2-178793491-G-A

Position:

chr2-178793491-G-A

Variant summary

Our verdict is Likely benign. Variant got -4 ACMG points: 0P and 4B. BP4_ModerateBP6BP7

The NM_001267550.2(TTN):c.1449C>T(p.Ala483=) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000133 in 1,613,918 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 0.00013 ( 0 hom., cov: 32)

Exomes 𝑓: 0.00013 ( 0 hom. )

Consequence

TTN
NM_001267550.2 synonymous

Scores

Clinical Significance

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

Conservation

PhyloP100: -0.0600

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:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -4 ACMG points.

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.36).

BP6

Variant 2-178793491-G-A is Benign according to our data. Variant chr2-178793491-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 166348.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=6, Uncertain_significance=1}. Variant chr2-178793491-G-A is described in Lovd as [Likely_benign].

BP7

Synonymous conserved (PhyloP=-0.06 with no splicing effect.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TTN	NM_001267550.2 linkuse as main transcript	c.1449C>T	p.Ala483=	synonymous_variant	9/363	ENST00000589042.5	NP_001254479.2
TTN	NM_133379.5 linkuse as main transcript	c.1449C>T	p.Ala483=	synonymous_variant	9/46	ENST00000360870.10	NP_596870.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5 linkuse as main transcript	c.1449C>T	p.Ala483=	synonymous_variant	9/363	5	NM_001267550.2	ENSP00000467141	P1
TTN	ENST00000360870.10 linkuse as main transcript	c.1449C>T	p.Ala483=	synonymous_variant	9/46	5	NM_133379.5	ENSP00000354117		Q8WZ42-6

Frequencies

GnomAD3 genomes

AF:

0.000125

AC:

AN:

152016

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000484

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:

0.000250

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000477

AC:

AN:

251380

Hom.:

AF XY:

0.0000515

AC XY:

AN XY:

135880

show subpopulations

Gnomad AFR exome

AF:

0.000123

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.0000653

Gnomad FIN exome

AF:

0.0000463

Gnomad NFE exome

AF:

0.0000615

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.000133

AC:

194

AN:

1461784

Hom.:

Cov.:

AF XY:

0.000106

AC XY:

AN XY:

727204

show subpopulations

Gnomad4 AFR exome

AF:

0.0000896

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000580

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.000164

Gnomad4 OTH exome

AF:

0.0000662

GnomAD4 genome

AF:

0.000131

AC:

AN:

152134

Hom.:

Cov.:

AF XY:

0.0000941

AC XY:

AN XY:

74370

show subpopulations

Gnomad4 AFR

AF:

0.0000723

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:

0.000250

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000965

Hom.:

Bravo

AF:

0.0000945

EpiCase

AF:

0.000273

EpiControl

AF:

0.0000593

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1Benign:9

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:1Benign:3

Likely benign, no assertion criteria provided	clinical testing	Genome Diagnostics Laboratory, University Medical Center Utrecht	-	- -
Likely benign, no assertion criteria provided	clinical testing	Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center	-	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Feb 28, 2017	- -
Likely benign, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Jun 01, 2024	TTN: BP4, BP7 -

not specified

Benign:3

Likely benign, criteria provided, single submitter	clinical testing	GeneDx	Dec 20, 2016	This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease. -
Likely benign, criteria provided, single submitter	clinical testing	Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine	Mar 19, 2012	Ala483Ala in exon 9 of TTN: This variant is not expected to have clinical signif icance because it does not alter an amino acid residue and is not located within the splice consensus sequence. It has been identified in 3/7020 European Americ an chromosomes by the NHLBI Exome Sequencing Project (http://evs.gs.washington.e du/EVS; dbSNP rs141617218). Ala483Ala in exon 9 of TTN (rs141617218; allele fre quency = 3/7020) ** -
Likely benign, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	May 28, 2022	- -

TTN-related disorder

Benign:1

Likely benign, no assertion criteria provided

clinical testing

PreventionGenetics, part of Exact Sciences

Apr 09, 2019

This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -

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 06, 2024

- -

Cardiovascular phenotype

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Ambry Genetics

Sep 18, 2019

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

BayesDel_noAF

Benign

-0.36

CADD

Benign

8.6

DANN

Benign

0.68

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.010

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