rs376371272

Variant summary

Our verdict is Likely benign. Variant got -3 ACMG points: 1P and 4B. PP2BP4_Strong

The NM_001267550.2(TTN):c.103434C>A(p.Asp34478Glu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000018 in 1,613,924 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/19 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. D34478N) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.00012 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000075 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

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

Conservation

PhyloP100: 1.39

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 -3 ACMG points.

PP2

Missense variant where missense usually causes diseases, TTN

BP4

Computational evidence support a benign effect (MetaRNN=0.033099085).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TTN	NM_001267550.2 linkuse as main transcript	c.103434C>A	p.Asp34478Glu	missense_variant	358/363	ENST00000589042.5
TTN-AS1	NR_038272.1 linkuse as main transcript	n.220-2551G>T		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.103434C>A	p.Asp34478Glu	missense_variant	358/363	5	NM_001267550.2	P1
TTN-AS1	ENST00000659121.1 linkuse as main transcript	n.416+9545G>T		intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes

AF:

0.000112

AC:

AN:

152128

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000410

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:

0.0000362

AC:

AN:

248332

Hom.:

AF XY:

0.0000371

AC XY:

AN XY:

134696

show subpopulations

Gnomad AFR exome

AF:

0.000581

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:

0.00000753

AC:

AN:

1461678

Hom.:

Cov.:

AF XY:

0.00000825

AC XY:

AN XY:

727124

show subpopulations

Gnomad4 AFR exome

AF:

0.000269

Gnomad4 AMR exome

AF:

0.0000447

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:

0.00

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.000118

AC:

AN:

152246

Hom.:

Cov.:

AF XY:

0.0000806

AC XY:

AN XY:

74428

show subpopulations

Gnomad4 AFR

AF:

0.000433

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

Alfa

AF:

0.0000680

Hom.:

Bravo

AF:

0.000166

ESP6500AA

AF:

0.000262

AC:

ESP6500EA

AF:

0.00

AC:

ExAC

AF:

0.0000662

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:5Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:2Benign:1

Uncertain significance, criteria provided, single submitter	clinical testing	AiLife Diagnostics, AiLife Diagnostics	Apr 26, 2021	- -
Likely benign, criteria provided, single submitter	clinical testing	GeneDx	Mar 22, 2019	See Variant Classification Assertion Criteria. -
Uncertain significance, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Mar 11, 2022	- -

not specified

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Aug 21, 2015

Variant classified as Uncertain Significance - Favor Benign. The p.Asp31910Glu v ariant in TTN has not been previously reported in individuals with cardiomyopath y, but has been identified in 8/9790 African chromosomes by the Exome Aggregatio n Consortium (ExAC, http://exac.broadinstitute.org; dbSNP rs376371272). Aspartic acid (Asp) at position 31910 is not conserved in mammals or evolutionarily dist ant species, of note naked mole rat and multiple fish species carried a glutamic acid (Glu) at this position, raising the possibility that this change may be to lerated. Additional computational prediction tools suggest that the p.Asp31910Gl u variant may not impact the protein, though this information is not predictive enough to rule out pathogenicity. In summary, while the clinical significance of the p.Asp31910Glu variant is uncertain, these data suggest that it is more like ly to be benign. -

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

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Mar 27, 2017

- -

Cardiovascular phenotype

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Oct 08, 2019

The p.D25413E variant (also known as c.76239C>A), located in coding exon 185 of the TTN gene, results from a C to A substitution at nucleotide position 76239. The aspartic acid at codon 25413 is replaced by glutamic acid, an amino acid with highly similar properties. This amino acid position is well conserved in available vertebrate species; however, glutamic acid 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

0.23

BayesDel_addAF

Benign

-0.38

BayesDel_noAF

Benign

-0.43

Cadd

Benign

Dann

Benign

0.85

Eigen

Benign

-0.16

Eigen_PC

Benign

0.074

FATHMM_MKL

Uncertain

0.78

LIST_S2

Benign

0.70

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

M_CAP

Benign

0.019

MetaRNN

Benign

0.033

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

MetaSVM

Benign

-0.92

MutationTaster

Benign

0.99

D;D;D;D;D;D

PrimateAI

Uncertain

0.51

PROVEAN

Benign

-2.0

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

REVEL

Benign

0.12

Sift

Benign

0.21

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

Polyphen

0.0010

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

Vest4

0.11

MutPred

0.23

.;.;.;Gain of disorder (P = 0.0539);.;.;Gain of disorder (P = 0.0539);

MVP

0.25

MPC

0.079

ClinPred

0.052

GERP RS

5.0

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