chr2-178794954-C-T

Position:

chr2-178794954-C-T

Variant summary

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

The NM_001267550.2(TTN):c.1213G>A(p.Ala405Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000866 in 1,604,320 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/18 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 0.00012 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000083 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1B:4

Conservation

PhyloP100: -0.412

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.

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=0.0077302456).

BP6

Variant 2-178794954-C-T is Benign according to our data. Variant chr2-178794954-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 166354.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=1, Uncertain_significance=1, Benign=2}. Variant chr2-178794954-C-T is described in Lovd as [Benign].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TTN	NM_001267550.2 linkuse as main transcript	c.1213G>A	p.Ala405Thr	missense_variant	7/363	ENST00000589042.5	NP_001254479.2	A0A0A0MTS7
TTN	NM_133379.5 linkuse as main transcript	c.1213G>A	p.Ala405Thr	missense_variant	7/46	ENST00000360870.10	NP_596870.2	Q8WZ42-6Q7Z3B7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5 linkuse as main transcript	c.1213G>A	p.Ala405Thr	missense_variant	7/363	5	NM_001267550.2	ENSP00000467141.1		A0A0A0MTS7
TTN	ENST00000360870.10 linkuse as main transcript	c.1213G>A	p.Ala405Thr	missense_variant	7/46	5	NM_133379.5	ENSP00000354117.4		Q8WZ42-6

Frequencies

GnomAD3 genomes

AF:

0.000112

AC:

AN:

152240

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00327

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:

0.000398

AC:

AN:

243686

Hom.:

AF XY:

0.000370

AC XY:

AN XY:

132316

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000289

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00523

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:

0.0000826

AC:

120

AN:

1451962

Hom.:

Cov.:

AF XY:

0.0000830

AC XY:

AN XY:

722706

show subpopulations

Gnomad4 AFR exome

AF:

0.0000597

Gnomad4 AMR exome

AF:

0.0000224

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00239

Gnomad4 SAS exome

AF:

0.0000232

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000719

Gnomad4 OTH exome

AF:

0.000199

GnomAD4 genome

AF:

0.000125

AC:

AN:

152358

Hom.:

Cov.:

AF XY:

0.000161

AC XY:

AN XY:

74508

show subpopulations

Gnomad4 AFR

AF:

0.0000481

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00328

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000916

Hom.:

Bravo

AF:

0.000140

ExAC

AF:

0.000420

AC:

Asia WGS

AF:

0.00173

AC:

AN:

3478

EpiCase

AF:

0.0000545

EpiControl

AF:

0.00

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1Benign:4

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Jun 26, 2014

Variant classified as Uncertain Significance - Favor Benign. The Ala405Thr varia nt in TTN has not been previously reported in individuals with cardiomyopathy. I t has also been identified in 1/10 Southern African chromosomes in the Bushman p opulation (dbSNP rs112266780). Computational prediction tools and conservation a nalysis suggest that this variant may not impact the protein (several mammals ca rry the variant amino acid), though this information is not predictive enough to rule out pathogenicity. In summary, while the clinical significance of the Ala4 05Thr variant is uncertain, these data suggest that it is more likely to be beni gn. -

TTN-related disorder

Benign:1

Likely benign, no assertion criteria provided

clinical testing

PreventionGenetics, part of Exact Sciences

Oct 22, 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

Benign, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 03, 2024

- -

not provided

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

GeneDx

Nov 13, 2020

- -

Cardiovascular phenotype

Benign:1

Benign, criteria provided, single submitter

clinical testing

Ambry Genetics

Aug 11, 2020

This alteration is classified as 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

Benign

0.070

BayesDel_addAF

Benign

-0.49

BayesDel_noAF

Benign

-0.48

CADD

Benign

DANN

Uncertain

0.99

Eigen

Benign

-0.87

Eigen_PC

Benign

-0.81

FATHMM_MKL

Benign

0.10

LIST_S2

Benign

0.70

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

M_CAP

Benign

0.035

MetaRNN

Benign

0.0049

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

MetaSVM

Benign

-1.0

PrimateAI

Benign

0.38

PROVEAN

Benign

0.0

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

REVEL

Benign

0.11

Sift

Benign

0.59

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

Sift4G

Benign

0.54

.;.;.;.;.;.;.;T;.

Polyphen

0.0, 0.095

.;.;.;B;.;.;B;B;.

Vest4

0.075

MutPred

0.35

Loss of helix (P = 0.0237);Loss of helix (P = 0.0237);Loss of helix (P = 0.0237);Loss of helix (P = 0.0237);Loss of helix (P = 0.0237);Loss of helix (P = 0.0237);Loss of helix (P = 0.0237);Loss of helix (P = 0.0237);.;

MVP

0.11

MPC

0.081

ClinPred

0.041

GERP RS

4.1

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