2-178720250-C-T

Variant names:

Variant summary

Our verdict is Likely benign. Variant got -3 ACMG points: 0P and 3B. BP4_ModerateBP6

The NM_001267550.2(TTN):c.23392G>A(p.Val7798Met) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000193 in 1,609,750 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/18 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 0.000013 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000020 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:7B:2

Conservation

PhyloP100: 0.302

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:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -3 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.120987624).

BP6

Variant 2-178720250-C-T is Benign according to our data. Variant chr2-178720250-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 46719.We mark this variant Likely_benign, oryginal submissions are: {Benign=2, Uncertain_significance=7}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2 link	c.23392G>A	p.Val7798Met	missense_variant	Exon 81 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.23392G>A	p.Val7798Met	missense_variant	Exon 81 of 363	5	NM_001267550.2	ENSP00000467141.1		A0A0A0MTS7

Frequencies

GnomAD3 genomes

AF:

0.0000197

AC:

AN:

152084

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000655

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000294

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000407

AC:

AN:

245768

Hom.:

AF XY:

0.0000601

AC XY:

AN XY:

133160

show subpopulations

Gnomad AFR exome

AF:

0.000130

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.000134

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000360

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000199

AC:

AN:

1457548

Hom.:

Cov.:

AF XY:

0.0000249

AC XY:

AN XY:

724342

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:

0.0000700

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000198

Gnomad4 OTH exome

AF:

0.0000166

GnomAD4 genome

AF:

0.0000131

AC:

AN:

152202

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74394

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000294

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000434

Hom.:

Bravo

AF:

0.0000151

ESP6500AA

AF:

0.000268

AC:

ESP6500EA

AF:

0.000122

AC:

ExAC

AF:

0.0000497

AC:

Asia WGS

AF:

0.000866

AC:

AN:

3478

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:7Benign:2

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:3

Jun 28, 2016

Eurofins Ntd Llc (ga)

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Feb 15, 2024

Athena Diagnostics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Available data are insufficient to determine the clinical significance of the variant at this time. The frequency of this variant in the general population is uninformative in assessment of its pathogenicity. (http://gnomad.broadinstitute.org) Computational tools disagree on the variant's effect on normal protein function. -

Sep 03, 2019

Revvity Omics, Revvity

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not specified

Uncertain:1

Feb 11, 2013

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant classified as Uncertain Significance - Favor Benign. The Val6554Met vari ant in TTN has not been reported in the literature nor previously identified by our laboratory. This variant has been identified in 2/122 African American chrom osomes from a broad population by the 1000 Genomes project (dbSNP rs144032104). Computational analyses (biochemical amino acid properties, conservation, AlignGV GD, and SIFT) suggest that the variant may not impact the protein and orangutan carries a methionine (Met; this variant) at this position, raising the possibili ty that this change may be tolerated. However, this computational information is not predictive enough to rule out pathogenicity. Although this data supports th at the Val6554Met variant may be benign, additional studies are needed to fully assess its clinical significance. -

Autosomal recessive limb-girdle muscular dystrophy type 2J

Uncertain:1

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Early-onset myopathy with fatal cardiomyopathy

Uncertain:1

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Myopathy, myofibrillar, 9, with early respiratory failure

Benign:1

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.18

BayesDel_addAF

Benign

-0.39

BayesDel_noAF

Benign

-0.59

CADD

Benign

DANN

Benign

0.83

Eigen

Uncertain

0.36

Eigen_PC

Uncertain

0.34

FATHMM_MKL

Uncertain

0.88

LIST_S2

Benign

0.71

T;T;.;T

M_CAP

Benign

0.041

MetaRNN

Benign

0.12

T;T;T;T

MetaSVM

Benign

-0.64

PrimateAI

Benign

0.41

PROVEAN

Benign

-1.2

N;.;.;.

REVEL

Benign

0.18

Sift

Benign

0.050

D;.;.;.

Polyphen

1.0

.;.;D;D

Vest4

0.23

MVP

0.28

MPC

0.36

ClinPred

0.068

GERP RS

5.0

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.010

Details are displayed if max score is > 0.2

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