Total submissions: 2
| Submitter | RCV | SCV | Clinical significance | Condition | Last evaluated | Review status | Method | Comment |
|---|---|---|---|---|---|---|---|---|
| Labcorp Genetics |
RCV000545277 | SCV000642444 | likely pathogenic | Dilated cardiomyopathy 1G; Autosomal recessive limb-girdle muscular dystrophy type 2J | 2020-01-30 | criteria provided, single submitter | clinical testing | This sequence change results in a premature translational stop signal in the TTN gene (p.Ile18867Leufs*30). While this is not anticipated to result in nonsense mediated decay, It is expected to result in a disrupted protein product. For these reasons, this variant has been classified as Likely Pathogenic. This variant is found in the A-band of this gene. While this particular variant has not been reported in the literature, truncating variants in the A-band of TTN are significantly overrepresented in patients with dilated cardiomyopathy and are considered to be likely pathogenic for the disease (PMID: 25589632). This variant has not been reported in the literature in individuals with TTN-related disease. ClinVar contains an entry for this variant (Variation ID: 466642). This variant is not present in population databases (ExAC no frequency). |
| Ambry Genetics | RCV004678743 | SCV005173475 | likely pathogenic | Cardiovascular phenotype | 2024-04-10 | criteria provided, single submitter | clinical testing | The c.29403delC variant, located in coding exon 117 of the TTN gene, results from a deletion of one nucleotide at nucleotide position 29403, causing a translational frameshift with a predicted alternate stop codon (p.I9802Lfs*30). This exon is located in the A-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 variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). 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). Based on the majority of available evidence to date, this variant is likely to be pathogenic. |