2-178632177-T-C

Variant names:

Variant summary

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

The NM_001267550.2(TTN):c.43717A>G(p.Met14573Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000143 in 1,607,972 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 16/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. M14573L) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000015 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:2

Conservation

PhyloP100: 1.50

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 0 ACMG points.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2 link	c.43717A>G	p.Met14573Val	missense_variant	Exon 236 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.43717A>G	p.Met14573Val	missense_variant	Exon 236 of 363	5	NM_001267550.2	ENSP00000467141.1		A0A0A0MTS7

Frequencies

GnomAD3 genomes

AF:

0.00000658

AC:

AN:

152080

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:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000125

AC:

AN:

239918

AF XY:

0.0000154

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:

0.0000277

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000151

AC:

AN:

1455892

Hom.:

Cov.:

AF XY:

0.0000166

AC XY:

AN XY:

723672

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33370

American (AMR)

AF:

0.00

AC:

AN:

44120

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

25904

East Asian (EAS)

AF:

0.00

AC:

AN:

39320

South Asian (SAS)

AF:

0.00

AC:

AN:

85124

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53120

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5742

European-Non Finnish (NFE)

AF:

0.0000198

AC:

AN:

1109030

Other (OTH)

AF:

0.00

AC:

AN:

60162

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.466

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

AF:

0.00000658

AC:

AN:

152080

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74276

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41440

American (AMR)

AF:

0.00

AC:

AN:

15250

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3468

East Asian (EAS)

AF:

0.00

AC:

AN:

5160

South Asian (SAS)

AF:

0.00

AC:

AN:

4828

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10624

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

67992

Other (OTH)

AF:

0.00

AC:

AN:

2092

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.475

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.00000378

ExAC

AF:

0.0000249

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Apr 28, 2013

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Missense variants in the TTN gene are considered 'unclassified' if they are not previously reported in the literature and do not have >1% frequency in the population to be considered a polymorphism. Research indicates that truncating mutations in the TTN gene are expected to account for approximately 25% of familial and 18% of sporadic idiopathic DCM; however, truncating variants in the TTN gene have been reported in approximately 3% of reported control alleles. There has been little investigation into non-truncating variants. (Herman D et al. Truncations of titin causing dilated cardiomyopathy. N Eng J Med 366:619-628, 2012) The variant is found in DCM panel(s). -

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

Uncertain:1

Jul 07, 2017

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces methionine with valine at codon 14573 of the TTN protein (p.Met14573Val). There is a small physicochemical difference between methionine and valine. This variant is present in population databases (rs755610701, ExAC 0.005%). This variant has not been reported in the literature in individuals with TTN-related disease. ClinVar contains an entry for this variant (Variation ID: 202633). This variant identified in the TTN gene is located in the I band of the resulting protein (PMID: 25589632). It is unclear how this variant impacts the function of this protein. Algorithms developed to predict the effect of missense changes on protein structure and function are unavailable for the TTN gene. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may alter RNA splicing, but this prediction has not been confirmed by published transcriptional studies. 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. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.081

BayesDel_addAF

Benign

-0.24

BayesDel_noAF

Benign

-0.52

CADD

Benign

9.8

(source)

DANN

Benign

0.61

Eigen

Benign

-1.2

Eigen_PC

Benign

-1.2

FATHMM_MKL

Uncertain

0.89

LIST_S2

Benign

0.79

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

M_CAP

Benign

0.017

MetaRNN

Benign

0.043

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

MetaSVM

Benign

-0.97

MutationAssessor

Benign

-0.88

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

PhyloP100

1.5

PrimateAI

Benign

0.33

PROVEAN

Benign

-0.18

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

REVEL

Benign

0.14

Sift

Benign

1.0

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

Polyphen

0.0

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

Vest4

0.11

MutPred

0.48

.;.;.;Gain of catalytic residue at M12932 (P = 0.0173);.;.;Gain of catalytic residue at M12932 (P = 0.0173);

MVP

0.11

MPC

0.085

ClinPred

0.020

GERP RS

-7.4

Mutation Taster

=90/10

polymorphism

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.24

Details are displayed if max score is > 0.2

DS_DG_spliceai

0.24

Position offset: 1

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

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2-178632177-T-C

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