chr2-178732074-A-G

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -1 ACMG points: 2P and 3B. PM2BP4_ModerateBP6

The NM_001267550.2(TTN):c.16895T>C(p.Ile5632Thr) variant causes a missense change. The variant allele was found at a frequency of 0.00000187 in 1,604,208 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/19 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 33)

Exomes 𝑓: 6.9e-7 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 4.09

Publications

2 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.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.18419197).

BP6

Variant 2-178732074-A-G is Benign according to our data. Variant chr2-178732074-A-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 179589.We mark this variant Likely_benign, oryginal submission is: [Conflicting_classifications_of_pathogenicity].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2 link	c.16895T>C	p.Ile5632Thr	missense_variant	Exon 57 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.16895T>C	p.Ile5632Thr	missense_variant	Exon 57 of 363	5	NM_001267550.2	ENSP00000467141.1		A0A0A0MTS7

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152188

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000482

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD4 exome

AF:

6.89e-7

AC:

AN:

1452020

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

720640

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33248

American (AMR)

AF:

0.00

AC:

AN:

44368

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

25674

East Asian (EAS)

AF:

0.00

AC:

AN:

39534

South Asian (SAS)

AF:

0.00

AC:

AN:

84936

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53092

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5708

European-Non Finnish (NFE)

AF:

9.05e-7

AC:

AN:

1105546

Other (OTH)

AF:

0.00

AC:

AN:

59914

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.575

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

AF:

0.0000131

AC:

AN:

152188

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74334

show subpopulations

African (AFR)

AF:

0.0000482

AC:

AN:

41460

American (AMR)

AF:

0.00

AC:

AN:

15276

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3466

East Asian (EAS)

AF:

0.00

AC:

AN:

5188

South Asian (SAS)

AF:

0.00

AC:

AN:

4830

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10624

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68024

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

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:

0.0000189

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Mar 24, 2014

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant classified as Uncertain Significance - Favor Benign. The Ile4388Thr vari ant in TTN has not been previously reported in indivdiuals with cardiomyopathy o r in large population studies. Isoleucine (Ile) at position 4388 is not conserve d in evolution and multiple bird and fish species carry a threonine (Thr) at thi s position, supporting that this change may be tolerated. Computational predicti on tools also suggest that this variant may not impact the protein, though this information is not predictive enough to rule out pathogenicity. While the presen ce of the variant amino acid in other species supports that the Ile4388Thr varia nt is less likely to be disease-causing, additional studies are needed to fully assess its clinical significance. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.068

BayesDel_addAF

Uncertain

0.086

BayesDel_noAF

Benign

-0.11

CADD

Benign

(source)

DANN

Benign

0.84

Eigen

Benign

-0.11

Eigen_PC

Benign

0.15

FATHMM_MKL

Benign

0.73

LIST_S2

Benign

0.71

T;T;.;T

M_CAP

Benign

0.018

MetaRNN

Benign

0.18

T;T;T;T

MetaSVM

Benign

-0.98

PhyloP100

4.1

PrimateAI

Uncertain

0.52

PROVEAN

Benign

-1.7

N;.;.;.

REVEL

Benign

0.26

Sift

Benign

0.46

T;.;.;.

Polyphen

0.0030

.;.;B;B

Vest4

0.40

MutPred

0.44

.;.;Loss of stability (P = 0.019);Loss of stability (P = 0.019);

MVP

0.66

MPC

0.11

ClinPred

0.27

GERP RS

6.2

Mutation Taster

=68/32

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

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over