dbSNP rs16866391: TTN:p.Ile30731Leu (chr2-178549435-T-A) – ACMG Classification: Likely_benign (-4 pts)

Variant summary

Our verdict is Likely benign. Variant got -4 ACMG points: 0P and 4B. BP4_ModerateBP6_Moderate

The NM_001267550.2(TTN):c.92191A>T(p.Ile30731Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000035 in 1,458,596 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 Likely benign (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. I30731V) has been classified as Benign.

Frequency

Genomes: not found (cov: 33)

Exomes 𝑓: 0.000035 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Likely benign criteria provided, single submitter B:1

Conservation

PhyloP100: 0.441

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:

ENSG00000270277 (HGNC:):

ENSG00000270277 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -4 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.07245973).

BP6

Variant 2-178549435-T-A is Benign according to our data. Variant chr2-178549435-T-A is described in ClinVar as [Likely_benign]. Clinvar id is 2691130.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2 link	c.92191A>T	p.Ile30731Leu	missense_variant	Exon 339 of 363	ENST00000589042.5	NP_001254479.2	A0A0A0MTS7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5 link	c.92191A>T	p.Ile30731Leu	missense_variant	Exon 339 of 363	5	NM_001267550.2	ENSP00000467141.1		A0A0A0MTS7

Frequencies

GnomAD3 genomes

Cov.:

GnomAD3 exomes

AF:

0.0000162

AC:

AN:

247460

Hom.:

AF XY:

0.0000223

AC XY:

AN XY:

134262

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.0000328

Gnomad FIN exome

AF:

0.0000467

Gnomad NFE exome

AF:

0.0000179

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000350

AC:

AN:

1458596

Hom.:

Cov.:

AF XY:

0.0000455

AC XY:

AN XY:

725012

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000232

Gnomad4 FIN exome

AF:

0.0000188

Gnomad4 NFE exome

AF:

0.0000415

Gnomad4 OTH exome

AF:

0.0000332

GnomAD4 genome

Cov.:

ExAC

AF:

0.0000248

AC:

ClinVar

Significance: Likely benign

Submissions summary: Benign:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Cardiomyopathy

Benign:1

Aug 23, 2022

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

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.18

BayesDel_addAF

Benign

-0.24

BayesDel_noAF

Benign

-0.48

CADD

Benign

4.5

DANN

Benign

0.49

Eigen

Benign

-1.1

Eigen_PC

Benign

-1.1

FATHMM_MKL

Benign

0.64

LIST_S2

Benign

0.76

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

M_CAP

Benign

0.021

MetaRNN

Benign

0.072

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

MetaSVM

Benign

-0.87

MutationAssessor

Benign

1.9

.;.;.;L;.;.;L

PrimateAI

Benign

0.30

PROVEAN

Benign

-1.4

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

REVEL

Benign

0.10

Sift

Uncertain

0.013

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

Polyphen

0.0050

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

Vest4

0.20

MutPred

0.51

.;.;.;Loss of glycosylation at S29088 (P = 0.1506);.;.;Loss of glycosylation at S29088 (P = 0.1506);

MVP

0.067

MPC

0.084

ClinPred

0.037

GERP RS

-0.22

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