Muscle weakness, stiffness, spasms and cramps are the primary symptoms of neuromuscular myopathies, which are disorders characterized by a dysfunction of muscle fiber, according to the National Institute of Neurological Disorders and Stroke. Muscular dystrophy, a form of myopathy, causes progressive muscle weakness and is commonly diagnosed early in life.
Various forms of muscle disease may impact different muscle groups, and symptoms can be as severe as paralysis, according to MedlinePlus. Causes of muscle disorders include genetic disorders, injury and overuse, inflammation, nerve diseases, and certain forms of cancer. In some cases, the cause is unknown.
Symptoms of Duchenne muscular dystrophy include frequent falls, trouble running and jumping, a waddling gait, enlarged calf muscles, and a tendency to walk on the toes, according to Mayo Clinic. Duchenne muscular dystrophy is the most common form of muscular dystrophy and often occurs in children as early as ages 2 and 3. Other forms of muscular dystrophy include Becker, myotonic, congenital, limp-girdle and facioscapulohumeral, also referred to as FSHD.
Congenital myopathy is a group of disorders that appears during infancy, usually the result of genetic defects, states Mayo Clinic. Curvature of the spine, weak bones, hip problems and trouble feeding and breathing are common signs of congenital myopathy. Physical therapy is used to treat the condition, as well as speech therapy, nutritional support, occupational therapy and assisted breathing. As of 2015, there is no cure for congenital myopathy.