2-178573416-A-T

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -1 ACMG points: 0P and 1B. BP6

The NM_001267550.2(TTN):c.72716T>A(p.Met24239Lys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000961 in 1,519,826 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. M24239T) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000046 ( 0 hom., cov: 32)

Exomes 𝑓: 0.00010 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3B:1

Conservation

PhyloP100: 9.27

Publications

1 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 -1 ACMG points.

BP6

Variant 2-178573416-A-T is Benign according to our data. Variant chr2-178573416-A-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 596933.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2 link	c.72716T>A	p.Met24239Lys	missense_variant	Exon 326 of 363	ENST00000589042.5	NP_001254479.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5 link	c.72716T>A	p.Met24239Lys	missense_variant	Exon 326 of 363	5	NM_001267550.2	ENSP00000467141.1

Frequencies

GnomAD3 genomes

AF:

0.0000460

AC:

AN:

152070

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

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:

0.0000882

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000455

AC:

AN:

175928

AF XY:

0.0000753

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000485

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000814

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.000102

AC:

139

AN:

1367756

Hom.:

Cov.:

AF XY:

0.0000865

AC XY:

AN XY:

670434

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

30290

American (AMR)

AF:

0.00

AC:

AN:

29234

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

20286

East Asian (EAS)

AF:

0.00

AC:

AN:

38676

South Asian (SAS)

AF:

0.00

AC:

AN:

68710

European-Finnish (FIN)

AF:

0.00

AC:

AN:

50092

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5332

European-Non Finnish (NFE)

AF:

0.000121

AC:

129

AN:

1068774

Other (OTH)

AF:

0.000177

AC:

AN:

56362

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:

0.0000460

AC:

AN:

152070

Hom.:

Cov.:

AF XY:

0.0000539

AC XY:

AN XY:

74268

show subpopulations

African (AFR)

AF:

0.0000241

AC:

AN:

41430

American (AMR)

AF:

0.00

AC:

AN:

15260

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5162

South Asian (SAS)

AF:

0.00

AC:

AN:

4828

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10608

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000882

AC:

AN:

67992

Other (OTH)

AF:

0.00

AC:

AN:

2092

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.518

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:

0.0000831

ExAC

AF:

0.0000167

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:3Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:2Benign:1

Sep 20, 2018

GeneDx

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Jul 11, 2018

Eurofins Ntd Llc (ga)

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

May 11, 2022

Revvity Omics, Revvity

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

not specified

Uncertain:1

Nov 14, 2022

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

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: TTN c.65012T>A (p.Met21671Lys) results in a non-conservative amino acid change located in the A-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 4.5e-05 in 175928 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.65012T>A has been reported in the literature in at least one individual affected with Cardiomyopathy without strong evidence of causality (Campuzano_2015, Martinez-Barrios_2022). These reports do not provide unequivocal conclusions about association of the variant with Dilated Cardiomyopathy. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Two clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. One laboratory classified the variant as likely benign, and one laboratory classified the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.98

BayesDel_addAF

Uncertain

0.12

BayesDel_noAF

Uncertain

0.12

CADD

Benign

(source)

DANN

Benign

0.88

Eigen

Uncertain

0.64

Eigen_PC

Uncertain

0.63

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.93

D;D;D;.;D;D;D

M_CAP

Benign

0.067

MetaRNN

Uncertain

0.45

T;T;T;T;T;T;T

MetaSVM

Benign

-0.31

MutationAssessor

Pathogenic

3.0

.;.;.;M;.;.;M

PhyloP100

9.3

PrimateAI

Uncertain

0.72

PROVEAN

Uncertain

-4.2

D;D;.;.;D;D;.

REVEL

Uncertain

0.51

Sift

Uncertain

0.0040

D;D;.;.;D;D;.

Polyphen

0.68

.;.;.;P;.;.;P

Vest4

0.68

MVP

0.68

MPC

0.29

ClinPred

0.33

GERP RS

4.9

Mutation Taster

=44/56

disease causing

(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

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over