2-178727656-G-T

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -5 ACMG points: 0P and 5B. BP4_StrongBP6

The NM_001267550.2(TTN):c.19922C>A(p.Thr6641Asn) variant causes a missense change. The variant allele was found at a frequency of 0.0000595 in 1,612,778 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/19 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. T6641T) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.000072 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000058 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1B:6

Conservation

PhyloP100: 3.85

Publications

0 publications found

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 was made for transcript

Our verdict: Likely_benign. The variant received -5 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.014575541).

BP6

Variant 2-178727656-G-T is Benign according to our data. Variant chr2-178727656-G-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 203281.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001267550.2. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
TTN	NM_001267550.2	MANE Select	c.19922C>A	p.Thr6641Asn	missense	Exon 68 of 363	NP_001254479.2
TTN	NM_001256850.1		c.18971C>A	p.Thr6324Asn	missense	Exon 66 of 313	NP_001243779.1
TTN	NM_133378.4		c.16190C>A	p.Thr5397Asn	missense	Exon 65 of 312	NP_596869.4

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
TTN	ENST00000589042.5	TSL:5 MANE Select	c.19922C>A	p.Thr6641Asn	missense	Exon 68 of 363	ENSP00000467141.1
TTN	ENST00000446966.2	TSL:1	c.19922C>A	p.Thr6641Asn	missense	Exon 68 of 361	ENSP00000408004.2
TTN	ENST00000436599.2	TSL:1	c.19646C>A	p.Thr6549Asn	missense	Exon 66 of 361	ENSP00000405517.2

Frequencies

GnomAD3 genomes

AF:

0.0000723

AC:

AN:

152068

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000721

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.000326

AC:

AN:

248214

AF XY:

0.000282

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00229

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.000333

GnomAD4 exome

AF:

0.0000582

AC:

AN:

1460710

Hom.:

Cov.:

AF XY:

0.0000537

AC XY:

AN XY:

726602

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33404

American (AMR)

AF:

0.00188

AC:

AN:

44684

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26094

East Asian (EAS)

AF:

0.00

AC:

AN:

39676

South Asian (SAS)

AF:

0.00

AC:

AN:

86152

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53364

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5752

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1111252

Other (OTH)

AF:

0.0000166

AC:

AN:

60332

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.480

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.0000723

AC:

AN:

152068

Hom.:

Cov.:

AF XY:

0.0000539

AC XY:

AN XY:

74278

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41432

American (AMR)

AF:

0.000721

AC:

AN:

15252

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5168

South Asian (SAS)

AF:

0.00

AC:

AN:

4830

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10620

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

67974

Other (OTH)

AF:

0.00

AC:

AN:

2092

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.511

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.000151

Hom.:

Bravo

AF:

0.000147

ExAC

AF:

0.000322

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1Benign:6

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not specified

Uncertain:1Benign:2

Oct 02, 2015

Eurofins Ntd Llc (ga)

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Sep 21, 2016

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Missense variants in the TTN gene are considered 'unclassified' if they are not previously reported in the literature and do not have >1% frequency in the population to be considered a polymorphism. Research indicates that truncating mutations in the TTN gene are expected to account for approximately 25% of familial and 18% of sporadic idiopathic DCM; however, truncating variants in the TTN gene have been reported in approximately 3% of reported control alleles. There has been little investigation into non-truncating variants. (Herman D et al. Truncations of titin causing dilated cardiomyopathy. N Eng J Med 366:619-628, 2012) The variant is found in DCM panel(s).

Nov 12, 2015

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

p.Thr5397Asn in exon 65 of TTN: This variant is not expected to have clinical si gnificance because it has been identified in 0.33% (38/11558) of Latino chromoso mes by the Exome Aggregation Consortium (ExAC, http://exac.broadinstitute.org).

TTN-related disorder

Benign:1

Aug 24, 2022

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;C1858763:Dilated cardiomyopathy 1G

Benign:1

Jan 22, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Cardiomyopathy

Benign:1

Sep 04, 2018

Center for Advanced Laboratory Medicine, UC San Diego Health, University of California San Diego

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

not provided

Benign:1

Oct 23, 2023

Revvity Omics, Revvity

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.14

BayesDel_addAF

Benign

-0.46

BayesDel_noAF

Benign

-0.43

CADD

Benign

(source)

DANN

Benign

0.88

Eigen

Benign

0.029

Eigen_PC

Benign

0.21

FATHMM_MKL

Uncertain

0.94

LIST_S2

Benign

0.74

M_CAP

Benign

0.022

MetaRNN

Benign

0.015

MetaSVM

Benign

-0.74

PhyloP100

3.9

PrimateAI

Uncertain

0.64

PROVEAN

Uncertain

-2.5

REVEL

Benign

0.089

Sift

Benign

0.30

Polyphen

0.096

Vest4

0.24

MutPred

0.39

Gain of ubiquitination at K6323 (P = 0.0566)

MVP

0.26

MPC

0.12

ClinPred

0.023

GERP RS

5.1

Mutation Taster

=77/23

polymorphism

(source)

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

You must be logged in to view publications. This limit was set because tens of millions (!) of queries from AI bots are generated daily.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over