chr2-178766596-C-T

Variant names:

Variant summary

Our verdict is Likely benign. Variant got -3 ACMG points: 0P and 3B. BP4_ModerateBP6

The NM_001267550.2(TTN):c.9488G>A(p.Arg3163His) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00034 in 1,612,956 control chromosomes in the GnomAD database, including 1 homozygotes. 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 0.00034 ( 0 hom., cov: 32)

Exomes 𝑓: 0.00034 ( 1 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:7B:5

Conservation

PhyloP100: 7.57

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:44124): (TTN antisense RNA 1) This gene encodes a non-coding RNA transcribed from the opposite strand to the titin gene. [provided by RefSeq, Aug 2016]

TTN-AS1 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -3 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.22953644).

BP6

Variant 2-178766596-C-T is Benign according to our data. Variant chr2-178766596-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 166298.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=4, Uncertain_significance=7}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2 link	c.9488G>A	p.Arg3163His	missense_variant	Exon 41 of 363	ENST00000589042.5	NP_001254479.2	A0A0A0MTS7
TTN	NM_133379.5 link	c.9488G>A	p.Arg3163His	missense_variant	Exon 41 of 46	ENST00000360870.10	NP_596870.2	Q8WZ42-6Q7Z3B7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5 link	c.9488G>A	p.Arg3163His	missense_variant	Exon 41 of 363	5	NM_001267550.2	ENSP00000467141.1		A0A0A0MTS7
TTN	ENST00000360870.10 link	c.9488G>A	p.Arg3163His	missense_variant	Exon 41 of 46	5	NM_133379.5	ENSP00000354117.4		Q8WZ42-6

Frequencies

GnomAD3 genomes

AF:

0.000335

AC:

AN:

152172

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000627

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:

0.000368

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.000180

AC:

AN:

250452

Hom.:

AF XY:

0.000177

AC XY:

AN XY:

135348

show subpopulations

Gnomad AFR exome

AF:

0.000246

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.0000654

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000345

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.000340

AC:

497

AN:

1460784

Hom.:

Cov.:

AF XY:

0.000326

AC XY:

237

AN XY:

726816

show subpopulations

Gnomad4 AFR exome

AF:

0.000388

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000252

Gnomad4 SAS exome

AF:

0.0000348

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.000406

Gnomad4 OTH exome

AF:

0.000481

GnomAD4 genome

AF:

0.000335

AC:

AN:

152172

Hom.:

Cov.:

AF XY:

0.000215

AC XY:

AN XY:

74338

show subpopulations

Gnomad4 AFR

AF:

0.000627

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:

0.000368

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.000273

Hom.:

Bravo

AF:

0.000374

TwinsUK

AF:

0.00

AC:

ALSPAC

AF:

0.000259

AC:

ESP6500AA

AF:

0.000227

AC:

ESP6500EA

AF:

0.000465

AC:

ExAC

AF:

0.000198

AC:

EpiCase

AF:

0.000273

EpiControl

AF:

0.00

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:7Benign:5

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:4Benign:3

Jun 21, 2023

Mayo Clinic Laboratories, Mayo Clinic

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jan 11, 2017

Eurofins Ntd Llc (ga)

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Sep 28, 2023

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The TTN c.9488G>A; p.Arg3163His variant (rs149755500; ClinVar Variation ID: 166298) is rare in the general population (<0.2% allele frequency in the Genome Aggregation Database) and has not been reported in the medical literature in association with dilated cardiomyopathy (DCM) or other TTN-related disease. The clinical relevance of rare missense variants in this gene, which are identified on average once per individual sequenced in affected populations (Herman 2012), is not well understood. Yet, evidence suggests that the vast majority of such missense variants do not contribute to the clinical outcome of DCM (Begay 2015). Thus, the clinical significance of the p.Arg3163His variant cannot be determined with certainty. -

Jan 21, 2021

GeneDx

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is associated with the following publications: (PMID: 23861362, 25790293, 30415094) -

Jun 24, 2013

Biesecker Lab/Clinical Genomics Section, National Institutes of Health

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: research

- -

Oct 04, 2023

Revvity Omics, Revvity

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Mar 01, 2025

CeGaT Center for Human Genetics Tuebingen

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

TTN: BS1 -

not specified

Uncertain:2

Nov 14, 2022

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: TTN c.9488G>A (p.Arg3163His) results in a non-conservative amino acid change located in the I-band region of the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 0.00018 in 250452 control chromosomes. This frequency is not higher than expected for a pathogenic variant in TTN causing Dilated Cardiomyopathy (0.00018 vs 0.00039), allowing no conclusion about variant significance. c.9488G>A has been reported in the literature in a sudden unexpected death case (Scheiper_2018), in a family with muscular dystrophy (Dardas_2020), and in a cohort of individuals not selected for arrhythmia, cardiomyopathy, or a family history of sudden death (Ng_2013). These report(s) do not provide unequivocal conclusions about association of the variant with Dilated Cardiomyopathy. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Six ClinVar submitters (evaluation after 2014) cite this variant as likely benign (n = 3) or uncertain significance (n = 3). Based on the evidence outlined above, the variant was classified as uncertain significance. -

May 26, 2015

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.Arg3163His variant in TTN has been previously identified by our laboratory in 1 unaffected individual with a family history of DCM, hypertrophy with fibro sis, and SCD. It has also been identified in 19/66478 European chromosomes by th e Exome Aggregation Consortium (ExAC, http://exac.broadinstitute.org; dbSNP rs14 9755500). Computational prediction tools and conservation analysis suggest that this variant may impact the protein, though this information is not predictive e nough to determine pathogenicity. In summary, the clinical significance of the p.Arg3163His variant is uncertain. -

Autosomal recessive limb-girdle muscular dystrophy type 2J;C1858763:Dilated cardiomyopathy 1G

Uncertain:1

Sep 15, 2016

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Cardiomyopathy

Benign:1

Apr 01, 2019

CHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern Ontario

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Cardiovascular phenotype

Benign:1

Aug 19, 2019

Ambry Genetics

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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

AlphaMissense

Benign

0.20

BayesDel_addAF

Benign

-0.081

BayesDel_noAF

Uncertain

-0.040

CADD

Pathogenic

DANN

Uncertain

0.99

Eigen

Pathogenic

0.89

Eigen_PC

Pathogenic

0.86

FATHMM_MKL

Pathogenic

1.0

LIST_S2

Uncertain

0.97

D;D;D;.;D;D;D;D

M_CAP

Benign

0.044

MetaRNN

Benign

0.23

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

MetaSVM

Uncertain

0.30

PrimateAI

Uncertain

0.56

PROVEAN

Uncertain

-3.2

D;D;.;.;D;D;.;D

REVEL

Uncertain

0.51

Sift

Benign

0.076

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

Sift4G

Uncertain

0.0020

.;.;.;.;.;.;.;D

Polyphen

1.0

.;.;.;D;.;.;D;D

Vest4

0.30

MVP

0.44

MPC

0.52

ClinPred

0.23

GERP RS

5.7

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.020

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