2-178728776-G-T

Variant names:

Variant summary

Our verdict is Benign. Variant got -13 ACMG points: 0P and 13B. BP4_StrongBP6BS1BS2

The NM_001267550.2(TTN):c.19150C>A(p.Pro6384Thr) variant causes a missense, splice region change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0029 in 1,594,088 control chromosomes in the GnomAD database, including 13 homozygotes. In-silico tool predicts 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). Synonymous variant affecting the same amino acid position (i.e. P6384P) has been classified as Benign.

Frequency

Genomes: 𝑓 0.0023 ( 1 hom., cov: 33)

Exomes 𝑓: 0.0030 ( 12 hom. )

Consequence

TTN
NM_001267550.2 missense, splice_region

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3B:19

Conservation

PhyloP100: 8.12

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 Benign. Variant got -13 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.008000225).

BP6

Variant 2-178728776-G-T is Benign according to our data. Variant chr2-178728776-G-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 46653.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=5, Benign=8, Uncertain_significance=3}. Variant chr2-178728776-G-T is described in Lovd as [Benign]. Variant chr2-178728776-G-T is described in Lovd as [Likely_benign].

BS1

Variant frequency is greater than expected in population eas. gnomad4 allele frequency = 0.00225 (343/152232) while in subpopulation EAS AF= 0.00503 (26/5166). AF 95% confidence interval is 0.00353. There are 1 homozygotes in gnomad4. There are 184 alleles in male gnomad4 subpopulation. Median coverage is 33. This position pass quality control queck.

BS2

High Homozygotes in GnomAdExome4 at 12 AD,AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2 link	c.19150C>A	p.Pro6384Thr	missense_variant, splice_region_variant	Exon 66 of 363	ENST00000589042.5	NP_001254479.2	A0A0A0MTS7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5 link	c.19150C>A	p.Pro6384Thr	missense_variant, splice_region_variant	Exon 66 of 363	5	NM_001267550.2	ENSP00000467141.1		A0A0A0MTS7

Frequencies

GnomAD3 genomes

AF:

0.00225

AC:

343

AN:

152114

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000458

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000328

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00502

Gnomad SAS

AF:

0.000622

Gnomad FIN

AF:

0.00877

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00282

Gnomad OTH

AF:

0.00239

GnomAD3 exomes

AF:

0.00304

AC:

738

AN:

242524

Hom.:

AF XY:

0.00297

AC XY:

390

AN XY:

131392

show subpopulations

Gnomad AFR exome

AF:

0.000260

Gnomad AMR exome

AF:

0.000418

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00752

Gnomad SAS exome

AF:

0.00111

Gnomad FIN exome

AF:

0.0106

Gnomad NFE exome

AF:

0.00283

Gnomad OTH exome

AF:

0.00309

GnomAD4 exome

AF:

0.00297

AC:

4285

AN:

1441856

Hom.:

Cov.:

AF XY:

0.00288

AC XY:

2052

AN XY:

713460

show subpopulations

Gnomad4 AFR exome

AF:

0.000365

Gnomad4 AMR exome

AF:

0.000413

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00390

Gnomad4 SAS exome

AF:

0.00109

Gnomad4 FIN exome

AF:

0.0110

Gnomad4 NFE exome

AF:

0.00296

Gnomad4 OTH exome

AF:

0.00274

GnomAD4 genome

AF:

0.00225

AC:

343

AN:

152232

Hom.:

Cov.:

AF XY:

0.00247

AC XY:

184

AN XY:

74410

show subpopulations

Gnomad4 AFR

AF:

0.000457

Gnomad4 AMR

AF:

0.000328

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00503

Gnomad4 SAS

AF:

0.000623

Gnomad4 FIN

AF:

0.00877

Gnomad4 NFE

AF:

0.00282

Gnomad4 OTH

AF:

0.00237

Alfa

AF:

0.00237

Hom.:

Bravo

AF:

0.00173

TwinsUK

AF:

0.00270

AC:

ALSPAC

AF:

0.00363

AC:

