Mutations in human PLB are known to cause familial cardiomyopathies; in particular there have been identified two mutations that result in dilated cardiomyopathy (DCM), the variants PLB R9C (a substitution of residue Arg9 for Cys), and PLB R14Δ (a deletion of residue Arg14) [16]–[18]. The gene discussed is PLN; the disease is familial cardiomyopathy.