rs201614524

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -1 ACMG points: 0P and 1B. BP4

The NM_001267550.2(TTN):c.64903C>T(p.Arg21635Cys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000018 in 1,613,344 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). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R21635H) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000046 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000015 ( 1 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

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

Conservation

PhyloP100: 9.94

Publications

1 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 -1 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.3977202).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2 link	c.64903C>T	p.Arg21635Cys	missense_variant	Exon 310 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.64903C>T	p.Arg21635Cys	missense_variant	Exon 310 of 363	5	NM_001267550.2	ENSP00000467141.1		A0A0A0MTS7

Frequencies

GnomAD3 genomes

AF:

0.0000460

AC:

AN:

152046

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000483

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000655

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.000388

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000294

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000604

AC:

AN:

248496

AF XY:

0.0000519

show subpopulations

Gnomad AFR exome

AF:

0.0000646

Gnomad AMR exome

AF:

0.0000290

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.000167

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000890

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000151

AC:

AN:

1461298

Hom.:

Cov.:

AF XY:

0.0000138

AC XY:

AN XY:

726920

show subpopulations

African (AFR)

AF:

0.0000897

AC:

AN:

33446

American (AMR)

AF:

0.0000224

AC:

AN:

44712

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26118

East Asian (EAS)

AF:

0.0000504

AC:

AN:

39682

South Asian (SAS)

AF:

0.00

AC:

AN:

86234

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53402

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5762

European-Non Finnish (NFE)

AF:

0.0000144

AC:

AN:

1111598

Other (OTH)

AF:

0.00

AC:

AN:

60344

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.495

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Exome Hom

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:

0.0000460

AC:

AN:

152046

Hom.:

Cov.:

AF XY:

0.0000539

AC XY:

AN XY:

74228

show subpopulations

African (AFR)

AF:

0.0000483

AC:

AN:

41438

American (AMR)

AF:

0.0000655

AC:

AN:

15256

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.000388

AC:

AN:

5156

South Asian (SAS)

AF:

0.00

AC:

AN:

4830

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10600

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000294

AC:

AN:

67978

Other (OTH)

AF:

0.00

AC:

AN:

2088

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.554

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:

0.000108

Hom.:

Bravo

AF:

0.0000793

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000243

AC:

ExAC

AF:

0.0000248

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:5Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:2Benign:1

Nov 20, 2019

Revvity Omics, Revvity

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Department of Pathology and Laboratory Medicine, Sinai Health System

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:clinical testing

The TTN p.Arg19994Cys variant was not identified in the literature nor was it identified in LOVD 3.0. The variant was identified in dbSNP (ID: rs201614524) and ClinVar (classified as likely benign by GeneDx and uncertain significance by Laboratory for Molecular Medicine). The variant was identified in control databases in 17 of 279872 chromosomes (1 homozygous) at a frequency of 0.00006074 (Genome Aggregation Database March 6, 2019, v2.1.1). The variant was observed in the following populations: East Asian in 5 of 19474 chromosomes (freq: 0.000257), European (non-Finnish) in 10 of 127774 chromosomes (freq: 0.000078), African in 1 of 24194 chromosomes (freq: 0.000041) and Latino in 1 of 35352 chromosomes (freq: 0.000028), but was not observed in the Ashkenazi Jewish, European (Finnish), Other, or South Asian populations. The p.Arg19994 residue is conserved across mammals and other organisms, and computational analyses (PolyPhen-2, SIFT, AlignGVGD, BLOSUM, MutationTaster) suggest that the variant may impact the protein; however, this information is not predictive enough to assume pathogenicity. The variant occurs outside of the splicing consensus sequence and in silico or computational prediction software programs (SpliceSiteFinder, MaxEntScan, NNSPLICE, GeneSplicer) do not predict a difference in splicing. In summary, based on the above information the clinical significance of this variant cannot be determined with certainty at this time. This variant is classified as a variant of uncertain significance. -

Apr 25, 2019

GeneDx

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant is associated with the following publications: (PMID: 24503780) -

not specified

Uncertain:2

Jun 13, 2023

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.57199C>T (p.Arg19067Cys) results in a non-conservative amino acid change located in the A-band of the encoded protein sequence. Three of four in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 6e-05 in 248496 control chromosomes in the gnomAD database, including 1 homozygotes. This frequency is not significantly higher than estimated for a pathogenic variant in TTN causing Dilated Cardiomyopathy (6e-05 vs 0.00039), allowing no conclusion about variant significance. c.57199C>T has been reported in the literature in an individual affected with Dilated Cardiomyopathy (Pugh_2014) without strong evidence for causality. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publication have been ascertained in the context of this evaluation (PMID: 24503780). Three clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 and classified as VUS (n=2) and likely benign (n=1). Based on the evidence outlined above, the variant was classified as uncertain significance. -

Oct 08, 2012

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant classified as Uncertain Significance - Favor Benign. The Arg19067Cys var iant in TTN has been identified in 2/8240 European American chromosomes from a b road population by the NHLBI Exome Sequencing Project (http://evs.gs.washington. edu/EVS/). This variant was also identified in one individual with DCM who had t wo other variants, including a TTN variant inherited in cis with this variant. F amily studies suggest that the TTN variants may be less likely disease causing b ut computational analyses (biochemical amino acid properties, conservation, Alig nGVGD, PolyPhen2, and SIFT) suggest that the Arg19067Cys variant may impact the protein (please note: the accuracy of these tools is unknown and this informatio n is not predictive enough to determine pathogenicity). Additional information i s needed to fully assess the clinical significance of the Arg19067Cys variant. -

Myopathy, myofibrillar, 9, with early respiratory failure

Uncertain:1

Jan 24, 2018

Baylor Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant was determined to be of uncertain significance according to ACMG Guidelines, 2015 [PMID:25741868]. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.22

BayesDel_addAF

Benign

-0.061

BayesDel_noAF

Uncertain

-0.060

CADD

Uncertain

(source)

DANN

Uncertain

0.98

Eigen

Pathogenic

1.0

Eigen_PC

Pathogenic

1.0

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.97

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

M_CAP

Benign

0.0083

MetaRNN

Benign

0.40

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

MetaSVM

Uncertain

-0.16

MutationAssessor

Benign

1.5

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

PhyloP100

9.9

PrimateAI

Uncertain

0.71

PROVEAN

Pathogenic

-5.5

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

REVEL

Uncertain

0.55

Sift

Uncertain

0.0090

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

Polyphen

1.0

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

Vest4

0.56

MVP

0.74

MPC

0.54

ClinPred

0.35

GERP RS

6.2

Mutation Taster

=92/8

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