rs201728165

Positions:

chr2-178725461-C-A

Variant summary

Our verdict is Likely benign. Variant got -4 ACMG points: 1P and 5B. PP2BP4_StrongBP6

The NM_001267550.2(TTN):c.20743G>T(p.Ala6915Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000062 in 1,612,938 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/18 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.00037 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000030 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:4B:3

Conservation

PhyloP100: 0.0550

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:

ENSG00000267784 (HGNC:):

ENSG00000267784 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -4 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=0.0127129555).

BP6

Variant 2-178725461-C-A is Benign according to our data. Variant chr2-178725461-C-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 178245.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=3, Uncertain_significance=3}. Variant chr2-178725461-C-A is described in Lovd as [Likely_benign].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TTN	NM_001267550.2 linkuse as main transcript	c.20743G>T	p.Ala6915Ser	missense_variant	71/363	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.20743G>T	p.Ala6915Ser	missense_variant	71/363	5	NM_001267550.2	ENSP00000467141.1		A0A0A0MTS7

Frequencies

GnomAD3 genomes

AF:

0.000375

AC:

AN:

152164

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00135

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000655

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000685

AC:

AN:

248048

Hom.:

AF XY:

0.0000669

AC XY:

AN XY:

134588

show subpopulations

Gnomad AFR exome

AF:

0.00110

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:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000301

AC:

AN:

1460656

Hom.:

Cov.:

AF XY:

0.0000303

AC XY:

AN XY:

726548

show subpopulations

Gnomad4 AFR exome

AF:

0.00108

Gnomad4 AMR exome

AF:

0.0000224

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:

0.00

Gnomad4 OTH exome

AF:

0.000116

GnomAD4 genome

AF:

0.000368

AC:

AN:

152282

Hom.:

Cov.:

AF XY:

0.000457

AC XY:

AN XY:

74450

show subpopulations

Gnomad4 AFR

AF:

0.00132

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:

0.00

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000278

Hom.:

Bravo

AF:

0.000397

ESP6500AA

AF:

0.00157

AC:

ESP6500EA

AF:

0.00

AC:

ExAC

AF:

0.0000828

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:4Benign:3

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:2Benign:1

Uncertain significance, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Nov 21, 2017	- -
Likely benign, criteria provided, single submitter	clinical testing	GeneDx	Apr 14, 2021	This variant is associated with the following publications: (PMID: 25447171) -
Uncertain significance, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Jun 30, 2023	- -

not specified

Uncertain:1Benign:1

Likely benign, criteria provided, single submitter	clinical testing	Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine	Aug 22, 2014	Ala5671Ser in exon 68 of TTN: This variant is not expected to have clinical sign ificance due to a lack of conservation across species, including mammals. Of not e, 4 mammals (Tibetan antelope, cow, sheep and domestic goat) and 2 fish (stickl eback and atlantic cod) have a serine (Ser) at this position despite high nearby amino acid conservation. In addition, this variant has been identified in 0.2% (6/3820) of African American chromosomes by the NHLBI Exome Sequencing Project ( http://evs.gs.washington.edu/EVS/; dbSNP rs201728165). -
Uncertain significance, criteria provided, single submitter	clinical testing	Genetic Services Laboratory, University of Chicago	Apr 29, 2014	- -

TTN-related disorder

Uncertain:1

Uncertain significance, no assertion criteria provided

clinical testing

PreventionGenetics, part of Exact Sciences

May 30, 2024

The TTN c.20743G>T variant is predicted to result in the amino acid substitution p.Ala6915Ser. This variant has been reported in a case of sudden cardiac death (described as p.A5671S in case #16, Campuzano et al. 2014. PubMed ID: 25447171). However, this individual also harbored additional variants, including two other TTN missense variants. This variant is reported in 0.13% of alleles in individuals of African descent in gnomAD, which may be too common to be an undocumented primary cause of disease. Although we suspect that this variant may be benign, 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

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 25, 2024

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.073

BayesDel_addAF

Benign

-0.50

BayesDel_noAF

Benign

-0.51

CADD

Benign

DANN

Benign

0.93

Eigen

Benign

-0.41

Eigen_PC

Benign

-0.22

FATHMM_MKL

Benign

0.54

LIST_S2

Benign

0.59

T;T;.;T

M_CAP

Benign

0.017

MetaRNN

Benign

0.013

T;T;T;T

MetaSVM

Benign

-1.0

PrimateAI

Benign

0.38

PROVEAN

Benign

-1.1

N;.;.;.

REVEL

Benign

0.073

Sift

Benign

0.69

T;.;.;.

Polyphen

0.0

.;.;B;B

Vest4

0.28

MVP

0.20

MPC

0.077

ClinPred

0.030

GERP RS

4.0

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