rs753334568

Variant summary

Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PP2PP3_ModeratePP5_Very_Strong

The NM_001267550.2(TTN):c.95195C>T(p.Pro31732Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000093 in 1,613,628 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 (★★). Synonymous variant affecting the same amino acid position (i.e. P31732P) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000089 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:11O:1

Conservation

PhyloP100: 10.0

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 Pathogenic. Variant got 11 ACMG points.

PP2

Missense variant where missense usually causes diseases, TTN

PP3

MetaRNN computational evidence supports a deleterious effect, 0.845

PP5

Variant 2-178546041-G-A is Pathogenic according to our data. Variant chr2-178546041-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 132137.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr2-178546041-G-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TTN	NM_001267550.2 linkuse as main transcript	c.95195C>T	p.Pro31732Leu	missense_variant	343/363	ENST00000589042.5
TTN-AS1	NR_038272.1 linkuse as main transcript	n.2043+3680G>A		intron_variant, non_coding_transcript_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TTN	ENST00000589042.5 linkuse as main transcript	c.95195C>T	p.Pro31732Leu	missense_variant	343/363	5	NM_001267550.2	P1
TTN-AS1	ENST00000659121.1 linkuse as main transcript	n.416+22405G>A		intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152164

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:

0.0000294

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000121

AC:

AN:

248136

Hom.:

AF XY:

0.00000743

AC XY:

AN XY:

134588

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:

0.0000327

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000178

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000890

AC:

AN:

1461464

Hom.:

Cov.:

AF XY:

0.00000550

AC XY:

AN XY:

727020

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.0000224

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000116

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000899

Gnomad4 OTH exome

AF:

0.0000166

GnomAD4 genome

AF:

0.0000131

AC:

AN:

152164

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74334

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:

0.0000294

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000282

Hom.:

Bravo

AF:

0.00000756

ExAC

AF:

0.0000165

AC:

EpiCase

AF:

0.0000545

EpiControl

AF:

0.00

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:11Other:1

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Pathogenic:6

Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Mar 22, 2023	Identified in a patient with Lambert-Eaton Myasthenic Syndrome (LEMS) who also harbored a pathogenic variant in the CACNA1S gene (Cerino et al., 2022); Not observed at significant frequency in large population cohorts (gnomAD); Published functional studies indicates this variant results in an insoluble protein due to improper folding (Hedburg et al., 2014); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 22526018, 25500009, 23486992, 23446887, 34839411, 24636144, 35741838, 32039858, 34670883) -
Pathogenic, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Dec 01, 2018	- -
Pathogenic, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Apr 01, 2023	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	AiLife Diagnostics, AiLife Diagnostics	Dec 14, 2021	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	Institute of Medical Genetics and Applied Genomics, University Hospital Tübingen	Oct 23, 2020	- -
Pathogenic, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Dec 03, 2017	- -

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

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Invitae

Dec 22, 2023

This sequence change replaces proline, which is neutral and non-polar, with leucine, which is neutral and non-polar, at codon 31732 of the TTN protein (p.Pro31732Leu). This variant is present in population databases (rs753334568, gnomAD 0.003%). This missense change has been observed in individual(s) with hereditary myopathy with early respiratory failure (HMERF) (PMID: 22526018, 23486992, 23606733, 25500009). In at least one individual the variant was observed to be de novo. This variant is also known as c.90272C>T (p.Pro30091Leu) and c.68576C>T (p.Pro22859Leu). ClinVar contains an entry for this variant (Variation ID: 132137). Algorithms developed to predict the effect of variants on protein 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: 24636144). This variant is located in the A band of TTN (PMID: 25589632). Variants in this region may be relevant for cardiac or neuromuscular disorders (PMID: 25589632, 23975875). For these reasons, this variant has been classified as Pathogenic. -

Dilated cardiomyopathy 1G

Pathogenic:1

Likely pathogenic, criteria provided, single submitter

research

Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center

Mar 25, 2024

- -

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

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Aug 14, 2021

- -

Primary familial dilated cardiomyopathy

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

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

Jan 09, 2024

Variant summary: TTN c.87491C>T (p.Pro29164Leu) results in a non-conservative amino acid change located in the A-band domain of the encoded protein sequence. Four of four in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 1.2e-05 in 248136 control chromosomes (gnomAD). c.87491C>T has been reported in the literature in multiple individuals with characteristic features of hereditary myopathy with early respiratory failure (Palmio_2013, Yue_2014, Hedberg_2014, Cerino_2022). These data indicate that the variant is very likely to be associated with disease. At least one publication reports experimental evidence evaluating an impact on protein function and this variant results in impaired protein solubility (Hedberg_2014). The following publications have been ascertained in the context of this evaluation (PMID: 35741838, 24231549, 23606733, 25500009). ClinVar contains an entry for this variant (Variation ID: 132137). Based on the evidence outlined above, the variant was classified as pathogenic. -

Cardiovascular phenotype

Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Jun 16, 2023

The p.P22667L variant (also known as c.68000C>T), located in coding exon 170 of the TTN gene, results from a C to T substitution at nucleotide position 68000. The proline at codon 22667 is replaced by leucine, an amino acid with similar properties. This variant (also referred to as p.P31732L and p.P30091L) has been detected in the homozygous and heterozygous states, including a de novo occurrence, in individuals with skeletal muscle and/or respiratory issues consistent with hereditary myopathy with early respiratory failure (HMERF). Homozygous individuals tended to be more severely affected, and not all heterozygous individuals were affected, suggesting this variant exhibits variable expressivity and reduced penetrance (Vasli N et al. Acta Neuropathol., 2012 Aug;124:273-83; Yue D et al. Neuromuscul. Disord., 2015 Feb;25:172-6; Palmio J et al. J Neurol Neurosurg Psychiatry, 2014 Mar;85:345-53; Pfeffer G et al. J. Neurol. Neurosurg. Psychiatry, 2014 Mar;85:331-8; Cerino M et al. Muscle Nerve, 2017 Nov;56:993-997; Savarese M et al. J Neuromuscul Dis, 2020;7:153-166; Rees M et al. Acta Neuropathol, 2021 Mar;141:431-453; Cerino M et al. Genes (Basel), 2022 Jun;13). Functional studies suggest this variant may be destabilizing and impact protein folding (Hedberg C et al. Neuromuscul. Disord. 2014 May;24(5):373-9; Rees M et al. Acta Neuropathol, 2021 Mar;141:431-453). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Based on the supporting evidence, this alteration is likely pathogenic for hereditary myopathy with early respiratory failure; however, the association of this alteration with cardiomyopathy is unknown. -

Myopathy, myofibrillar, 9, with early respiratory failure

Other:1

not provided, no classification provided

literature only

GeneReviews

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.95

BayesDel_addAF

Pathogenic

0.19

BayesDel_noAF

Pathogenic

0.14

Cadd

Uncertain

Dann

Uncertain

0.98

Eigen

Pathogenic

1.2

Eigen_PC

Pathogenic

1.1

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.94

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

M_CAP

Pathogenic

0.34

MetaRNN

Pathogenic

0.84

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

MetaSVM

Pathogenic

0.89

MutationTaster

Benign

1.0

D;D;D;D;D;D

PrimateAI

Uncertain

0.70

PROVEAN

Pathogenic

-7.5

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

REVEL

Pathogenic

0.73

Sift

Pathogenic

0.0

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

Polyphen

1.0

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

Vest4

0.58

MutPred

0.79

.;.;.;Loss of disorder (P = 0.085);.;.;Loss of disorder (P = 0.085);

MVP

0.91

MPC

0.47

ClinPred

0.99

GERP RS

5.8

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