TTN and cardiomyopathy: Interestingly, only 1 patient (1%) had a likely pathogenic variant in one of the causative MVP genes (DCHS1), but in 8 probands (8%) a likely pathogenic variant in four cardiomyopathy genes was observed (DSP, HCN4, MYH6 and TTN), suggesting a common genetic foundation in the development of both myocardial and mitral valve disease.