2-178536584-CAAAA-CAAAAA

Variant names:

Variant summary

Our verdict is Benign. The variant received -9 ACMG points: 0P and 9B. BP6BS1BS2

The NM_001267550.2(TTN):c.100172-10dupT variant causes a intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0049 in 1,480,024 control chromosomes in the GnomAD database, including 45 homozygotes. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.0046 ( 4 hom., cov: 33)

Exomes 𝑓: 0.0049 ( 41 hom. )

Consequence

TTN
NM_001267550.2 intron

Scores

Not classified

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:6B:15

Conservation

PhyloP100: 1.72

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:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Benign. The variant received -9 ACMG points.

BP6

Variant 2-178536584-C-CA is Benign according to our data. Variant chr2-178536584-C-CA is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 47626.

BS1

Variant frequency is greater than expected in population sas. GnomAd4 allele frequency = 0.00457 (693/151632) while in subpopulation SAS AF = 0.00933 (45/4822). AF 95% confidence interval is 0.00717. There are 4 homozygotes in GnomAd4. There are 360 alleles in the male GnomAd4 subpopulation. Median coverage is 33. This position passed quality control check.

BS2

High Homozygotes in GnomAd4 at 4 AD,AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2 link	c.100172-10dupT		intron_variant	Intron 356 of 362	ENST00000589042.5	NP_001254479.2	A0A0A0MTS7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5 link	c.100172-10_100172-9insT		intron_variant	Intron 356 of 362	5	NM_001267550.2	ENSP00000467141.1		A0A0A0MTS7

Frequencies

GnomAD3 genomes

AF:

0.00457

AC:

693

AN:

151514

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00102

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00538

Gnomad ASJ

AF:

0.0150

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00932

Gnomad FIN

AF:

0.00250

Gnomad MID

AF:

0.0158

Gnomad NFE

AF:

0.00638

Gnomad OTH

AF:

0.00384

GnomAD2 exomes

AF:

0.00550

AC:

817

AN:

148510

AF XY:

0.00623

show subpopulations

Gnomad AFR exome

AF:

0.00116

Gnomad AMR exome

AF:

0.00449

Gnomad ASJ exome

AF:

0.0168

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00263

Gnomad NFE exome

AF:

0.00643

Gnomad OTH exome

AF:

0.00680

GnomAD4 exome

AF:

0.00494

AC:

6564

AN:

1328392

Hom.:

Cov.:

AF XY:

0.00524

AC XY:

3401

AN XY:

648882

show subpopulations

African (AFR)

AF:

0.000744

AC:

AN:

29556

American (AMR)

AF:

0.00382

AC:

AN:

24842

Ashkenazi Jewish (ASJ)

AF:

0.0164

AC:

318

AN:

19388

East Asian (EAS)

AF:

0.0000530

AC:

AN:

37712

South Asian (SAS)

AF:

0.0129

AC:

806

AN:

62400

European-Finnish (FIN)

AF:

0.00268

AC:

110

AN:

41012

Middle Eastern (MID)

AF:

0.0245

AC:

128

AN:

5230

European-Non Finnish (NFE)

AF:

0.00453

AC:

4775

AN:

1053400

Other (OTH)

AF:

0.00562

AC:

308

AN:

54852

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.489

Heterozygous variant carriers

336

673

1009

1346

1682

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Exome Hom

Variant carriers

176

352

528

704

880

<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:

0.00457

AC:

693

AN:

151632

Hom.:

Cov.:

AF XY:

0.00486

AC XY:

360

AN XY:

74076

show subpopulations

African (AFR)

AF:

0.00102

AC:

AN:

41366

American (AMR)

AF:

0.00538

AC:

AN:

15248

Ashkenazi Jewish (ASJ)

AF:

0.0150

AC:

AN:

3468

East Asian (EAS)

AF:

0.00

AC:

AN:

5172

South Asian (SAS)

AF:

0.00933

AC:

AN:

4822

European-Finnish (FIN)

AF:

0.00250

AC:

AN:

10394

Middle Eastern (MID)

AF:

0.0170

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.00638

AC:

433

AN:

67854

Other (OTH)

AF:

0.00380

AC:

AN:

2104

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.500

Heterozygous variant carriers

103

138

172

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Genome 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

Alfa

AF:

0.00326

Hom.:

Bravo

AF:

0.00412

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:6Benign:15

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not specified

Benign:8

Jan 26, 2015

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

92468-10_92468-9insT in intron 305 of TTN: This variant is not expected to have clinical significance because it has been identified in 1.2% (104/8792) of South Asian chromosomes by the Exome Aggregation Consortium (ExAC, http://exac.broadi nstitute.org; dbSNP rs397517782). -

Jun 16, 2014

GeneDx

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The variant is found in CARDIOMYOPATHY,DCM-CRDM panel(s). -

Joint Genome Diagnostic Labs from Nijmegen and Maastricht, Radboudumc and MUMC+

Significance:Benign

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Clinical Genetics, Academic Medical Center

Significance:Benign

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Jan 26, 2024

Athena Diagnostics

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Aug 13, 2019

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

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: TTN c.92468-10dupT alters a nucleotide located close to a canonical splice site and therefore could affect mRNA splicing, leading to a significantly altered protein sequence. 5/5 computational tools predict no significant impact on normal splicing. However, these predictions have yet to be confirmed by functional studies. The variant allele was found at a frequency of 0.0055 in 178860 control chromosomes, predominantly at a frequency of 0.011 within the South Asian subpopulation in the gnomAD database, including 1 homozygotes. The observed variant frequency within South Asian control individuals in the gnomAD database is approximately 18-folds over the estimated maximal expected allele frequency for a pathogenic variant in TTN causing Cardiomyopathy phenotype (0.00063), strongly suggesting that the variant is a benign polymorphism found primarily in populations of South Asian origin. Five ClinVar submissions (evaluation after 2014) cite the variant three times as benign, once as likely benign and once as uncertain significance. Based on the evidence outlined above, the variant was classified as benign. -

Nov 13, 2017

Genetic Services Laboratory, University of Chicago

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

- -

not provided

Benign:4

Apr 01, 2025

CeGaT Center for Human Genetics Tuebingen

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

TTN: BS1, BS2 -

Genome Diagnostics Laboratory, University Medical Center Utrecht

Significance:Likely benign

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

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

Significance:Likely benign

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Laboratory of Diagnostic Genome Analysis, Leiden University Medical Center (LUMC)

Significance:Likely benign

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Limb-girdle muscular dystrophy, recessive

Uncertain:1

Jun 14, 2016

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

Jun 14, 2016

Illumina Laboratory Services, Illumina

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Dilated Cardiomyopathy, Dominant

Uncertain:1

Jun 14, 2016

Illumina Laboratory Services, Illumina

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Myopathy, myofibrillar, 9, with early respiratory failure

Uncertain:1

Jun 14, 2016

Illumina Laboratory Services, Illumina

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Tibial muscular dystrophy

Uncertain:1

Jun 14, 2016

Illumina Laboratory Services, Illumina

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Hypertrophic cardiomyopathy

Uncertain:1

Jun 14, 2016

Illumina Laboratory Services, Illumina

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

TTN-related disorder

Benign:1

Jul 11, 2019

PreventionGenetics, part of Exact Sciences

Significance:Benign

Review Status:no assertion criteria provided

Collection Method:clinical testing

This variant is classified as 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

Feb 04, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Cardiomyopathy

Benign:1

Apr 25, 2017

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

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

PhyloP100

1.7

Mutation Taster

=100/0

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