| A rare, complex subtype of hereditary spastic paraplegia characterized by variable onset of slowly progressive lower limb spasticity and weakness and prominent cerebellar ataxia, associated with gait disturbances, dysarthria, increased deep tendon reflexes and extensor plantar responses. Additional features may include involuntary movements (i.e. clonus, tremor, fasciculations, chorea), decreased vibration sense, oculomotor abnormalities (e.g. nystagmus) and distal amyotrophy in the upper and lower limbs. |