Cardiac and skeletal myopathies: can genotype explain phenotype?

The inherited muscle diseases, skeletal muscle nemaline myopathy and cardia c muscle hypertrophic myopathy (HCM) have been recognised for decades. Rece ntly it has become apparent that mutations in almost any protein component of the sarcomere could cause myopathy. Thus changes in many sarcomeric prot ein genes can produce a common phenotype. Several recent publications indic ate the opposite property: mutations in one sarcomeric protein can produce different muscle disease phenotypes. The most dramatic example of this prop erty is actin, mutations in which are associated with hypertrophic cardiomy opathy, dilated cardiomyopathy, nemaline myopathy and actin myopathy.