rs72648973
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Variant summary
Our verdict is Likely benign. Variant got -6 ACMG points: 1P and 7B. PP2BP4_ModerateBP6BS2
The NM_001267550.2(TTN):c.23302G>A(p.Asp7768Asn) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00127 in 1,613,640 control chromosomes in the GnomAD database, including 3 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).
Frequency
Genomes: 𝑓 0.00081 ( 0 hom., cov: 33)
Exomes 𝑓: 0.0013 ( 3 hom. )
Consequence
TTN
NM_001267550.2 missense
NM_001267550.2 missense
Scores
4
4
8
Clinical Significance
Conservation
PhyloP100: 7.91
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 Likely_benign. Variant got -6 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=0.11322686).
BP6
Variant 2-178720460-C-T is Benign according to our data. Variant chr2-178720460-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 46717.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=4, Uncertain_significance=10, Benign=3}. Variant chr2-178720460-C-T is described in Lovd as [Benign]. Variant chr2-178720460-C-T is described in Lovd as [Likely_benign].
BS2
High Homozygotes in GnomAdExome4 at 3 AD,AR gene
Transcripts
RefSeq
| Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | MANE | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|
| TTN | NM_001267550.2 | c.23302G>A | p.Asp7768Asn | missense_variant | 80/363 | ENST00000589042.5 | NP_001254479.2 |
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | TSL | MANE | Protein | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|---|
| TTN | ENST00000589042.5 | c.23302G>A | p.Asp7768Asn | missense_variant | 80/363 | 5 | NM_001267550.2 | ENSP00000467141.1 |
Frequencies
GnomAD3 genomes 0.000809 AC: 123AN: 152114Hom.: 0 Cov.: 33
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GnomAD3 exomes AF: 0.000756 AC: 188AN: 248662Hom.: 0 AF XY: 0.000741 AC XY: 100AN XY: 134884
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GnomAD4 exome AF: 0.00132 AC: 1934AN: 1461408Hom.: 3 Cov.: 35 AF XY: 0.00128 AC XY: 931AN XY: 726976
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GnomAD4 genome 0.000808 AC: 123AN: 152232Hom.: 0 Cov.: 33 AF XY: 0.000699 AC XY: 52AN XY: 74414
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ClinVar
Significance: Conflicting classifications of pathogenicity
Submissions summary: Uncertain:10Benign:13
Revision: criteria provided, conflicting classifications
LINK: link
Submissions by phenotype
not provided Uncertain:3Benign:6
| Likely benign, no assertion criteria provided | clinical testing | Diagnostic Laboratory, Department of Genetics, University Medical Center Groningen | - | - - |
| Uncertain significance, criteria provided, single submitter | clinical testing | Mayo Clinic Laboratories, Mayo Clinic | Aug 07, 2020 | - - |
| 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 | Joint Genome Diagnostic Labs from Nijmegen and Maastricht, Radboudumc and MUMC+ | - | - - |
| Likely benign, no assertion criteria provided | clinical testing | Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center | - | - - |
| Likely benign, criteria provided, single submitter | clinical testing | GeneDx | May 19, 2021 | This variant is associated with the following publications: (PMID: 25163546, 27930701, 28771489, 23861362) - |
| Uncertain significance, criteria provided, single submitter | clinical testing | Eurofins Ntd Llc (ga) | Oct 06, 2015 | - - |
| Likely benign, criteria provided, single submitter | research | Biesecker Lab/Clinical Genomics Section, National Institutes of Health | Jun 24, 2013 | - - |
| Uncertain significance, criteria provided, single submitter | clinical testing | CeGaT Center for Human Genetics Tuebingen | Mar 01, 2024 | - - |
not specified Uncertain:1Benign:2
| Likely benign, criteria provided, single submitter | clinical testing | Women's Health and Genetics/Laboratory Corporation of America, LabCorp | Mar 21, 2023 | - - |
| 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 | Mar 04, 2015 | Variant classified as Uncertain Significance - Favor Benign. The p.Asp6524Asn va riant in TTN has been previously identified by our laboratory in 4 individuals w ith cardiomyopathy (1 infant with LVNC, 1 infant with RCM, 1 adult with HCM, and 1 adult with DCM). This variant has also been identified in 0.1% (85/66642) of European chromosomes by the Exome Aggregation Consortium (ExAC, http://exac.broa dinstitute.org; dbSNP rs72648973). Computational prediction tools and conservati on analysis suggest that this variant may impact the protein, though this inform ation is not predictive enough to determine pathogenicity. In summary, while the clinical significance of the p.Asp6524Asn variant is uncertain, the broad pheno typic spectrum seen in individuals with this variant and its frequency in the ge neral population suggest that it is more likely to be benign. - |
