2-178578951-C-T

Variant names:

Variant summary

Our verdict is Benign. The variant received -21 ACMG points: 0P and 21B. BP4_StrongBP6_Very_StrongBP7BS1BS2

The NM_001267550.2(TTN):c.68079G>A(p.Thr22693Thr) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000947 in 1,613,192 control chromosomes in the GnomAD database, including 7 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★).

Frequency

Genomes: 𝑓 0.0044 ( 0 hom., cov: 32)

Exomes 𝑓: 0.00058 ( 7 hom. )

Consequence

TTN
NM_001267550.2 synonymous

Scores

Clinical Significance

Benign/Likely benign criteria provided, multiple submitters, no conflicts B:20

Conservation

PhyloP100: -3.14

Publications

1 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:

ENSG00000270574 (HGNC:):

ENSG00000270574 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Benign. The variant received -21 ACMG points.

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.63).

BP6

Variant 2-178578951-C-T is Benign according to our data. Variant chr2-178578951-C-T is described in ClinVar as Benign/Likely_benign. ClinVar VariationId is 47260.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

BP7

Synonymous conserved (PhyloP=-3.14 with no splicing effect.

BS1

Variant frequency is greater than expected in population afr. GnomAd4 allele frequency = 0.00444 (675/152080) while in subpopulation AFR AF = 0.0155 (642/41496). AF 95% confidence interval is 0.0145. There are 0 homozygotes in GnomAd4. There are 283 alleles in the male GnomAd4 subpopulation. Median coverage is 32. This position passed quality control check.

BS2

High Homozygotes in GnomAdExome4 at 7 AD,AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2 link	c.68079G>A	p.Thr22693Thr	synonymous_variant	Exon 320 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.68079G>A	p.Thr22693Thr	synonymous_variant	Exon 320 of 363	5	NM_001267550.2	ENSP00000467141.1		A0A0A0MTS7

Frequencies

GnomAD3 genomes

AF:

0.00442

AC:

672

AN:

151962

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0154

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000524

Gnomad ASJ

AF:

0.00461

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000441

Gnomad OTH

AF:

0.00288

GnomAD2 exomes

AF:

0.00142

AC:

352

AN:

248474

AF XY:

0.00102

show subpopulations

Gnomad AFR exome

AF:

0.0167

Gnomad AMR exome

AF:

0.000696

Gnomad ASJ exome

AF:

0.00428

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000142

Gnomad OTH exome

AF:

0.000994

GnomAD4 exome

AF:

0.000584

AC:

853

AN:

1461112

Hom.:

Cov.:

AF XY:

0.000510

AC XY:

371

AN XY:

726846

show subpopulations

African (AFR)

AF:

0.0160

AC:

534

AN:

33442

American (AMR)

AF:

0.000716

AC:

AN:

44700

Ashkenazi Jewish (ASJ)

AF:

0.00456

AC:

119

AN:

26120

East Asian (EAS)

AF:

0.000101

AC:

AN:

39606

South Asian (SAS)

AF:

0.000139

AC:

AN:

86250

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53392

Middle Eastern (MID)

AF:

0.000521

AC:

AN:

5760

European-Non Finnish (NFE)

AF:

0.0000603

AC:

AN:

1111504

Other (OTH)

AF:

0.00136

AC:

AN:

60338

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.473

Heterozygous variant carriers

121

181

242

302

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Exome Hom

Variant carriers

100

<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:

0.00444

AC:

675

AN:

152080

Hom.:

Cov.:

AF XY:

0.00381

AC XY:

283

AN XY:

74340

show subpopulations

African (AFR)

AF:

0.0155

AC:

642

AN:

41496

American (AMR)

AF:

0.000524

AC:

AN:

15274

Ashkenazi Jewish (ASJ)

AF:

0.00461

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5144

South Asian (SAS)

AF:

0.00

AC:

AN:

4818

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10600

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.0000441

AC:

AN:

67968

Other (OTH)

AF:

0.00285

AC:

AN:

2106

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.508

Heterozygous variant carriers

108

144

180

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:

0.00273

Hom.:

Bravo

AF:

0.00508

Asia WGS

AF:

0.000577

AC:

AN:

3478

EpiCase

AF:

0.000218

EpiControl

AF:

0.000237

ClinVar

Significance: Benign/Likely benign

Submissions summary: Benign:20

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not specified

Benign:7

Clinical Genetics, Academic Medical Center

Significance:Benign

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Oct 17, 2020

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

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Mar 19, 2012

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Thr20125Thr in exon 269 of TTN: This variant is not expected to have clinical si gnificance because it does not alter an amino acid residue, is not located withi n the splice consensus sequence, and it has been identified in 1.4% (45/3288) of African American chromosomes from a broad population by the NHLBI Exome Sequenc ing Project (http://evs.gs.washington.edu/EVS/; dbSNP rs11904444). -

Apr 08, 2013

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. -

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

- -

Oct 17, 2024

Athena Diagnostics

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

- -

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 13, 2018

Illumina Laboratory Services, Illumina

Significance:Likely 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 likely benign is not then subjected to further curation. The score for this variant resulted in a classification of likely benign for this disease. -

Early-onset myopathy with fatal cardiomyopathy

Benign:2

Sep 10, 2021

Genome-Nilou Lab

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Tibial muscular dystrophy

Benign:2

Sep 10, 2021

Genome-Nilou Lab

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

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. -

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 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. -

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

Benign:1

Feb 02, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Dilated cardiomyopathy 1G

Benign:1

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Cardiomyopathy

Benign:1

Nov 13, 2020

CHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern Ontario

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

not provided

Benign:1

Jun 21, 2024

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Cardiovascular phenotype

Benign:1

Dec 06, 2012

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: 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

-0.63

CADD

Benign

0.092

(source)

DANN

Benign

0.75

PhyloP100

-3.1

Mutation Taster

=82/18

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

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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