2-178785988-C-T

Variant summary

Our verdict is Benign. Variant got -8 ACMG points: 1P and 9B. PP2BP4_StrongBP6BS1

The NM_001267550.2(TTN):c.2230G>A(p.Ala744Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000285 in 1,614,044 control chromosomes in the GnomAD database, including 3 homozygotes. 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 0.00022 ( 0 hom., cov: 32)

Exomes 𝑓: 0.00029 ( 3 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1B:5

Conservation

PhyloP100: 0.0500

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 Benign. Variant got -8 ACMG points.

PP2

Missense variant where missense usually causes diseases, TTN

BP4

Computational evidence support a benign effect (MetaRNN=0.005292356).

BP6

Variant 2-178785988-C-T is Benign according to our data. Variant chr2-178785988-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 202278.We mark this variant Likely_benign, oryginal submissions are: {Uncertain_significance=1, Benign=2, Likely_benign=3}.

BS1

Variant frequency is greater than expected in population eas. gnomad4 allele frequency = 0.000217 (33/152218) while in subpopulation EAS AF= 0.00482 (25/5186). AF 95% confidence interval is 0.00335. There are 0 homozygotes in gnomad4. There are 17 alleles in male gnomad4 subpopulation. Median coverage is 32. This position pass quality control queck.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TTN	NM_001267550.2 linkuse as main transcript	c.2230G>A	p.Ala744Thr	missense_variant	14/363	ENST00000589042.5
TTN	NM_133379.5 linkuse as main transcript	c.2230G>A	p.Ala744Thr	missense_variant	14/46	ENST00000360870.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TTN	ENST00000589042.5 linkuse as main transcript	c.2230G>A	p.Ala744Thr	missense_variant	14/363	5	NM_001267550.2	P1
TTN	ENST00000360870.10 linkuse as main transcript	c.2230G>A	p.Ala744Thr	missense_variant	14/46	5	NM_133379.5		Q8WZ42-6

Frequencies

GnomAD3 genomes

AF:

0.000210

AC:

AN:

152100

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000655

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00481

Gnomad SAS

AF:

0.000415

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000588

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.000398

AC:

100

AN:

251072

Hom.:

AF XY:

0.000413

AC XY:

AN XY:

135662

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000289

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00409

Gnomad SAS exome

AF:

0.000490

Gnomad FIN exome

AF:

0.0000462

Gnomad NFE exome

AF:

0.0000705

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.000292

AC:

427

AN:

1461826

Hom.:

Cov.:

AF XY:

0.000305

AC XY:

222

AN XY:

727218

show subpopulations

Gnomad4 AFR exome

AF:

0.0000299

Gnomad4 AMR exome

AF:

0.0000447

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00640

Gnomad4 SAS exome

AF:

0.000464

Gnomad4 FIN exome

AF:

0.0000187

Gnomad4 NFE exome

AF:

0.000103

Gnomad4 OTH exome

AF:

0.000232

GnomAD4 genome

AF:

0.000217

AC:

AN:

152218

Hom.:

Cov.:

AF XY:

0.000228

AC XY:

AN XY:

74426

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.0000654

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00482

Gnomad4 SAS

AF:

0.000622

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000588

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000578

Hom.:

Bravo

AF:

0.000178

ExAC

AF:

0.000362

AC:

Asia WGS

AF:

0.00173

AC:

AN:

3478

EpiCase

AF:

0.00

EpiControl

AF:

0.0000593

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1Benign:5

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not specified

Benign:2

Likely benign, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Oct 09, 2017	- -
Benign, criteria provided, single submitter	clinical testing	GeneDx	Nov 07, 2014	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. -

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

CeGaT Center for Human Genetics Tuebingen

Jun 01, 2016

- -

TTN-related disorder

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

PreventionGenetics, part of Exact Sciences

Jan 26, 2022

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

Invitae

Jan 30, 2024

- -

Cardiovascular phenotype

Benign:1

Benign, criteria provided, single submitter

clinical testing

Ambry Genetics

Jun 23, 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

0.062

BayesDel_addAF

Benign

-0.62

BayesDel_noAF

Benign

-0.67

Cadd

Benign

Dann

Benign

0.70

Eigen

Benign

-1.2

Eigen_PC

Benign

-1.1

FATHMM_MKL

Benign

0.077

LIST_S2

Benign

0.65

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

M_CAP

Benign

0.019

MetaRNN

Benign

0.0053

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

MetaSVM

Benign

-1.0

MutationTaster

Benign

1.0

N;N;N;N;N;N;N

PrimateAI

Benign

0.24

PROVEAN

Benign

0.26

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

REVEL

Benign

0.087

Sift

Benign

0.89

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

Polyphen

0.0

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

Vest4

0.042

MVP

0.048

MPC

0.081

ClinPred

0.0034

GERP RS

-0.20

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.060

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