rs375159973

Variant names:

Variant summary

Our verdict is Likely pathogenic. Variant got 9 ACMG points: 9P and 0B. PP3PP5_Very_Strong

The NM_001267550.2(TTN):c.102214T>C(p.Trp34072Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000217 in 1,610,942 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★).

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000022 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:5

Conservation

PhyloP100: 9.30

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_pathogenic. Variant got 9 ACMG points.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.784

PP5

Variant 2-178534401-A-G is Pathogenic according to our data. Variant chr2-178534401-A-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 405075.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr2-178534401-A-G is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2 link	c.102214T>C	p.Trp34072Arg	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.102214T>C	p.Trp34072Arg	missense_variant	Exon 358 of 363	5	NM_001267550.2	ENSP00000467141.1		A0A0A0MTS7

Frequencies

GnomAD3 genomes

AF:

0.0000197

AC:

AN:

152120

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:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000441

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.00000811

AC:

AN:

246606

Hom.:

AF XY:

0.00000746

AC XY:

AN XY:

134018

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:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000178

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000219

AC:

AN:

1458822

Hom.:

Cov.:

AF XY:

0.0000220

AC XY:

AN XY:

725922

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.0000224

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000252

Gnomad4 SAS exome

AF:

0.0000116

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000252

Gnomad4 OTH exome

AF:

0.0000166

GnomAD4 genome

AF:

0.0000197

AC:

AN:

152120

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74302

show subpopulations

Gnomad4 AFR

AF:

0.00

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:

0.0000441

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000658

Hom.:

Bravo

AF:

0.0000264

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000121

AC:

ExAC

AF:

0.0000165

AC:

EpiCase

AF:

0.000109

EpiControl

AF:

0.00

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:5

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Autosomal recessive limb-girdle muscular dystrophy type 2J

Pathogenic:2

Feb 18, 2020

Johns Hopkins Genomics, Johns Hopkins University

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

c.102214T>C has been reported in ClinVar. This variant (rs375159973) is rare (<0.1%) in large population datasets (gnomAD: 2/246606 total alleles; 0.0018%; no homozygotes). Two bioinformatics tools queried predict that it would be deleterious. The amino acid residue at this position is evolutionarily conserved across all species assessed. This variant changes a highly conserved amino acid in the core of the TTN serine-threonine kinase (TK) domain and has been reported to have a deleterious effect on protein function. This variant has been observed in combination with a different frameshift variant (c.9388+1G>C) in an individual affected with congenital core myopathy combined with primary heart disease. We consider this variant likely pathogenic. -

Jul 15, 2024

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: TTN c.94510T>C (p.Trp31504Arg), also reported as p.Trp34072Arg, results in a non-conservative amino acid change located in the M-band region of the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 8.1e-06 in 246606 control chromosomes. c.94510T>C has been reported in the literature in the presumed compound heterozygous or compound heterozygous state in multiple individuals affected with clinical features of autosomal recessive TTN-related myopathies (example, Chaveau_2014, Avila-Polo_2018, Savarese_2020, Laquerriere_2022, Rees_2021). These data indicate that the variant is likely to be associated with disease. At least one publication reports experimental evidence evaluating an impact on protein function. In vitro experiments have shown this variant severely decreases interaction with binding partners and destabilizes the protein (example, Chaveau_2014, Rees_2021). The following publications have been ascertained in the context of this evaluation (PMID: 30365001, 24105469, 33820833, 31983221, 33449170, 32778822). ClinVar contains an entry for this variant (Variation ID: 405075). Based on the evidence outlined above, the variant was classified as pathogenic. -

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

Pathogenic:1

Aug 19, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces tryptophan, which is neutral and slightly polar, with arginine, which is basic and polar, at codon 34072 of the TTN protein (p.Trp34072Arg). This variant is present in population databases (rs375159973, gnomAD 0.002%). This missense change has been observed in individual(s) with autosomal recessive congenital myopathy and/or clinical features of dilated cardiomyopathy (PMID: 24105469, 30365001, 31983221, 32778822; Invitae). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 405075). Algorithms developed to predict the effect of variants on gene product structure and function are not available or were not evaluated for this variant. Experimental studies have shown that this missense change affects TTN function (PMID: 24105469). This variant is located in the M band of TTN (PMID: 25589632). Non-truncating variants in this region may be relevant for neuromuscular disorders, but have not been definitively shown to cause cardiomyopathy (PMID: 23975875). For these reasons, this variant has been classified as Pathogenic. -

Early-onset myopathy with fatal cardiomyopathy

Pathogenic:1

Jul 16, 2024

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

not provided

Pathogenic:1

Jan 09, 2023

Clinical Genetics Laboratory, Skane University Hospital Lund

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.98

BayesDel_addAF

Pathogenic

0.17

BayesDel_noAF

Uncertain

0.020

CADD

Benign

DANN

Benign

0.87

Eigen

Pathogenic

1.1

Eigen_PC

Pathogenic

0.97

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.87

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

M_CAP

Pathogenic

0.60

MetaRNN

Pathogenic

0.78

D;D;D;D;D;D;D

MetaSVM

Uncertain

0.58

MutationAssessor

Pathogenic

4.4

.;.;.;H;.;.;H

PrimateAI

Uncertain

0.75

PROVEAN

Pathogenic

-10

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

REVEL

Pathogenic

0.83

Sift

Pathogenic

0.0

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

Polyphen

1.0

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

Vest4

0.59

MutPred

0.76

.;.;.;Gain of disorder (P = 3e-04);.;.;Gain of disorder (P = 3e-04);

MVP

0.78

MPC

0.62

ClinPred

0.42

GERP RS

5.9

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

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