rs779874042

Variant names:

Your query was ambiguous. Multiple possible variants found:

Variant summary

Our verdict is The variant received 14 classification points (ACMG Germline Pathogenicity v2019). PVS1PM2PP5_Strong

The NM_001267550.2(TTN):c.82639G>T (p.Glu27547*) variant causes a stop gained change involving the alteration of a conserved nucleotide. The variant is predicted to lead to nonsense-mediated mRNA decay (NMD). The variant allele was found at a cumulative frequency of 0.00000479 (AC=7) in the gnomAD database across 1,461,516 control chromosomes (no homozygotes observed). The grpmax filtering allele frequency (95% CI) is 0.00000262. In-silico predictor (BayesDel (noAF)) classifies this variant as likely damaging/oncogenic. Splicing prediction tools (SpliceAI) predict no significant impact on normal splicing. The affected nucleotide is highly conserved across species (PhyloP 100-way vertebrate score: 7.86). Variant has been reported in ClinVar as Pathogenic/Likely Pathogenic (★★).

Frequency

Genomes: not found (cov: 33)

Exomes 𝑓: 0.0000048 ( 0 hom. )

Consequence

TTN
NM_001267550.2 stop_gained

Scores

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:4

Conservation

PhyloP100: 7.86

Publications

3 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 Gene-Disease associations (from GenCC):

dilated cardiomyopathy 1G
Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: G2P, ClinGen, Ambry Genetics, Labcorp Genetics (formerly Invitae)
myopathy, myofibrillar, 9, with early respiratory failure
Inheritance: AD Classification: DEFINITIVE, STRONG, MODERATE, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, Orphanet, ClinGen
early-onset myopathy with fatal cardiomyopathy
Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, G2P, Labcorp Genetics (formerly Invitae)
TTN-related myopathy
Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
tibial muscular dystrophy
Inheritance: AD Classification: STRONG, MODERATE, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, Orphanet, ClinGen
autosomal recessive limb-girdle muscular dystrophy type 2J
Inheritance: AR Classification: STRONG, MODERATE, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet, Ambry Genetics
TTN-related myopathy, dominant-negative TTNsv
Inheritance: AD Classification: MODERATE Submitted by: ClinGen
familial isolated dilated cardiomyopathy
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
autosomal recessive centronuclear myopathy
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
childhood-onset progressive contractures-limb-girdle weakness-muscle dystrophy syndrome
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
arrhythmogenic right ventricular cardiomyopathy
Inheritance: AD Classification: LIMITED, NO_KNOWN Submitted by: ClinGen, G2P
congenital myopathy
Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics
familial hypertrophic cardiomyopathy
Inheritance: AD Classification: LIMITED Submitted by: G2P
hereditary skeletal muscle disorder
Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics
hypertrophic cardiomyopathy
Inheritance: AD Classification: LIMITED Submitted by: ClinGen
hypertrophic cardiomyopathy 9
Inheritance: AD Classification: LIMITED Submitted by: Labcorp Genetics (formerly Invitae)

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

new If you want to explore the variant's impact on the transcript NM_001267550.2, check out the Mutation Effect Viewer. This is especially useful for frameshift variants or if you want to visualize the effect of exon loss / intron retention.

Classification according to ACMG Germline Pathogenicity v2019

Classification was made for transcript

Our verdict: Pathogenic. The variant received 14 points.

PVS1

Frameshift/stop-gained, NMD predicted, LoF disease mechanism — very strong (PVS1); Stop-gained (exon 326 of 363) at amino acid 27547 of 35991, predicted to trigger nonsense-mediated mRNA decay. Loss of function is a known disease mechanism for this gene.

PM2

Very rare in gnomAD for AD/XL gene (popmax AF < threshold/10) — PM2; GnomAD popmax AF = 0.00000262 — very rare for AD+AR gene (base 0.0001, raised to 0.000161 by highest known P/LP ClinVar AF 0.000161) — PM2 moderate.

PP5

ClinVar 2-star pathogenic — strong (PP5); ClinVar germline classification: Pathogenic/Likely Pathogenic, 2 star(s).

Variant Effect in Transcripts

Automated classification analysis was done for transcript: NM_001267550.2. You can select a different transcript below to see updated classification assignments.

RefSeq Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
TTN	NM_001267550.2	MANE Select	c.82639G>T	p.Glu27547*	stop_gained	Exon 326 of 363	NP_001254479.2	Q8WZ42-12
TTN	NM_001256850.1		c.77716G>T	p.Glu25906*	stop_gained	Exon 276 of 313	NP_001243779.1	Q8WZ42-1
TTN	NM_133378.4		c.74935G>T	p.Glu24979*	stop_gained	Exon 275 of 312	NP_596869.4	Q8WZ42-11

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
TTN	ENST00000589042.5	TSL:5 MANE Select	c.82639G>T	p.Glu27547*	stop_gained	Exon 326 of 363	ENSP00000467141.1	Q8WZ42-12
TTN	ENST00000446966.2	TSL:1	c.82483G>T	p.Glu27495*	stop_gained	Exon 324 of 361	ENSP00000408004.2	A0A1B0GXE3
TTN	ENST00000436599.2	TSL:1	c.82363G>T	p.Glu27455*	stop_gained	Exon 324 of 361	ENSP00000405517.2	A0A0C4DG59

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

0.00000479

AC:

AN:

1461516

Hom.:

Cov.:

AF XY:

0.00000550

AC XY:

AN XY:

727046

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33466

American (AMR)

AF:

0.00

AC:

AN:

44720

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26130

East Asian (EAS)

AF:

0.00

AC:

AN:

39666

South Asian (SAS)

AF:

0.00

AC:

AN:

86256

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53400

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5766

European-Non Finnish (NFE)

AF:

0.00000630

AC:

AN:

1111752

Other (OTH)

AF:

0.00

AC:

AN:

60360

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

Cov.:

ClinVar

ClinVar submissions

Significance:Pathogenic/Likely pathogenic

Revision:criteria provided, multiple submitters, no conflicts

View on ClinVar

Pathogenic

VUS

Benign

Condition

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)

not provided (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.62

BayesDel_noAF

Pathogenic

0.66

CADD

Pathogenic

(source)

DANN

Benign

0.97

Eigen

Pathogenic

1.2

Eigen_PC

Pathogenic

1.1

FATHMM_MKL

Pathogenic

0.99

PhyloP100

7.9

AlphaGenome AVI

Pathogenic

(source)

GPN-Star LLR

-11

(source)

GPN-Star score

(source)

Mutation Taster

=0/200

disease causing (ClinVar)

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.0

Details are displayed if max score is > 0.2

Pangolin (max)

Benign

0.060

(source)

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

Classification according to ACMG Germline Pathogenicity v2019

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over