2-178718769-T-G

Position:

chr2-178718769-T-G

Variant summary

Our verdict is Benign. Variant got -19 ACMG points: 1P and 20B. PP2BP4_StrongBP6_Very_StrongBA1

The NM_001267550.2(TTN):c.24431A>C(p.Glu8144Ala) variant causes a missense change. The variant allele was found at a frequency of 0.163 in 1,613,646 control chromosomes in the GnomAD database, including 24,242 homozygotes. In-silico tool predicts a benign outcome for this variant. 12/17 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. E8144G) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.16 ( 2381 hom., cov: 33)

Exomes 𝑓: 0.16 ( 21861 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Benign/Likely benign criteria provided, multiple submitters, no conflicts B:21

Conservation

PhyloP100: 5.95

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 Benign. Variant got -19 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=0.0055182576).

BP6

Variant 2-178718769-T-G is Benign according to our data. Variant chr2-178718769-T-G is described in ClinVar as [Likely_benign]. Clinvar id is 46731.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr2-178718769-T-G is described in Lovd as [Benign].

BA1

GnomAd4 highest subpopulation (EAS) allele frequency at 95% confidence interval = 0.417 is higher than 0.05.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TTN	NM_001267550.2 linkuse as main transcript	c.24431A>C	p.Glu8144Ala	missense_variant	84/363	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.24431A>C	p.Glu8144Ala	missense_variant	84/363	5	NM_001267550.2	ENSP00000467141.1		A0A0A0MTS7

Frequencies

GnomAD3 genomes

AF:

0.165

AC:

25039

AN:

152014

Hom.:

2378

Cov.:

show subpopulations

Gnomad AFR

AF:

0.154

Gnomad AMI

AF:

0.471

Gnomad AMR

AF:

0.170

Gnomad ASJ

AF:

0.126

Gnomad EAS

AF:

0.433

Gnomad SAS

AF:

0.224

Gnomad FIN

AF:

0.0987

Gnomad MID

AF:

0.120

Gnomad NFE

AF:

0.154

Gnomad OTH

AF:

0.165

GnomAD3 exomes

AF:

0.177

AC:

44075

AN:

248598

Hom.:

4743

AF XY:

0.179

AC XY:

24116

AN XY:

134848

show subpopulations

Gnomad AFR exome

AF:

0.152

Gnomad AMR exome

AF:

0.173

Gnomad ASJ exome

AF:

0.123

Gnomad EAS exome

AF:

0.431

Gnomad SAS exome

AF:

0.223

Gnomad FIN exome

AF:

0.0959

Gnomad NFE exome

AF:

0.150

Gnomad OTH exome

AF:

0.165

GnomAD4 exome

AF:

0.163

AC:

238728

AN:

1461514

Hom.:

21861

Cov.:

AF XY:

0.165

AC XY:

119738

AN XY:

727042

show subpopulations

Gnomad4 AFR exome

AF:

0.153

Gnomad4 AMR exome

AF:

0.175

Gnomad4 ASJ exome

AF:

0.123

Gnomad4 EAS exome

AF:

0.444

Gnomad4 SAS exome

AF:

0.220

Gnomad4 FIN exome

AF:

0.0935

Gnomad4 NFE exome

AF:

0.153

Gnomad4 OTH exome

AF:

0.170

GnomAD4 genome

AF:

0.165

AC:

25049

AN:

152132

Hom.:

2381

Cov.:

AF XY:

0.166

AC XY:

12333

AN XY:

74384

show subpopulations

Gnomad4 AFR

AF:

0.153

Gnomad4 AMR

AF:

0.170

Gnomad4 ASJ

AF:

0.126

Gnomad4 EAS

AF:

0.432

Gnomad4 SAS

AF:

0.223

Gnomad4 FIN

AF:

0.0987

Gnomad4 NFE

AF:

0.154

Gnomad4 OTH

AF:

0.170

Alfa

AF:

0.159

Hom.:

4691

Bravo

AF:

