rs72646898
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Variant summary
Our verdict is Benign. Variant got -8 ACMG points: 1P and 9B. PP2BP4_StrongBP6BS2
The NM_001267550.2(TTN):āc.74602A>Gā(p.Ile24868Val) variant causes a missense change. The variant allele was found at a frequency of 0.000466 in 1,609,588 control chromosomes in the GnomAD database, including 2 homozygotes. In-silico tool predicts a benign outcome for this variant. 14/19 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: š 0.00027 ( 0 hom., cov: 32)
Exomes š: 0.00049 ( 2 hom. )
Consequence
TTN
NM_001267550.2 missense
NM_001267550.2 missense
Scores
3
14
Clinical Significance
Conservation
PhyloP100: 5.00
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 -8 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=0.057338238).
BP6
Variant 2-178571530-T-C is Benign according to our data. Variant chr2-178571530-T-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 332783.We mark this variant Likely_benign, oryginal submissions are: {Benign=2, Uncertain_significance=8, Likely_benign=4}. Variant chr2-178571530-T-C is described in Lovd as [Likely_benign].
BS2
High Homozygotes in GnomAdExome4 at 2 AD,AR gene
Transcripts
RefSeq
| Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | MANE | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|
| TTN | NM_001267550.2 | c.74602A>G | p.Ile24868Val | missense_variant | 326/363 | ENST00000589042.5 | NP_001254479.2 | |
| TTN-AS1 | NR_038272.1 | n.2044-11042T>C | intron_variant, non_coding_transcript_variant |
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | TSL | MANE | Protein | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|---|
| TTN | ENST00000589042.5 | c.74602A>G | p.Ile24868Val | missense_variant | 326/363 | 5 | NM_001267550.2 | ENSP00000467141 | P1 | |
| TTN-AS1 | ENST00000659121.1 | n.417-26066T>C | intron_variant, non_coding_transcript_variant |
Frequencies
GnomAD3 genomes 0.000277 AC: 42AN: 151806Hom.: 0 Cov.: 32
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GnomAD3 exomes AF: 0.000235 AC: 58AN: 247298Hom.: 0 AF XY: 0.000239 AC XY: 32AN XY: 134152
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GnomAD4 exome AF: 0.000486 AC: 709AN: 1457664Hom.: 2 Cov.: 38 AF XY: 0.000458 AC XY: 332AN XY: 725096
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GnomAD4 genome 0.000270 AC: 41AN: 151924Hom.: 0 Cov.: 32 AF XY: 0.000269 AC XY: 20AN XY: 74268
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ClinVar
Significance: Conflicting classifications of pathogenicity
Submissions summary: Uncertain:8Benign:11
Revision: criteria provided, conflicting classifications
LINK: link
Submissions by phenotype
not provided Uncertain:3Benign:7
| Likely benign, no assertion criteria provided | clinical testing | Joint Genome Diagnostic Labs from Nijmegen and Maastricht, Radboudumc and MUMC+ | - | - - |
| Uncertain significance, criteria provided, single submitter | clinical testing | Eurofins Ntd Llc (ga) | Apr 23, 2018 | - - |
| Likely benign, no assertion criteria provided | clinical testing | Genome Diagnostics Laboratory, University Medical Center Utrecht | - | - - |
| Likely benign, no assertion criteria provided | clinical testing | Clinical Genetics, Academic Medical Center | - | - - |
| Likely benign, no assertion criteria provided | clinical testing | Diagnostic Laboratory, Department of Genetics, University Medical Center Groningen | - | - - |
| Likely benign, criteria provided, single submitter | clinical testing | GeneDx | Apr 29, 2021 | - - |
| Uncertain significance, criteria provided, single submitter | clinical testing | CeGaT Center for Human Genetics Tuebingen | Nov 01, 2024 | TTN: PM2 - |
| Likely benign, no assertion criteria provided | clinical testing | Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center | - | - - |
| Uncertain significance, criteria provided, single submitter | clinical testing | Mayo Clinic Laboratories, Mayo Clinic | Apr 22, 2020 | - - |
| Likely benign, criteria provided, single submitter | clinical testing | Revvity Omics, Revvity | Nov 07, 2023 | - - |
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 | Nov 16, 2017 | - - |
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. - |
Cardiovascular phenotype Uncertain:1
| Uncertain significance, criteria provided, single submitter | clinical testing | Ambry Genetics | Nov 02, 2018 | The p.I15803V variant (also known as c.47407A>G), located in coding exon 153 of the TTN gene, results from an A to G substitution at nucleotide position 47407. The isoleucine at codon 15803 is replaced by valine, an amino acid with highly similar properties. This amino acid position is well conserved in available vertebrate species. In addition, this alteration is predicted to be tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. - |
not specified Benign:1
| Likely benign, criteria provided, single submitter | clinical testing | Women's Health and Genetics/Laboratory Corporation of America, LabCorp | Aug 01, 2022 | Variant summary: TTN c.66898A>G (p.Ile22300Val) results in a conservative amino acid change located in the A-band region of the encoded protein sequence. Four of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 0.00023 in 247298 control chromosomes, predominantly at a frequency of 0.00045 within the Non-Finnish European subpopulation in the gnomAD database. The observed variant frequency within Non-Finnish European control individuals in the gnomAD database is approximately equal to the estimated maximal expected allele frequency for a pathogenic variant in TTN causing Dilated Cardiomyopathy phenotype (0.00039), strongly suggesting that the variant is a benign polymorphism found primarily in populations of Non-Finnish European origin. c.66898A>G has been reported in the literature in a European individual affected with Arrhythmogenic Right Ventricular Cardiomyopathy (Campuzano_2015, Martnez-Barrios_2022). These reports do not provide unequivocal conclusions about association of the variant with Dilated Cardiomyopathy. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Six ClinVar submitters (evaluation after 2014) cite the variant as uncertain significance (n=4), likely benign (n=1) and benign (n=1). Based on the evidence outlined above, the variant was classified as likely benign. - |
Cardiomyopathy Benign:1
| Likely benign, criteria provided, single submitter | clinical testing | CHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern Ontario | Jun 10, 2021 | - - |
Tibial muscular dystrophy Benign:1
| Benign, 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 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. - |
Myopathy, myofibrillar, 9, with early respiratory failure Benign:1
| Benign, 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 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. - |
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
Uncertain
D
LIST_S2
Uncertain
D;D;D;.;D;D;D
M_CAP
Benign
T
MetaRNN
Benign
T;T;T;T;T;T;T
MetaSVM
Benign
T
MutationAssessor
Benign
.;.;.;L;.;.;L
MutationTaster
Benign
D;D;D;D;D;D
PrimateAI
Uncertain
T
PROVEAN
Benign
N;N;.;.;N;N;.
REVEL
Benign
Sift
Benign
T;T;.;.;T;T;.
Polyphen
0.44
.;.;.;B;.;.;B
Vest4
MVP
MPC
0.13
ClinPred
T
GERP RS
RBP_binding_hub_radar
RBP_regulation_power_radar
Splicing
Name
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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