through clinics affiliated with the Muscular Dystrophy Association. Diagnosis Electrodiagnostic testing Electrodiagnostic testing (also called electrophysiologic) includes nerve conduction studies which involves stimulating a peripheral motor or sensory nerve and recording the response, and needle electromyography, where a thin needle or pin-like electrode is inserted into the muscle tissue to look for abnormal electrical activity. Electrodiagnostic testing can help distinguish myopathies from neuropathies, which can help determine the course of further work-up. Most of the electrodiagnostic abnormalities seen in myopathies are also seen in neuropathies (nerve disorders). Electrodiagnostic abnormalities common to myopathies and neuropathies include; abnormal spontaneous activity (e.g., fibrillations, positive sharp waves, etc.) on needle EMG and, small amplitudes of the motor responses compound muscle action potential, or CMAP during nerve conduction studies. Many neuropathies, however, cause abnormalities of sensory nerve studies, whereas myopathies involve only the muscle, with normal sensory nerves. The most important factor distinguishing a myopathy from a neuropathy on needle EMG is the careful analysis of the motor unit action potential (MUAP) size, shape, and recruitment pattern. There is substantial overlap between the electrodiagnostic findings the various types of myopathy. Thus, electrodiagnostic testing can help distinguish neuropathy from myopathy, but is not effective at distinguishing which specific myopathy is present, here muscle biopsy and perhaps subsequent genetic testing are required. Treatment Currently there is no cure for myotubular or centronuclear myopathies. Treatment often focuses on trying to maximize functional abilities and minimize medical complications, and involvement by physicians specializing in Physical Medicine and Rehabilitation, and by physical therapists and occupational therapists. Medical management generally involves efforts to prevent pulmonary complications, since lung infections can be fatal in patients lacking the muscle strength necessary to clear secretions via coughing. Medical devices to assist with coughing help patients maintain clear airways, avoiding mucous plugs and avoiding the need for tracheostomy tubes. Monitoring for scoliosis is also important, since weakness of the trunk muscles can lead to deviations in spinal alignment, with resultant compromise of respiratory function. Many patients with congenital myopathies may eventually require surgical treatment of scoliosis. Epidemiology The overall incidence of myotubular myopathy is 1 in 50,000 male live births. The incidence of other centronuclear myopathies is extremely rare, with there only being nineteen families identified with CNM throughout the world. The symptoms currently range from the majority who only need to walk with aids, from a stick to a walking frame, to total dependence