0.172

TwinsUK

AF:

0.149

AC:

551

ALSPAC

AF:

0.154

AC:

592

ESP6500AA

AF:

0.149

AC:

590

ESP6500EA

AF:

0.152

AC:

1266

ExAC

AF:

0.176

AC:

21301

Asia WGS

AF:

0.330

AC:

1151

AN:

3478

EpiCase

AF:

0.153

EpiControl

AF:

0.160

ClinVar

Significance: Benign/Likely benign

Submissions summary: Benign:21

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not specified

Benign:8

Benign, no assertion criteria provided	clinical testing	Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center	-	- -
Benign, no assertion criteria provided	clinical testing	Clinical Genetics, Academic Medical Center	-	- -
Benign, criteria provided, single submitter	clinical testing	Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine	Apr 03, 2012	Glu6900Ala in exon 81 of TTN: This variant is not expected to have clinical sign ificance because it has been identified in 14% (1033/6756) of European American chromosomes and 15% (470/3284) of African American chromosomes from a broad popu lation by the NHLBI Exome Sequencing Project (http://evs.gs.washington.edu/EVS/; dbSNP rs16866465) -
Likely benign, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Aug 16, 2020	- -
Benign, criteria provided, single submitter	clinical testing	Genetic Services Laboratory, University of Chicago	Aug 15, 2013	- -
Benign, criteria provided, single submitter	clinical testing	GeneDx	Oct 31, 2012	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. -
Benign, criteria provided, single submitter	research	Biesecker Lab/Clinical Genomics Section, National Institutes of Health	Jun 24, 2013	- -
Benign, criteria provided, single submitter	clinical testing	PreventionGenetics, part of Exact Sciences	-	- -

Autosomal recessive limb-girdle muscular dystrophy type 2J

Benign:2

Benign, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Sep 10, 2021	- -
Benign, criteria provided, single submitter	clinical testing	Illumina Laboratory Services, Illumina	Jan 12, 2018	This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -

Early-onset myopathy with fatal cardiomyopathy

Benign:2

Benign, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Sep 10, 2021	- -
Benign, criteria provided, single submitter	clinical testing	Illumina Laboratory Services, Illumina	Jan 12, 2018	This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -

not provided

Benign:2

Benign, criteria provided, single submitter	clinical testing	Athena Diagnostics	Jun 21, 2018	- -
Likely benign, criteria provided, single submitter	not provided	Breakthrough Genomics, Breakthrough Genomics	-	- -

Tibial muscular dystrophy

Benign:2

Benign, criteria provided, single submitter	clinical testing	Illumina Laboratory Services, Illumina	Jan 12, 2018	This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -
Benign, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Sep 10, 2021	- -

Myopathy, myofibrillar, 9, with early respiratory failure

Benign:2

Benign, criteria provided, single submitter	clinical testing	Illumina Laboratory Services, Illumina	Jan 12, 2018	This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -
Benign, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Sep 10, 2021	- -

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

Feb 01, 2024

- -

Dilated cardiomyopathy 1G

Benign:1

Benign, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 12, 2018

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -

Cardiovascular phenotype

Benign:1

Benign, criteria provided, single submitter

clinical testing

Ambry Genetics

Jan 16, 2013

This alteration is classified as benign based on a combination of the following: 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

0.15

BayesDel_addAF

Benign

-0.54

BayesDel_noAF

Benign

-0.41

CADD

Benign

DANN

Benign

0.75

Eigen

Benign

-0.12

Eigen_PC

Benign

0.038

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Benign

0.69

T;T;.;T

MetaRNN

Benign

0.0055

T;T;T;T

MetaSVM

Benign

-1.0

PrimateAI

Benign

0.34

PROVEAN

Uncertain

-2.4

N;.;.;.

REVEL

Benign

0.23

Sift

Uncertain

0.023

D;.;.;.

Polyphen

0.0030

.;.;B;B

Vest4

0.078

MPC

0.092

ClinPred

0.018

GERP RS

6.0

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