2-178785974-C-T

Variant names:

Variant summary

Our verdict is Benign. The variant received -19 ACMG points: 0P and 19B. BP4_ModerateBP6_Very_StrongBP7BA1

The NM_001267550.2(TTN):c.2244G>A(p.Glu748Glu) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.369 in 1,613,814 control chromosomes in the GnomAD database, including 116,401 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Benign (★★).

Frequency

Genomes: 𝑓 0.32 ( 8777 hom., cov: 31)

Exomes 𝑓: 0.37 ( 107624 hom. )

Consequence

TTN
NM_001267550.2 synonymous

Scores

Clinical Significance

Benign criteria provided, multiple submitters, no conflicts B:22

Conservation

PhyloP100: 2.15

Publications

17 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 Gene-Disease associations (from GenCC):

dilated cardiomyopathy
Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
dilated cardiomyopathy 1G
Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, G2P
early-onset myopathy with fatal cardiomyopathy
Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet, G2P
TTN-related myopathy
Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
myopathy, myofibrillar, 9, with early respiratory failure
Inheritance: AD Classification: STRONG, MODERATE, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet, ClinGen, Ambry Genetics
tibial muscular dystrophy
Inheritance: AD Classification: STRONG, MODERATE, SUPPORTIVE Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae), ClinGen, Orphanet
autosomal recessive limb-girdle muscular dystrophy type 2J
Inheritance: AR Classification: STRONG, MODERATE, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, Orphanet
hypertrophic cardiomyopathy 9
Inheritance: AD Classification: MODERATE, LIMITED Submitted by: Labcorp Genetics (formerly Invitae), PanelApp Australia
familial isolated dilated cardiomyopathy
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
autosomal recessive centronuclear myopathy
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
childhood-onset progressive contractures-limb-girdle weakness-muscle dystrophy syndrome
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
arrhythmogenic right ventricular cardiomyopathy
Inheritance: AD Classification: LIMITED Submitted by: ClinGen
congenital myopathy
Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics
hereditary skeletal muscle disorder
Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics
hypertrophic cardiomyopathy
Inheritance: AD Classification: LIMITED Submitted by: ClinGen

TTN links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Benign. The variant received -19 ACMG points.

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.35).

BP6

Variant 2-178785974-C-T is Benign according to our data. Variant chr2-178785974-C-T is described in ClinVar as Benign. ClinVar VariationId is 46774.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

BP7

Synonymous conserved (PhyloP=2.15 with no splicing effect.

BA1

GnomAd4 highest subpopulation (NFE) allele frequency at 95% confidence interval = 0.405 is higher than 0.05.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2 link	c.2244G>A	p.Glu748Glu	synonymous_variant	Exon 14 of 363	ENST00000589042.5	NP_001254479.2	A0A0A0MTS7
TTN	NM_133379.5 link	c.2244G>A	p.Glu748Glu	synonymous_variant	Exon 14 of 46	ENST00000360870.10	NP_596870.2	Q8WZ42-6Q7Z3B7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5 link	c.2244G>A	p.Glu748Glu	synonymous_variant	Exon 14 of 363	5	NM_001267550.2	ENSP00000467141.1		A0A0A0MTS7
TTN	ENST00000360870.10 link	c.2244G>A	p.Glu748Glu	synonymous_variant	Exon 14 of 46	5	NM_133379.5	ENSP00000354117.4		Q8WZ42-6

Frequencies

GnomAD3 genomes

AF:

0.320

AC:

48659

AN:

151868

Hom.:

8780

Cov.:

show subpopulations

Gnomad AFR

AF:

0.194

Gnomad AMI

AF:

0.563

Gnomad AMR

AF:

0.245

Gnomad ASJ

AF:

0.336

Gnomad EAS

AF:

0.0816

Gnomad SAS

AF:

0.251

Gnomad FIN

AF:

0.475

Gnomad MID

AF:

0.414

Gnomad NFE

AF:

0.409

Gnomad OTH

AF:

0.317

GnomAD2 exomes

AF:

0.316

AC:

79397

AN:

251086

AF XY:

0.323

show subpopulations

Gnomad AFR exome

AF:

0.192

Gnomad AMR exome

AF:

0.170

Gnomad ASJ exome

AF:

0.329

Gnomad EAS exome

AF:

