2-178561869-C-T

Variant names:

Variant summary

Our verdict is Benign. The variant received -9 ACMG points: 0P and 9B. BP4_StrongBP6BS2

The NM_001267550.2(TTN):c.84263G>A(p.Ser28088Asn) variant causes a missense change. The variant allele was found at a frequency of 0.00124 in 1,613,636 control chromosomes in the GnomAD database, including 3 homozygotes. In-silico tool predicts a benign outcome for this variant. 15/20 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. S28088T) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.00061 ( 0 hom., cov: 33)

Exomes 𝑓: 0.0013 ( 3 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:8B:10

Conservation

PhyloP100: 3.73

Publications

11 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.

BP4

Computational evidence support a benign effect (MetaRNN=0.013604939).

BP6

Variant 2-178561869-C-T is Benign according to our data. Variant chr2-178561869-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 47432.

BS2

High Homozygotes in GnomAdExome4 at 3 AD,AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2 link	c.84263G>A	p.Ser28088Asn	missense_variant	Exon 326 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.84263G>A	p.Ser28088Asn	missense_variant	Exon 326 of 363	5	NM_001267550.2	ENSP00000467141.1		A0A0A0MTS7

Frequencies

GnomAD3 genomes

AF:

0.000611

AC:

AN:

152160

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000145

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000196

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.000754

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00110

Gnomad OTH

AF:

0.000478

GnomAD2 exomes

AF:

0.000612

AC:

152

AN:

248232

AF XY:

0.000646

show subpopulations

Gnomad AFR exome

AF:

0.000194

Gnomad AMR exome

AF:

0.000319

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.000836

Gnomad NFE exome

AF:

0.00105

Gnomad OTH exome

AF:

0.000332

GnomAD4 exome

AF:

0.00130

AC:

1902

AN:

1461358

Hom.:

Cov.:

AF XY:

0.00121

AC XY:

882

AN XY:

726942

show subpopulations

African (AFR)

AF:

0.000149

AC:

AN:

33460

American (AMR)

AF:

0.000514

AC:

AN:

44704

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26128

East Asian (EAS)

AF:

0.00

AC:

AN:

39606

South Asian (SAS)

AF:

0.00

AC:

AN:

86240

European-Finnish (FIN)

AF:

0.000768

AC:

AN:

53366

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00160

AC:

1777

AN:

1111724

Other (OTH)

AF:

0.000928

AC:

AN:

60362

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.471

Heterozygous variant carriers

115

230

346

461

576

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Exome Hom

Variant carriers

152

228

304

380

<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:

0.000611

AC:

AN:

152278

Hom.:

Cov.:

AF XY:

0.000618

AC XY:

AN XY:

74452

show subpopulations

African (AFR)

AF:

0.000144

AC:

AN:

41564

American (AMR)

AF:

0.000196

AC:

AN:

15288

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3468

East Asian (EAS)

AF:

0.00

AC:

AN:

5180

South Asian (SAS)

AF:

0.00

AC:

AN:

4830

European-Finnish (FIN)

AF:

0.000754

AC:

AN:

10616

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.00110

AC:

AN:

68012

Other (OTH)

AF:

0.000473

AC:

AN:

2114

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.495

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:

0.000957

Hom.:

Bravo

AF:

0.000733

TwinsUK

AF:

0.00243

AC:

ALSPAC

AF:

0.00130

AC:

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000850

AC:

ExAC

AF:

0.000588

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:8Benign:10

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:5Benign:1

Sep 28, 2020

GeneDx

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Missense variant in a gene in which most reported pathogenic variants are truncating/loss-of-function; In silico analysis supports that this missense variant does not alter protein structure/function; This variant is associated with the following publications: (PMID: 23396983) -

Mar 02, 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.84263G>A; p.Ser28088Asn variant (rs200450022; ClinVar Variation ID: 47432) 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). Thus, the clinical significance of the p.Ser28088Asn variant cannot be determined with certainty. -

Dec 29, 2017

Eurofins Ntd Llc (ga)

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Sep 14, 2017

Athena Diagnostics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Jun 24, 2013

Biesecker Lab/Clinical Genomics Section, National Institutes of Health

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:research

- -

Feb 01, 2019

CeGaT Center for Human Genetics Tuebingen

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

not specified

Benign:3

Feb 09, 2018

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

proposed classification - variant undergoing re-assessment, contact laboratory -

Mar 14, 2025

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

- -

Autosomal recessive limb-girdle muscular dystrophy type 2J

Uncertain:1

Jan 13, 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 13, 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 13, 2018

Illumina Laboratory Services, Illumina

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

TTN-related disorder

Benign:1

Aug 09, 2024

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 29, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Cardiomyopathy

Benign:1

Sep 29, 2021

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

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Tibial muscular dystrophy

Benign:1

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:1

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. -

Cardiovascular phenotype

Benign:1

Mar 28, 2022

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: seen in unaffected individuals, 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

AlphaMissense

Benign

0.16

BayesDel_addAF

Benign

-0.46

BayesDel_noAF

Benign

-0.44

CADD

Benign

(source)

DANN

Benign

0.80

Eigen

Benign

-0.047

Eigen_PC

Benign

0.15

FATHMM_MKL

Uncertain

0.85

LIST_S2

Uncertain

0.92

D;D;D;.;D;D;D

M_CAP

Benign

0.0094

MetaRNN

Benign

0.014

T;T;T;T;T;T;T

MetaSVM

Benign

-0.96

MutationAssessor

Benign

0.68

.;.;.;N;.;.;N

PhyloP100

3.7

PrimateAI

Uncertain

0.57

PROVEAN

Benign

-1.7

N;N;.;.;N;N;.

REVEL

Benign

0.057

Sift

Benign

0.14

T;T;.;.;T;T;.

Polyphen

0.0040

.;.;.;B;.;.;B

Vest4

0.35

MVP

0.26

MPC

0.081

ClinPred

0.018

GERP RS

5.3

Mutation Taster

=89/11

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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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