Mondo Description Autosomal recessive spastic paraplegia type 21 is a complex type of hereditary spastic paraplegia characterized by an onset in adolescence or adulthood of slowly progressive spastic paraparesis associated with the additional manifestations of apraxia, cognitive and speech decline (leading to dementia and akinetic mutism in some cases), personality disturbances and extrapyramidal (e.g. oromandibular dyskinesia, rigidity) and cerebellar (i.e. dysdiadochokinesia and incoordination) signs. Subtle abnormalities (e.g. developmental delays) may be noted earlier in childhood. A thin corpus callosum and white matter abnormalities are equally reported on magnetic resonance imaging.

Uniprot Description A form of spastic paraplegia, a neurodegenerative disorder characterized by a slow, gradual, progressive weakness and spasticity of the lower limbs. Rate of progression and the severity of symptoms are quite variable. Initial symptoms may include difficulty with balance, weakness and stiffness in the legs, muscle spasms, and dragging the toes when walking. In some forms of the disorder, bladder symptoms (such as incontinence) may appear, or the weakness and stiffness may spread to other parts of the body. SPG21 is associated with dementia and other central nervous system abnormalities. Subtle childhood abnormalities may be present, but the main features develop in early adulthood. The disease is slowly progressive, and cerebellar and extrapyramidal signs are also found in patients with advanced disease. Patients have a thin corpus callosum and white-matter abnormalities.

Disease Ontology Description A hereditary spastic paraplegia associated with dementia.