Neuromuscular diseases are a heterogeneous group of conditions that affect the voluntary (skeletal) muscles, the peripheral nerves that control them, or the neuromuscular junction. Symptoms may include muscle weakness (progressive or non-progressive), muscle wasting, cramping, stiffness, and impaired heart/lung function. Occasionally, neuromuscular diseases may involve other organ systems such as the brain, cardiovascular, or endocrine system. They may present at any age, from congenital (present at birth) to advanced age.
Genetic neuromuscular diseases are individually rare, but together are estimated to affect 1 in 3,000 individuals. (Laing. (2012), Crit Rev Clin Lab Sci, 49:33-48.)