rs376932266

Variant summary

Our verdict is Likely benign. Variant got -1 ACMG points: 1P and 2B. PP2BP4_Moderate

The NM_001267550.2(TTN):c.54167G>A(p.Arg18056Gln) variant causes a missense change. The variant allele was found at a frequency of 0.0000263 in 1,599,844 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/19 in silico tools predict 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. R18056L) has been classified as Uncertain significance.

Frequency

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

Exomes 𝑓: 0.000024 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:8

Conservation

PhyloP100: 3.80

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 -1 ACMG points.

PP2

Missense variant where missense usually causes diseases, TTN

BP4

Computational evidence support a benign effect (MetaRNN=0.1774328).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TTN	NM_001267550.2 linkuse as main transcript	c.54167G>A	p.Arg18056Gln	missense_variant	280/363	ENST00000589042.5
TTN-AS1	NR_038272.1 linkuse as main transcript	n.4197C>T		non_coding_transcript_exon_variant	17/17

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TTN	ENST00000589042.5 linkuse as main transcript	c.54167G>A	p.Arg18056Gln	missense_variant	280/363	5	NM_001267550.2	P1
TTN-AS1	ENST00000659121.1 linkuse as main transcript	n.502+7329C>T		intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes

AF:

0.0000461

AC:

AN:

151904

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000242

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:

0.0000883

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000125

AC:

AN:

239712

Hom.:

AF XY:

0.0000154

AC XY:

AN XY:

129732

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.0000704

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000919

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000242

AC:

AN:

1447940

Hom.:

Cov.:

AF XY:

0.0000278

AC XY:

AN XY:

718754

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.0000794

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000356

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000254

Gnomad4 OTH exome

AF:

0.0000335

GnomAD4 genome

AF:

0.0000461

AC:

AN:

151904

Hom.:

Cov.:

AF XY:

0.0000270

AC XY:

AN XY:

74170

show subpopulations

Gnomad4 AFR

AF:

0.0000242

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:

0.0000883

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000659

Hom.:

Bravo

AF:

0.0000302

TwinsUK

AF:

0.00

AC:

ALSPAC

AF:

0.000259

AC:

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000121

AC:

ExAC

AF:

0.0000248

AC:

Asia WGS

AF:

0.000289

AC:

AN:

3476

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:8

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Uncertain:4

Uncertain significance, criteria provided, single submitter	clinical testing	Mayo Clinic Laboratories, Mayo Clinic	Oct 26, 2021	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Athena Diagnostics	Sep 28, 2018	- -
Uncertain significance, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Feb 01, 2024	TTN: PM2:Supporting, BP4 -
Uncertain significance, criteria provided, single submitter	clinical testing	ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories	Jan 03, 2023	The TTN c.54167G>A; p.Arg18056Gln variant (rs376932266; ClinVar Variation ID: 47084) 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.Arg18056Gln variant cannot be determined with certainty. -

not specified

Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine	Jan 31, 2017	The p.Arg15488Gln variant in TTN has been identified in one infant with DCM who also carried a likely pathogenic variant in VCL (LMM data). It has been identifi ed in 2/65398 of European chromosomes by the Exome Aggregation Consortium (ExAC, http://exac.broadinstitute.org; dbSNP rs376932266). Computational prediction to ols and conservation analysis suggest that this variant may impact the protein, though this information is not predictive enough to determine pathogenicity. In summary, the clinical significance of the p.Arg15488Gln variant is uncertain. -
Uncertain significance, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Dec 27, 2022	Variant summary: TTN c.46463G>A (p.Arg15488Gln) results in a conservative amino acid change located in the A-band region of the encoded protein sequence. Three of four in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 1.3e-05 in 239712 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.46463G>A has been reported in the literature in an individual affected with Dilated Cardiomyopathy, however other potentially causative co-occurring variants were also identified in this patient (Pugh_2014). Therefore, these reports 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. Four ClinVar submitters (evaluation after 2014) have cited the variant, and all laboratories classified the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance. -

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

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jun 28, 2017

- -

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

Uncertain significance, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Oct 30, 2021

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.14

BayesDel_addAF

Benign

-0.18

BayesDel_noAF

Benign

-0.32

Cadd

Benign

Dann

Uncertain

0.98

Eigen

Uncertain

0.23

Eigen_PC

Uncertain

0.33

FATHMM_MKL

Uncertain

0.86

LIST_S2

Uncertain

0.92

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

M_CAP

Benign

0.055

MetaRNN

Benign

0.18

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

MetaSVM

Benign

-0.72

MutationTaster

Benign

1.0

D;D;D;D;D;D

PrimateAI

Benign

0.34

PROVEAN

Benign

-2.2

N;N;.;.;N;N;.

REVEL

Benign

0.18

Sift

Benign

0.20

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

Polyphen

0.77

.;.;.;P;.;.;P

Vest4

0.45

MVP

0.20

MPC

0.15

ClinPred

0.24

GERP RS

5.1

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

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