ESP6500AA

AF:

0.000267

AC:

ESP6500EA

AF:

0.00219

AC:

ExAC

AF:

0.00296

AC:

358

Asia WGS

AF:

0.00144

AC:

AN:

3478

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:3Benign:19

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not specified

Benign:8

Genome Diagnostics Laboratory, University Medical Center Utrecht

Significance: Benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

May 25, 2018

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.Pro5140Thr variant in TTN is classified as benign because it has been iden tified in 1% (263/25312) of Finnish chromosomes by the Genome Aggregation Databa se (gnomAD, http://gnomad.broadinstitute.org; dbSNP rs72648953). ACMG/AMP Criter ia applied: BA1 -

Clinical Genetics, Academic Medical Center

Significance: Benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Nov 02, 2023

Athena Diagnostics

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center

Significance: Benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Sep 14, 2015

Eurofins Ntd Llc (ga)

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Joint Genome Diagnostic Labs from Nijmegen and Maastricht, Radboudumc and MUMC+

Significance: Benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Mar 15, 2021

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

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: TTN c.15418C>A (p.Pro5140Thr) results in a non-conservative amino acid change located in the I-band region (cardiodb.org) of the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 0.003 in 242524 control chromosomes in the gnomAD database, including 2 homozygotes. The observed variant frequency is approximately 7.8-fold the estimated maximal expected allele frequency for a pathogenic variant in TTN causing Dilated Cardiomyopathy phenotype (0.00039), strongly suggesting that the variant is benign. c.15418C>A has been reported in the literature in individuals affected with Dilated Cardiomyopathy (e.g. Lopes_2013, Pugh_2014, Forleo_2017). These reports do not provide unequivocal conclusions about association of the variant with Dilated Cardiomyopathy. In at least one of these cases, co-occurrence with another pathogenic variant was reported (LMNA c.673C>T, p.Arg225X; Pugh_2014), providing supporting evidence for a benign role. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. 11 other clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation, citing the variant as benign/likely benign (n=9) and uncertain significance (n=2). Based on the evidence outlined above, the variant was classified as benign. -

not provided

Benign:6

Diagnostic Laboratory, Department of Genetics, University Medical Center Groningen

Significance: Likely benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Jun 24, 2013

Biesecker Lab/Clinical Genomics Section, National Institutes of Health

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: research

- -

Sep 25, 2023

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Nov 01, 2024

CeGaT Center for Human Genetics Tuebingen

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

TTN: BS2 -

Aug 21, 2020

GeneDx

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is associated with the following publications: (PMID: 23861362, 24503780, 23396983, 28750076) -

May 30, 2017

Center for Pediatric Genomic Medicine, Children's Mercy Hospital and Clinics

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Autosomal recessive limb-girdle muscular dystrophy type 2J

Uncertain:1

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Early-onset myopathy with fatal cardiomyopathy

Uncertain:1

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

TTN-related disorder

Benign:1

Sep 13, 2021

PreventionGenetics, part of Exact Sciences

Significance: Benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

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

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

Benign:1

Feb 03, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Cardiomyopathy

Benign:1

Jul 24, 2017

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

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Myopathy, myofibrillar, 9, with early respiratory failure

Benign:1

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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

Uncertain

0.39

BayesDel_addAF

Benign

-0.43

BayesDel_noAF

Benign

-0.39

CADD

Benign

DANN

Benign

0.69

Eigen

Pathogenic

0.89

Eigen_PC

Pathogenic

0.81

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Benign

0.80

T;T;.;T

M_CAP

Benign

0.020

MetaRNN

Benign

0.0080

T;T;T;T

MetaSVM

Uncertain

-0.17

PrimateAI

Uncertain

0.63

PROVEAN

Pathogenic

-4.5

D;.;.;.

REVEL

Uncertain

0.40

Sift

Benign

0.048

D;.;.;.

Polyphen

1.0

.;.;D;D

Vest4

0.18

MVP

0.42

MPC

0.49

ClinPred

0.040

GERP RS

5.6

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.040

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