2-178528273-C-T

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 20 ACMG points: 20P and 0B. PVS1PS3PP5_Very_Strong

The NM_001267550.2(TTN):c.107377+1G>A variant causes a splice donor, intron change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000359 in 1,613,396 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★). ClinVar reports functional evidence for this variant: "SCV000491354: Canonical splice site variant for which RNA studies demonstrate alteration of normal gene transcription and expression (PMID:28716623); SCV004092465: Functional studies have also indicated this variant to result in aberrant splicing (Harris E et al. Neuromuscul Disord, 2017 Nov;27:1009-1017).; SCV004847677: cDNA and Western blot analysis of patient cells demonstrated an impact to splicing (Harris 2017, Savarese 2018).".

Frequency

Genomes: 𝑓 0.000026 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000037 ( 0 hom. )

Consequence

TTN
NM_001267550.2 splice_donor, intron

Scores

Splicing: ADA: 1.000

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:11

Conservation

PhyloP100: 7.65

Publications

8 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: Pathogenic. The variant received 20 ACMG points.

PVS1

Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, No cryptic splice site detected. Exon removal results in frameshift change.

PS3

PS3 evidence extracted from ClinVar submissions: SCV000491354: Canonical splice site variant for which RNA studies demonstrate alteration of normal gene transcription and expression (PMID: 28716623); SCV004092465: Functional studies have also indicated this variant to result in aberrant splicing (Harris E et al. Neuromuscul Disord, 2017 Nov;27:1009-1017).; SCV004847677: cDNA and Western blot analysis of patient cells demonstrated an impact to splicing (Harris 2017, Savarese 2018).

PP5

Variant 2-178528273-C-T is Pathogenic according to our data. Variant chr2-178528273-C-T is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 196723.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

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	Effect	Exon Rank	Protein	UniProt
TTN	NM_001267550.2	MANE Select	c.107377+1G>A	splice_donor intron	N/A	NP_001254479.2	Q8WZ42-12
TTN	NM_001256850.1		c.102454+1G>A	splice_donor intron	N/A	NP_001243779.1	Q8WZ42-1
TTN	NM_133378.4		c.99673+1G>A	splice_donor intron	N/A	NP_596869.4	Q8WZ42-11

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	Effect	Exon Rank	Protein	UniProt
TTN	ENST00000589042.5	TSL:5 MANE Select	c.107377+1G>A	splice_donor intron	N/A	ENSP00000467141.1	Q8WZ42-12
TTN	ENST00000446966.2	TSL:1	c.107221+1G>A	splice_donor intron	N/A	ENSP00000408004.2	A0A1B0GXE3
TTN	ENST00000436599.2	TSL:1	c.107101+1G>A	splice_donor intron	N/A	ENSP00000405517.2	A0A0C4DG59

Frequencies

GnomAD3 genomes

AF:

0.0000263

AC:

AN:

152170

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:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000294

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000121

AC:

AN:

248508

AF XY:

0.0000148

show subpopulations

Gnomad AFR exome

AF:

0.0000646

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000557

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000887

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000370

AC:

AN:

1461108

Hom.:

Cov.:

AF XY:

0.0000330

AC XY:

AN XY:

726780

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33454

American (AMR)

AF:

0.00

AC:

AN:

44640

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26104

East Asian (EAS)

AF:

0.0000252

AC:

AN:

39686

South Asian (SAS)

AF:

0.0000116

AC:

AN:

86114

European-Finnish (FIN)

AF:

0.0000187

AC:

AN:

53388

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5758

European-Non Finnish (NFE)

AF:

0.0000432

AC:

AN:

1111602

Other (OTH)

AF:

0.0000497

AC:

AN:

60362

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.465

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:

152288

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74456

show subpopulations

African (AFR)

AF:

0.0000481

AC:

AN:

41568

American (AMR)

AF:

0.00

AC:

AN:

15292

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5180

South Asian (SAS)

AF:

0.00

AC:

AN:

4828

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10594

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.0000294

AC:

AN:

68032

Other (OTH)

AF:

0.00

AC:

AN:

2116

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.438

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:

0.0000329

Hom.:

Bravo

AF:

0.0000227

ExAC

AF:

0.0000165

AC:

EpiCase

AF:

0.0000546

EpiControl

AF:

0.00

ClinVar

ClinVar submissions

Significance:Pathogenic/Likely pathogenic

Revision:criteria provided, multiple submitters, no conflicts

View on ClinVar

Pathogenic

VUS

Benign

Condition

not provided (6)

Autosomal recessive limb-girdle muscular dystrophy type 2J;C1838244:Tibial muscular dystrophy;C1858763:Dilated cardiomyopathy 1G;C1861065:Hypertrophic cardiomyopathy 9;C1863599:Myopathy, myofibrillar, 9, with early respiratory failure;C2673677:Early-onset myopathy with fatal cardiomyopathy (1)

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

Cardiovascular phenotype (1)

Neuromuscular disease (1)

Primary dilated cardiomyopathy (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.24

BayesDel_noAF

Pathogenic

0.29

CADD

Pathogenic

(source)

DANN

Uncertain

0.99

Eigen

Pathogenic

1.1

Eigen_PC

Pathogenic

0.91

FATHMM_MKL

Pathogenic

0.97

PhyloP100

7.6

GERP RS

5.0

Mutation Taster

=0/100

disease causing (ClinVar)

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Pathogenic

0.93

SpliceAI score (max)

1.0

Details are displayed if max score is > 0.2

DS_DL_spliceai

1.0

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

Computational scores

Splicing

Publications

Other links and lift over