Neuromuscular disorders represent a broad range of conditions that involve dysfunction of peripheral nerves, muscles or the communication between them. This most often results in muscle weakness, muscle atrophy (loss) and disturbance of sensation (like numbness and tingling). Neuromuscular disorders can cause other symptoms as well, depending on the type. 

Types of neuromuscular disorders

There are several subgroups of neuromuscular disorders based on the area of dysfunction, with several types of conditions in each subgroup.

A neuromuscular disorder represents any condition that affects the structure and/or function of any component of your neuromuscular system, including:

• Anterior horn cells.
• Nerve roots (including dorsal root ganglia).
• Plexuses (like the brachial plexus and lumbosacral plexus).
• Peripheral nerves.
• Neuromuscular junction.
• Muscle fibers.

Symptoms of neuromuscular disorders

Symptoms of neuromuscular disorders vary based on the specific type. But in general, muscle-related symptoms may include:

• Muscle weakness.
• Muscle atrophy (loss).
• Muscle twitches (fasciculations), cramps or spasms.
• Muscle pain.
• Spasticity.
• Difficulty walking.
• Issues with coordination and balance.
• Drooping eyelids or other facial features.
• Difficulty speaking due to tongue weakness or weakness of other oral or facial muscles (dysarthria).
• Difficulty swallowing (dysphagia) due to throat (pharynx) muscle weakness.
• Difficulty breathing due to diaphragm muscle weakness.

Other symptoms may include:

• Fatigue.
• Numbness.
• Tingling or other abnormal sensations (paresthesia).

What causes neuromuscular disorders ?

Neuromuscular disorders have many different causes. But a some of them are genetic. This means that you inherited the genes from your biological parents, or a genetic mutation (change) happened randomly. A neuromuscular disorder may result from an error in a single gene or several genes.

Some neuromuscular disorders are autoimmune diseases. Others are a result of an injury, nutritional or metabolic disturbance, toxin exposure or inflammation. Sometimes, there's no known cause.