<prompt> Age criteria for JRA10 years12 years14 years16 years  <response>: The general rule in that :Myopathies have proximal muscle weakness.Neuropathies have distal muscle weakness.Myotonic dystrophy is an exception to this general rule and mainly involves the distal muscles. Also knowThe difference between myopathy and muscular dystrophy.MyopathyAny skeletal muscle disorder that causes structural changes or functional impairment of muscle. It also includes muscular dystrophies.Muscular dystrophyThe muscular dystrophy means abnormal growth of muscle.It is characterized by -It is a primary myopathy iii Course is progressiveIt has genetic basis iv Degeneration Death of muscle fibers occur at some stage of the diseaseSo, muscular dystrophy is a type of myopathy. 