chr2-178565274-G-A
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Variant summary
Our verdict is Benign. Variant got -12 ACMG points: 1P and 13B. PP2BP4_StrongBP6BS1BS2
The NM_001267550.2(TTN):c.80858C>T(p.Thr26953Met) variant causes a missense change. The variant allele was found at a frequency of 0.000401 in 1,613,564 control chromosomes in the GnomAD database, including 5 homozygotes. In-silico tool predicts a benign outcome for this variant. 12/19 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: 𝑓 0.00024 ( 0 hom., cov: 33)
Exomes 𝑓: 0.00042 ( 5 hom. )
Consequence
TTN
NM_001267550.2 missense
NM_001267550.2 missense
Scores
1
5
11
Clinical Significance
Conservation
PhyloP100: 6.84
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 Benign. Variant got -12 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=0.010902077).
BP6
Variant 2-178565274-G-A is Benign according to our data. Variant chr2-178565274-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 179002.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=1, Uncertain_significance=6, Benign=6}. Variant chr2-178565274-G-A is described in Lovd as [Likely_benign].
BS1
Variant frequency is greater than expected in population sas. gnomad4 allele frequency = 0.000243 (37/152152) while in subpopulation SAS AF= 0.00705 (34/4824). AF 95% confidence interval is 0.00518. There are 0 homozygotes in gnomad4. There are 26 alleles in male gnomad4 subpopulation. Median coverage is 33. This position pass quality control queck.
BS2
High Homozygotes in GnomAdExome4 at 5 AD,AR gene
Transcripts
RefSeq
Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | MANE | Protein | UniProt |
---|---|---|---|---|---|---|---|---|
TTN | NM_001267550.2 | c.80858C>T | p.Thr26953Met | missense_variant | 326/363 | ENST00000589042.5 | NP_001254479.2 |
Ensembl
Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | TSL | MANE | Protein | Appris | UniProt |
---|---|---|---|---|---|---|---|---|---|---|
TTN | ENST00000589042.5 | c.80858C>T | p.Thr26953Met | missense_variant | 326/363 | 5 | NM_001267550.2 | ENSP00000467141.1 |
Frequencies
GnomAD3 genomes AF: 0.000243 AC: 37AN: 152034Hom.: 0 Cov.: 33
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GnomAD3 exomes AF: 0.000919 AC: 228AN: 248210Hom.: 2 AF XY: 0.00124 AC XY: 167AN XY: 134622
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GnomAD4 exome AF: 0.000417 AC: 610AN: 1461412Hom.: 5 Cov.: 37 AF XY: 0.000605 AC XY: 440AN XY: 727016
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GnomAD4 genome AF: 0.000243 AC: 37AN: 152152Hom.: 0 Cov.: 33 AF XY: 0.000350 AC XY: 26AN XY: 74372
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ClinVar
Significance: Conflicting classifications of pathogenicity
Submissions summary: Uncertain:6Benign:10
Revision: criteria provided, conflicting classifications
LINK: link
Submissions by phenotype
not provided Uncertain:1Benign:3
Uncertain significance, criteria provided, single submitter | research | Biesecker Lab/Clinical Genomics Section, National Institutes of Health | Jun 24, 2013 | - - |
Benign, criteria provided, single submitter | clinical testing | GeneDx | Feb 18, 2021 | - - |
Likely benign, no assertion criteria provided | clinical testing | Laboratory of Diagnostic Genome Analysis, Leiden University Medical Center (LUMC) | - | - - |
Likely benign, no assertion criteria provided | clinical testing | Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center | - | - - |
not specified Uncertain:1Benign:2
Benign, criteria provided, single submitter | clinical testing | Athena Diagnostics | Feb 25, 2020 | - - |
Benign, no assertion criteria provided | clinical testing | Clinical Genetics, Academic Medical Center | - | - - |
Uncertain significance, criteria provided, single submitter | clinical testing | Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine | Aug 27, 2014 | The Thr24385Met variant in TTN has previously been identified by our laboratory in 1 adult with HCM, and was absent from large population studies. Computational prediction tools and conservation analysis do not provide strong support for or against an impact to the protein, though 1 mammal (pika) carries a methionine ( Met; this variant) at this position, raising the possibility that this change ma y be tolerated. In summary, the clinical significance of the Thr24385Met 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 12, 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. - |
Dilated cardiomyopathy 1G Uncertain:1
Uncertain significance, criteria provided, single submitter | clinical testing | Illumina Laboratory Services, Illumina | Jan 12, 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 12, 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 20, 2013 | The p.T24385M variant (also known as c.73154C>T) is located in coding exon 274 of the TTN gene. This alteration results from a C to T substitution at nucleotide position 73154. The threonine at codon 24385 is replaced by methionine, an amino acid with some similar properties. This variant was not reported in population-based cohorts in the following databases: Database of Single Nucleotide Polymorphisms (dbSNP), the 1000 Genomes Project and the NHLBI Exome Sequencing Project (ESP). In the ESP, this variant was not reported in 6002 samples (12004 alleles) with coverage at this position. Based on protein sequence alignment, this amino acid position is well conserved in available vertebrate species, though methionine is the reference amino acid in one species.In addition, this alteration is predicted to be benign by PolyPhen analysis. Since supporting evidence is limited at this time, the clinical significance of this variant remains unclear. - |
Autosomal recessive limb-girdle muscular dystrophy type 2J;C1858763:Dilated cardiomyopathy 1G Benign:1
Benign, criteria provided, single submitter | clinical testing | Labcorp Genetics (formerly Invitae), Labcorp | Jan 19, 2024 | - - |
Cardiomyopathy Benign:1
Benign, criteria provided, single submitter | clinical testing | CHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern Ontario | Feb 20, 2018 | - - |
Myopathy, myofibrillar, 9, with early respiratory failure Benign:1
Benign, criteria provided, single submitter | clinical testing | Illumina Laboratory Services, Illumina | Jan 12, 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 benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. - |
Tibial muscular dystrophy Benign:1
Benign, criteria provided, single submitter | clinical testing | Illumina Laboratory Services, Illumina | Jan 12, 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 benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. - |
Primary dilated cardiomyopathy Benign:1
Likely benign, criteria provided, single submitter | research | Genetics and Genomics Program, Sidra Medicine | - | - - |
Computational scores
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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
Uncertain
D;D;D;.;D;D;D
M_CAP
Benign
D
MetaRNN
Benign
T;T;T;T;T;T;T
MetaSVM
Benign
T
MutationAssessor
Uncertain
.;.;.;M;.;.;M
PrimateAI
Benign
T
PROVEAN
Uncertain
D;D;.;.;D;D;.
REVEL
Uncertain
Sift
Uncertain
D;D;.;.;D;D;.
Polyphen
0.51
.;.;.;P;.;.;P
Vest4
MutPred
0.57
.;.;.;Loss of glycosylation at T25312 (P = 0.0438);.;.;Loss of glycosylation at T25312 (P = 0.0438);
MVP
MPC
0.12
ClinPred
T
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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