2-178740185-C-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.13048G>A(p.Val4350Met) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000026 in 1,613,370 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 16/19 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.000026 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000026 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:2B:1

Conservation

PhyloP100: -0.495

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 -5 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.063806206).

BP6

Variant 2-178740185-C-T is Benign according to our data. Variant chr2-178740185-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 404906.

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.13048G>A	p.Val4350Met	missense	Exon 48 of 363	NP_001254479.2
TTN	NM_001256850.1		c.12097G>A	p.Val4033Met	missense	Exon 46 of 313	NP_001243779.1
TTN	NM_133437.4		c.12535G>A	p.Val4179Met	missense	Exon 46 of 192	NP_597681.4

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
TTN	ENST00000589042.5	TSL:5 MANE Select	c.13048G>A	p.Val4350Met	missense	Exon 48 of 363	ENSP00000467141.1
TTN	ENST00000446966.2	TSL:1	c.13048G>A	p.Val4350Met	missense	Exon 48 of 361	ENSP00000408004.2
TTN	ENST00000436599.2	TSL:1	c.12772G>A	p.Val4258Met	missense	Exon 46 of 361	ENSP00000405517.2

Frequencies

GnomAD3 genomes

AF:

0.0000263

AC:

AN:

152194

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

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:

0.0000588

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000403

AC:

AN:

248228

AF XY:

0.0000371

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000581

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000712

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000260

AC:

AN:

1461176

Hom.:

Cov.:

AF XY:

0.0000220

AC XY:

AN XY:

726892

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33406

American (AMR)

AF:

0.0000448

AC:

AN:

44654

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26114

East Asian (EAS)

AF:

0.00

AC:

AN:

39684

South Asian (SAS)

AF:

0.00

AC:

AN:

86190

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53372

Middle Eastern (MID)

AF:

0.000174

AC:

AN:

5760

European-Non Finnish (NFE)

AF:

0.0000297

AC:

AN:

1111642

Other (OTH)

AF:

0.0000331

AC:

AN:

60354

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.482

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:

0.0000263

AC:

AN:

152194

Hom.:

Cov.:

AF XY:

0.0000404

AC XY:

AN XY:

74342

show subpopulations

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.00

AC:

AN:

41472

American (AMR)

AF:

0.00

AC:

AN:

15276

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5182

South Asian (SAS)

AF:

0.00

AC:

AN:

4828

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10616

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000588

AC:

AN:

68032

Other (OTH)

AF:

0.00

AC:

AN:

2088

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0.00000192981), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.400

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:

0.0000987

Hom.:

Bravo

AF:

0.0000718

TwinsUK

AF:

0.00

AC:

ALSPAC

AF:

0.000519

AC:

ExAC

AF:

0.0000331

AC:

EpiCase

AF:

0.000109

EpiControl

AF:

0.000178

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:2Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

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

Uncertain:1

Aug 01, 2016

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

not provided

Uncertain:1

May 01, 2024

CeGaT Center for Human Genetics Tuebingen

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

TTN: PM2, BP4

not specified

Benign:1

Jan 30, 2018

GeneDx

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease.

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.12

BayesDel_addAF

Benign

-0.39

BayesDel_noAF

Benign

-0.60

CADD

Benign

2.7

(source)

DANN

Benign

0.63

Eigen

Benign

-1.0

Eigen_PC

Benign

-1.0

FATHMM_MKL

Benign

0.060

LIST_S2

Benign

0.81

M_CAP

Benign

0.010

MetaRNN

Benign

0.064

MetaSVM

Benign

-1.0

PhyloP100

-0.49

PrimateAI

Benign

0.24

PROVEAN

Benign

-0.72

REVEL

Benign

0.023

Sift

Benign

0.14

Vest4

0.040

MutPred

0.23

Loss of sheet (P = 0.1158)

MVP

0.17

MPC

0.090

ClinPred

0.031

GERP RS

-1.0

Mutation Taster

=92/8

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