| A form of hereditary spastic paraplegia with high intrafamilial clinical variability. Characterized in most cases as a pure phenotype with an adult onset (mainly the third to fifth decade of life, but that can present at any age) with progressive gait impairment due to bilateral lower-limb spasticity and weakness as well as very mild proximal weakness and urinary urgency. In some cases, a complex phenotype is also reported with additional manifestations including cognitive impairment, cerebellar ataxia, epilepsy and neuropathy. A faster disease progression is noted in patients with a later age of onset. Caused by mutations in the SPAST gene (2p24-p21), encoding spastin. |
