rs751502842

Variant names:

Your query was ambiguous. Multiple possible variants found:

Variant summary

Our verdict is Pathogenic. Variant got 19 ACMG points: 19P and 0B. PVS1PM2PP3PP5_Very_Strong

The NM_001267550.2(TTN):c.50083C>T(p.Arg16695*) variant causes a stop gained change. The variant allele was found at a frequency of 0.00000205 in 1,460,466 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: not found (cov: 33)

Exomes 𝑓: 0.0000021 ( 0 hom. )

Consequence

TTN
NM_001267550.2 stop_gained

Scores

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:8

Conservation

PhyloP100: 4.76

Variant links:

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]

TTN links:

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]

TTN-AS1 links:

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ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 19 ACMG points.

PVS1

Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.

PM2

Very rare variant in population databases, with high coverage;

PP3

Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.

PP5

Variant 2-178612442-G-A is Pathogenic according to our data. Variant chr2-178612442-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 202377.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr2-178612442-G-A is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2 link	c.50083C>T	p.Arg16695*	stop_gained	Exon 266 of 363	ENST00000589042.5	NP_001254479.2	A0A0A0MTS7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5 link	c.50083C>T	p.Arg16695*	stop_gained	Exon 266 of 363	5	NM_001267550.2	ENSP00000467141.1		A0A0A0MTS7

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

0.00000205

AC:

AN:

1460466

Hom.:

Cov.:

AF XY:

0.00000275

AC XY:

AN XY:

726530

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.0000188

Gnomad4 NFE exome

AF:

0.00000180

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

Cov.:

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:8

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Pathogenic:4

May 27, 2022

Clinical Genetics Laboratory, Skane University Hospital Lund

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Nov 03, 2015

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The Arg15054Stop variant in the TTN gene has not been reported previously as a disease-causing mutation nor as a benign polymorphism, to our knowledge. Arg15054Stop is predicted to cause loss of normal protein function either due to production of an abnormal, prematurely truncated protein, or by absence of protein product due to nonsense mediated mRNA decay. Arg15054Stop is located in the A-band region of titin, where the majority of truncating mutations associated with DCM have been reported (Herman D et al., 2012). -

Clinical Genetics, Academic Medical Center

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Diagnostic Laboratory, Department of Genetics, University Medical Center Groningen

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Autosomal recessive limb-girdle muscular dystrophy type 2J;C1858763:Dilated cardiomyopathy 1G

Pathogenic:1

Oct 18, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Arg16695*) in the TTN gene. While this is not anticipated to result in nonsense mediated decay, it is expected to create a truncated TTN protein. This variant is not present in population databases (gnomAD no frequency). This premature translational stop signal has been observed in individuals with dilated cardiomyopathy (PMID: 25163546; internal data). ClinVar contains an entry for this variant (Variation ID: 202377). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site. This variant is located in the A band of TTN (PMID: 25589632). Truncating variants in this region are significantly overrepresented in patients affected with dilated cardiomyopathy (PMID: 25589632). Truncating variants in this region have also been reported in individuals affected with autosomal recessive centronuclear myopathy (PMID: 23975875). For these reasons, this variant has been classified as Pathogenic. -

Cardiomyopathy

Pathogenic:1

Jan 03, 2020

CHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern Ontario

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Tibial muscular dystrophy

Pathogenic:1

May 21, 2019

Centre for Mendelian Genomics, University Medical Centre Ljubljana

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was classified as: Pathogenic. The following ACMG criteria were applied in classifying this variant: PVS1,PM2,PP4,PP5. -

Cardiovascular phenotype

Pathogenic:1

Jul 12, 2023

Ambry Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.R7630* variant (also known as c.22888C>T), located in coding exon 93 of the TTN gene, results from a C to T substitution at nucleotide position 22888. This changes the amino acid from an arginine to a stop codon within coding exon 93. This exon is located in the A-band region of the N2-B isoform of the titin protein and is constitutively expressed in TTN transcripts (percent spliced in or PSI 100%). This variant (also referred to as NM_133437:c.23464C>T p.R7822X) has been detected in a dilated cardiomyopathy cohort (Haas J et al. Eur Heart J, 2015 May;36:1123-35a). This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). This alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. While truncating variants in TTN are present in 1-3% of the general population, truncating variants in the A-band are the most common cause of dilated cardiomyopathy (DCM) (Herman DS et al. N. Engl. J. Med., 2012 Feb;366:619-28; Roberts AM et al. Sci Transl Med, 2015 Jan;7:270ra6). TTN truncating variants encoded in constitutive exons (PSI >90%) have been found to be significantly associated with DCM regardless of their position in titin (Schafer S et al. Nat. Genet., 2017 01;49:46-53). Based on the majority of available evidence to date, this variant is likely to be pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.61

BayesDel_noAF

Pathogenic

0.63

CADD

Pathogenic

DANN

Uncertain

0.99

Eigen

Pathogenic

0.99

Eigen_PC

Pathogenic

0.83

FATHMM_MKL

Uncertain

0.96

Vest4

0.97

GERP RS

4.8

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.57

Details are displayed if max score is > 0.2

DS_DG_spliceai

0.57

Position offset: 2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over