rs201991864

Variant summary

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

The NM_001267550.2(TTN):c.32953C>T(p.Arg10985Trp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000145 in 1,612,204 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/18 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. R10985P) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.00017 ( 0 hom., cov: 32)

Exomes 𝑓: 0.00014 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:7B:4

Conservation

PhyloP100: 0.0350

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:

LOC124906100 (HGNC:):

LOC124906100 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 where missense usually causes diseases, TTN

BP4

Computational evidence support a benign effect (MetaRNN=0.010427117).

BP6

Variant 2-178682838-G-A is Benign according to our data. Variant chr2-178682838-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 178226.We mark this variant Likely_benign, oryginal submissions are: {Uncertain_significance=7, Likely_benign=2, Benign=2}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TTN	NM_001267550.2 linkuse as main transcript	c.32953C>T	p.Arg10985Trp	missense_variant	135/363	ENST00000589042.5
LOC124906100	XR_007087318.1 linkuse as main transcript	n.2186-30916G>A		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.32953C>T	p.Arg10985Trp	missense_variant	135/363	5	NM_001267550.2	P1
TTN-AS1	ENST00000659121.1 linkuse as main transcript	n.503-51666G>A		intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes

AF:

0.000171

AC:

AN:

151634

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000131

Gnomad ASJ

AF:

0.00462

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.000118

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.000278

AC:

AN:

248278

Hom.:

AF XY:

0.000282

AC XY:

AN XY:

134758

show subpopulations

Gnomad AFR exome

AF:

0.0000648

Gnomad AMR exome

AF:

0.000407

Gnomad ASJ exome

AF:

0.00378

Gnomad EAS exome

AF:

0.000111

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000979

Gnomad OTH exome

AF:

0.000498

GnomAD4 exome

AF:

0.000142

AC:

208

AN:

1460570

Hom.:

Cov.:

AF XY:

0.000147

AC XY:

107

AN XY:

726538

show subpopulations

Gnomad4 AFR exome

AF:

0.0000897

Gnomad4 AMR exome

AF:

0.000336

Gnomad4 ASJ exome

AF:

0.00402

Gnomad4 EAS exome

AF:

0.0000757

Gnomad4 SAS exome

AF:

0.0000465

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000396

Gnomad4 OTH exome

AF:

0.000547

GnomAD4 genome

AF:

0.000171

AC:

AN:

151634

Hom.:

Cov.:

AF XY:

0.000189

AC XY:

AN XY:

74046

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.000131

Gnomad4 ASJ

AF:

0.00462

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.000118

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.000374

Hom.:

Bravo

AF:

0.000212

ExAC

AF:

0.000257

AC:

EpiCase

AF:

0.000164

EpiControl

AF:

0.000119

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:7Benign:4

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not specified

Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine	Jul 16, 2014	The Arg9741Trp variant in TTN has not been previously reported in individuals wi th cardiomyopathy, but has been identified in 1/587 of European chromosomes by t he ClinSeq project (dbSNP rs201991864). Arginine (Arg) at position 9741 is not w ell conserved in evolution, decreasing the likelihood that a change would be pat hogenic. In summary, the clinical significance of the Arg9741Trp variant is unce rtain. -
Uncertain significance, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Nov 05, 2019	Variant summary: TTN c.29221C>T (p.Arg9741Trp) results in a non-conservative amino acid change located in the I-band region of the encoded protein sequence. Two of four in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 0.00028 in 248278 control chromosomes. This frequency is not significantly higher than expected for a pathogenic variant in TTN causing Cardiomyopathy (0.00028 vs 0.00063), allowing no conclusion about variant significance. c.29221C>T has been reported in the literature in an individual affected with HCM (Mademont-Soler_2017). This report does not provide unequivocal conclusions about association of the variant with Cardiomyopathy. Co-occurrence with another pathogenic variant has been internally reported ( RYR2 c.1258C>T , p.Arg420Trp), providing supporting evidence for a benign role. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Three clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. Two classified as likely benign while one classified as VUS. Based on the evidence outlined above, the variant was classified as uncertain significance. -

not provided

Uncertain:1Benign:1

Likely benign, criteria provided, single submitter	clinical testing	GeneDx	Jun 10, 2019	This variant is associated with the following publications: (PMID: 23861362, 28771489) -
Uncertain significance, criteria provided, single submitter	research	Biesecker Lab/Clinical Genomics Section, National Institutes of Health	Jun 24, 2013	- -

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. -

Dilated cardiomyopathy 1G

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 13, 2018

Cardiomyopathy

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

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

Apr 06, 2017

- -

Early-onset myopathy with fatal cardiomyopathy

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 13, 2018

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

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Invitae

Oct 16, 2017

- -

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. -

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. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.14

BayesDel_addAF

Benign

-0.21

BayesDel_noAF

Benign

-0.23

Cadd

Benign

Dann

Benign

0.97

Eigen

Benign

-0.55

Eigen_PC

Benign

-0.46

FATHMM_MKL

Benign

0.088

LIST_S2

Benign

0.68

T;T;.;T;T

M_CAP

Benign

0.054

MetaRNN

Benign

0.010

T;T;T;T;T

MetaSVM

Benign

-0.75

MutationTaster

Benign

1.0

N;N;N;N;N;N

PrimateAI

Benign

0.33

PROVEAN

Uncertain

-3.3

D;.;.;.;D

REVEL

Benign

0.20

Sift

Uncertain

0.0040

D;.;.;.;D

Polyphen

0.0

.;.;B;B;.

Vest4

0.31

MVP

0.26

MPC

0.087

ClinPred

0.047

GERP RS

2.4

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