Spastic ataxia

Spastic ataxia (Orphanet code 316226) is a clinical grouping term that encompasses a spectrum of rare neurological disorders characterized by the combined presence of both spasticity (increased muscle tone and stiffness due to upper motor neuron dysfunction) and cerebellar ataxia (impaired coordination and balance due to cerebellar dysfunction). These conditions affect the central nervous system, primarily involving the corticospinal tracts (which control voluntary movement) and the cerebellum (which coordinates movement and balance). The combination of spastic paraplegia and cerebellar ataxia reflects overlapping neurodegeneration in these two motor systems. Patients with spastic ataxia typically present with progressive difficulty walking due to both stiffness and unsteadiness, impaired coordination of limbs, dysarthria (slurred speech), abnormal eye movements such as nystagmus, and hyperreflexia with extensor plantar responses. Additional features may include peripheral neuropathy, cognitive impairment, urinary dysfunction, and skeletal deformities depending on the specific genetic subtype. The severity and age of onset vary considerably across the different subtypes grouped under this umbrella term. Spastic ataxia includes multiple genetic subtypes with both autosomal recessive and autosomal dominant inheritance patterns, involving various genes such as MARS2 (SPAX3), KIF1C (SPAX2/SAX2), MTPAP (SPAX4), and AFG3L2 (SPAX5), among others. Charlevoix-Saguenay type spastic ataxia (ARSACS, caused by SACS gene mutations) is one of the best-characterized forms. There is currently no curative treatment for spastic ataxias. Management is supportive and symptomatic, including physical therapy, occupational therapy, antispasticity medications (such as baclofen or tizanidine), speech therapy, and assistive devices for mobility. Genetic counseling is recommended for affected families.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

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