The diverse group of neurodegenerative disorders known as hereditary spastic paraplegia (HSP) is characterized by spasticity and weakness of the bilateral lower extremity due to degeneration of the corticospinal tract. The pathogenesis of HSP is broad, with autosomal dominant, autosomal recessive, X-linked recessive, mitochondrial inheritance, and de novo mutations reported, along with remarkable heterogeneity of mutations and clinical presentation. Of these, the most common subtype of HSP is HSP type 4 (HSP-