Primary lateral sclerosis

Primary Lateral Sclerosis
Other names	PLS
Specialty	Neurology
Types	Primary Lateral Sclerosis (adult-onset), Juvenile Primary Lateral Sclerosis
Differential diagnosis	Amyotrophic Lateral Sclerosis, Multiple Sclerosis

Primary lateral sclerosis (PLS) is a very rare neuromuscular disease characterized by progressive muscle weakness in the voluntary muscles. PLS belongs to a group of disorders known as motor neuron diseases. Motor neuron diseases develop when the nerve cells that control voluntary muscle movement degenerate and die, causing weakness in the muscles they control.

PLS only affects upper motor neurons.^[1] There is no evidence of the degeneration of spinal motor neurons or muscle wasting (amyotrophy) that occurs in amyotrophic lateral sclerosis (ALS).