rs183245562

Variant summary

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

The NM_001267550.2(TTN):c.45499G>A(p.Val15167Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000154 in 1,612,320 control chromosomes in the GnomAD database, with no homozygous occurrence. 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 0.00080 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000087 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1B:11

Conservation

PhyloP100: 0.566

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 -4 ACMG points.

PP2

Missense variant where missense usually causes diseases, TTN

BP4

Computational evidence support a benign effect (MetaRNN=0.004189819).

BP6

Variant 2-178621219-C-T is Benign according to our data. Variant chr2-178621219-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 46989.We mark this variant Likely_benign, oryginal submissions are: {Benign=3, Likely_benign=5, Uncertain_significance=1}. Variant chr2-178621219-C-T is described in Lovd as [Benign]. Variant chr2-178621219-C-T is described in Lovd as [Likely_benign].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TTN	NM_001267550.2 linkuse as main transcript	c.45499G>A	p.Val15167Ile	missense_variant	246/363	ENST00000589042.5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TTN	ENST00000589042.5 linkuse as main transcript	c.45499G>A	p.Val15167Ile	missense_variant	246/363	5	NM_001267550.2	P1
TTN-AS1	ENST00000659121.1 linkuse as main transcript	n.502+23538C>T		intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes

AF:

0.000797

AC:

121

AN:

151858

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00287

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000657

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:

0.000479

GnomAD3 exomes

AF:

0.000194

AC:

AN:

247566

Hom.:

AF XY:

0.000134

AC XY:

AN XY:

134304

show subpopulations

Gnomad AFR exome

AF:

0.00246

Gnomad AMR exome

AF:

0.000146

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.0000327

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000268

Gnomad OTH exome

AF:

0.000167

GnomAD4 exome

AF:

0.0000870

AC:

127

AN:

1460344

Hom.:

Cov.:

AF XY:

0.0000674

AC XY:

AN XY:

726468

show subpopulations

Gnomad4 AFR exome

AF:

0.00243

Gnomad4 AMR exome

AF:

0.000202

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000116

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000252

Gnomad4 OTH exome

AF:

0.000116

GnomAD4 genome

AF:

0.000796

AC:

121

AN:

151976

Hom.:

Cov.:

AF XY:

0.000821

AC XY:

AN XY:

74264

show subpopulations

Gnomad4 AFR

AF:

0.00287

Gnomad4 AMR

AF:

0.0000656

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:

0.000474

Alfa

AF:

0.000237

Hom.:

Bravo

AF:

0.000850

ESP6500AA

AF:

0.00211

AC:

ESP6500EA

AF:

0.000122

AC:

ExAC

AF:

0.000215

AC:

Asia WGS

AF:

0.00115

AC:

AN:

3478

EpiCase

AF:

0.0000546

EpiControl

AF:

0.0000593

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1Benign:11

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not specified

Benign:5

Benign, no assertion criteria provided	clinical testing	Clinical Genetics, Academic Medical Center	-	- -
Likely benign, criteria provided, single submitter	clinical testing	Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine	Feb 25, 2013	p.Val12599Ile in exon 195 of TTN: This variant is not expected to have clinical significance due to a lack of conservation across species. Multiple mammals hav e an isoleucine (Ile; this variant) at this position, despite high nearby amino acid conservation. Computational analyses (AlignGVGD, PolyPhen2, SIFT) do not su ggest a high likelihood of impact to the protein. This variant has also been ide ntified in 0.2% (8/3600) of African American chromosomes from a broad population by the NHLBI Exome Sequencing Project (http://evs.gs.washington.edu/EVS/; dbSNP rs183245562). -
Benign, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Nov 29, 2021	Variant summary: TTN c.37795G>A (p.Val12599Ile) results in a conservative amino acid change located in the I-band region of the encoded protein sequence. Five of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 0.0008 in 150630 control chromosomes, predominantly at a frequency of 0.0029 within the African or African-American subpopulation in the gnomAD database (v3.1 genomes dataset). The observed variant frequency within African or African-American control individuals in the gnomAD database is approximately 7-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 found primarily in populations of African or African-American origin. To our knowledge, no occurrence of c.37795G>A in individuals affected with Dilated Cardiomyopathy and no experimental evidence demonstrating its impact on protein function have been reported. Four clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation, and reported the variant as VUS (n=1), likely benign (n=2) / benign (n=1). Based on the evidence outlined above, the variant was classified as benign. -
Benign, criteria provided, single submitter	clinical testing	Athena Diagnostics	Jan 05, 2021	- -
Benign, no assertion criteria provided	clinical testing	Joint Genome Diagnostic Labs from Nijmegen and Maastricht, Radboudumc and MUMC+	-	- -

not provided

Uncertain:1Benign:2

Likely benign, criteria provided, single submitter	clinical testing	GeneDx	Jun 10, 2020	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Nov 12, 2015	- -
Likely benign, no assertion criteria provided	clinical testing	Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center	-	- -

TTN-related disorder

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

PreventionGenetics, part of Exact Sciences

Jun 27, 2023

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

Invitae

Jan 20, 2024

- -

Cardiomyopathy

Benign:1

Benign, criteria provided, single submitter

clinical testing

CHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern Ontario

Aug 09, 2021

- -

Cardiovascular phenotype

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Ambry Genetics

Jun 26, 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

Benign

0.053

BayesDel_addAF

Benign

-0.59

BayesDel_noAF

Benign

-0.63

Cadd

Benign

3.7

Dann

Benign

0.74

Eigen

Benign

-1.2

Eigen_PC

Benign

-1.2

FATHMM_MKL

Benign

0.053

LIST_S2

Benign

0.77

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

M_CAP

Benign

0.062

MetaRNN

Benign

0.0042

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

MetaSVM

Benign

-0.95

MutationTaster

Benign

1.0

N;N;N;N;N;N

PrimateAI

Benign

0.24

PROVEAN

Benign

0.090

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

REVEL

Benign

0.26

Sift

Benign

1.0

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

Polyphen

0.0

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

Vest4

0.10

MVP

0.19

MPC

0.069

ClinPred

0.0049

GERP RS

-8.7

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