2-178563747-G-A

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.82385C>T(p.Thr27462Met) variant causes a missense change. The variant allele was found at a frequency of 0.0000886 in 1,613,642 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/20 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. T27462K) has been classified as Likely benign.

Frequency

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

Exomes 𝑓: 0.000090 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

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

Conservation

PhyloP100: 5.27

Publications

7 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=0.05043006).

BP6

Variant 2-178563747-G-A is Benign according to our data. Variant chr2-178563747-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 202911.

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.82385C>T	p.Thr27462Met	missense	Exon 326 of 363	NP_001254479.2
TTN	NM_001256850.1		c.77462C>T	p.Thr25821Met	missense	Exon 276 of 313	NP_001243779.1
TTN	NM_133378.4		c.74681C>T	p.Thr24894Met	missense	Exon 275 of 312	NP_596869.4

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
TTN	ENST00000589042.5	TSL:5 MANE Select	c.82385C>T	p.Thr27462Met	missense	Exon 326 of 363	ENSP00000467141.1
TTN	ENST00000446966.2	TSL:1	c.82229C>T	p.Thr27410Met	missense	Exon 324 of 361	ENSP00000408004.2
TTN	ENST00000436599.2	TSL:1	c.82109C>T	p.Thr27370Met	missense	Exon 324 of 361	ENSP00000405517.2

Frequencies

GnomAD3 genomes

AF:

0.0000724

AC:

AN:

152022

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000483

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.000621

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000882

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000604

AC:

AN:

248482

AF XY:

0.0000964

show subpopulations

Gnomad AFR exome

AF:

0.0000646

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000534

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000903

AC:

132

AN:

1461502

Hom.:

Cov.:

AF XY:

0.000106

AC XY:

AN XY:

727044

show subpopulations

African (AFR)

AF:

0.0000896

AC:

AN:

33470

American (AMR)

AF:

0.00

AC:

AN:

44716

Ashkenazi Jewish (ASJ)

AF:

0.0000383

AC:

AN:

26122

East Asian (EAS)

AF:

0.00

AC:

AN:

39664

South Asian (SAS)

AF:

0.000301

AC:

AN:

86254

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53394

Middle Eastern (MID)

AF:

0.000173

AC:

AN:

5764

European-Non Finnish (NFE)

AF:

0.0000872

AC:

AN:

1111754

Other (OTH)

AF:

0.0000663

AC:

AN:

60364

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.483

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:

152140

Hom.:

Cov.:

AF XY:

0.0000941

AC XY:

AN XY:

74380

show subpopulations

African (AFR)

AF:

0.0000482

AC:

AN:

41512

American (AMR)

AF:

0.00

AC:

AN:

15264

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3468

East Asian (EAS)

AF:

0.00

AC:

AN:

5156

South Asian (SAS)

AF:

0.000622

AC:

AN:

4824

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10604

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.0000882

AC:

AN:

67994

Other (OTH)

AF:

0.00

AC:

AN:

2112

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.516

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:

0.00

Hom.:

Bravo

AF:

0.0000680

TwinsUK

AF:

0.00

AC:

ALSPAC

AF:

0.000259

AC:

ExAC

AF:

0.0000662

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:3Benign:3

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:3Benign:1

Sep 10, 2019

GeneDx

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant is associated with the following publications: (PMID: 31983221)

May 13, 2024

Mayo Clinic Laboratories, Mayo Clinic

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

BP4_strong

Sep 24, 2024

Revvity Omics, Revvity

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Sep 15, 2015

Eurofins Ntd Llc (ga)

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Cardiomyopathy

Benign:1

Jul 20, 2021

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

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Cardiovascular phenotype

Benign:1

Oct 19, 2021

Ambry Genetics

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity.

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.054

BayesDel_addAF

Benign

-0.37

BayesDel_noAF

Benign

-0.47

CADD

Benign

(source)

DANN

Benign

0.76

Eigen

Benign

-0.80

Eigen_PC

Benign

-0.76

FATHMM_MKL

Benign

0.10

LIST_S2

Benign

0.79

M_CAP

Uncertain

0.093

MetaRNN

Benign

0.050

MetaSVM

Benign

-0.77

MutationAssessor

Benign

1.6

PhyloP100

5.3

PrimateAI

Benign

0.26

PROVEAN

Benign

0.030

REVEL

Benign

0.18

Sift

Benign

0.038

Polyphen

0.082

Vest4

0.20

MutPred

0.30

Gain of catalytic residue at T25821 (P = 0.0026)

MVP

0.20

MPC

0.088

ClinPred

0.036

GERP RS

0.93

Mutation Taster

=91/9

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

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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