0.0729

Gnomad FIN exome

AF:

0.470

Gnomad NFE exome

AF:

0.403

Gnomad OTH exome

AF:

0.334

GnomAD4 exome

AF:

0.374

AC:

547035

AN:

1461828

Hom.:

107624

Cov.:

AF XY:

0.372

AC XY:

270315

AN XY:

727220

show subpopulations

African (AFR)

AF:

0.189

AC:

6335

AN:

33480

American (AMR)

AF:

0.178

AC:

7943

AN:

44722

Ashkenazi Jewish (ASJ)

AF:

0.328

AC:

8582

AN:

26136

East Asian (EAS)

AF:

0.0662

AC:

2628

AN:

39690

South Asian (SAS)

AF:

0.256

AC:

22068

AN:

86258

European-Finnish (FIN)

AF:

0.462

AC:

24680

AN:

53412

Middle Eastern (MID)

AF:

0.380

AC:

2190

AN:

5768

European-Non Finnish (NFE)

AF:

0.406

AC:

451696

AN:

1111972

Other (OTH)

AF:

0.346

AC:

20913

AN:

60390

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.484

Heterozygous variant carriers

22598

45196

67793

90391

112989

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Exome Hom

Variant carriers

13544

27088

40632

54176

67720

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.320

AC:

48653

AN:

151986

Hom.:

8777

Cov.:

AF XY:

0.317

AC XY:

23520

AN XY:

74276

show subpopulations

African (AFR)

AF:

0.193

AC:

8011

AN:

41440

American (AMR)

AF:

0.244

AC:

3728

AN:

15270

Ashkenazi Jewish (ASJ)

AF:

0.336

AC:

1164

AN:

3466

East Asian (EAS)

AF:

0.0816

AC:

423

AN:

5184

South Asian (SAS)

AF:

0.251

AC:

1204

AN:

4804

European-Finnish (FIN)

AF:

0.475

AC:

5007

AN:

10544

Middle Eastern (MID)

AF:

0.428

AC:

125

AN:

292

European-Non Finnish (NFE)

AF:

0.409

AC:

27815

AN:

67966

Other (OTH)

AF:

0.315

AC:

663

AN:

2108

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.501

Heterozygous variant carriers

1588

3175

4763

6350

7938

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Genome Hom

Variant carriers

478

956

1434

1912

2390

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.364

Hom.:

19082

Bravo

AF:

0.294

Asia WGS

AF:

0.152

AC:

530

AN:

3478

EpiCase

AF:

0.396

EpiControl

AF:

0.392

ClinVar

Significance: Benign

Submissions summary: Benign:22

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not specified

Benign:9

Aug 15, 2013

Genetic Services Laboratory, University of Chicago

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Aug 09, 2019

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

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Sep 16, 2011

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center

Significance:Benign

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Oct 30, 2012

GeneDx

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

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. -

Clinical Genetics, Academic Medical Center

Significance:Benign

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Diagnostic Laboratory, Department of Genetics, University Medical Center Groningen

Significance:Benign

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

PreventionGenetics, part of Exact Sciences

Significance: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:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Autosomal recessive limb-girdle muscular dystrophy type 2J

Benign:2

Sep 10, 2021

Genome-Nilou Lab

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Jan 12, 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. -

Early-onset myopathy with fatal cardiomyopathy

Benign:2

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Sep 10, 2021

Genome-Nilou Lab

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

not provided

Benign:2

Nov 02, 2018

Athena Diagnostics

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Breakthrough Genomics, Breakthrough Genomics

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:not provided

- -

Tibial muscular dystrophy

Benign:2

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Sep 10, 2021

Genome-Nilou Lab

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Myopathy, myofibrillar, 9, with early respiratory failure

Benign:2

Sep 10, 2021

Genome-Nilou Lab

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

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

Benign:1

Feb 04, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Dilated cardiomyopathy 1G

Benign:1

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Cardiovascular phenotype

Benign:1

Feb 07, 2019

Ambry Genetics

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This alteration is classified as benign based on a combination of the following: 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

BayesDel_noAF

Benign

-0.35

CADD

Benign

(source)

DANN

Benign

0.42

PhyloP100

2.2

Mutation Taster

=83/17

polymorphism (auto)

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.060

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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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