rs752015224

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.98759G>A(p.Arg32920Gln) variant causes a missense change. The variant allele was found at a frequency of 0.0000384 in 1,613,562 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 Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R32920W) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000033 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000039 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:6

Conservation

PhyloP100: 6.12

Publications

2 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=0.24107516).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2 link	c.98759G>A	p.Arg32920Gln	missense_variant	Exon 353 of 363	ENST00000589042.5	NP_001254479.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5 link	c.98759G>A	p.Arg32920Gln	missense_variant	Exon 353 of 363	5	NM_001267550.2	ENSP00000467141.1

Frequencies

GnomAD3 genomes

AF:

0.0000329

AC:

AN:

152028

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

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:

0.000189

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000441

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000562

AC:

AN:

248930

AF XY:

0.0000815

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000870

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.0000929

Gnomad NFE exome

AF:

0.0000355

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000390

AC:

AN:

1461534

Hom.:

Cov.:

AF XY:

0.0000481

AC XY:

AN XY:

727062

show subpopulations

African (AFR)

AF:

0.0000299

AC:

AN:

33462

American (AMR)

AF:

0.000112

AC:

AN:

44714

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26130

East Asian (EAS)

AF:

0.0000252

AC:

AN:

39694

South Asian (SAS)

AF:

0.000162

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.0000936

AC:

AN:

53396

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.0000270

AC:

AN:

1111748

Other (OTH)

AF:

0.0000166

AC:

AN:

60364

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.493

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:

0.0000329

AC:

AN:

152028

Hom.:

Cov.:

AF XY:

0.0000404

AC XY:

AN XY:

74232

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41394

American (AMR)

AF:

0.00

AC:

AN:

15256

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5174

South Asian (SAS)

AF:

0.00

AC:

AN:

4818

European-Finnish (FIN)

AF:

0.000189

AC:

AN:

10590

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000441

AC:

AN:

68006

Other (OTH)

AF:

0.00

AC:

AN:

2090

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

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:

0.000115

Hom.:

Bravo

AF:

0.0000453

ExAC

AF:

0.0000496

AC:

EpiCase

AF:

0.0000545

EpiControl

AF:

0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:6

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Aug 18, 2014

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Missense variants in the TTN gene are considered 'unclassified' if they are not previously reported in the literature and do not have >1% frequency in the population to be considered a polymorphism. Research indicates that truncating mutations in the TTN gene are expected to account for approximately 25% of familial and 18% of sporadic idiopathic DCM; however, truncating variants in the TTN gene have been reported in approximately 3% of reported control alleles. There has been little investigation into non-truncating variants. (Herman D et al. Truncations of titin causing dilated cardiomyopathy. N Eng J Med 366:619-628, 2012) The variant is found in DCM-CRDM panel(s). -

Dilated cardiomyopathy 1S

Uncertain:1

May 01, 2016

Institut für Laboratoriums- und Transfusionsmedizin, Herz- und Diabeteszentrum Nordrhein-Westfalen

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:research

- -

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

Uncertain:1

Jan 29, 2018

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces arginine with glutamine at codon 32920 of the TTN protein (p.Arg32920Gln). There is a small physicochemical difference between arginine and glutamine. This variant is present in population databases (rs752015224, ExAC 0.02%). This variant has not been reported in the literature in individuals with TTN-related disease. ClinVar contains an entry for this variant (Variation ID: 191836). This variant identified in the TTN gene is located in the A band of the resulting protein (PMID: 25589632). It is unclear how this variant impacts the function of this protein. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site, but this prediction has not been confirmed by published transcriptional studies. Algorithms developed to predict the effect of missense changes on protein structure and function are unavailable for the TTN gene. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Autosomal recessive limb-girdle muscular dystrophy type 2J;C1838244:Tibial muscular dystrophy;C1858763:Dilated cardiomyopathy 1G;C1861065:Hypertrophic cardiomyopathy 9;C1863599:Myopathy, myofibrillar, 9, with early respiratory failure;C2673677:Early-onset myopathy with fatal cardiomyopathy

Uncertain:1

Aug 17, 2021

Fulgent Genetics, Fulgent Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

not provided

Uncertain: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

- -

Cardiovascular phenotype

Uncertain:1

Aug 08, 2017

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The p.R23855Q variant (also known as c.71564G>A), located in coding exon 180 of the TTN gene, results from a G to A substitution at nucleotide position 71564. The arginine at codon 23855 is replaced by glutamine, an amino acid with highly similar properties. This alteration has been reported as a secondary cardiac variant in an exome cohort (Ng D et al. Circ Cardiovasc Genet, 2013 Aug;6:337-46). This amino acid position is highly 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

0.32

BayesDel_addAF

Benign

-0.22

BayesDel_noAF

Benign

-0.29

CADD

Benign

(source)

DANN

Uncertain

0.98

Eigen

Pathogenic

0.77

Eigen_PC

Pathogenic

0.83

FATHMM_MKL

Uncertain

0.96

LIST_S2

Uncertain

0.97

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

M_CAP

Benign

0.018

MetaRNN

Benign

0.24

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

MetaSVM

Benign

-0.60

MutationAssessor

Benign

0.81

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

PhyloP100

6.1

PrimateAI

Uncertain

0.70

PROVEAN

Uncertain

-2.6

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

REVEL

Uncertain

0.32

Sift

Benign

0.034

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

Polyphen

1.0

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

Vest4

0.48

MVP

0.26

MPC

0.50

ClinPred

0.29

GERP RS

6.2

Mutation Taster

=88/12

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