NM_001267550.2:c.78446C>G

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.78446C>G(p.Thr26149Ser) variant causes a missense change. The variant allele was found at a frequency of 0.000044 in 1,612,068 control chromosomes in the GnomAD database, with no homozygous occurrence. 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 0.00022 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000025 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3B:2

Conservation

PhyloP100: 5.84

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=0.0845809).

BP6

Variant 2-178567686-G-C is Benign according to our data. Variant chr2-178567686-G-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 202889.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=2, Uncertain_significance=3}. Variant chr2-178567686-G-C is described in Lovd as [Likely_benign].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2 link	c.78446C>G	p.Thr26149Ser	missense_variant	Exon 326 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.78446C>G	p.Thr26149Ser	missense_variant	Exon 326 of 363	5	NM_001267550.2	ENSP00000467141.1		A0A0A0MTS7

Frequencies

GnomAD3 genomes

AF:

0.000217

AC:

AN:

152112

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000772

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

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:

0.00

Gnomad OTH

AF:

0.000478

GnomAD3 exomes

AF:

0.0000647

AC:

AN:

247336

Hom.:

AF XY:

0.0000820

AC XY:

AN XY:

134130

show subpopulations

Gnomad AFR exome

AF:

0.000711

Gnomad AMR exome

AF:

0.000116

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.000167

GnomAD4 exome

AF:

0.0000253

AC:

AN:

1459838

Hom.:

Cov.:

AF XY:

0.0000262

AC XY:

AN XY:

725930

show subpopulations

Gnomad4 AFR exome

AF:

0.000778

Gnomad4 AMR exome

AF:

0.000112

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

9.00e-7

Gnomad4 OTH exome

AF:

0.0000829

GnomAD4 genome

AF:

0.000223

AC:

AN:

152230

Hom.:

Cov.:

AF XY:

0.000228

AC XY:

AN XY:

74410

show subpopulations

Gnomad4 AFR

AF:

0.000794

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:

0.00

Gnomad4 OTH

AF:

0.000473

Alfa

AF:

0.000142

Hom.:

Bravo

AF:

0.000287

ESP6500AA

AF:

0.00104

AC:

ESP6500EA

AF:

0.00

AC:

ExAC

AF:

0.0000662

AC:

Asia WGS

AF:

0.000289

AC:

AN:

3478

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:3Benign:2

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:1Benign:1

Apr 26, 2021

GeneDx

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Nov 08, 2022

Revvity Omics, Revvity

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not specified

Uncertain:1

Feb 06, 2017

Athena Diagnostics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

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

Uncertain:1

May 22, 2017

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces threonine with serine at codon 26149 of the TTN protein (p.Thr26149Ser). There is a small physicochemical difference between threonine and serine. This variant is present in population databases (rs191263181, ExAC 0.06%). This variant has not been reported in the literature in individuals with a TTN-related disease. ClinVar contains an entry for this variant (Variation ID: 202889). This variant identified in the TTN gene is located in the A band of the resulting protein (PMID: 25589632). It is unclear how this variant impacts the function of this protein. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site, but this prediction has not been confirmed by published transcriptional studies. In summary, this variant has uncertain impact on TTN function. The available evidence is currently insufficient to determine its role in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Cardiovascular phenotype

Benign:1

May 18, 2020

Ambry Genetics

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.15

BayesDel_addAF

Benign

-0.28

BayesDel_noAF

Benign

-0.25

CADD

Benign

DANN

Benign

0.84

Eigen

Uncertain

0.58

Eigen_PC

Uncertain

0.58

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Uncertain

0.96

D;D;D;.;D;D;D

M_CAP

Benign

0.029

MetaRNN

Benign

0.085

T;T;T;T;T;T;T

MetaSVM

Benign

-0.44

MutationAssessor

Uncertain

2.4

.;.;.;M;.;.;M

PrimateAI

Uncertain

0.65

PROVEAN

Uncertain

-2.8

D;D;.;.;D;D;.

REVEL

Uncertain

0.29

Sift

Uncertain

0.0080

D;D;.;.;D;D;.

Polyphen

0.82

.;.;.;P;.;.;P

Vest4

0.41

MutPred

0.54

.;.;.;Gain of disorder (P = 0.1057);.;.;Gain of disorder (P = 0.1057);

MVP

0.20

MPC

0.22

ClinPred

0.14

GERP RS

4.9

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.0

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