Total submissions: 3
| Submitter | RCV | SCV | Clinical significance | Condition | Last evaluated | Review status | Method | Comment |
|---|---|---|---|---|---|---|---|---|
| Invitae | RCV000465555 | SCV000542721 | likely pathogenic | Dilated cardiomyopathy 1G; Autosomal recessive limb-girdle muscular dystrophy type 2J | 2023-12-11 | criteria provided, single submitter | clinical testing | This sequence change creates a premature translational stop signal (p.Cys15052*) in the TTN gene. While this is not anticipated to result in nonsense mediated decay, it is expected to create a truncated TTN protein. This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with TTN-related conditions. ClinVar contains an entry for this variant (Variation ID: 404904). This variant is located in the I band of TTN (PMID: 25589632). Truncating variants in this region have been reported in individuals affected with autosomal recessive centronuclear myopathy (PMID: 23975875). Truncating variants in this region have also been identified in individuals affected with autosomal dominant dilated cardiomyopathy and/or cardio-related conditions (PMID: 27869827, 32964742). In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. |
| Gene |
RCV001547474 | SCV001767188 | likely pathogenic | not provided | 2021-08-03 | criteria provided, single submitter | clinical testing | Has not been previously published as pathogenic or benign to our knowledge; Not observed in large population cohorts (Lek et al., 2016); Nonsense variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss-of-function is a known mechanism of disease; Located in one of the constitutive exons in the I-band region. Studies suggest that truncating variants affecting constitutive exons throughout the TTN gene are significantly associated with DCM (Deo, 2016; Schafer et al., 2017) |
| Ambry Genetics | RCV002402234 | SCV002714539 | likely pathogenic | Cardiovascular phenotype | 2020-07-29 | criteria provided, single submitter | clinical testing | The p.C5987* variant (also known as c.17961T>A), located in coding exon 72 of the TTN gene, results from a T to A substitution at nucleotide position 17961. This changes the amino acid from a cysteine to a stop codon within coding exon 72. This exon is located in the I-band region of the N2-B isoform of the titin protein and is constitutively expressed in TTN transcripts (percent spliced in or PSI 100%). This alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. While truncating variants in TTN are present in 1-3% of the general population, truncating variants in the A-band are the most common cause of dilated cardiomyopathy (DCM) (Herman DS et al. N. Engl. J. Med., 2012 Feb;366:619-28; Roberts AM et al. Sci Transl Med, 2015 Jan;7:270ra6). TTN truncating variants encoded in constitutive exons (PSI >90%) have been found to be significantly associated with DCM regardless of their position in titin (Schafer S et al. Nat. Genet., 2017 01;49:46-53). As such, this alteration is classified as likely pathogenic. |