chr2-178531025-C-T

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -1 ACMG points: 0P and 1B. BP4

The NM_001267550.2(TTN):c.105590G>A(p.Gly35197Asp) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000434 in 1,613,774 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 Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. G35197G) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.000026 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000045 ( 1 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:5O:1

Conservation

PhyloP100: 7.91

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: Likely_benign. The variant received -1 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.38884562).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2 link	c.105590G>A	p.Gly35197Asp	missense_variant	Exon 358 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.105590G>A	p.Gly35197Asp	missense_variant	Exon 358 of 363	5	NM_001267550.2	ENSP00000467141.1		A0A0A0MTS7

Frequencies

GnomAD3 genomes

AF:

0.0000263

AC:

AN:

152104

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

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:

0.0000588

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000602

AC:

AN:

249154

AF XY:

0.0000444

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000290

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000556

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000106

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000452

AC:

AN:

1461670

Hom.:

Cov.:

AF XY:

0.0000468

AC XY:

AN XY:

727114

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33478

American (AMR)

AF:

0.0000671

AC:

AN:

44722

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.0000252

AC:

AN:

39700

South Asian (SAS)

AF:

0.000162

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53372

Middle Eastern (MID)

AF:

0.000347

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.0000378

AC:

AN:

1111862

Other (OTH)

AF:

0.0000663

AC:

AN:

60374

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.479

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:

0.0000263

AC:

AN:

152104

Hom.:

Cov.:

AF XY:

0.0000538

AC XY:

AN XY:

74290

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41390

American (AMR)

AF:

0.00

AC:

AN:

15272

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5198

South Asian (SAS)

AF:

0.00

AC:

AN:

4822

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10604

Middle Eastern (MID)

AF:

0.00

AC:

AN:

314

European-Non Finnish (NFE)

AF:

0.0000588

AC:

AN:

68034

Other (OTH)

AF:

0.00

AC:

AN:

2086

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.488

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:

0.000135

Hom.:

Bravo

AF:

0.0000416

ExAC

AF:

0.0000414

AC:

EpiCase

AF:

0.000164

EpiControl

AF:

0.000119

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:5Other:1

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Uncertain:2Other:1

Mar 01, 2013

GeneDx

Significance:not provided

Review Status:no classification provided

Collection Method:clinical testing

- -

Sep 01, 2023

Athena Diagnostics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Available data are insufficient to determine the clinical significance of the variant at this time. The frequency of this variant in the general population is uninformative in assessment of its pathogenicity (http://gnomad.broadinstitute.org). This variant has been seen where an alternate explanation for disease was also identified, suggesting this variant may not cause disease. Computational tools disagree on the variant's effect on normal protein function. -

Jan 03, 2020

Revvity Omics, Revvity

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

not specified

Uncertain:1

Feb 23, 2012

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The Gly32629Asp variant (TTN) has not been previously reported but has bee ident ified by our laboratory in 1 individual with DCM who carried other likely diseas e causing DCM variants. This variant has also been identified in 1/6692 European American chromosomes from a broad population by the NHLBI Exome Sequencing Proj ect (http://evs.gs.washington.edu/EVS). Glycine (Gly) at position 32629 is highl y conserved in evolutionarily distant species, increasing the likelihood that a change would not be tolerated. Computational tools are mixed on the predicted im pact to the protein (AlignGVGD = benign, SIFT = pathogenic), though the accuracy of these tools is unknown. Additional information is needed to fully assess the Gly32629Asp variant. -

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

Uncertain:1

Dec 11, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces glycine, which is neutral and non-polar, with aspartic acid, which is acidic and polar, at codon 35197 of the TTN protein (p.Gly35197Asp). This variant is present in population databases (rs397517796, gnomAD 0.01%). This missense change has been observed in individual(s) with dilated cardiomyopathy (PMID: 25163546). ClinVar contains an entry for this variant (Variation ID: 47695). Experimental studies and prediction algorithms are not available or were not evaluated, and the functional significance of this variant is currently unknown. This variant is located in the M band of TTN (PMID: 25589632). Non-truncating variants in this region may be relevant for neuromuscular disorders, but have not been definitively shown to cause cardiomyopathy (PMID: 23975875). In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Autosomal recessive limb-girdle muscular dystrophy type 2J;C1838244:Tibial muscular dystrophy;C1858763:Dilated cardiomyopathy 1G;C1861065:Hypertrophic cardiomyopathy 9;C1863599:Myopathy, myofibrillar, 9, with early respiratory failure;C2673677:Early-onset myopathy with fatal cardiomyopathy

Uncertain:1

Sep 30, 2021

Fulgent Genetics, Fulgent Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.68

BayesDel_addAF

Benign

0.0078

BayesDel_noAF

Uncertain

-0.010

CADD

Benign

(source)

DANN

Benign

0.81

Eigen

Pathogenic

0.80

Eigen_PC

Uncertain

0.66

FATHMM_MKL

Uncertain

0.97

LIST_S2

Uncertain

0.93

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

M_CAP

Benign

0.066

MetaRNN

Benign

0.39

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

MetaSVM

Uncertain

0.77

MutationAssessor

Pathogenic

3.2

.;.;.;M;.;.;M

PhyloP100

7.9

PrimateAI

Uncertain

0.67

PROVEAN

Pathogenic

-5.1

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

REVEL

Pathogenic

0.79

Sift

Uncertain

0.0020

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

Polyphen

1.0

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

Vest4

0.48

MVP

0.55

MPC

0.53

ClinPred

0.76

GERP RS

4.8

Mutation Taster

=52/48

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