2-178783799-A-G

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -5 ACMG points: 0P and 5B. BP4_StrongBP6

The NM_001267550.2(TTN):c.2776-14T>C variant causes a intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000104 in 1,609,644 control chromosomes in the GnomAD database, including 1 homozygotes. 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 0.000079 ( 0 hom., cov: 32)

Exomes 𝑓: 0.00011 ( 1 hom. )

Consequence

TTN
NM_001267550.2 intron

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:4B:6

Conservation

PhyloP100: 2.67

Publications

0 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: Likely_benign. The variant received -5 ACMG points.

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.72).

BP6

Variant 2-178783799-A-G is Benign according to our data. Variant chr2-178783799-A-G is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 46850.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2 link	c.2776-14T>C		intron_variant	Intron 16 of 362	ENST00000589042.5	NP_001254479.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5 link	c.2776-14T>C		intron_variant	Intron 16 of 362	5	NM_001267550.2	ENSP00000467141.1

Frequencies

GnomAD3 genomes

AF:

0.0000789

AC:

AN:

152042

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00288

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

GnomAD2 exomes

AF:

0.000219

AC:

AN:

250838

AF XY:

0.000243

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00468

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000618

Gnomad OTH exome

AF:

0.000164

GnomAD4 exome

AF:

0.000106

AC:

155

AN:

1457602

Hom.:

Cov.:

AF XY:

0.000121

AC XY:

AN XY:

725378

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33358

American (AMR)

AF:

0.00

AC:

AN:

44700

Ashkenazi Jewish (ASJ)

AF:

0.00426

AC:

111

AN:

26046

East Asian (EAS)

AF:

0.00

AC:

AN:

39580

South Asian (SAS)

AF:

0.00

AC:

AN:

86170

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53276

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5756

European-Non Finnish (NFE)

AF:

0.0000289

AC:

AN:

1108502

Other (OTH)

AF:

0.000199

AC:

AN:

60214

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.472

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Exome Hom

Variant carriers

<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:

0.0000789

AC:

AN:

152042

Hom.:

Cov.:

AF XY:

0.0000539

AC XY:

AN XY:

74270

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41402

American (AMR)

AF:

0.00

AC:

AN:

15254

Ashkenazi Jewish (ASJ)

AF:

0.00288

AC:

AN:

3468

East Asian (EAS)

AF:

0.00

AC:

AN:

5186

South Asian (SAS)

AF:

0.00

AC:

AN:

4814

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10586

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000294

AC:

AN:

68016

Other (OTH)

AF:

0.00

AC:

AN:

2088

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.517

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<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:

0.000608

Hom.:

Bravo

AF:

0.000132

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:4Benign:6

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not specified

Uncertain:1Benign:2

Mar 08, 2013

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The 2776-14T>C variant in TTN has not been reported in the literature nor previo usly identified by our laboratory. This variant has been identified in 1/1275 ch romosomes from a broad, though clinically and racially unspecified population (d bSNP rs201611946). This variant is located in the 3' splice region. Computationa l tools do not suggest an impact to splicing. However, this information is not p redictive enough to rule out pathogenicity. Additional studies are needed to ful ly assess its clinical significance.

Sep 14, 2017

GeneDx

Significance:Likely 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.

Dec 12, 2024

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

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Autosomal recessive limb-girdle muscular dystrophy type 2J

Uncertain:1

Jan 12, 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 12, 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 12, 2018

Illumina Laboratory Services, Illumina

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

TTN-related disorder

Benign:1

Oct 28, 2022

PreventionGenetics, part of Exact Sciences

Significance:Likely benign

Review Status:no assertion criteria provided

Collection Method:clinical testing

This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications).

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

Benign:1

Jan 21, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Tibial muscular dystrophy

Benign:1

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.

Myopathy, myofibrillar, 9, with early respiratory failure

Benign:1

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.

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.72

CADD

Benign

(source)

DANN

Benign

0.82

PhyloP100

2.7

Mutation Taster

=99/1

polymorphism

(source)

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

You must be logged in to view publications. This limit was set because tens of millions (!) of queries from AI bots are generated daily.

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