2-178625396-C-T

Position:

chr2-178625396-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 1P and 0B. PP2

The NM_001267550.2(TTN):c.44425G>A(p.Val14809Met) variant causes a missense, splice region change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000646 in 1,546,820 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★★).

Frequency

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

Exomes 𝑓: 0.0000065 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense, splice_region

Scores

Splicing: ADA: 0.9986

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:3

Conservation

PhyloP100: 1.88

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:):

TTN-AS1 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 1 ACMG points.

PP2

Missense variant in gene, where missense usually causes diseases (based on misZ statistic), TTN. . Gene score misZ -1.1021 (greater than the threshold 3.09). Trascript score misZ 6.9794 (greater than threshold 3.09). GenCC has associacion of gene with dilated cardiomyopathy, tibial muscular dystrophy, early-onset myopathy with fatal cardiomyopathy, autosomal recessive centronuclear myopathy, hypertrophic cardiomyopathy, hypertrophic cardiomyopathy 9, TTN-related myopathy, dilated cardiomyopathy 1G, arrhythmogenic right ventricular cardiomyopathy, myopathy, myofibrillar, 9, with early respiratory failure, familial isolated dilated cardiomyopathy, childhood-onset progressive contractures-limb-girdle weakness-muscle dystrophy syndrome, autosomal recessive limb-girdle muscular dystrophy type 2J.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TTN	NM_001267550.2 linkuse as main transcript	c.44425G>A	p.Val14809Met	missense_variant, splice_region_variant	241/363	ENST00000589042.5	NP_001254479.2	A0A0A0MTS7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5 linkuse as main transcript	c.44425G>A	p.Val14809Met	missense_variant, splice_region_variant	241/363	5	NM_001267550.2	ENSP00000467141.1		A0A0A0MTS7

Frequencies

GnomAD3 genomes

AF:

0.00000660

AC:

AN:

151510

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

GnomAD4 exome

AF:

0.00000645

AC:

AN:

1395310

Hom.:

Cov.:

AF XY:

0.00000578

AC XY:

AN XY:

691620

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:

0.00000644

Gnomad4 OTH exome

AF:

0.0000347

GnomAD4 genome

AF:

0.00000660

AC:

AN:

151510

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

73938

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:

0.0000147

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000336

Hom.:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

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

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Feb 03, 2020

This sequence change replaces valine with methionine at codon 14809 of the TTN protein (p.Val14809Met). Conservation data is not available for this valine residue. There is a small physicochemical difference between valine and methionine. This variant also falls at the first nucleotide of exon 241 of the TTN coding sequence, which is part of the consensus splice site for this exon. This variant is not present in population databases (ExAC no frequency) and has not been reported in the literature in individuals with a TTN-related disease. Experimental studies and protein prediction algorithms are not available for this variant, and the functional significance of this missense variant is currently unknown. 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, this is a novel missense change with uncertain impact on splicing and protein function. It has been classified as a Variant of Uncertain Significance. -

Autosomal recessive limb-girdle muscular dystrophy type 2J;C1838244:Tibial muscular dystrophy;C1858763:Dilated cardiomyopathy 1G;C1861065:Hypertrophic cardiomyopathy 9;C1863599:Myopathy, myofibrillar, 9, with early respiratory failure;C2673677:Early-onset myopathy with fatal cardiomyopathy

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Jul 17, 2021

- -

Cardiovascular phenotype

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jul 17, 2019

The p.V5744M variant (also known as c.17230G>A), located in coding exon 68 of the TTN gene, results from a G>A substitution at nucleotide position 17230. The valine at codon 5744 is replaced by methionine, an amino acid with highly similar properties. This change occurs in the first base pair of coding exon 68. The splice prediction software does not produce a reliable prediction for the nearby native splice acceptor site. This amino acid position is well conserved in available vertebrate species. In addition, the amino acid change 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

0.26

BayesDel_addAF

Benign

-0.040

BayesDel_noAF

Benign

-0.30

CADD

Uncertain

DANN

Benign

0.94

Eigen

Pathogenic

0.73

Eigen_PC

Pathogenic

0.71

FATHMM_MKL

Uncertain

0.94

LIST_S2

Uncertain

0.94

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

M_CAP

Benign

0.040

MetaRNN

Benign

0.37

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

MetaSVM

Uncertain

-0.13

MutationAssessor

Uncertain

2.7

.;.;.;M;.;.;M

PrimateAI

Uncertain

0.55

PROVEAN

Benign

-2.1

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

REVEL

Uncertain

0.37

Sift

Uncertain

0.0070

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

Polyphen

0.99

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

Vest4

0.38

MutPred

0.43

.;.;.;Loss of methylation at K13167 (P = 0.0301);.;.;Loss of methylation at K13167 (P = 0.0301);

MVP

0.63

MPC

0.44

ClinPred

0.65

GERP RS

6.0

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Pathogenic

0.75

SpliceAI score (max)

0.020

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