chr2-178620715-C-T

Position:

chr2-178620715-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 1P and 0B. PP2

The NM_001267550.2(TTN):c.45895G>A(p.Glu15299Lys) variant causes a missense, splice region change. The variant allele was found at a frequency of 0.0000116 in 1,460,202 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★★).

Frequency

Genomes: not found (cov: 33)

Exomes 𝑓: 0.000012 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense, splice_region

Scores

Splicing: ADA: 0.9999

Clinical Significance

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

Conservation

PhyloP100: 4.03

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:):

TTN-AS1 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 1 ACMG points.

PP2

Missense variant in gene, where missense usually causes diseases (based on misZ statistic), TTN. . Gene score misZ -1.1021 (greater than the threshold 3.09). Trascript score misZ 6.9794 (greater than threshold 3.09). GenCC has associacion of gene with dilated cardiomyopathy, tibial muscular dystrophy, early-onset myopathy with fatal cardiomyopathy, autosomal recessive centronuclear myopathy, hypertrophic cardiomyopathy, hypertrophic cardiomyopathy 9, TTN-related myopathy, dilated cardiomyopathy 1G, arrhythmogenic right ventricular cardiomyopathy, myopathy, myofibrillar, 9, with early respiratory failure, familial isolated dilated cardiomyopathy, childhood-onset progressive contractures-limb-girdle weakness-muscle dystrophy syndrome, autosomal recessive limb-girdle muscular dystrophy type 2J.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TTN	NM_001267550.2 linkuse as main transcript	c.45895G>A	p.Glu15299Lys	missense_variant, splice_region_variant	247/363	ENST00000589042.5	NP_001254479.2	A0A0A0MTS7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5 linkuse as main transcript	c.45895G>A	p.Glu15299Lys	missense_variant, splice_region_variant	247/363	5	NM_001267550.2	ENSP00000467141.1		A0A0A0MTS7

Frequencies

GnomAD3 genomes

Cov.:

GnomAD3 exomes

AF:

0.00000808

AC:

AN:

247536

Hom.:

AF XY:

0.00000745

AC XY:

AN XY:

134240

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:

0.0000179

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000116

AC:

AN:

1460202

Hom.:

Cov.:

AF XY:

0.0000138

AC XY:

AN XY:

726336

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000153

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

Cov.:

Bravo

AF:

0.00000378

ExAC

AF:

0.00000828

AC:

EpiCase

AF:

0.0000546

EpiControl

AF:

0.0000593

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:6

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not specified

Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Oct 18, 2021	Variant summary: TTN c.38191G>A (p.Glu12731Lys) results in a conservative amino acid change located in the I-band region of the encoded protein sequence. Three of five in-silico tools predict a damaging effect of the variant on protein function. Several computational tools predict a significant impact on normal splicing: Three predict the variant weakens a 5' donor site. However, these predictions have yet to be confirmed by functional studies. The variant allele was found at a frequency of 8.1e-06 in 247536 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.38191G>A has been reported in the literature in an individual affected with hypertrophic cardiomyopathy (Burstein_2021). This report does 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. Two ClinVar submitters (evaluation after 2014) cite the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance. -
Uncertain significance, criteria provided, single submitter	clinical testing	Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine	Aug 16, 2018	The p.Glu12731Lys variant in TTN has not been previously reported in individual s with cardiomyopathy, but has been identified in 2/110474 of European chromosom es by the Genome Aggregation Database (gnomAD, http://gnomad.broadinstitute.org; dbSNP rs397517582). This variant is located in the last three bases of the exon , which is part of the 5? splice region. While computational tools do not predic t altered splicing, other computational analysis suggest that this variant may i mpact the protein, though this information is not predictive enough to determine pathogenicity. In summary, the clinical significance of the p.Glu12731Lys varia nt is uncertain. ACMG/AMP Criteria applied: PM2, PP3. -

TTN-related disorder

Uncertain:1

Uncertain significance, no assertion criteria provided

clinical testing

PreventionGenetics, part of Exact Sciences

Apr 28, 2024

The TTN c.45895G>A variant is predicted to result in the amino acid substitution p.Glu15299Lys. This variant was reported along with additional TTN variants in an individual with hypertrophic cardiomyopathy (Table S2, Burstein et al. 2021. PubMed ID: 32746448). This variant is reported in 0.0018% of alleles in individuals of European (Non-Finnish) descent in gnomAD. At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -

