DES and myofibrillar myopathy: In patients suspected to have DMD/BMD but genetic testing is negative, a classical skeletal muscle biopsy for western blot and immunohistochemistry studies of dystrophin or genetic testing of more comprehensive neuromuscular diseases such as limb-girdle muscular dystrophy (LGMD), myofibrillar myopathy, desmin-related myofibrillar myopathy, and myotonic dystrophy can be considered [43].