Early-onset myopathy with fatal cardiomyopathy Uncertain:2
| Uncertain significance, criteria provided, single submitter | clinical testing | Baylor Genetics | Jul 01, 2020 | This variant was determined to be of uncertain significance according to ACMG Guidelines, 2015 [PMID:25741868]. - |
| 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 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. - |
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. - |
Tip-toe gait Uncertain:1
| Uncertain significance, criteria provided, single submitter | clinical testing | Practice for Gait Abnormalities, David Pomarino, Competency Network Toe Walking c/o Practice Pomarino | Nov 27, 2020 | Myopathy refers to diseases that affect skeletal Muscles. These diseases attack muscle fibers, making muscles weak. Inherited myopathies are often caused by inheriting an abnormal gene mutation from a parent that causes the disease. Symptoms of congenital myopathies usually start at birth or in early childhood, but may not appear until the teen years or even later in adulthood. Congenital myopathies are somewhat unique compared with other inherited myopathies, as weakness typically affects all muscles and is often not progressive. Symptoms are: Muscle weakness, most commonly of upper arms and shoulders and thighs, muscle cramps, stiffness and spasms, fatigue with exertion and lack of energy. Our patients all walk on tiptoe, so they show similar symptoms. When we genetically test them with our toe walking panel, we find that around 90 per cent of them have a genetic variant that explains their toe walking. These can be assigned, for example, to the area of myopathies (such as variants of the COL6A3 gene), the area of hereditary neuropathies (such as variants of the KMT2C gene) or the area of metabolic diseases (such as variants of the PYGM gene). In a smaller group of patients with almost identical symptoms, no abnormality is found in the genes of our panel, but spastic paraplegia can be detected. In another small group of our toe walkers, no abnormalities can be detected in the genes analysed in our toe walking panel, nor do they suffer from spastic paraplegia, as is also the case with healthy children. In contrast to these, however, they show a tiptoe gait. These patients suffer from infantile cerebral palsy, in which toe walking can also be observed. - |
Cardiovascular phenotype Uncertain:1
| Uncertain significance, criteria provided, single submitter | clinical testing | Ambry Genetics | May 03, 2013 | There is insufficient or conflicting evidence for classification of this alteration. - |
TTN-related disorder Benign:1
| Likely benign, no assertion criteria provided | clinical testing | PreventionGenetics, part of Exact Sciences | Oct 03, 2023 | This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). - |
Autosomal recessive limb-girdle muscular dystrophy type 2J;C1858763:Dilated cardiomyopathy 1G Benign:1
| Likely benign, criteria provided, single submitter | clinical testing | Labcorp Genetics (formerly Invitae), Labcorp | Jan 25, 2024 | - - |
Cardiomyopathy Benign:1
| Benign, criteria provided, single submitter | clinical testing | CHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern Ontario | Dec 05, 2017 | - - |
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. - |
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. - |
Computational scores
Source:
Name
Calibrated prediction
Score
Prediction
AlphaMissense
Pathogenic
BayesDel_addAF
Benign
T
BayesDel_noAF
Benign
CADD
Benign
DANN
Benign
Eigen
Pathogenic
Eigen_PC
Pathogenic
FATHMM_MKL
Pathogenic
D
LIST_S2
Benign
T;T;.;T
M_CAP
Benign
D
MetaRNN
Benign
T;T;T;T
MetaSVM
Uncertain
D
PrimateAI
Uncertain
T
PROVEAN
Uncertain
D;.;.;.
REVEL
Uncertain
Sift
Benign
T;.;.;.
Polyphen
1.0
.;.;D;D
Vest4
MVP
MPC
0.46
ClinPred
T
GERP RS
Splicing
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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