rs202012910

Positions:

chr2-178590316-A-G

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 1P and 3B. PP2BP4_ModerateBP6

The NM_001267550.2(TTN):c.61409T>C(p.Ile20470Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000649 in 1,570,582 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 0.00024 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000046 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:11B:2

Conservation

PhyloP100: 9.27

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 Likely_benign. Variant got -2 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=0.11688176).

BP6

Variant 2-178590316-A-G is Benign according to our data. Variant chr2-178590316-A-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 47173.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=2, Uncertain_significance=8}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TTN	NM_001267550.2 linkuse as main transcript	c.61409T>C	p.Ile20470Thr	missense_variant	304/363	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.61409T>C	p.Ile20470Thr	missense_variant	304/363	5	NM_001267550.2	ENSP00000467141.1		A0A0A0MTS7

Frequencies

GnomAD3 genomes

AF:

0.000243

AC:

AN:

152010

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000797

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000657

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:

0.0000294

Gnomad OTH

AF:

0.000479

GnomAD3 exomes

AF:

0.000108

AC:

AN:

213576

Hom.:

AF XY:

0.0000968

AC XY:

AN XY:

113650

show subpopulations

Gnomad AFR exome

AF:

0.000862

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:

0.000101

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000458

AC:

AN:

1418454

Hom.:

Cov.:

AF XY:

0.0000485

AC XY:

AN XY:

700372

show subpopulations

Gnomad4 AFR exome

AF:

0.000900

Gnomad4 AMR exome

AF:

0.0000247

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:

0.0000293

Gnomad4 OTH exome

AF:

0.0000513

GnomAD4 genome

AF:

0.000243

AC:

AN:

152128

Hom.:

Cov.:

AF XY:

0.000242

AC XY:

AN XY:

74352

show subpopulations

Gnomad4 AFR

AF:

0.000794

Gnomad4 AMR

AF:

0.0000656

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000294

Gnomad4 OTH

AF:

0.000474

Alfa

AF:

0.0000986

Hom.:

Bravo

AF:

0.000287

ESP6500AA

AF:

0.000511

AC:

ESP6500EA

AF:

0.000241

AC:

ExAC

AF:

0.000108

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:11Benign:2

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:8Benign:1

Likely benign, criteria provided, single submitter	clinical testing	GeneDx	Dec 24, 2019	This variant is associated with the following publications: (PMID: 28152038) -
Uncertain significance, criteria provided, single submitter	clinical testing	Genetic Services Laboratory, University of Chicago	Jan 10, 2014	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	May 25, 2020	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Feb 24, 2017	- -
Uncertain significance, no assertion criteria provided	clinical testing	Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center	-	- -
Uncertain significance, no assertion criteria provided	clinical testing	Department of Pathology and Laboratory Medicine, Sinai Health System	-	The TTN p.I17902T variant was not identified in the literature but was identified in dbSNP (ID: rs202012910) and ClinVar (classified as uncertain significance by Invitae, GeneDx and five other laboratories). The variant was identified in control databases in 30 of 244940 chromosomes at a frequency of 0.0001225 (Genome Aggregation Database March 6, 2019, v2.1.1). The p.I17902 residue is conserved in mammals and computational analyses (MUT Assesor, PolyPhen-2, SIFT, MutationTaster, Revel, FATHMM, MetaLR, DANN) provide inconsistent predictions regarding the impact to the protein; this information is not very predictive of pathogenicity. The variant occurs outside of the splicing consensus sequence and in silico or computational prediction software programs (Splice AI exome) do not predict a difference in splicing. In summary, based on the above information the clinical significance of this variant cannot be determined with certainty at this time. This variant is classified as a variant of uncertain significance. -
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	ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories	Feb 08, 2022	The TTN c.61409T>C; p.Ile20470Thr variant (rs202012910; ClinVar Variation ID: 47173) is rare in the general population (<0.2% 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.Ile20470Thr variant cannot be determined with certainty. -
Uncertain significance, criteria provided, single submitter	clinical testing	Mayo Clinic Laboratories, Mayo Clinic	Dec 13, 2023	BS1 -

not specified

Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Nov 11, 2019	Variant summary: TTN c.53705T>C (p.Ile17902Thr) results in a non-conservative amino acid change located in the A-band region of the encoded protein sequence. Three of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 0.00011 in 213576 control chromosomes. This frequency is not significantly higher than expected for a pathogenic variant in TTN causing Dilated Cardiomyopathy (0.00011 vs 0.00063), allowing no conclusion about variant significance. To our knowledge, no occurrence of c.53705T>C in individuals affected with Dilated Cardiomyopathy and no experimental evidence demonstrating its impact on protein function have been reported. Four clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All laboratories classified the variant as uncertain significance. 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	Nov 07, 2012	The Ile17902Thr variant in TTN has not been reported in the literature nor previ ously identified by our laboratory. This variant has been identified in 2/8304 E uropean American chromosomes and 2/3916 African American chromosomes from a broa d population by the NHLBI Exome Sequencing Project (http://evs.gs.washington.edu /EVS). Computational analyses (biochemical amino acid properties, conservation, AlignGVGD, PolyPhen2, and SIFT) do not provide strong support for or against an impact to the protein. In summary, additional information is needed to fully ass ess the variant's clinical significance. -

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

Dec 09, 2017

- -

Cardiovascular phenotype

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Ambry Genetics

May 20, 2020

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.51

BayesDel_addAF

Benign

-0.32

BayesDel_noAF

Benign

-0.31

CADD

Benign

DANN

Benign

0.88

Eigen

Uncertain

0.65

Eigen_PC

Pathogenic

0.72

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.95

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

M_CAP

Benign

0.023

MetaRNN

Benign

0.12

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

MetaSVM

Benign

-0.85

MutationAssessor

Uncertain

2.3

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

PrimateAI

Uncertain

0.74

PROVEAN

Uncertain

-3.4

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

REVEL

Uncertain

0.31

Sift

Uncertain

0.026

D;T;.;.;T;T;.

Polyphen

0.88

.;.;.;P;.;.;P

Vest4

0.47

MVP

0.51

MPC

0.24

ClinPred

0.25

GERP RS

6.1

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