Our verdict is Benign. Variant got -8 ACMG points: 1P and 9B. PP2BP4_StrongBP6BS1
The NM_001267550.2(TTN):c.32186C>T(p.Thr10729Met) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000207 in 1,612,070 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/18 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).
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]
TTN-AS1 (HGNC:44124): (TTN antisense RNA 1) This gene encodes a non-coding RNA transcribed from the opposite strand to the titin gene. [provided by RefSeq, Aug 2016]
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=0.005835533).
BP6
Variant 2-178688688-G-A is Benign according to our data. Variant chr2-178688688-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 46860.We mark this variant Likely_benign, oryginal submissions are: {Benign=2, Uncertain_significance=2, Likely_benign=4}.
BS1
Variant frequency is greater than expected in population afr. gnomad4 allele frequency = 0.00111 (169/152284) while in subpopulation AFR AF= 0.00392 (163/41556). AF 95% confidence interval is 0.00343. There are 0 homozygotes in gnomad4. There are 73 alleles in male gnomad4 subpopulation. Median coverage is 32. This position pass quality control queck.
Likely benign, criteria provided, single submitter
clinical testing
Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine
Apr 18, 2012
Thr9485Met in exon 123 of TTN: This variant is not expected to have clinical sig nificance because it has been identified in 0.4% (11/3076) of African American c hromosomes from a broad population by the NHLBI Exome Sequencing Project (http:/ /evs.gs.washington.edu/EVS; dbSNP rs115119858). Thr9485Met in exon 123 of TTN ( rs115119858; allele frequency = 0.4%, 11/3076) ** -
Likely benign, criteria provided, single submitter
clinical testing
GeneDx
Oct 23, 2017
This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease. -
Likely benign, criteria provided, single submitter
clinical testing
Eurofins Ntd Llc (ga)
Jul 29, 2015
- -
Benign, criteria provided, single submitter
clinical testing
Athena Diagnostics
Feb 17, 2020
- -
Dilated cardiomyopathy 1G;C1861065:Hypertrophic cardiomyopathy 9;C2673677:Early-onset myopathy with fatal cardiomyopathy Uncertain:1
Uncertain significance, criteria provided, single submitter
clinical testing
New York Genome Center
Jul 12, 2019
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Cardiovascular phenotype Uncertain:1
Uncertain significance, criteria provided, single submitter
clinical testing
Ambry Genetics
May 20, 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
Aug 31, 2020
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 24, 2024
- -
Cardiomyopathy Benign:1
Benign, criteria provided, single submitter
clinical testing
CHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern Ontario