2-178717960-G-C

Variant names:

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 1P and 0B. PP3

The NM_001267550.2(TTN):c.25046C>G(p.Ala8349Gly) variant causes a missense change. The variant allele was found at a frequency of 0.000036 in 1,612,456 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000038 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

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

Conservation

PhyloP100: 3.90

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 made for transcript

Verdict is Uncertain_significance. Variant got 1 ACMG points.

PP3

Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2 link	c.25046C>G	p.Ala8349Gly	missense_variant	Exon 86 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.25046C>G	p.Ala8349Gly	missense_variant	Exon 86 of 363	5	NM_001267550.2	ENSP00000467141.1		A0A0A0MTS7

Frequencies

GnomAD3 genomes

AF:

0.0000197

AC:

AN:

152176

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:

0.0000441

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000161

AC:

AN:

248226

Hom.:

AF XY:

0.00000743

AC XY:

AN XY:

134626

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 SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000356

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000377

AC:

AN:

1460280

Hom.:

Cov.:

AF XY:

0.0000344

AC XY:

AN XY:

726150

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

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:

0.0000423

Gnomad4 OTH exome

AF:

0.000133

GnomAD4 genome

AF:

0.0000197

AC:

AN:

152176

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74340

show subpopulations

Gnomad4 AFR

AF:

0.00

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:

0.0000441

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000282

Hom.:

Bravo

AF:

0.00000378

ExAC

AF:

0.00000826

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

May 11, 2012

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The Ala7105Gly variant in TTN has not been previously reported, but has been det ected in 1 individual with DCM tested by our laboratory. Computational analyses (biochemical amino acid properties, conservation, AlignGVGD, PolyPhen2, and SIF T) do not provide strong support for or against an impact to the protein. Compu tational tools predict that this variant may affect splicing, but additional stu dies are needed to further investigate this. In summary, additional information is needed to fully assess the clinical significance of the Ala7105Gly variant. -

not provided

Uncertain:1

Oct 16, 2017

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The A8032G variant of uncertain significance in the TTN gene has not been published as a pathogenic or benignvariant to our knowledge. The A8032G variant is not observed at a significant frequency in large population cohorts(Lek et al., 2016). This variant could be functionally significant at the mRNA or protein level. At the mRNA level,several in silico splicing models predict that this variant probably affects splicing by creating a strong cryptic donorsite upstream of the natural donor site for intron 84. However, in the absence of functional mRNA studies, thephysiological consequence of this variant cannot be determined. At the protein level, the A8032G variant is aconservative amino acid substitution that occurs at a position that is not conserved across species. In silico analysis isinconsistent in its predictions as to whether or not the variant is damaging to the protein structure/function. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.25

BayesDel_addAF

Benign

-0.18

BayesDel_noAF

Benign

-0.43

CADD

Uncertain

DANN

Benign

0.90

Eigen

Benign

0.098

Eigen_PC

Uncertain

0.28

FATHMM_MKL

Benign

0.67

LIST_S2

Benign

0.59

T;T;.;T

M_CAP

Benign

0.031

MetaRNN

Benign

0.24

T;T;T;T

MetaSVM

Benign

-0.63

PrimateAI

Benign

0.42

PROVEAN

Uncertain

-2.5

N;.;.;.

REVEL

Benign

0.26

Sift

Uncertain

0.0050

D;.;.;.

Polyphen

0.034

.;.;B;B

Vest4

0.25

MutPred

0.61

.;.;Loss of stability (P = 0.0342);Loss of stability (P = 0.0342);

MVP

0.32

MPC

0.11

ClinPred

0.16

GERP RS

6.2

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.68

Details are displayed if max score is > 0.2

DS_DG_spliceai

0.68

Position offset: 1

DS_DL_spliceai

0.41

Position offset: -17

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