rs376039623

Positions:

chr2-178543858-C-T

Variant summary

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

The NM_001267550.2(TTN):c.96286G>A(p.Ala32096Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000378 in 1,613,556 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 Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.000053 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000036 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:6B:1

Conservation

PhyloP100: 3.31

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 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.

BP4

Computational evidence support a benign effect (MetaRNN=0.22199097).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TTN	NM_001267550.2 linkuse as main transcript	c.96286G>A	p.Ala32096Thr	missense_variant	346/363	ENST00000589042.5	NP_001254479.2
TTN-AS1	NR_038272.1 linkuse as main transcript	n.2043+1497C>T		intron_variant, non_coding_transcript_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5 linkuse as main transcript	c.96286G>A	p.Ala32096Thr	missense_variant	346/363	5	NM_001267550.2	ENSP00000467141	P1
TTN-AS1	ENST00000659121.1 linkuse as main transcript	n.416+20222C>T		intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes

AF:

0.0000526

AC:

AN:

152150

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000196

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:

0.000958

GnomAD3 exomes

AF:

0.0000806

AC:

AN:

248148

Hom.:

AF XY:

0.0000669

AC XY:

AN XY:

134616

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.000174

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:

0.000125

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000363

AC:

AN:

1461406

Hom.:

Cov.:

AF XY:

0.0000330

AC XY:

AN XY:

726984

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.000201

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:

0.0000378

Gnomad4 OTH exome

AF:

0.0000331

GnomAD4 genome

AF:

0.0000526

AC:

AN:

152150

Hom.:

Cov.:

AF XY:

0.0000673

AC XY:

AN XY:

74326

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.000196

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:

0.000958

Alfa

AF:

0.0000676

Hom.:

Bravo

AF:

0.0000680

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000243

AC:

ExAC

AF:

0.0000662

AC:

EpiCase

AF:

0.00

EpiControl

AF:

0.000296

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:6Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Mar 25, 2020	- -
Uncertain significance, criteria provided, single submitter	clinical testing	GeneDx	Aug 11, 2017	The A29528T variant has been reported in one individual with dilated cardiomyopathy; however, this individual harbored additional cardiogenetic variants and segregation data was not provided (Pugh et al., 2014). Additionally, A29528T was reported in an individual with unexplained sudden death, however, detailed clinical information and segregation data was not provided (Sanchez et al., 2016). The A29528T variant is observed in 6/66,468 (0.01%) alleles from individuals of European background (Lek et al., 2016; 1000 Genomes Consortium et al., 2015; Exome Variant Server). Most reported pathogenic variants in the TTN gene are truncating/loss-of-function. However, this variant is a non-conservative amino acid substitution, which is likely to impact secondary protein structure as these residues differ in polarity, charge, size and/or other properties. Additionally, this substitution occurs at a position that is conserved in mammals, and is located in the A-band of the titin protein, where the majority of pathogenic truncating variants have been reported. In silico analysis predicts this variant is probably damaging to the protein structure/function. -

not specified

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Dec 12, 2012

Variant classified as Uncertain Significance - Favor Benign. The Ala29528Thr var iant in TTN has not been reported in the literature, but has been identified by our laboratory in 2 Caucasian individuals with DCM (including this individual). Both individuals also carried likely disease-causing variants in TTN, 1 of which was likely on the same copy of the gene (in cis). In addition, this variant has been identified in 2/8246 European American chromosomes from a broad population by the NHLBI Exome Sequencing Project (http://evs.gs.washington.edu/EVS). Alani ne (Ala) at position 29528 is conserved in mammals and in evolutionarily distant species down to fish, though the change to threonine (Thr) is present in medaka . Additional computational analyses (biochemical amino acid properties, AlignGVG D, PolyPhen2, and SIFT) do not provide strong support for or against and impact to the protein. In summary, although collectively this information supports that the Ala29528Thr variant may be benign, additional studies are needed to fully a ssess its clinical significance. -

TTN-related disorder

Uncertain:1

Uncertain significance, no assertion criteria provided

clinical testing

PreventionGenetics, part of Exact Sciences

Jun 08, 2024

The TTN c.96286G>A variant is predicted to result in the amino acid substitution p.Ala32096Thr. This variant has been reported in an individual with dilated cardiomyopathy (referred to as p.Ala29528Thr in Table S3, Pugh et al. 2014. PubMed ID: 24503780) and in a case of sudden unexplained death (Sanchez et al. 2016. PubMed ID: 27930701). This variant is reported in 0.017% of alleles in individuals of Latino descent in gnomAD. At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -

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

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Aug 31, 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

Jul 20, 2021

- -

Cardiovascular phenotype

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Ambry Genetics

Nov 09, 2021

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.11

BayesDel_addAF

Benign

-0.21

BayesDel_noAF

Benign

-0.29

CADD

Benign

DANN

Benign

0.97

Eigen

Uncertain

0.35

Eigen_PC

Uncertain

0.47

FATHMM_MKL

Uncertain

0.94

LIST_S2

Uncertain

0.87

D;D;D;.;T;D;D

M_CAP

Benign

0.027

MetaRNN

Benign

0.22

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

MetaSVM

Benign

-0.54

MutationAssessor

Benign

1.1

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

MutationTaster

Benign

0.99

D;D;D;D;D;D

PrimateAI

Uncertain

0.59

PROVEAN

Uncertain

-2.4

N;D;.;.;D;D;.

REVEL

Benign

0.25

Sift

Benign

0.14

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

Polyphen

0.58

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

Vest4

0.47

MVP

0.42

MPC

0.13

ClinPred

0.11

GERP RS

6.1

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