NM_001267550.2:c.26528C>T

Variant names:

Variant summary

Our verdict is Benign. The variant received -13 ACMG points: 0P and 13B. BP4_StrongBP6BS1BS2

The NM_001267550.2(TTN):c.26528C>T(p.Thr8843Met) variant causes a missense change. The variant allele was found at a frequency of 0.000381 in 1,613,490 control chromosomes in the GnomAD database, including 2 homozygotes. In-silico tool predicts a benign outcome for this variant. 13/19 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. T8843K) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.00032 ( 0 hom., cov: 33)

Exomes 𝑓: 0.00039 ( 2 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:7B:6

Conservation

PhyloP100: 6.58

Publications

6 publications found

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:

LOC124906100 (HGNC:):

LOC124906100 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Benign. The variant received -13 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.065653354).

BP6

Variant 2-178714130-G-A is Benign according to our data. Variant chr2-178714130-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 46782.We mark this variant Benign, oryginal submissions are: {Uncertain_significance=7, Likely_benign=6}.

BS1

Variant frequency is greater than expected in population mid. GnomAdExome4 allele frequency = 0.000388 (567/1461286) while in subpopulation MID AF = 0.00295 (17/5762). AF 95% confidence interval is 0.00188. There are 2 homozygotes in GnomAdExome4. There are 286 alleles in the male GnomAdExome4 subpopulation. Median coverage is 34. This position passed quality control check.

BS2

High Homozygotes in GnomAdExome4 at 2 AD,AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2 link	c.26528C>T	p.Thr8843Met	missense_variant	Exon 92 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.26528C>T	p.Thr8843Met	missense_variant	Exon 92 of 363	5	NM_001267550.2	ENSP00000467141.1		A0A0A0MTS7

Frequencies

GnomAD3 genomes

AF:

0.000322

AC:

AN:

152086

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000121

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000524

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00633

Gnomad NFE

AF:

0.000426

Gnomad OTH

AF:

0.00240

GnomAD2 exomes

AF:

0.000402

AC:

100

AN:

248552

AF XY:

0.000378

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00108

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000435

Gnomad OTH exome

AF:

0.000831

GnomAD4 exome

AF:

0.000388

AC:

567

AN:

1461286

Hom.:

Cov.:

AF XY:

0.000393

AC XY:

286

AN XY:

726900

show subpopulations

African (AFR)

AF:

0.000239

AC:

AN:

33438

American (AMR)

AF:

0.00103

AC:

AN:

44680

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26122

East Asian (EAS)

AF:

0.00

AC:

AN:

39692

South Asian (SAS)

AF:

0.000429

AC:

AN:

86178

European-Finnish (FIN)

AF:

0.0000375

AC:

AN:

53390

Middle Eastern (MID)

AF:

0.00295

AC:

AN:

5762

European-Non Finnish (NFE)

AF:

0.000376

AC:

418

AN:

1111672

Other (OTH)

AF:

0.000646

AC:

AN:

60352

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.487

Heterozygous variant carriers

131

164

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

AF:

0.000315

AC:

AN:

152204

Hom.:

Cov.:

AF XY:

0.000282

AC XY:

AN XY:

74410

show subpopulations

African (AFR)

AF:

0.000120

AC:

AN:

41538

American (AMR)

AF:

0.000523

AC:

AN:

15282

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5176

South Asian (SAS)

AF:

0.00

AC:

AN:

4814

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10606

Middle Eastern (MID)

AF:

0.00340

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.000426

AC:

AN:

68006

Other (OTH)

AF:

0.00237

AC:

AN:

2106

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.498

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.000409

Hom.:

Bravo

AF:

0.000472

TwinsUK

AF:

0.000270

AC:

ALSPAC

AF:

0.000519

AC:

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000856

AC:

ExAC

AF:

0.000348

AC:

EpiCase

AF:

0.000764

EpiControl

AF:

0.000652

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:7Benign:6

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:2Benign:4

Jul 03, 2018

Eurofins Ntd Llc (ga)

