2-178563378-G-T

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 0P and 2B. BP4BP6

The NM_001267550.2(TTN):c.82754C>A(p.Ser27585Tyr) variant causes a missense change. The variant allele was found at a frequency of 0.0000707 in 1,613,434 control chromosomes in the GnomAD database, with no homozygous occurrence. 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 0.000092 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000068 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1U:5B:2

Conservation

PhyloP100: 5.50

Publications

3 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: Likely_benign. The variant received -2 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.27840793).

BP6

Variant 2-178563378-G-T is Benign according to our data. Variant chr2-178563378-G-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 202914.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001267550.2. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
TTN	NM_001267550.2	MANE Select	c.82754C>A	p.Ser27585Tyr	missense	Exon 326 of 363	NP_001254479.2
TTN	NM_001256850.1		c.77831C>A	p.Ser25944Tyr	missense	Exon 276 of 313	NP_001243779.1
TTN	NM_133378.4		c.75050C>A	p.Ser25017Tyr	missense	Exon 275 of 312	NP_596869.4

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
TTN	ENST00000589042.5	TSL:5 MANE Select	c.82754C>A	p.Ser27585Tyr	missense	Exon 326 of 363	ENSP00000467141.1
TTN	ENST00000446966.2	TSL:1	c.82598C>A	p.Ser27533Tyr	missense	Exon 324 of 361	ENSP00000408004.2
TTN	ENST00000436599.2	TSL:1	c.82478C>A	p.Ser27493Tyr	missense	Exon 324 of 361	ENSP00000405517.2

Frequencies

GnomAD3 genomes

AF:

0.0000921

AC:

AN:

152018

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.000191

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000927

AC:

AN:

248046

AF XY:

0.0000818

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000205

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000684

AC:

100

AN:

1461416

Hom.:

Cov.:

AF XY:

0.0000578

AC XY:

AN XY:

727002

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33464

American (AMR)

AF:

0.00

AC:

AN:

44702

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26126

East Asian (EAS)

AF:

0.00

AC:

AN:

39626

South Asian (SAS)

AF:

0.0000116

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53394

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5766

European-Non Finnish (NFE)

AF:

0.0000864

AC:

AN:

1111718

Other (OTH)

AF:

0.0000497

AC:

AN:

60362

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.483

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome 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

GnomAD4 genome

AF:

0.0000921

AC:

AN:

152018

Hom.:

Cov.:

AF XY:

0.0000943

AC XY:

AN XY:

74232

show subpopulations

African (AFR)

AF:

0.0000241

AC:

AN:

41410

American (AMR)

AF:

0.00

AC:

AN:

15248

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5146

South Asian (SAS)

AF:

0.00

AC:

AN:

4832

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10614

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.000191

AC:

AN:

67984

Other (OTH)

AF:

0.00

AC:

AN:

2086

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.521

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:

0.000140

Hom.:

Bravo

AF:

0.0000340

ExAC

AF:

0.0000910

AC:

EpiCase

AF:

0.000109

EpiControl

AF:

0.000119

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1Uncertain:5Benign:2

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:2Benign:1

Jun 09, 2021

GeneDx

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Jan 03, 2017

Eurofins Ntd Llc (ga)

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Aug 11, 2025

Revvity Omics, Revvity

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

not specified

Uncertain:1Benign:1

Dec 18, 2014

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The p.Ser25017Tyr variant in TTN has not been previously reported in individuals with cardiomyopathy, but has been identified in 11/67626 European chromosomes b y the Exome Aggregation Consortium (ExAC, http://exac.broadinstitute.org; dbSNP rs72648215). Computational prediction tools and conservation analysis do not pro vide strong support for or against an impact to the protein. In summary, the cli nical significance of the p.Ser25017Tyr variant is uncertain.

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

Tip-toe gait

Pathogenic:1

Practice for Gait Abnormalities, David Pomarino, Competency Network Toe Walking c/o Practice Pomarino

Significance:Likely pathogenic

Review Status:no assertion criteria provided

Collection Method:clinical testing

Myopathy refers to diseases that affect skeletal Muscles. These diseases attack muscle fibers, making muscles weak. Inherited myopathies are often caused by inheriting an abnormal gene mutation from a parent that causes the disease. Symptoms of congenital myopathies usually start at birth or in early childhood, but may not appear until the teen years or even later in adulthood. Congenital myopathies are somewhat unique compared with other inherited myopathies, as weakness typically affects all muscles and is often not progressive. Symptoms are: Muscle weakness, most commonly of upper arms and shoulders and thighs, muscle cramps, stiffness and spasms, fatigue with exertion and lack of energy. Our patients all walk on tiptoe, so they show similar symptoms. When we genetically test them with our toe walking panel, we find that around 90 per cent of them have a genetic variant that explains their toe walking. These can be assigned, for example, to the area of myopathies (such as variants of the COL6A3 gene), the area of hereditary neuropathies (such as variants of the KMT2C gene) or the area of metabolic diseases (such as variants of the PYGM gene). In a smaller group of patients with almost identical symptoms, no abnormality is found in the genes of our panel, but spastic paraplegia can be detected. In another small group of our toe walkers, no abnormalities can be detected in the genes analysed in our toe walking panel, nor do they suffer from spastic paraplegia, as is also the case with healthy children. In contrast to these, however, they show a tiptoe gait. These patients suffer from infantile cerebral palsy, in which toe walking can also be observed.

TTN-related disorder

Uncertain:1

Feb 04, 2024

PreventionGenetics, part of Exact Sciences

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:clinical testing

The TTN c.82754C>A variant is predicted to result in the amino acid substitution p.Ser27585Tyr. This variant was reported in a dilated cardiomyopathy cohort; however, no additional studies were performed to help assess the pathogenicity of this variant (Begay et al. 2015. PubMed ID: 26567375). This variant is reported in 0.020% of alleles in individuals of European (Non-Finnish) descent in gnomAD. At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence.

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

Uncertain:1

Feb 26, 2016

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.17

BayesDel_addAF

Benign

-0.18

BayesDel_noAF

Benign

-0.22

CADD

Benign

(source)

DANN

Benign

0.83

Eigen

Pathogenic

0.70

Eigen_PC

Uncertain

0.66

FATHMM_MKL

Uncertain

0.96

LIST_S2

Uncertain

0.91

M_CAP

Benign

0.059

MetaRNN

Benign

0.28

MetaSVM

Uncertain

-0.060

MutationAssessor

Pathogenic

3.2

PhyloP100

5.5

PrimateAI

Uncertain

0.65

PROVEAN

Uncertain

-4.2

REVEL

Uncertain

0.39

Sift

Uncertain

0.0030

Polyphen

0.98

Vest4

0.49

MVP

0.39

MPC

0.43

ClinPred

0.59

GERP RS

5.0

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Mutation Taster

=93/7

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

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over