This gene encodes a 134 kDa protein named strumpellin that is predicted to have multiple transmembrane domains and a spectrin-repeat-containing domain. This ubiquitously expressed gene has its highest expression in skeletal muscle. The protein is named for Strumpell disease\; a form of hereditary spastic paraplegia (HSP). Spastic paraplegias are a diverse group of disorders in which the autosomal dominant forms are characterized by progressive, lower extremity spasticity caused by axonal degeneration in the terminal portions of the longest descending and ascending corticospinal tracts. More than 30 loci (SPG1-33) have been implicated in hereditary spastic paraplegia diseases.