This information is provided by the National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD).
Primary lateral sclerosis (PLS) is a rare neuromuscular disease that affects the nerve cells that control the voluntary muscles. Problems in the legs (such as weakness, stiffness, spasticity, and balance problems) are often observed first, but hand clumsiness and changes in speech can be early symptoms, as well. The condition is progressive (gradually becomes worse over time); however, affected people have a normal life expectancy. The underlying cause of adult PLS is currently unknown. In most cases, it occurs sporadically in people with no family history of the condition. A subtype of PLS, called juvenile PLS, is caused by changes (mutations) in the ALS2 gene and is inherited in an autosomal recessive manner. Treatment is based on the signs and symptoms present in each person.
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