chr2-178727129-C-T

Variant names:

Variant summary

Our verdict is Benign. Variant got -16 ACMG points: 0P and 16B. BP4_StrongBP6_Very_StrongBS1

The NM_001267550.2(TTN):c.20236G>A(p.Ala6746Thr) variant causes a missense change. The variant allele was found at a frequency of 0.000146 in 1,596,980 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★).

Frequency

Genomes: 𝑓 0.00074 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000083 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Benign/Likely benign criteria provided, multiple submitters, no conflicts B:12

Conservation

PhyloP100: 6.16

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:

ENSG00000267784 (HGNC:):

ENSG00000267784 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Benign. Variant got -16 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.018306553).

BP6

Variant 2-178727129-C-T is Benign according to our data. Variant chr2-178727129-C-T is described in ClinVar as [Likely_benign]. Clinvar id is 46668.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

BS1

Variant frequency is greater than expected in population afr. gnomad4 allele frequency = 0.000742 (113/152206) while in subpopulation AFR AF= 0.00257 (107/41558). AF 95% confidence interval is 0.00218. There are 0 homozygotes in gnomad4. There are 58 alleles in male gnomad4 subpopulation. Median coverage is 33. This position pass quality control queck.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2 link	c.20236G>A	p.Ala6746Thr	missense_variant	Exon 69 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.20236G>A	p.Ala6746Thr	missense_variant	Exon 69 of 363	5	NM_001267550.2	ENSP00000467141.1		A0A0A0MTS7

Frequencies

GnomAD3 genomes

AF:

0.000723

AC:

110

AN:

152088

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00251

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000197

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.000207

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000147

Gnomad OTH

AF:

0.000478

GnomAD3 exomes

AF:

0.000243

AC:

AN:

243062

Hom.:

AF XY:

0.000167

AC XY:

AN XY:

131852

show subpopulations

Gnomad AFR exome

AF:

0.00315

Gnomad AMR exome

AF:

0.000179

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.0000680

Gnomad FIN exome

AF:

0.0000469

Gnomad NFE exome

AF:

0.0000181

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000831

AC:

120

AN:

1444774

Hom.:

Cov.:

AF XY:

0.0000628

AC XY:

AN XY:

716314

show subpopulations

Gnomad4 AFR exome

AF:

0.00254

Gnomad4 AMR exome

AF:

0.0000913

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000254

Gnomad4 SAS exome

AF:

0.0000481

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000191

Gnomad4 OTH exome

AF:

0.000101

GnomAD4 genome

AF:

0.000742

AC:

113

AN:

152206

Hom.:

Cov.:

AF XY:

0.000780

AC XY:

AN XY:

74406

show subpopulations

Gnomad4 AFR

AF:

0.00257

Gnomad4 AMR

AF:

0.000196

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.000207

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000147

Gnomad4 OTH

AF:

0.000473

Alfa

AF:

0.000164

Hom.:

Bravo

AF:

0.000945

ESP6500AA

AF:

0.00394

AC:

ESP6500EA

AF:

0.00

AC:

ExAC

AF:

0.000281

AC:

Asia WGS

AF:

0.00115

AC:

AN:

3476

ClinVar

Significance: Benign/Likely benign

Submissions summary: Benign:12

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not specified

Benign:4

Clinical Genetics, Academic Medical Center

Significance: Benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Jan 24, 2012

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Ala5502Thr in exon 66 of TTN: This variant is not expected to have clinical sign ificance because it has been identified in 0.4% (12/3120) of African American ch romosomes by the NHLBI Exome Sequencing Project in a broad population (http://ev s.gs.washington.edu/EVS). Ala5502Thr in exon 66 of TTN (allele frequency = 0.4% , 12/3120) ** -

Aug 21, 2015

Eurofins Ntd Llc (ga)

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Oct 28, 2016

Athena Diagnostics

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided

Benign:2

Laboratory of Diagnostic Genome Analysis, Leiden University Medical Center (LUMC)

Significance: Likely benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Feb 17, 2021

GeneDx

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

TTN-related disorder

Benign:1

Jan 27, 2021

PreventionGenetics, part of Exact Sciences

Significance: Likely benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

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). -

Autosomal recessive limb-girdle muscular dystrophy type 2J

Benign:1

Sep 10, 2021

Genome-Nilou Lab

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

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

Benign:1

Jan 28, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Early-onset myopathy with fatal cardiomyopathy

Benign:1

Sep 10, 2021

Genome-Nilou Lab

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Tibial muscular dystrophy

Benign:1

Sep 10, 2021

Genome-Nilou Lab

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Myopathy, myofibrillar, 9, with early respiratory failure

Benign:1

Sep 10, 2021

Genome-Nilou Lab

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.30

BayesDel_addAF

Benign

-0.39

BayesDel_noAF

Benign

-0.34

CADD

Uncertain

DANN

Benign

0.95

Eigen

Pathogenic

0.97

Eigen_PC

Pathogenic

0.93

FATHMM_MKL

Uncertain

0.89

LIST_S2

Benign

0.81

T;T;.;T

M_CAP

Benign

0.036

MetaRNN

Benign

0.018

T;T;T;T

MetaSVM

Uncertain

0.35

PrimateAI

Uncertain

0.58

PROVEAN

Benign

-2.1

N;.;.;.

REVEL

Uncertain

0.44

Sift

Benign

0.36

T;.;.;.

Polyphen

1.0

.;.;D;D

Vest4

0.41

MVP

0.42

MPC

0.43

ClinPred

0.036

GERP RS

6.0

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.010

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