rs374295768

Positions:

chr2-178537163-C-T

Variant summary

Our verdict is Benign. Variant got -9 ACMG points: 0P and 9B. BP4_StrongBP6BS2

The NM_001267550.2(TTN):c.99946G>A(p.Ala33316Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000136 in 1,613,608 control chromosomes in the GnomAD database, including 4 homozygotes. In-silico tool predicts a benign outcome for this variant. 16/19 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 0.00014 ( 0 hom., cov: 33)

Exomes 𝑓: 0.00014 ( 4 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1B:5

Conservation

PhyloP100: 2.18

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 Benign. Variant got -9 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.010286748).

BP6

Variant 2-178537163-C-T is Benign according to our data. Variant chr2-178537163-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 203051.We mark this variant Likely_benign, oryginal submissions are: {Uncertain_significance=1, Likely_benign=3, Benign=1}.

BS2

High Homozygotes in GnomAdExome4 at 4 AD,AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TTN	NM_001267550.2 link	c.99946G>A	p.Ala33316Thr	missense_variant	356/363	ENST00000589042.5	NP_001254479.2	A0A0A0MTS7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5 link	c.99946G>A	p.Ala33316Thr	missense_variant	356/363	5	NM_001267550.2	ENSP00000467141.1		A0A0A0MTS7

Frequencies

GnomAD3 genomes

AF:

0.000145

AC:

AN:

152140

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000483

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00259

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00145

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000588

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.000274

AC:

AN:

248192

Hom.:

AF XY:

0.000319

AC XY:

AN XY:

134626

show subpopulations

Gnomad AFR exome

AF:

0.0000646

Gnomad AMR exome

AF:

0.000116

Gnomad ASJ exome

AF:

0.00279

Gnomad EAS exome

AF:

0.0000558

Gnomad SAS exome

AF:

0.000949

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000267

Gnomad OTH exome

AF:

0.000333

GnomAD4 exome

AF:

0.000135

AC:

198

AN:

1461350

Hom.:

Cov.:

AF XY:

0.000166

AC XY:

121

AN XY:

726966

show subpopulations

Gnomad4 AFR exome

AF:

0.0000299

Gnomad4 AMR exome

AF:

0.0000895

Gnomad4 ASJ exome

AF:

0.00230

Gnomad4 EAS exome

AF:

0.0000252

Gnomad4 SAS exome

AF:

0.00101

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000315

Gnomad4 OTH exome

AF:

0.000166

GnomAD4 genome

AF:

0.000144

AC:

AN:

152258

Hom.:

Cov.:

AF XY:

0.000121

AC XY:

AN XY:

74440

show subpopulations

Gnomad4 AFR

AF:

0.0000481

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00259

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00145

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000588

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.000280

Hom.:

Bravo

AF:

0.000106

ExAC

AF:

0.000257

AC:

Asia WGS

AF:

0.00144

AC:

AN:

3478

EpiCase

AF:

0.000164

EpiControl

AF:

0.00

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1Benign:5

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:1Benign:1

Likely benign, criteria provided, single submitter	clinical testing	GeneDx	Feb 24, 2021	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Aug 10, 2018	- -

not specified

Benign:1

Benign, criteria provided, single submitter

clinical testing

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

Mar 11, 2024

Variant summary: TTN c.92242G>A (p.Ala30748Thr) results in a non-conservative amino acid change located in the A-band region of the encoded protein sequence. Three of four in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 0.00014 in 1606638 control chromosomes, predominantly at a frequency of 0.001 within the South Asian subpopulation in the gnomAD database, including 4 homozygotes. The observed variant frequency within South Asian control individuals in the gnomAD database is approximately 2.6 fold of the estimated maximal expected allele frequency for a pathogenic variant in TTN causing Dilated Cardiomyopathy phenotype (0.00039), strongly suggesting that the variant is a benign polymorphism. To our knowledge, no occurrence of c.92242G>A in individuals affected with Dilated Cardiomyopathy and no experimental evidence demonstrating its impact on protein function have been reported. ClinVar contains an entry for this variant (Variation ID: 203051). Based on the evidence outlined above, the variant was classified as benign. -

TTN-related disorder

Benign:1

Likely benign, no assertion criteria provided

clinical testing

PreventionGenetics, part of Exact Sciences

Feb 10, 2021

This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -

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 30, 2024

- -

Cardiovascular phenotype

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Ambry Genetics

Oct 29, 2018

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

0.081

BayesDel_addAF

Benign

-0.46

BayesDel_noAF

Benign

-0.51

CADD

Benign

9.0

DANN

Benign

0.95

Eigen

Benign

-0.41

Eigen_PC

Benign

-0.21

FATHMM_MKL

Benign

0.71

LIST_S2

Benign

0.72

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

M_CAP

Benign

0.018

MetaRNN

Benign

0.010

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

MetaSVM

Benign

-0.96

MutationAssessor

Benign

0.18

.;.;.;N;.;.;N

PrimateAI

Benign

0.25

PROVEAN

Benign

-1.6

N;N;.;.;N;N;.

REVEL

Benign

0.042

Sift

Benign

0.44

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

Polyphen

0.0040

.;.;.;B;.;.;B

Vest4

0.25

MVP

0.13

MPC

0.081

ClinPred

0.012

GERP RS

3.5

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