2-178768931-T-C

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 2P and 1B. PP3_ModerateBP6

The NM_001267550.2(TTN):c.8905A>G(p.Ile2969Val) variant causes a missense, splice region change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000211 in 1,613,558 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/21 in silico tools predict a benign outcome for this variant. 1/1 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. I2969I) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 31)

Exomes 𝑓: 0.000021 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense, splice_region

Scores

Clinical Significance

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

Conservation

PhyloP100: 2.35

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: Uncertain_significance. The variant received 1 ACMG points.

PP3

Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.

BP6

Variant 2-178768931-T-C is Benign according to our data. Variant chr2-178768931-T-C is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 405166.

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.8905A>G	p.Ile2969Val	missense splice_region	Exon 38 of 363	NP_001254479.2
TTN	NM_001256850.1		c.8905A>G	p.Ile2969Val	missense splice_region	Exon 38 of 313	NP_001243779.1
TTN	NM_133378.4		c.8905A>G	p.Ile2969Val	missense splice_region	Exon 38 of 312	NP_596869.4

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
TTN	ENST00000589042.5	TSL:5 MANE Select	c.8905A>G	p.Ile2969Val	missense splice_region	Exon 38 of 363	ENSP00000467141.1
TTN	ENST00000446966.2	TSL:1	c.8905A>G	p.Ile2969Val	missense splice_region	Exon 38 of 361	ENSP00000408004.2
TTN	ENST00000436599.2	TSL:1	c.8629A>G	p.Ile2877Val	missense splice_region	Exon 36 of 361	ENSP00000405517.2

Frequencies

GnomAD3 genomes

AF:

0.0000197

AC:

AN:

152132

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000196

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:

0.0000997

AC:

AN:

250650

AF XY:

0.0000664

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.000695

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000883

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000212

AC:

AN:

1461426

Hom.:

Cov.:

AF XY:

0.0000138

AC XY:

AN XY:

727034

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33476

American (AMR)

AF:

0.000626

AC:

AN:

44710

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26130

East Asian (EAS)

AF:

0.00

AC:

AN:

39614

South Asian (SAS)

AF:

0.00

AC:

AN:

86248

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53138

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5766

European-Non Finnish (NFE)

AF:

0.00000270

AC:

AN:

1111960

Other (OTH)

AF:

0.00

AC:

AN:

60384

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.496

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:

0.0000197

AC:

AN:

152132

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74316

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41412

American (AMR)

AF:

0.000196

AC:

AN:

15274

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5200

South Asian (SAS)

AF:

0.00

AC:

AN:

4832

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10602

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68026

Other (OTH)

AF:

0.00

AC:

AN:

2088

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.525

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:

0.0000282

Hom.:

Bravo

AF:

0.0000302

ExAC

AF:

0.0000330

AC:

ClinVar

ClinVar submissions as Germline

Significance:Conflicting classifications of pathogenicity

Revision:criteria provided, conflicting classifications

View on ClinVar

Pathogenic

VUS

Benign

Condition

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

not provided (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.085

BayesDel_addAF

Benign

-0.28

BayesDel_noAF

Benign

-0.27

CADD

Pathogenic

(source)

DANN

Benign

0.96

Eigen

Benign

-0.11

Eigen_PC

Benign

0.088

FATHMM_MKL

Uncertain

0.81

LIST_S2

Uncertain

0.86

M_CAP

Benign

0.025

MetaRNN

Benign

0.058

MetaSVM

Benign

-0.94

PhyloP100

2.3

PrimateAI

Benign

0.47

PROVEAN

Benign

-0.40

REVEL

Benign

0.17

Sift

Benign

0.42

Sift4G

Benign

0.21

Polyphen

0.020

Vest4

0.20

MutPred

0.47

Gain of catalytic residue at I2969 (P = 0.0598)

MVP

0.56

MPC

0.072

ClinPred

0.052

GERP RS

5.5

Mutation Taster

=90/10

polymorphism

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.92

Details are displayed if max score is > 0.2

DS_AG_spliceai

0.92

Position offset: -1

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

ClinVar submissions as Germline

Computational scores

Splicing

Publications

Other links and lift over