Causes

• Many neuromuscular disorders have a genetic basis. For example, spinal muscular atrophy is caused by mutations in the SMN1 gene. Its severity is influenced by the number of copies of the similar SMN2 gene. Other causes include viral infections, autoimmune disorders, hormonal disorders, metabolic disorder, dietary deficiencies, certain drugs and poisons. Some neuromuscular disorders have no known cause.
  
  

Action

• Neuromuscular disorders act on the nerves responsible for controlling the body's voluntary muscles. When these nerves become unhealthy and die, the communication between the body's central nervous system and the voluntary muscles is damaged. Muscles that were previously controllable, such as those of the arms and legs. gradually weaken and eventually waste away. During this process, sufferers may experience twitching, cramps, aches and joint problems. In severe cases, neuromuscular disorders can affect the ability to breathe and interfere with the heart's functioning. Disorders may also cause droopy eyelids and double vision.
  
  

Types

• Numerous specific conditions are associated with neuromuscular disorder. These include amyotrophic lateral sclerosis, multiple sclerosis, muscular dystrophy, myasthenia gravis, spinal muscular atrophy, Barth syndrome, congenital myasthenia, congenital myopathy, hereditary spastic paraplegia, hypertonia, Isaac's syndrome, Kearns-Sayre syndrome, Lambert-Eaton myasthenic syndrome, mitochondrial myopathies, myotonia congenita, myotonia, opsoclonus myoclonus, piriformis syndrome, primary lateral sclerosis, spasticity, stiff-person syndrome, thyrotoxic myopathy and Troyer syndrome.
  
  

Onset

• Different conditions appear at different times. Some, such as Emery-Dreifuss muscular dystrophy and Duchenne muscular dystrophy, appear in early childhood. Others, such as dermatomyositis, Lambert-Eaton myasthenic syndrome, Becker muscular dystrophy and Facioscapulohumeral muscular dystrophy appear during adolescence. Those that appear in adulthood include polymyositis, hyperthyroid myopathy and phosphofructokinase deficiency.
  
  

Treatment

• Once the specific condition is identified, treatment may include a course of drugs. Some neuromuscular disorders can be effectively treated with medication. such as immuno-suppressive drugs. Anti-convulsants or anti-depressants may be issued to lessen the severity of some of the disorders' side effects. Physical therapy can help reduce twitching and cramping but cannot halt the progress of conditions. Occupational therapists and counselors can help the sufferers and their families to adapt to the symptoms of the disorder.