In these diseases, the motor neurons that control voluntary movement break down and die, which causes problems with walking, speech, swallowing, arm and hand movement and, in some cases, breathing. The cause of these disorders is unknown, and in 90% of cases there is no family history. Currently, there is no cure and treatment is symptomatic.

These diseases are extremely rare, meaning they affect fewer than 30,000 people. PLS is the rarest of all. Aggressive estimates put the global incidence rate at 3000 individuals; conservative estimates have it at 1500. Because of this, funding for research is limited and raising those funds is left to individuals with the disease and patient groups or private foundations like the Spastic Paraplegia Foundation (SPF).

For more information, go to:
http://www.ninds.nih.gov/disorders/motor_neuron_diseases/
motor_neuron_diseases.htm


http://www.ninds.nih.gov/disorders/primary_lateral_sclerosis/
primary_lateral_sclerosis.htm


http://www.ninds.nih.gov/disorders/hereditary_spastic_paraplegia/
hereditary_spastic_paraplegia.htm