2-178535237-T-A

Position:

chr2-178535237-T-A

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 1P and 1B. PP2BP4

The NM_001267550.2(TTN):c.101378A>T(p.Asp33793Val) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000177 in 1,613,854 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 Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.000085 ( 0 hom., cov: 33)

Exomes 𝑓: 0.00019 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:8B:1

Conservation

PhyloP100: 8.02

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 0 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.

BP4

Computational evidence support a benign effect (MetaRNN=0.35315526).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TTN	NM_001267550.2 linkuse as main transcript	c.101378A>T	p.Asp33793Val	missense_variant	358/363	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.101378A>T	p.Asp33793Val	missense_variant	358/363	5	NM_001267550.2	ENSP00000467141.1		A0A0A0MTS7

Frequencies

GnomAD3 genomes

AF:

0.0000854

AC:

AN:

152228

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000654

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:

0.000162

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000883

AC:

AN:

249074

Hom.:

AF XY:

0.0000962

AC XY:

AN XY:

135114

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:

0.000195

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.000187

AC:

273

AN:

1461626

Hom.:

Cov.:

AF XY:

0.000166

AC XY:

121

AN XY:

727086

show subpopulations

Gnomad4 AFR exome

AF:

0.00

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:

0.000225

Gnomad4 OTH exome

AF:

0.000348

GnomAD4 genome

AF:

0.0000854

AC:

AN:

152228

Hom.:

Cov.:

AF XY:

0.000108

AC XY:

AN XY:

74378

show subpopulations

Gnomad4 AFR

AF:

0.0000241

Gnomad4 AMR

AF:

0.0000654

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.000162

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.000227

Hom.:

Bravo

AF:

0.000113

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000611

AC:

ExAC

AF:

0.000116

AC:

EpiCase

AF:

0.000436

EpiControl

AF:

0.000237

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:8Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:2Benign:1

Likely benign, criteria provided, single submitter	clinical testing	GeneDx	Sep 26, 2019	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Dec 05, 2017	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Feb 07, 2023	- -

not specified

Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Dec 12, 2023	Variant summary: TTN c.93674A>T (p.Asp31225Val) results in a non-conservative amino acid change located in the M-band domain of the encoded protein sequence. Three of four in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 8.8e-05 in 249074 control chromosomes (gnomAD). This frequency is not significantly higher than estimated for a pathogenic variant in TTN causing Dilated Cardiomyopathy (8.8e-05 vs 0.00039), allowing no conclusion about variant significance. To our knowledge, no occurrence of c.93674A>T in individuals affected with Dilated Cardiomyopathy and no experimental evidence demonstrating its impact on protein function have been reported. Seven submitters have cited clinical-significance assessments for this variant to ClinVar after 2014 and classified this variant as uncertain significance (n=6) and likely benign (n=1). Based on the evidence outlined above, the variant was classified as uncertain significance. -
Uncertain significance, criteria provided, single submitter	clinical testing	Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine	Mar 05, 2015	The p.Asp31225Val variant in TTN has not been previously reported in individuals with cardiomyopathy, but has been identified in 14/66724 of European American c hromosomes by the Exome Aggregation Consortium (ExAC, http://exac.broadinstitute .org; dbSNP rs200675195). Computational prediction tools and conservation analys is suggest that this variant may impact the protein, though this information is not predictive enough to determine pathogenicity. In summary, the clinical signi ficance of the p.Asp31225Val variant is uncertain. -

TTN-related disorder

Uncertain:1

Uncertain significance, no assertion criteria provided

clinical testing

PreventionGenetics, part of Exact Sciences

Sep 11, 2024

The TTN c.101378A>T variant is predicted to result in the amino acid substitution p.Asp33793Val. To our knowledge, this variant has not been reported in the literature. This variant is reported in 0.019% of alleles in individuals of European (Non-Finnish) descent in gnomAD. At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -

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

Nov 23, 2017

- -

Cardiomyopathy

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

CHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern Ontario

Apr 28, 2017

- -

Cardiovascular phenotype

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Dec 04, 2019

The p.D24728V variant (also known as c.74183A>T), located in coding exon 185 of the TTN gene, results from an A to T substitution at nucleotide position 74183. The aspartic acid at codon 24728 is replaced by valine, an amino acid with highly dissimilar properties. This amino acid position is highly conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. 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

Pathogenic

0.79

BayesDel_addAF

Benign

-0.080

BayesDel_noAF

Uncertain

-0.080

CADD

Benign

DANN

Benign

0.90

Eigen

Uncertain

0.64

Eigen_PC

Pathogenic

0.69

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.96

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

M_CAP

Uncertain

0.15

MetaRNN

Benign

0.35

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

MetaSVM

Benign

-0.29

MutationAssessor

Benign

0.0

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

PrimateAI

Uncertain

0.67

PROVEAN

Pathogenic

-6.4

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

REVEL

Uncertain

0.43

Sift

Uncertain

0.0010

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

Polyphen

1.0

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

Vest4

0.55

MVP

0.68

MPC

0.55

ClinPred

0.48

GERP RS

5.8

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