rs72650030

Variant summary

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

The NM_001267550.2(TTN):c.32480C>T(p.Ala10827Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00201 in 1,602,160 control chromosomes in the GnomAD database, including 6 homozygotes. In-silico tool predicts a benign outcome for this variant. 14/17 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.0013 ( 1 hom., cov: 32)

Exomes 𝑓: 0.0021 ( 5 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3B:16

Conservation

PhyloP100: 0.804

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=0.004187286).

BP6

Variant 2-178684980-G-A is Benign according to our data. Variant chr2-178684980-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 46868.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=7, Benign=4, Uncertain_significance=3}. Variant chr2-178684980-G-A is described in Lovd as [Benign]. Variant chr2-178684980-G-A 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.32480C>T	p.Ala10827Val	missense_variant	130/363	ENST00000589042.5
LOC124906100	XR_007087318.1 linkuse as main transcript	n.2186-28774G>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.32480C>T	p.Ala10827Val	missense_variant	130/363	5	NM_001267550.2	P1
TTN-AS1	ENST00000659121.1 linkuse as main transcript	n.503-49524G>A		intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes

AF:

0.00133

AC:

202

AN:

152142

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000362

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000262

Gnomad ASJ

AF:

0.000864

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00124

Gnomad FIN

AF:

0.0000943

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00251

Gnomad OTH

AF:

0.000957

GnomAD3 exomes

AF:

0.00156

AC:

356

AN:

228620

Hom.:

AF XY:

0.00169

AC XY:

209

AN XY:

123782

show subpopulations

Gnomad AFR exome

AF:

0.000222

Gnomad AMR exome

AF:

0.000394

Gnomad ASJ exome

AF:

0.00128

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.000957

Gnomad FIN exome

AF:

0.000292

Gnomad NFE exome

AF:

0.00285

Gnomad OTH exome

AF:

0.00125

GnomAD4 exome

AF:

0.00209

AC:

3025

AN:

1449900

Hom.:

Cov.:

AF XY:

0.00204

AC XY:

1467

AN XY:

720080

show subpopulations

Gnomad4 AFR exome

AF:

0.000360

Gnomad4 AMR exome

AF:

0.000298

Gnomad4 ASJ exome

AF:

0.000974

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00101

Gnomad4 FIN exome

AF:

0.000190

Gnomad4 NFE exome

AF:

0.00252

Gnomad4 OTH exome

AF:

0.00130

GnomAD4 genome

AF:

0.00133

AC:

202

AN:

152260

Hom.:

Cov.:

AF XY:

0.00134

AC XY:

100

AN XY:

74444

show subpopulations

Gnomad4 AFR

AF:

0.000361

Gnomad4 AMR

AF:

0.000261

Gnomad4 ASJ

AF:

0.000864

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00124

Gnomad4 FIN

AF:

0.0000943

Gnomad4 NFE

AF:

0.00251

Gnomad4 OTH

AF:

0.000947

Alfa

AF:

0.00242

Hom.:

Bravo

AF:

0.00137

TwinsUK

AF:

0.00189

AC:

ALSPAC

AF:

0.00337

AC:

ESP6500AA

AF:

0.000552

AC:

ESP6500EA

AF:

0.00208

AC:

ExAC

AF:

0.00145

AC:

174

Asia WGS

AF:

0.000577

AC:

AN:

3478

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:3Benign:16

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Benign:6

Likely benign, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Feb 01, 2024	TTN: BP4, BS2 -
Likely benign, criteria provided, single submitter	clinical testing	GeneDx	Oct 05, 2020	This variant is associated with the following publications: (PMID: 24503780, 23861362, 23396983) -
Likely benign, criteria provided, single submitter	research	Biesecker Lab/Clinical Genomics Section, National Institutes of Health	Jun 24, 2013	- -
Likely benign, no assertion criteria provided	clinical testing	Diagnostic Laboratory, Department of Genetics, University Medical Center Groningen	-	- -
Likely benign, no assertion criteria provided	clinical testing	Genome Diagnostics Laboratory, University Medical Center Utrecht	-	- -
Likely benign, no assertion criteria provided	clinical testing	Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center	-	- -

not specified

Benign:5

Benign, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Dec 04, 2020	Variant summary: TTN c.28748C>T (p.Ala9583Val) 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 0.0016 in 228620 control chromosomes, predominantly at a frequency of 0.0028 within the Non-Finnish European subpopulation in the gnomAD database. The observed variant frequency within Non-Finnish European control individuals in the gnomAD database is approximately 4 fold of the estimated maximal expected allele frequency for a pathogenic variant in TTN causing Cardiomyopathy phenotype (0.00063), strongly suggesting that the variant is a benign polymorphism found primarily in populations of Non-Finnish European origin. c.28748C>T has been reported in the literature in at least one individual affected with Sudden Arrhythmia Death Syndrome (Nunn_2016). This report does not provide unequivocal conclusions about association of the variant with Cardiomyopathy. Co-occurrence with a pathogenic variant has been reported (MYBPC3 c.3628-41_3628-17del25), providing supporting evidence for a benign role. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Seven clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation (benign/likely benign n=7, VUS n=1). Based on the evidence outlined above, the variant was classified as benign. -
Benign, no assertion criteria provided	clinical testing	Clinical Genetics, Academic Medical Center	-	- -
Likely benign, criteria provided, single submitter	clinical testing	Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine	Apr 14, 2016	p.Ala9583Val in exon 127 of TTN: This variant is not expected to have clinical s ignificance due to a lack of conservation across species, including mammals. Of note, 7 mammals have a valine (Val) at this position despite high nearby amino a cid conservation. This variant has also been identified in 0.4% (138/32684) of European chromosomes including 1 homozygote by the Exome Aggregation Consortium (ExAC, http://exac.broadinstitute.org; dbSNP 72650030). -
Likely benign, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Apr 20, 2015	- -
Benign, no assertion criteria provided	clinical testing	Joint Genome Diagnostic Labs from Nijmegen and Maastricht, Radboudumc and MUMC+	-	- -

Autosomal recessive limb-girdle muscular dystrophy type 2J

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 12, 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 12, 2018

Early-onset myopathy with fatal cardiomyopathy

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 12, 2018

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

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Invitae

Jan 29, 2024

- -

Cardiomyopathy

Benign:1

Benign, criteria provided, single submitter

clinical testing

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

Mar 03, 2023

- -

TTN-related condition

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

PreventionGenetics, part of Exact Sciences

Mar 10, 2022

This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -

Tibial muscular dystrophy

Benign:1

Benign, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 12, 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 12, 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

0.082

BayesDel_addAF

Benign

-0.53

BayesDel_noAF

Benign

-0.52

Cadd

Benign

Dann

Benign

0.96

Eigen

Benign

-0.55

Eigen_PC

Benign

-0.37

FATHMM_MKL

Benign

0.33

LIST_S2

Benign

0.59

T;T;.;T

M_CAP

Benign

0.019

MetaRNN

Benign

0.0042

T;T;T;T

MetaSVM

Benign

-1.1

MutationTaster

Benign

1.0

D;D;D;N;N;N

PrimateAI

Benign

0.29

PROVEAN

Benign

-0.68

N;.;.;.

REVEL

Benign

0.10

Sift

Benign

0.77

T;.;.;.

Polyphen

0.0

.;.;B;B

Vest4

0.062

MVP

0.16

MPC

0.083

ClinPred

0.011

GERP RS

2.1

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