GAA and facioscapulohumeral muscular dystrophy: Selective type II fiber degeneration has been previously reported in other myopathies such as Duchenne muscular dystrophy, facioscapulohumeral muscular dystrophy, myotonic dystrophy type 226 as well as in the alpha-glucosidase knock-out mouse model that mimics the late-onset form of Pompe disease27,28.