
Primary dilated cardiomyopathy Uncertain:1
Uncertain significance, criteria provided, single submitter | research | Cardiovascular Biomedical Research Unit, Royal Brompton & Harefield NHS Foundation Trust | Oct 08, 2014 | This TTN truncating variant (TTNtv) was identified in one individual in this cohort and is located in an exon that is highly expressed in the heart. In the seven cohorts assessed, TTNtv were found in 14% of ambulant DCM, 22% end-stage or familial DCM, and 2% controls. Heterozygous nonsense, frameshift and canonical splice-disrupting variants found in constitutive and other highly utilised exons are highly likely to be pathogenic when identified in individuals with phenotypically confirmed DCM. TTNtv found incidentally in healthy individuals (excluding familial assessment of DCM relatives) are thought to have low penetrance, particularly when identified in exons that are not constitutively expressed in the heart. - |
Cardiovascular phenotype Uncertain:1
Uncertain significance, criteria provided, single submitter | clinical testing | Ambry Genetics | Aug 21, 2020 | The c.69997+4A>G intronic variant results from an A to G substitution 4 nucleotides after coding exon 175 in the TTN gene. This variant has been reported in the Jackson Heart Study cohort with alternate nomenclature (as NM_001267550.1:c.97192+4A>G); however, clinical details were limited (Roberts AM et al. Sci Transl Med, 2015 Jan;7:270ra6). This nucleotide position is highly conserved in available vertebrate species. In silico splice site analysis for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. - |
Computational scores
Source:
Name
Calibrated prediction
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BayesDel_noAF
Benign
Cadd
Benign
Dann
Benign
Splicing
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dbscSNV1_ADA
Pathogenic
dbscSNV1_RF
Benign
SpliceAI score (max)
Details are displayed if max score is > 0.2
Find out detailed SpliceAI scores and Pangolin per-transcript scores at