Mutations in the <i>TCAP</i> gene (OMIM #604488) encoding the Z-disc protein Telethonin associated with a mixed phenotype of hypertrophic and restrictive cardiomyopathy with poor prognosis have not yet been reported.<h4>Case summary</h4>A 47-year-old male presented with heart failure symptoms over a year, which had worsened in the past week. Here, TCAP is linked to restrictive cardiomyopathy.