Thought to be first described in 1880 by German neurologist Adolf Strumpell, hereditary spastic paraplegia (HSP) is a neurodegenerative disease resulting in degeneration of the spinal cord, primarily the corticospinal tract and dorsal columns. Unlike most other heritable neurological diseases, HSP can be inherited via almost any pattern, though most commonly autosomal dominant. Additionally, mutations in many genes have been implicated on at least 17 chromosomes and > 75 loci. The most common causal mutation is in the SPAST gene located on chromosome 2, producing the most common subtype, SPG4.