rs950940404

chr2-178612063-A-G

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 3P and 1B. PM2PP2BP4

The NM_001267550.2(TTN):c.50348T>C(p.Ile16783Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000311 in 1,609,944 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 Uncertain significance (★★).

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 33)

Exomes 𝑓: 0.0000021 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:4

Conservation

PhyloP100: 9.27

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 2 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PP2

Missense variant where missense usually causes diseases, TTN

BP4

Computational evidence support a benign effect (MetaRNN=0.3901881).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TTN	NM_001267550.2 linkuse as main transcript	c.50348T>C	p.Ile16783Thr	missense_variant	267/363	ENST00000589042.5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TTN	ENST00000589042.5 linkuse as main transcript	c.50348T>C	p.Ile16783Thr	missense_variant	267/363	5	NM_001267550.2	P1
TTN-AS1	ENST00000659121.1 linkuse as main transcript	n.502+14382A>G		intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes

AF:

0.0000132

AC:

AN:

152054

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000483

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.00000821

AC:

AN:

243728

Hom.:

AF XY:

0.00000757

AC XY:

AN XY:

132104

show subpopulations

Gnomad AFR exome

AF:

0.000131

Gnomad AMR exome

AF:

0.00

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:

0.00

GnomAD4 exome

AF:

0.00000206

AC:

AN:

1457890

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

724974

show subpopulations

Gnomad4 AFR exome

AF:

0.0000300

Gnomad4 AMR exome

AF:

0.00

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:

9.01e-7

Gnomad4 OTH exome

AF:

0.0000166

GnomAD4 genome

AF:

0.0000132

AC:

AN:

152054

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74252

show subpopulations

Gnomad4 AFR

AF:

0.0000483

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:

0.00

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.0000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

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

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Aug 02, 2017

- -

Autosomal recessive limb-girdle muscular dystrophy type 2J;C1838244:Tibial muscular dystrophy;C1858763:Dilated cardiomyopathy 1G;C1861065:Hypertrophic cardiomyopathy 9;C1863599:Myopathy, myofibrillar, 9, with early respiratory failure;C2673677:Early-onset myopathy with fatal cardiomyopathy

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Aug 24, 2021

- -

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Revvity Omics, Revvity

Jun 25, 2019

- -

Cardiovascular phenotype

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jul 28, 2020

The p.I7718T variant (also known as c.23153T>C), located in coding exon 94 of the TTN gene, results from a T to C substitution at nucleotide position 23153. The isoleucine at codon 7718 is replaced by threonine, an amino acid with similar properties. This amino acid position is well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. 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

Pathogenic

0.98

BayesDel_addAF

Benign

-0.041

BayesDel_noAF

Uncertain

-0.060

Cadd

Benign

Dann

Benign

0.90

Eigen

Pathogenic

0.97

Eigen_PC

Pathogenic

0.94

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.94

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

M_CAP

Benign

0.041

MetaRNN

Benign

0.39

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

MetaSVM

Uncertain

0.24

MutationTaster

Benign

1.0

D;D;D;D;D;D

PrimateAI

Uncertain

0.71

PROVEAN

Uncertain

-3.4

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

REVEL

Uncertain

0.54

Sift

Uncertain

0.0020

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

Polyphen

0.98

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

Vest4

0.53

MVP

0.75

MPC

0.43

ClinPred

0.35

GERP RS

6.2

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