chr2-178572829-G-A

Position:

chr2-178572829-G-A

Variant summary

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

The NM_001267550.2(TTN):c.73303C>T(p.Arg24435Cys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000115 in 1,613,332 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. R24435R) has been classified as Benign.

Frequency

Genomes: 𝑓 0.00014 ( 1 hom., cov: 32)

Exomes 𝑓: 0.00011 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:9B:1

Conservation

PhyloP100: 9.94

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 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=0.33727843).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TTN	NM_001267550.2 linkuse as main transcript	c.73303C>T	p.Arg24435Cys	missense_variant	326/363	ENST00000589042.5	NP_001254479.2
TTN-AS1	NR_038272.1 linkuse as main transcript	n.2044-9743G>A		intron_variant, non_coding_transcript_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5 linkuse as main transcript	c.73303C>T	p.Arg24435Cys	missense_variant	326/363	5	NM_001267550.2	ENSP00000467141	P1
TTN-AS1	ENST00000659121.1 linkuse as main transcript	n.417-24767G>A		intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes

AF:

0.000138

AC:

AN:

152004

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000242

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000524

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:

0.000147

Gnomad OTH

AF:

0.000958

GnomAD3 exomes

AF:

0.000117

AC:

AN:

248010

Hom.:

AF XY:

0.000126

AC XY:

AN XY:

134510

show subpopulations

Gnomad AFR exome

AF:

0.000129

Gnomad AMR exome

AF:

0.0000580

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.0000327

Gnomad FIN exome

AF:

0.000140

Gnomad NFE exome

AF:

0.000170

Gnomad OTH exome

AF:

0.000332

GnomAD4 exome

AF:

0.000113

AC:

165

AN:

1461210

Hom.:

Cov.:

AF XY:

0.000120

AC XY:

AN XY:

726890

show subpopulations

Gnomad4 AFR exome

AF:

0.0000299

Gnomad4 AMR exome

AF:

0.000268

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000116

Gnomad4 FIN exome

AF:

0.0000749

Gnomad4 NFE exome

AF:

0.000125

Gnomad4 OTH exome

AF:

0.000133

GnomAD4 genome

AF:

0.000138

AC:

AN:

152122

Hom.:

Cov.:

AF XY:

0.000134

AC XY:

AN XY:

74358

show subpopulations

Gnomad4 AFR

AF:

0.0000241

Gnomad4 AMR

AF:

0.000523

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.000147

Gnomad4 OTH

AF:

0.000948

Alfa

AF:

0.000203

Hom.:

Bravo

AF:

0.000314

TwinsUK

AF:

0.00

AC:

ALSPAC

AF:

0.000259

AC:

ESP6500AA

AF:

0.000257

AC:

ESP6500EA

AF:

0.000241

AC:

ExAC

AF:

0.000124

AC:

EpiCase

AF:

0.000164

EpiControl

AF:

0.000237

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:9Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:5Benign:1

Uncertain significance, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Nov 01, 2022	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Mayo Clinic Laboratories, Mayo Clinic	May 17, 2023	- -
Uncertain significance, no assertion criteria provided	clinical testing	Joint Genome Diagnostic Labs from Nijmegen and Maastricht, Radboudumc and MUMC+	-	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Aug 03, 2023	- -
Likely benign, criteria provided, single submitter	clinical testing	GeneDx	Oct 12, 2018	- -
Uncertain significance, no assertion criteria provided	clinical testing	Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center	-	- -

not specified

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Sep 26, 2018

The TTN c.65599C>T; p.Arg21867Cys variant (rs200028088; ClinVar Variation ID: 202847) is rare in the general population (<1% allele frequency in the Genome Aggregation Database) and has not been reported in the medical literature in association with dilated cardiomyopathy (DCM) or other TTN-related disease. The clinical relevance of rare missense variants in this gene, which are identified on average once per individual sequenced in affected populations (Herman 2012), is not well understood. Yet, evidence suggests that the vast majority of such missense variants do not contribute to the clinical outcome of DCM (Begay 2015). Thus, the clinical significance of the p.Arg21867Cys variant cannot be determined with certainty. -

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 02, 2017

- -

See cases

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Centre for Mendelian Genomics, University Medical Centre Ljubljana

Mar 17, 2020

This variant was classified as: Uncertain significance. The available evidence on this variant's pathogenicity is insufficient or conflicting. The following ACMG criteria were applied in classifying this variant: PM2,PP3. -

Cardiovascular phenotype

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jan 16, 2018

The p.R15370C variant (also known as c.46108C>T), located in coding exon 153 of the TTN gene, results from a C to T substitution at nucleotide position 46108. The arginine at codon 15370 is replaced by cysteine, 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

0.74

BayesDel_addAF

Benign

-0.083

BayesDel_noAF

Benign

-0.090

CADD

Uncertain

DANN

Benign

0.89

Eigen

Pathogenic

0.98

Eigen_PC

Pathogenic

0.95

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Pathogenic

0.99

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

M_CAP

Benign

0.021

MetaRNN

Benign

0.34

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

MetaSVM

Uncertain

0.13

MutationAssessor

Pathogenic

3.7

.;.;.;H;.;.;H

MutationTaster

Benign

1.0

D;D;D;D;D;D

PrimateAI

Uncertain

0.76

PROVEAN

Pathogenic

-5.8

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

REVEL

Uncertain

0.50

Sift

Pathogenic

0.0

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

Polyphen

1.0

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

Vest4

0.45

MVP

0.79

MPC

0.54

ClinPred

0.31

GERP RS

5.9

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