rs72648235

Positions:

chr2-178554662-C-T

Variant summary

Our verdict is Likely benign. Variant got -6 ACMG points: 1P and 7B. PP2BP4_ModerateBP6BS2

The NM_001267550.2(TTN):c.88685G>A(p.Gly29562Asp) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000165 in 1,613,822 control chromosomes in the GnomAD database, including 2 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G29562S) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.00013 ( 0 hom., cov: 33)

Exomes 𝑓: 0.00017 ( 2 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:6B:2

Conservation

PhyloP100: 7.91

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 -6 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=0.18641487).

BP6

Variant 2-178554662-C-T is Benign according to our data. Variant chr2-178554662-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 196150.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=2, Uncertain_significance=6}. Variant chr2-178554662-C-T is described in Lovd as [Likely_benign].

BS2

High Homozygotes in GnomAdExome4 at 2 AD,AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TTN	NM_001267550.2 linkuse as main transcript	c.88685G>A	p.Gly29562Asp	missense_variant	332/363	ENST00000589042.5
TTN-AS1	NR_038272.1 linkuse as main transcript	n.2043+12301C>T		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.88685G>A	p.Gly29562Asp	missense_variant	332/363	5	NM_001267550.2	P1
	ENST00000624360.1 linkuse as main transcript	n.102C>T		non_coding_transcript_exon_variant	1/1
TTN-AS1	ENST00000659121.1 linkuse as main transcript	n.416+31026C>T		intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes

AF:

0.000131

AC:

AN:

152184

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000724

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000393

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00316

Gnomad NFE

AF:

0.0000882

Gnomad OTH

AF:

0.00191

GnomAD3 exomes

AF:

0.000221

AC:

AN:

248698

Hom.:

AF XY:

0.000208

AC XY:

AN XY:

134886

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.000898

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:

0.000169

Gnomad OTH exome

AF:

0.000828

GnomAD4 exome

AF:

0.000168

AC:

246

AN:

1461638

Hom.:

Cov.:

AF XY:

0.000149

AC XY:

108

AN XY:

727098

show subpopulations

Gnomad4 AFR exome

AF:

0.000149

Gnomad4 AMR exome

AF:

0.000850

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000232

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.000148

Gnomad4 OTH exome

AF:

0.000431

GnomAD4 genome

AF:

0.000131

AC:

AN:

152184

Hom.:

Cov.:

AF XY:

0.000108

AC XY:

AN XY:

74348

show subpopulations

Gnomad4 AFR

AF:

0.0000724

Gnomad4 AMR

AF:

0.000393

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000882

Gnomad4 OTH

AF:

0.00191

Alfa

AF:

0.000219

Hom.:

Bravo

AF:

0.000298

TwinsUK

AF:

0.00

AC:

ALSPAC

AF:

0.000519

AC:

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000239

AC:

ExAC

AF:

0.000149

AC:

EpiCase

AF:

0.000164

EpiControl

AF:

0.000178

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:6Benign:2

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:2Benign:1

Uncertain significance, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	May 30, 2023	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Jul 03, 2018	- -
Likely benign, criteria provided, single submitter	clinical testing	Athena Diagnostics	Nov 07, 2018	- -

not specified

Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	GeneDx	Oct 07, 2016	Missense variants in the TTN gene are considered 'unclassified' if they are not previously reported in the literature and do not have >1% frequency in the population to be considered a polymorphism. Research indicates that truncating mutations in the TTN gene are expected to account for approximately 25% of familial and 18% of sporadic idiopathic DCM; however, truncating variants in the TTN gene have been reported in approximately 3% of reported control alleles. There has been little investigation into non-truncating variants. (Herman D et al. Truncations of titin causing dilated cardiomyopathy. N Eng J Med 366:619-628, 2012) The variant is found in DCM,DCM-CRDM panel(s). -
Uncertain significance, criteria provided, single submitter	clinical testing	Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine	Apr 03, 2015	The p.Gly26994Asp variant in TTN has not been previously reported in individuals with cardiomyopathy, but has been identified in 8/11566 Latino chromosomes by t he Exome Aggregation Consortium (ExAC, http://exac.broadinstitute.org; dbSNP rs7 2648235). Computational prediction tools and conservation analysis do not provid e strong support for or against an impact to the protein. In summary, the clinic al significance of the p.Gly26994Asp variant is uncertain. -

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

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Aug 22, 2017

- -

Hypertrophic cardiomyopathy

Uncertain:1

Uncertain significance, criteria provided, single submitter

research

Genetics and Genomics Program, Sidra Medicine

- -

Cardiovascular phenotype

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Ambry Genetics

Sep 01, 2020

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

1.0

BayesDel_addAF

Benign

-0.13

BayesDel_noAF

Uncertain

-0.030

CADD

Benign

DANN

Benign

0.97

Eigen

Pathogenic

1.0

Eigen_PC

Pathogenic

0.96

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.94

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

M_CAP

Benign

0.036

MetaRNN

Benign

0.19

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

MetaSVM

Uncertain

0.10

MutationAssessor

Pathogenic

3.4

.;.;.;M;.;.;M

MutationTaster

Benign

1.0

D;D;D;D;D;D

PrimateAI

Uncertain

0.70

PROVEAN

Pathogenic

-5.3

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

REVEL

Uncertain

0.54

Sift

Pathogenic

0.0

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

Polyphen

1.0

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

Vest4

0.62

MVP

0.45

MPC

0.53

ClinPred

0.22

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