Adults over 18 with hereditary or sporadic cerebellar degeneration. Sporadic cerebellar degeneration may include the cerebellar predominant variant of Multiple System Atrophy (MSA-C). Hereditary ataxia is limited to the SCAs (spinocerebellar ataxias) or those patients with clear autosomal dominant ataxia. Patients must also have evidence for an immune component to their condition such as gluten-sensitivity or antiganglioside antibodies.