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rs1553479603

chr2-178528523-CTTACTGGCAGGTTGTTTTTAAACCATTCGA-C

Variant summary

Our verdict is Pathogenic. Variant got 13 ACMG points: 13P and 0B. PVS1PM2PP3PP5_Moderate

The NM_001267550.2(TTN):c.107198_107223+4del variant causes a splice donor, splice donor region, coding sequence, intron change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000187 in 1,601,458 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★). Synonymous variant affecting the same amino acid position (i.e. I35733I) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 33)
Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

TTN
NM_001267550.2 splice_donor, splice_donor_region, coding_sequence, intron

Scores

Not classified

Clinical Significance

Likely pathogenic criteria provided, single submitter P:1

Conservation

PhyloP100: 8.72
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-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]

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 13 ACMG points.

PVS1
?
    PVS1 - null variant (nonsense, frameshift, canonical ±1 or 2 splice sites, initiation codon, single or multiexon deletion) in a gene where LOF is a known mechanism of disease
Splicing variant, LoF is a know mechanism of disease, No cryptic splice site detected. Exon removal results in frameshift change.
PM2
?
    PM2 - Absent from controls (or at extremely low frequency if recessive) in Exome Sequencing Project, 1000 Genomes Project, or Exome Aggregation Consortium
Very rare variant in population databases, with high coverage;
PP3
?
    PP3 - Multiple lines of computational evidence support a deleterious effect on the gene or gene product (conservation, evolutionary, splicing impact, etc.)
No computational evidence supports a deleterious effect, but strongly conserved according to phyloP
PP5
?
    PP5 - Reputable source recently reports variant as pathogenic, but the evidence is not available to the laboratory to perform an independent evaluation
Variant 2-178528523-CTTACTGGCAGGTTGTTTTTAAACCATTCGA-C is Pathogenic according to our data. Variant chr2-178528523-CTTACTGGCAGGTTGTTTTTAAACCATTCGA-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 505097.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect #exon/exons MANE UniProt
TTNNM_001267550.2 linkuse as main transcriptc.107198_107223+4del splice_donor_variant, splice_donor_region_variant, coding_sequence_variant, intron_variant 360/363 ENST00000589042.5
TTN-AS1NR_038272.1 linkuse as main transcriptn.219+4890_219+4919del intron_variant, non_coding_transcript_variant

Ensembl

Gene Transcript HGVSc HGVSp Effect #exon/exons TSL MANE Appris UniProt
TTNENST00000589042.5 linkuse as main transcriptc.107198_107223+4del splice_donor_variant, splice_donor_region_variant, coding_sequence_variant, intron_variant 360/3635 NM_001267550.2 P1
TTN-AS1ENST00000659121.1 linkuse as main transcriptn.416+4890_416+4919del intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes
?
    Genome Aggregation Database, over 76,156 genomes
AF:
0.00000657
AC:
1
AN:
152188
Hom.:
0
Cov.:
33
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:
0.0000147
Gnomad OTH
AF:
0.00
GnomAD4 exome
AF:
0.00000138
AC:
2
AN:
1449270
Hom.:
0
AF XY:
0.00000139
AC XY:
1
AN XY:
719512
show subpopulations
Gnomad4 AFR exome
AF:
0.00
Gnomad4 AMR exome
AF:
0.00
Gnomad4 ASJ exome
AF:
0.00
Gnomad4 EAS exome
AF:
0.00
Gnomad4 SAS exome
AF:
0.00
Gnomad4 FIN exome
AF:
0.00
Gnomad4 NFE exome
AF:
0.00000181
Gnomad4 OTH exome
AF:
0.00
GnomAD4 genome
?
    Genome Aggregation Database, over 76,156 genomes
AF:
0.00000657
AC:
1
AN:
152188
Hom.:
0
Cov.:
33
AF XY:
0.0000135
AC XY:
1
AN XY:
74348
show subpopulations
Gnomad4 AFR
AF:
0.00
Gnomad4 AMR
AF:
0.00
Gnomad4 ASJ
AF:
0.00
Gnomad4 EAS
AF:
0.00
Gnomad4 SAS
AF:
0.00
Gnomad4 FIN
AF:
0.00
Gnomad4 NFE
AF:
0.0000147
Gnomad4 OTH
AF:
0.00
Bravo
AF:
0.00000378

ClinVar

Significance: Likely pathogenic
Submissions summary: Pathogenic:1
Revision: criteria provided, single submitter
LINK: link

Submissions by phenotype

Primary dilated cardiomyopathy Pathogenic:1
Likely pathogenic, criteria provided, single submitterclinical testingLaboratory for Molecular Medicine, Mass General Brigham Personalized MedicineJan 31, 2024The c.99494_99519+4del variant in TTN has been identified in a child with DCM (LMM data). It has also been identified in 0.0003% (3/1172860) of European chromosomes in gnomAD (http://gnomad.broadinstitute.org, v4.0.0). This variant is a 30 base-pair deletion that spans the canonical +1 and +2 positions in the 5' splice site consensus sequence of intron 309 and is therefore expected to disrupt splicing and lead to a truncated or absent protein. TTN truncating variants encoded in constitutive exons (PSI >95%) have been found to be significantly associated with DCM regardless of their position in titin (Roberts 2015 PMID:25589632, Schafer 2017 PMID:27869827). The c.99494_99519+4del variant is located in such a highly expressed exon in the M band. In summary, although additional studies are required to fully establish its clinical significance, this variant meets criteria to be classified as likely pathogenic for autosomal dominant DCM. ACMG/AMP Criteria applied: PVS1_Strong, PM2_Supporting. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction

Splicing

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

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Other links and lift over

dbSNP: rs1553479603; hg19: chr2-179393250; API