Rare neurological diseases (with a prevalence of 5 cases per 100,000 persons) are a large group of disorders that include: changes in development of the nervous system in the absence of known causes (idiopathic) or caused by genetic mutations; forms characterized by degeneration of the nervous system in children or in adults; and infectious and inflammatory processes or mediated by immunological mechanisms (e.g., autoantibodies).
The Istituto Superiore di Sanità (ISS, the National Institute of Health in Italy) studies some of these diseases, including pediatric ataxia, megalencephalic leukoencephalopathy with subcortical cysts, Creutzfeldt-Jakob disease, amyotrophic lateral sclerosis and Rett syndrome.