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Feb 24, 2021

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The TTN c.26528C>T; p.Thr8843Met variant (rs72648990; ClinVar Variation ID: 46782) is rare in the general population (<0.2% allele frequency in the Genome Aggregation Database) and has not been reported in the medical literature in association with dilated cardiomyopathy (DCM) or other TTN-related disease. The clinical relevance of rare missense variants in this gene, which are identified on average once per individual sequenced in affected populations (Herman 2012), is not well understood. Yet, evidence suggests that the vast majority of such missense variants do not contribute to the clinical outcome of DCM (Begay 2015). Given the available evidence, the clinical significance of the p.Thr8843Met variant cannot be determined with certainty. -

Feb 22, 2021

GeneDx

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant is associated with the following publications: (PMID: 24503780, 27066507) -

Jul 01, 2023

CeGaT Center for Human Genetics Tuebingen

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

TTN: BP4 -

Dec 30, 2019

Athena Diagnostics

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

May 30, 2023

Revvity Omics, Revvity

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

not specified

Uncertain:1Benign:2

Jun 28, 2017

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 p.Thr7599Met va riant in TTN has been identified by our laboratory in 1 Asian adult with HCM, 1 Ethiopian neonate with congenital HCM, and 2 Caucasian adults with DCM, of which 1 carried a likely pathogenic variant in another gene sufficient to explain the ir disease (Pugh 2014). Additionally, this variant has been identified in 0.1% ( 38/34342) of Latino chromosomes by the Genome Aggregation Database (gnomAD, http ://gnomad.broadinstitute.org/; dbSNP rs72648990) and has been reported in ClinVa r (Variation ID: 46782). Threonine (Thr) at position 7599 is not conserved in ma mmals or evolutionarily distant species, and one mammal (white rhinoceros) carri es a methionine (Met) at this position, raising the possibility that this change may be tolerated. Additional computational prediction tools do not provide stro ng support for or against an impact to the protein. In summary, while the clinic al significance of the p.Thr7599Met variant is uncertain, its frequency and lack of conservation suggest that it is more likely to be benign. -

Aug 06, 2022

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Apr 09, 2025

Molecular Diagnostic Laboratory for Inherited Cardiovascular Disease, Montreal Heart Institute

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

TTN-related disorder

Uncertain:1

Aug 07, 2018

Genomic Research Center, Shahid Beheshti University of Medical Sciences

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

Aug 22, 2017

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Autosomal recessive limb-girdle muscular dystrophy type 2J;C1838244:Tibial muscular dystrophy;C1858763:Dilated cardiomyopathy 1G;C1861065:Hypertrophic cardiomyopathy 9;C1863599:Myopathy, myofibrillar, 9, with early respiratory failure;C2673677:Early-onset myopathy with fatal cardiomyopathy

Uncertain:1

Jan 25, 2023

Department of Pathology and Laboratory Medicine, Sinai Health System

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:research

- -

Hypertrophic cardiomyopathy

Uncertain:1

Genetics and Genomics Program, Sidra Medicine

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:research

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.085

BayesDel_addAF

Benign

-0.47

BayesDel_noAF

Benign

-0.50

CADD

Benign

(source)

DANN

Benign

0.90

Eigen

Benign

0.13

Eigen_PC

Uncertain

0.34

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Benign

0.82

T;T;.;T

M_CAP

Benign

0.034

MetaRNN

Benign

0.066

T;T;T;T

MetaSVM

Benign

-1.0

PhyloP100

6.6

PrimateAI

Benign

0.32

PROVEAN

Uncertain

-2.5

D;.;.;.

REVEL

Benign

0.14

Sift

Benign

0.085

T;.;.;.

Polyphen

0.029

.;.;B;B

Vest4

0.19

MVP

0.30

MPC

0.089

ClinPred

0.047

GERP RS

5.9

Mutation Taster

=88/12

polymorphism

(source)

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

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NM_001267550.2:c.26528C>T

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over