rs559712998

Positions:

chr2-178601562-C-T

Variant summary

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

The NM_001267550.2(TTN):c.55435G>A(p.Val18479Ile) variant causes a missense, splice region change. The variant allele was found at a frequency of 0.000041 in 1,608,652 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. 13/19 in silico tools predict a benign outcome for this variant. 1/1 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 0.000066 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000038 ( 1 hom. )

Consequence

TTN
NM_001267550.2 missense, splice_region

Scores

Clinical Significance

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

Conservation

PhyloP100: 3.90

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 in gene, where missense usually causes diseases (based on misZ statistic), TTN. . Gene score misZ -1.1021 (greater than the threshold 3.09). Trascript score misZ 6.9794 (greater than threshold 3.09). GenCC has associacion of gene with dilated cardiomyopathy, tibial muscular dystrophy, early-onset myopathy with fatal cardiomyopathy, autosomal recessive centronuclear myopathy, hypertrophic cardiomyopathy, hypertrophic cardiomyopathy 9, TTN-related myopathy, dilated cardiomyopathy 1G, arrhythmogenic right ventricular cardiomyopathy, myopathy, myofibrillar, 9, with early respiratory failure, familial isolated dilated cardiomyopathy, childhood-onset progressive contractures-limb-girdle weakness-muscle dystrophy syndrome, autosomal recessive limb-girdle muscular dystrophy type 2J.

BP4

Computational evidence support a benign effect (MetaRNN=0.009603083).

BP6

Variant 2-178601562-C-T is Benign according to our data. Variant chr2-178601562-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 413072.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=1, Uncertain_significance=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TTN	NM_001267550.2 linkuse as main transcript	c.55435G>A	p.Val18479Ile	missense_variant, splice_region_variant	287/363	ENST00000589042.5	NP_001254479.2
TTN-AS1	NR_038272.1 linkuse as main transcript	n.3917+895C>T		intron_variant, non_coding_transcript_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5 linkuse as main transcript	c.55435G>A	p.Val18479Ile	missense_variant, splice_region_variant	287/363	5	NM_001267550.2	ENSP00000467141	P1
TTN-AS1	ENST00000659121.1 linkuse as main transcript	n.502+3881C>T		intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes

AF:

0.0000658

AC:

AN:

152050

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:

0.00194

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:

0.000192

AC:

AN:

244830

Hom.:

AF XY:

0.000173

AC XY:

AN XY:

132718

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00257

Gnomad SAS exome

AF:

0.0000336

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000384

AC:

AN:

1456484

Hom.:

Cov.:

AF XY:

0.0000345

AC XY:

AN XY:

724172

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.0000226

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00134

Gnomad4 SAS exome

AF:

0.0000117

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00

Gnomad4 OTH exome

AF:

0.0000166

GnomAD4 genome

AF:

0.0000657

AC:

AN:

152168

Hom.:

Cov.:

AF XY:

0.0000941

AC XY:

AN XY:

74388

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00195

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.000129

Hom.:

Bravo

AF:

0.000113

ExAC

AF:

0.000207

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Dilated cardiomyopathy 1G;C1861065:Hypertrophic cardiomyopathy 9

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

New York Genome Center

Feb 10, 2022

The c.55435G>A (p. Val18479Ile) missense variant in the TTN gene identified in exon 287 (of 363) has not been reported in affected individuals in the literature. The variant has 0.0001436 allele frequency in the gnomAD (v2.1.1 and v3.1.2) databases (57 out of 396880 heterozygous alleles, no homozygotes), and 0.002682 allele frequency in the East Asian subpopulation represented in the gnomAD(v2) database (52 out of 19392 heterozygous alleles, no homozygotes). This variant is reported as a likely benign in the ClinVar database (Variation ID: 413072). The variant affects a moderately conserved residue (Val18479) located in the Ig-like 106 domain (Uniprot) of A-band region (PMID: 29238064) of TTN protein. In silico tools provide conflicting predictions about the potential pathogenicity of this variant (CADD score = 24.2, REVEL score = 0.121). Based on the available evidence, the c.55435G>A (p. Val18479Ile) missense variant identified in the TTN gene is reported as a Variant of Uncertain Significance. -

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

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 24, 2024

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.091

BayesDel_addAF

Benign

-0.52

BayesDel_noAF

Benign

-0.52

CADD

Benign

DANN

Benign

0.94

Eigen

Uncertain

0.20

Eigen_PC

Uncertain

0.35

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Benign

0.84

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

M_CAP

Benign

0.043

MetaRNN

Benign

0.0096

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

MetaSVM

Benign

-0.84

MutationAssessor

Benign

1.6

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

MutationTaster

Benign

0.97

D;D;D;D;D;D

PrimateAI

Benign

0.44

PROVEAN

Benign

-0.66

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

REVEL

Benign

0.12

Sift

Benign

0.30

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

Polyphen

0.088

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

Vest4

0.29

MutPred

0.26

.;.;.;Gain of ubiquitination at K16843 (P = 0.0831);.;.;Gain of ubiquitination at K16843 (P = 0.0831);

MVP

0.31

MPC

0.079

ClinPred

0.024

GERP RS

5.7

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