rs368527534

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 1P and 1B. PP2BP6

The NM_001267550.2(TTN):c.48850G>A(p.Gly16284Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000403 in 1,612,238 control chromosomes in the GnomAD database, including 1 homozygotes. 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. G16284E) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000020 ( 1 hom., cov: 32)

Exomes 𝑓: 0.000042 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:6B:2

Conservation

PhyloP100: 7.79

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 0 ACMG points.

PP2

Missense variant where missense usually causes diseases, TTN

BP6

Variant 2-178614664-C-T is Benign according to our data. Variant chr2-178614664-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 535028.We mark this variant Likely_benign, oryginal submissions are: {Uncertain_significance=6, Benign=2}. Variant chr2-178614664-C-T is described in Lovd as [Likely_benign].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TTN	NM_001267550.2 linkuse as main transcript	c.48850G>A	p.Gly16284Arg	missense_variant	261/363	ENST00000589042.5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TTN	ENST00000589042.5 linkuse as main transcript	c.48850G>A	p.Gly16284Arg	missense_variant	261/363	5	NM_001267550.2	P1
TTN-AS1	ENST00000659121.1 linkuse as main transcript	n.502+16983C>T		intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes

AF:

0.0000198

AC:

AN:

151810

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:

0.000414

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.000480

GnomAD3 exomes

AF:

0.0000323

AC:

AN:

247404

Hom.:

AF XY:

0.0000447

AC XY:

AN XY:

134230

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000291

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.0000981

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000358

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000425

AC:

AN:

1460310

Hom.:

Cov.:

AF XY:

0.0000427

AC XY:

AN XY:

726458

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.0000672

Gnomad4 ASJ exome

AF:

0.0000383

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.000104

Gnomad4 FIN exome

AF:

0.0000187

Gnomad4 NFE exome

AF:

0.0000396

Gnomad4 OTH exome

AF:

0.0000664

GnomAD4 genome

AF:

0.0000197

AC:

AN:

151928

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74248

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:

0.000415

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.000475

Alfa

AF:

0.0000494

Hom.:

Bravo

AF:

0.00000378

ESP6500AA

AF:

0.000268

AC:

ESP6500EA

AF:

0.00

AC:

ExAC

AF:

0.0000166

AC:

EpiCase

AF:

0.00

EpiControl

AF:

0.000119

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:6Benign:2

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Dec 04, 2021

- -

Autosomal recessive limb-girdle muscular dystrophy type 2J

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 13, 2018

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

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

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Feb 11, 2019

This sequence change replaces glycine with arginine at codon 16284 of the TTN protein (p.Gly16284Arg). There is a moderate physicochemical difference between glycine and arginine. This variant is present in population databases (rs368527534, ExAC 0.01%). This variant has not been reported in the literature in individuals with TTN-related disease. This variant identified in the TTN gene is located in the A band of the resulting protein (PMID: 25589632). It is unclear how this variant impacts the function of this protein. Algorithms developed to predict the effect of missense changes on protein structure and function are unavailable for the TTN gene. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site, but this prediction has not been confirmed by published transcriptional studies. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Dilated cardiomyopathy 1G

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 13, 2018

Early-onset myopathy with fatal cardiomyopathy

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 13, 2018

Cardiovascular phenotype

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Nov 27, 2019

The p.G7219R variant (also known as c.21655G>A), located in coding exon 88 of the TTN gene, results from a G to A substitution at nucleotide position 21655. The glycine at codon 7219 is replaced by arginine, an amino acid with dissimilar properties. This amino acid position is highly 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. -

Myopathy, myofibrillar, 9, with early respiratory failure

Benign:1

Benign, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 13, 2018

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -

Tibial muscular dystrophy

Benign:1

Benign, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 13, 2018

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

1.0

BayesDel_addAF

Uncertain

0.10

BayesDel_noAF

Uncertain

0.11

Cadd

Uncertain

Dann

Benign

0.95

Eigen

Pathogenic

1.1

Eigen_PC

Pathogenic

1.0

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.96

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

M_CAP

Uncertain

0.10

MetaRNN

Uncertain

0.65

D;D;D;D;D;D;D

MetaSVM

Pathogenic

0.92

MutationTaster

Benign

1.0

D;D;D;D;D;D

PrimateAI

Uncertain

0.71

PROVEAN

Pathogenic

-6.0

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

REVEL

Pathogenic

0.82

Sift

Pathogenic

0.0

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

Polyphen

1.0

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

Vest4

0.59

MutPred

0.91

.;.;.;Loss of ubiquitination at K14648 (P = 0.0424);.;.;Loss of ubiquitination at K14648 (P = 0.0424);

MVP

0.89

MPC

0.51

ClinPred

0.73

GERP RS

5.6

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