Dilated cardiomyopathy 1G

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Victorian Clinical Genetics Services, Murdoch Childrens Research Institute

May 06, 2021

Based on the classification scheme VCGS_Germline_v1.3.4, this variant is classified as VUS-3B. Following criteria are met: 0103 - Loss of function is an established mechanism of disease while dominant negative is a likely mechanism, as not all truncated transcripts in dilated cardiomyopathy (DCM) undergo nonsense mediated decay (PMID: 25589632). (I) 0108 - This gene is associated with both recessive and dominant disease (OMIM). (I) 0112 - The condition associated with this gene has incomplete penetrance. Protein truncating variants in this gene are known to have reduced penetrance in DCM (PMID: 25589632). (I) 0200 - Variant is predicted to result in a missense amino acid change from glutamic acid to lysine. (I) 0219 - This variant is non-coding in an alternative transcript. However, this variant is coding in the cardiac transcript (PMID: 27854229). (I) 0251 - This variant is heterozygous. (I) 0302 - Variant is present in gnomAD (v2) <0.001 for a dominant condition (2 heterozygotes, 0 homozygotes). (SP) 0502 - Missense variant with conflicting in silico predictions and uninformative conservation. In addition, the nucleotide at c.45895 has high conservation (PhyloP) however, splicing in silico analyses do not predict a change in splicing. (I) 0600 - Variant is located in the annotated Ig-like domain within the I-band (PMID: 25589632). (I) 0705 - No comparable missense variants have previous evidence for pathogenicity. (I) 0809 - Previous evidence of pathogenicity for this variant is inconclusive. It has been reported as a VUS in ClinVar with no condition provided. (I) 0905 - No published segregation evidence has been identified for this variant. (I) 1007 - No published functional evidence has been identified for this variant. (I) 1208 - Inheritance information for this variant is not currently available in this individual. (I) Legend: (SP) - Supporting pathogenic, (I) - Information, (SB) - Supporting benign -

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Athena Diagnostics

Oct 09, 2017

- -

Cardiovascular phenotype

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jan 23, 2019

The c.18700G>A variant (also known as p.E6234K), located in coding exon 74 of the TTN gene, results from a G to A substitution at nucleotide position 18700. This change occurs in the last base pair of coding exon 74, which makes it likely to have some effect on normal mRNA splicing. In addition to potential splicing impact, the amino acid change results in glutamic acid to lysine at codon 6234, an amino acid with similar properties. Both the nucleotide and amino acid positions are highly conserved in available vertebrate species. Using two different splice site prediction tools, this alteration is predicted by ESEfinder to weaken the efficiency of the native splice donor site, but is not predicted to have a deleterious effect on this splice donor site by BDGP; however, direct evidence is unavailable. 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 variant remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.16

BayesDel_addAF

Benign

-0.086

BayesDel_noAF

Benign

-0.35

CADD

Uncertain

DANN

Uncertain

0.98

Eigen

Pathogenic

0.70

Eigen_PC

Pathogenic

0.74

FATHMM_MKL

Uncertain

0.96

LIST_S2

Uncertain

0.95

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

M_CAP

Benign

0.025

MetaRNN

Benign

0.38

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

MetaSVM

Benign

-0.84

MutationAssessor

Benign

1.9

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

MutationTaster

Benign

1.0

D;D;D;D;D;D

PrimateAI

Uncertain

0.64

PROVEAN

Uncertain

-3.1

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

REVEL

Benign

0.26

Sift

Uncertain

0.021

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

Polyphen

1.0

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

Vest4

0.57

MutPred

0.47

.;.;.;Gain of ubiquitination at E13658 (P = 0.0258);.;.;Gain of ubiquitination at E13658 (P = 0.0258);

MVP

0.26

MPC

0.48

ClinPred

0.57

GERP RS

5.8

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Pathogenic

0.94

SpliceAI score (max)

0.020

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