2-178549332-C-G

Position:

chr2-178549332-C-G

Variant summary

Our verdict is Likely benign. Variant got -4 ACMG points: 1P and 5B. PP2BP4_StrongBP6

The NM_001267550.2(TTN):c.92294G>C(p.Arg30765Thr) variant causes a missense change. The variant allele was found at a frequency of 0.0000892 in 1,613,924 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.00057 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000039 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:5B:3

Conservation

PhyloP100: 6.07

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:

(HGNC:):

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 -4 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=0.036843985).

BP6

Variant 2-178549332-C-G is Benign according to our data. Variant chr2-178549332-C-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 178814.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=3, Uncertain_significance=5}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TTN	NM_001267550.2 linkuse as main transcript	c.92294G>C	p.Arg30765Thr	missense_variant	339/363	ENST00000589042.5
TTN-AS1	NR_038272.1 linkuse as main transcript	n.2043+6971C>G		intron_variant, non_coding_transcript_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris
TTN	ENST00000589042.5 linkuse as main transcript	c.92294G>C	p.Arg30765Thr	missense_variant	339/363	5	NM_001267550.2	P1
	ENST00000603415.1 linkuse as main transcript	n.449C>G		non_coding_transcript_exon_variant	1/1
TTN-AS1	ENST00000659121.1 linkuse as main transcript	n.416+25696C>G		intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes

AF:

0.000572

AC:

AN:

152198

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00193

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000458

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000963

AC:

AN:

249096

Hom.:

AF XY:

0.0000888

AC XY:

AN XY:

135144

show subpopulations

Gnomad AFR exome

AF:

0.00142

Gnomad AMR exome

AF:

0.0000290

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:

0.00

Gnomad OTH exome

AF:

0.000165

GnomAD4 exome

AF:

0.0000390

AC:

AN:

1461608

Hom.:

Cov.:

AF XY:

0.0000344

AC XY:

AN XY:

727086

show subpopulations

Gnomad4 AFR exome

AF:

0.00146

Gnomad4 AMR exome

AF:

0.000134

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:

0.00

Gnomad4 OTH exome

AF:

0.0000331

GnomAD4 genome

AF:

0.000571

AC:

AN:

152316

Hom.:

Cov.:

AF XY:

0.000497

AC XY:

AN XY:

74470

show subpopulations

Gnomad4 AFR

AF:

0.00192

Gnomad4 AMR

AF:

0.000458

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.000427

Hom.:

Bravo

AF:

0.000601

ESP6500AA

AF:

0.000774

AC:

ESP6500EA

AF:

0.00

AC:

ExAC

AF:

0.000157

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:5Benign:3

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:3Benign:1

Uncertain significance, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Sep 23, 2016	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Athena Diagnostics	Sep 21, 2017	- -
Likely benign, criteria provided, single submitter	clinical testing	GeneDx	Apr 30, 2018	This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease. -
Uncertain significance, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Sep 22, 2022	- -

not specified

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Mar 26, 2013

The Arg28197Thr variant in TTN has not been reported in the literature nor previ ously identified by our laboratory. This variant has been identified in 3/3878 A frican American chromosomes from a broad population by the NHLBI Exome Sequencin g Project (http://evs.gs.washington.edu/EVS). Computational analyses (biochemica l amino acid properties, conservation, AlignGVGD, PolyPhen2, and SIFT) do not pr ovide strong support for or against an impact to the protein. Additional informa tion is needed to fully assess the clinical significance of this variant. -

TTN-related disorder

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

PreventionGenetics, part of Exact Sciences

Mar 16, 2023

The TTN c.92294G>C variant is predicted to result in the amino acid substitution p.Arg30765Thr. To our knowledge, this variant has not been reported in the literature. This variant is reported in 0.14% of alleles in individuals of African descent in gnomAD, which is probably too common for a causative autosomal dominant variant (http://gnomad.broadinstitute.org/variant/2-179414059-C-G). 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

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 17, 2024

- -

Cardiovascular phenotype

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Ambry Genetics

Jul 22, 2019

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

Pathogenic

0.59

BayesDel_addAF

Benign

-0.33

BayesDel_noAF

Benign

-0.27

CADD

Benign

DANN

Benign

0.89

Eigen

Pathogenic

0.71

Eigen_PC

Pathogenic

0.73

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.92

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

M_CAP

Benign

0.021

MetaRNN

Benign

0.037

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

MetaSVM

Benign

-0.57

MutationAssessor

Benign

1.8

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

MutationTaster

Benign

1.0

D;D;D;D;D;D

PrimateAI

Uncertain

0.70

PROVEAN

Uncertain

-4.4

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

REVEL

Uncertain

0.29

Sift

Benign

0.048

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

Polyphen

0.97

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

Vest4

0.39

MVP

0.40

MPC

0.44

ClinPred

0.074

GERP RS

5.7

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