2-178609755-C-T

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 0P and 2B. BP4_Moderate

The NM_001267550.2(TTN):c.51668G>A(p.Arg17223Gln) variant causes a missense change. The variant allele was found at a frequency of 0.000018 in 1,612,656 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).

Frequency

Genomes: 𝑓 0.000092 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000010 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:6B:1

Conservation

PhyloP100: 3.79

Publications

3 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 -2 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.17638275).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2 link	c.51668G>A	p.Arg17223Gln	missense_variant	Exon 272 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.51668G>A	p.Arg17223Gln	missense_variant	Exon 272 of 363	5	NM_001267550.2	ENSP00000467141.1		A0A0A0MTS7

Frequencies

GnomAD3 genomes

AF:

0.0000921

AC:

AN:

151934

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000266

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:

0.0000294

Gnomad OTH

AF:

0.000479

GnomAD2 exomes

AF:

0.0000242

AC:

AN:

248168

AF XY:

0.0000223

show subpopulations

Gnomad AFR exome

AF:

0.000194

Gnomad AMR exome

AF:

0.0000870

Gnomad ASJ exome

AF:

0.00

Gnomad EAS 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:

0.0000103

AC:

AN:

1460604

Hom.:

Cov.:

AF XY:

0.00000963

AC XY:

AN XY:

726578

show subpopulations

African (AFR)

AF:

0.000180

AC:

AN:

33404

American (AMR)

AF:

0.0000447

AC:

AN:

44704

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26092

East Asian (EAS)

AF:

0.00

AC:

AN:

39644

South Asian (SAS)

AF:

0.00

AC:

AN:

86174

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53372

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5754

European-Non Finnish (NFE)

AF:

0.00000540

AC:

AN:

1111154

Other (OTH)

AF:

0.0000166

AC:

AN:

60306

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.452

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:

0.0000921

AC:

AN:

152052

Hom.:

Cov.:

AF XY:

0.000121

AC XY:

AN XY:

74312

show subpopulations

African (AFR)

AF:

0.000265

AC:

AN:

41528

American (AMR)

AF:

0.00

AC:

AN:

15250

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3468

East Asian (EAS)

AF:

0.00

AC:

AN:

5118

South Asian (SAS)

AF:

0.00

AC:

AN:

4816

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10626

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.0000294

AC:

AN:

67930

Other (OTH)

AF:

0.000474

AC:

AN:

2110

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.486

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:

0.0000986

Hom.:

Bravo

AF:

0.000117

ESP6500AA

AF:

0.000263

AC:

ESP6500EA

AF:

0.00

AC:

ExAC

AF:

0.0000248

AC:

EpiCase

AF:

0.0000546

EpiControl

AF:

0.00

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:6Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:3Benign:1

Genome Diagnostics Laboratory, Amsterdam University Medical Center

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Joint Genome Diagnostic Labs from Nijmegen and Maastricht, Radboudumc and MUMC+

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Feb 24, 2021

GeneDx

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Aug 01, 2024

CeGaT Center for Human Genetics Tuebingen

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

TTN: PM2, BP4 -

not specified

Uncertain:1

Jan 28, 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.Arg14655Gln variant in TTN has not been previously reported in individuals with cardiomyopathy, but has been identified in 2/9966 African chromosomes by t he Exome Aggregation Consortium (ExAC, http://exac.broadinstitute.org; dbSNP rs1 42395261). Computational prediction tools and conservation analysis do not provi de strong support for or against an impact to the protein. In summary, the clini cal significance of the p.Arg14655Gln variant is uncertain. -

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

Uncertain:1

May 20, 2016

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Cardiovascular phenotype

Uncertain:1

Sep 30, 2019

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The p.R8158Q variant (also known as c.24473G>A), located in coding exon 99 of the TTN gene, results from a G to A substitution at nucleotide position 24473. The arginine at codon 8158 is replaced by glutamine, an amino acid with highly similar properties. This amino acid position is well conserved in available vertebrate species. In addition, this alteration is predicted to be tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.22

BayesDel_addAF

Benign

-0.17

BayesDel_noAF

Benign

-0.20

CADD

Uncertain

(source)

DANN

Uncertain

0.98

Eigen

Pathogenic

0.74

Eigen_PC

Pathogenic

0.73

FATHMM_MKL

Uncertain

0.95

LIST_S2

Uncertain

0.97

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

M_CAP

Benign

0.041

MetaRNN

Benign

0.18

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

MetaSVM

Benign

-0.30

MutationAssessor

Uncertain

2.8

.;.;.;M;.;.;M

PhyloP100

3.8

PrimateAI

Uncertain

0.50

PROVEAN

Uncertain

-2.8

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

REVEL

Benign

0.29

Sift

Benign

0.087

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

Polyphen

1.0

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

Vest4

0.33

MVP

0.24

MPC

0.40

ClinPred

0.30

GERP RS

5.8

Mutation Taster

=89/11

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