chr2-178583009-C-T

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 1P and 0B. PP3

The NM_001267550.2(TTN):c.65794G>A(p.Gly21932Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000212 in 1,604,246 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.000026 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000021 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:7B:1

Conservation

PhyloP100: 7.86

Publications

0 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: Uncertain_significance. The variant received 1 ACMG points.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.77

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2 link	c.65794G>A	p.Gly21932Arg	missense_variant	Exon 313 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.65794G>A	p.Gly21932Arg	missense_variant	Exon 313 of 363	5	NM_001267550.2	ENSP00000467141.1		A0A0A0MTS7

Frequencies

GnomAD3 genomes

AF:

0.0000263

AC:

AN:

152068

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:

0.000388

Gnomad SAS

AF:

0.000414

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000530

AC:

AN:

245088

AF XY:

0.0000526

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000295

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.000285

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.000169

GnomAD4 exome

AF:

0.0000207

AC:

AN:

1452178

Hom.:

Cov.:

AF XY:

0.0000208

AC XY:

AN XY:

721494

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33186

American (AMR)

AF:

0.0000226

AC:

AN:

44168

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

25870

East Asian (EAS)

AF:

0.000127

AC:

AN:

39254

South Asian (SAS)

AF:

0.000213

AC:

AN:

84558

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53148

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5726

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1106310

Other (OTH)

AF:

0.000100

AC:

AN:

59958

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.462

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:

152068

Hom.:

Cov.:

AF XY:

0.0000404

AC XY:

AN XY:

74260

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41428

American (AMR)

AF:

0.00

AC:

AN:

15256

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.000388

AC:

AN:

5152

South Asian (SAS)

AF:

0.000414

AC:

AN:

4828

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10626

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

67986

Other (OTH)

AF:

0.00

AC:

AN:

2094

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.463

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:

0.00

Hom.:

Bravo

AF:

0.0000113

ExAC

AF:

0.0000331

AC:

Asia WGS

AF:

0.00318

AC:

AN:

3478

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:7Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:5Benign:1

Dec 06, 2019

GeneDx

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

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

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Jun 30, 2023

Revvity Omics, Revvity

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Clinical Genetics, Academic Medical Center

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

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

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Dec 15, 2019

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The TTN c.65794G>A; p.Gly21932Arg variant (rs373636513; ClinVar Variation ID: 202798) is rare in the general population (<1% 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.Gly21932Arg variant cannot be determined with certainty. References: Begay RL et al. Role of Titin Missense Variants in Dilated Cardiomyopathy. J Am Heart Assoc. 2015 Nov 13;4(11). Herman DS et al. Truncations of titin causing dilated cardiomyopathy. N Engl J Med. 2012 Feb 16;366(7):619-28. -

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

Uncertain:1

Dec 04, 2017

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Cardiomyopathy

Uncertain:1

Aug 22, 2019

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

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

0.94

BayesDel_addAF

Benign

0.0064

BayesDel_noAF

Uncertain

0.080

CADD

Benign

(source)

DANN

Benign

0.77

Eigen

Pathogenic

0.95

Eigen_PC

Pathogenic

0.83

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.93

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

M_CAP

Benign

0.075

MetaRNN

Pathogenic

0.77

D;D;D;D;D;D;D

MetaSVM

Pathogenic

0.80

MutationAssessor

Pathogenic

4.9

.;.;.;H;.;.;H

PhyloP100

7.9

PrimateAI

Uncertain

0.72

PROVEAN

Pathogenic

-5.9

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

REVEL

Pathogenic

0.76

Sift

Uncertain

0.0020

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

Polyphen

1.0

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

Vest4

0.43

MutPred

0.90

.;.;.;Loss of ubiquitination at K20288 (P = 0.0547);.;.;Loss of ubiquitination at K20288 (P = 0.0547);

MVP

0.84

MPC

0.51

ClinPred

0.32

GERP RS

5.8

Mutation Taster

=60/40

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