Induced shift in myosin heavy chain expression in myosin myopathy by endurance training

We recently described a new autosomal dominant myopathy (OMIM #605637) associated with a missense mutation in the myosin heavy chain (MyHC) IIa gene (MYH2), which encodes for the fast myosin isoform that is expressed in type 2A muscle fibers. There was a correlation between muscle pathology and expression of MyHC IIa. Low expression of the mutation was associated with a milder phenotype. Since physical activity influences MyHC isoform expression in normal individuals, we investigated whether endurance training can alter the expression of MyHC isoforms in patients with the MYH2 mutation.