rs373351577

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 3P and 2B. PM1PP2BP4_Moderate

The NM_001267550.2(TTN):c.56960T>C(p.Ile18987Thr) variant causes a missense, splice region change. The variant allele was found at a frequency of 0.0000329 in 1,611,158 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/21 in silico tools predict a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.000033 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000033 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense, splice_region

Scores

Splicing: ADA: 0.0002485

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3B:1

Conservation

PhyloP100: 6.24

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 Uncertain_significance. Variant got 1 ACMG points.

PM1

In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 2 benign, 5 uncertain in NM_001267550.2

PP2

Missense variant where missense usually causes diseases, TTN

BP4

Computational evidence support a benign effect (MetaRNN=0.17541069).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TTN	NM_001267550.2 linkuse as main transcript	c.56960T>C	p.Ile18987Thr	missense_variant, splice_region_variant	291/363	ENST00000589042.5
TTN-AS1	NR_038272.1 linkuse as main transcript	n.3568+77A>G		intron_variant, non_coding_transcript_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TTN	ENST00000589042.5 linkuse as main transcript	c.56960T>C	p.Ile18987Thr	missense_variant, splice_region_variant	291/363	5	NM_001267550.2	P1
TTN-AS1	ENST00000659121.1 linkuse as main transcript	n.502+1069A>G		intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes

AF:

0.0000329

AC:

AN:

152086

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

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:

0.0000735

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000366

AC:

AN:

245916

Hom.:

AF XY:

0.0000150

AC XY:

AN XY:

133420

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.000118

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000561

Gnomad SAS exome

AF:

0.0000334

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000269

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000329

AC:

AN:

1459072

Hom.:

Cov.:

AF XY:

0.0000317

AC XY:

AN XY:

725836

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.0000907

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000252

Gnomad4 SAS exome

AF:

0.0000117

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000360

Gnomad4 OTH exome

AF:

0.0000332

GnomAD4 genome

AF:

0.0000329

AC:

AN:

152086

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74282

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000735

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000282

Hom.:

Bravo

AF:

0.0000189

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000245

AC:

ExAC

AF:

0.0000331

AC:

EpiCase

AF:

0.0000546

EpiControl

AF:

0.0000594

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:3Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:1Benign:1

Likely benign, criteria provided, single submitter	clinical testing	GeneDx	Aug 17, 2018	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Jun 07, 2017	- -

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

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jun 09, 2017

- -

Cardiovascular phenotype

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Apr 12, 2018

The p.I9922T variant (also known as c.29765T>C), located in coding exon 118 of the TTN gene, results from a T to C substitution at nucleotide position 29765. The isoleucine at codon 9922 is replaced by threonine, an amino acid with similar properties. This amino acid position is not well conserved in available vertebrate species, and threonine is the reference amino acid in other vertebrate species. In addition, this alteration is predicted to be tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.20

BayesDel_addAF

Benign

-0.22

BayesDel_noAF

Benign

-0.33

Cadd

Benign

Dann

Benign

0.82

Eigen

Benign

-0.00054

Eigen_PC

Benign

0.14

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Benign

0.78

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

M_CAP

Benign

0.085

MetaRNN

Benign

0.18

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

MetaSVM

Benign

-0.66

MutationTaster

Benign

0.96

D;D;D;D;D;D

PrimateAI

Benign

0.38

PROVEAN

Uncertain

-3.2

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

REVEL

Benign

0.14

Sift

Benign

0.057

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

Polyphen

0.0

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

Vest4

0.45

MVP

0.38

MPC

0.11

ClinPred

0.080

GERP RS

4.8

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Benign

0.00025

dbscSNV1_RF

Benign

0.0080

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