2-178534907-C-T

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -5 ACMG points: 0P and 5B. BP4_StrongBP6

The NM_001267550.2(TTN):c.101708G>A(p.Arg33903His) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000926 in 1,609,828 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). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R33903C) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.00019 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000082 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3B:3

Conservation

PhyloP100: 7.91

Publications

7 publications found

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 was made for transcript

Our verdict: Likely_benign. The variant received -5 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.0177069).

BP6

Variant 2-178534907-C-T is Benign according to our data. Variant chr2-178534907-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 191823.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2 link	c.101708G>A	p.Arg33903His	missense_variant	Exon 358 of 363	ENST00000589042.5	NP_001254479.2	A0A0A0MTS7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5 link	c.101708G>A	p.Arg33903His	missense_variant	Exon 358 of 363	5	NM_001267550.2	ENSP00000467141.1		A0A0A0MTS7

Frequencies

GnomAD3 genomes

AF:

0.000191

AC:

AN:

152170

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00192

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00141

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000441

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.000244

AC:

AN:

245652

AF XY:

0.000277

show subpopulations

Gnomad AFR exome

AF:

0.0000647

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00201

Gnomad FIN exome

AF:

0.000745

Gnomad NFE exome

AF:

0.0000712

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000823

AC:

120

AN:

1457540

Hom.:

Cov.:

AF XY:

0.0000938

AC XY:

AN XY:

725312

show subpopulations

African (AFR)

AF:

0.0000598

AC:

AN:

33470

American (AMR)

AF:

0.00

AC:

AN:

44714

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26128

East Asian (EAS)

AF:

0.000983

AC:

AN:

39684

South Asian (SAS)

AF:

0.0000116

AC:

AN:

86248

European-Finnish (FIN)

AF:

0.000647

AC:

AN:

49432

Middle Eastern (MID)

AF:

0.000173

AC:

AN:

5766

European-Non Finnish (NFE)

AF:

0.0000360

AC:

AN:

1111752

Other (OTH)

AF:

0.0000829

AC:

AN:

60346

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.490

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.000190

AC:

AN:

152288

Hom.:

Cov.:

AF XY:

0.000269

AC XY:

AN XY:

74462

show subpopulations

African (AFR)

AF:

0.0000241

AC:

AN:

41566

American (AMR)

AF:

0.00

AC:

AN:

15290

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00193

AC:

AN:

5186

South Asian (SAS)

AF:

0.00

AC:

AN:

4824

European-Finnish (FIN)

AF:

0.00141

AC:

AN:

10606

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.0000441

AC:

AN:

68026

Other (OTH)

AF:

0.00

AC:

AN:

2114

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.511

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.0000782

Hom.:

Bravo

AF:

0.0000907

TwinsUK

AF:

0.00

AC:

ALSPAC

AF:

0.000259

AC:

ExAC

AF:

0.000215

AC:

Asia WGS

AF:

0.000289

AC:

AN:

3478

EpiCase

AF:

0.0000545

EpiControl

AF:

0.000178

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:3Benign:3

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:2Benign:1

Jun 24, 2013

Biesecker Lab/Clinical Genomics Section, National Institutes of Health

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:research

- -

May 20, 2020

GeneDx

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Jul 28, 2021

Revvity Omics, Revvity

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Primary dilated cardiomyopathy

Uncertain:1

Jun 01, 2023

Clinical Center for Gene Diagnosis and Therapy, Department of Cardiovascular Surgery, The Second Xiangya Hospital of Central South University

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

TTN-related disorder

Benign:1

Jan 26, 2022

PreventionGenetics, part of Exact Sciences

Significance:Likely benign

Review Status:no assertion criteria provided

Collection Method:clinical testing

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

Oct 18, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.37

BayesDel_addAF

Benign

-0.20

BayesDel_noAF

Uncertain

-0.070

CADD

Benign

(source)

DANN

Benign

0.95

Eigen

Pathogenic

0.73

Eigen_PC

Pathogenic

0.79

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.94

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

M_CAP

Benign

0.016

MetaRNN

Benign

0.018

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

MetaSVM

Benign

-0.45

MutationAssessor

Benign

1.1

.;.;.;L;.;.;L

PhyloP100

7.9

PrimateAI

Uncertain

0.71

PROVEAN

Uncertain

-3.5

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

REVEL

Uncertain

0.45

Sift

Pathogenic

0.0

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

Polyphen

1.0

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

Vest4

0.28

MVP

0.39

MPC

0.52

ClinPred

0.19

GERP RS

6.0

Mutation Taster

=64/36

polymorphism

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over