rs727503702

Variant summary

Our verdict is Likely benign. Variant got -3 ACMG points: 1P and 4B. PP2BP4_Strong

The NM_001267550.2(TTN):c.2084T>C(p.Val695Ala) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000062 in 1,613,614 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/18 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. V695F) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000039 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000027 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

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

Conservation

PhyloP100: -0.347

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:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -3 ACMG points.

PP2

Missense variant where missense usually causes diseases, TTN

BP4

Computational evidence support a benign effect (MetaRNN=0.035856664).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TTN	NM_001267550.2 linkuse as main transcript	c.2084T>C	p.Val695Ala	missense_variant	14/363	ENST00000589042.5
TTN	NM_133379.5 linkuse as main transcript	c.2084T>C	p.Val695Ala	missense_variant	14/46	ENST00000360870.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TTN	ENST00000589042.5 linkuse as main transcript	c.2084T>C	p.Val695Ala	missense_variant	14/363	5	NM_001267550.2	P1
TTN	ENST00000360870.10 linkuse as main transcript	c.2084T>C	p.Val695Ala	missense_variant	14/46	5	NM_133379.5		Q8WZ42-6

Frequencies

GnomAD3 genomes

AF:

0.0000395

AC:

AN:

152078

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000145

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

GnomAD3 exomes

AF:

0.00000803

AC:

AN:

249134

Hom.:

AF XY:

0.00

AC XY:

AN XY:

134910

show subpopulations

Gnomad AFR exome

AF:

0.0000626

Gnomad AMR exome

AF:

0.0000290

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000274

AC:

AN:

1461536

Hom.:

Cov.:

AF XY:

0.00000413

AC XY:

AN XY:

727046

show subpopulations

Gnomad4 AFR exome

AF:

0.0000597

Gnomad4 AMR exome

AF:

0.0000447

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000395

AC:

AN:

152078

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74278

show subpopulations

Gnomad4 AFR

AF:

0.000145

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000662

Hom.:

Bravo

AF:

0.0000642

ExAC

AF:

0.00000824

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

Uncertain significance, criteria provided, single submitter

clinical testing

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Dec 26, 2013

Variant classified as Uncertain Significance - Favor Benign. The Val695Ala varia nt in TTN has not been reported in individuals with cardiomyopathy and data from large population studies is insufficient to assess the frequency of this varian t. Valine (Val) at position 695 is not conserved in mammals or across evolutiona rily distant species, and several other mammals have an alanine (Ala) at this po sition, suggesting that this change can be tolerated. Computational analyses (bi ochemical amino acid properties, conservation, AlignGVGD, PolyPhen2, and SIFT) s uggest that the Val695Ala variant may not impact the protein, though this inform ation is not predictive enough to rule out pathogenicity. Although this data sup ports that the Val695Ala variant may be benign, additional studies are needed to fully assess its clinical significance. -

Cardiovascular phenotype

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Dec 05, 2018

The p.V649A variant (also known as c.1946T>C), located in coding exon 12 of the TTN gene, results from a T to C substitution at nucleotide position 1946. The valine at codon 649 is replaced by alanine, an amino acid with similar properties. This amino acid position is not well conserved in available vertebrate species, and alanine is the reference amino acid in other vertebrate species. In addition, this alteration is predicted to be tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.073

BayesDel_addAF

Benign

-0.31

BayesDel_noAF

Benign

-0.50

Cadd

Benign

Dann

Benign

0.88

Eigen

Benign

-0.88

Eigen_PC

Benign

-0.83

FATHMM_MKL

Benign

0.041

LIST_S2

Benign

0.56

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

M_CAP

Benign

0.019

MetaRNN

Benign

0.036

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

MetaSVM

Benign

-1.0

MutationTaster

Benign

1.0

N;N;N;N;N;N;N

PrimateAI

Benign

0.31

PROVEAN

Benign

-0.97

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

REVEL

Benign

0.064

Sift

Benign

0.29

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

Polyphen

0.0, 0.0010

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

Vest4

0.078

MVP

0.17

MPC

0.10

ClinPred

0.013

GERP RS

-3.1

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

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over