The recent implementation of European Reference Networks for Rare Diseases (ERNs) is an unprecedented move to improve the care of patients suffering from rare health disorders by transnational collaboration. ERN-RND, the ERN for Rare Neurological Diseases, oversees more than 35,000 patients in 31 specialist centers in 13 countries. The ERN-RND registry aims to gather information on patient cohorts in the multiple specialist centers and to provide an overview on patient numbers principally accessible for translational studies.

The ERN-RND (European Reference Network on Rare Neurological Diseases) Registry aims to establish a demographic platform for collection of relevant core patient information. This will be accomplished by the construction and implementation of a single data base encompassing all rare neurological diseases in pediatric and adult patients (the ERN-RND Registry), which will collect information according to the "Set of common data elements for Rare Diseases Registration" as it has been defined by the European Commission.

The ERN-RND network covers the following six disease groups in patients of all age groups: (i) Ataxia and Hereditary Spastic Spinal Paralysis (HSP), (ii) Leukodystrophies, (iii) Frontotemporal Dementia, (iv) Dystonia, Paroxysmal Disorders and Neurodegeneration with Brain Iron Accumulation (NBIA), (v) Atypical Parkinsonism and (vi) Huntington's Disease & Choreas.

Inclusion Criteria:

Patients suffering of one of the rare neurological diseases indicated below or probands who are at risk to develop such a disease since they are first degree relatives of patients affected by a RND including:

• Ataxia and HSP
• Leukodystrophies
• Frontotemporal Dementia
• Dystonia, Paroxysmal Disorders and Neurodegeneration with Brain Iron Accumulation (NBIA)
• Atypical Parkinsonism
• Huntington's Disease & Choreas

Exclusion Criteria:

• Missing informed consent of the patient and/ or their parents

Patients suffering of one of the rare neurological diseases indicated according to the inclusion criteria or probands who are at risk to develop such a disease since they are first degree relatives of patients affected by a RND. Patients visiting in Tübingen, Germany the specialist center Department of Neurology and/ or the Department of Neuropediatric Diseases at the University Hospital.

The full pseudonymised dataset will be exported once a year as an Excel file that is made accessible in an encrypted form to the coordinators of each specialist center who contribute to the ERN-RND registry. To this end the encrypted dataset will be provided in a specific folder of the Hertie Institute for Clinical Brain Research Tübingen, Germany (HIH) cloud for a limited amount of time (one week). Coordinators of all ERN-RND health care providers will get access to this folder to download the encrypted file. In addition, they will receive a password that enables decryption of the file. Each coordinator needs to confirm a priori with its local institutional review board the issues of data storage. This is part of the local project plan, patient information and consent that is premise for data entry. This procedure enables each center who contributes data to consider studies of their special interest within the ERN.

Data will become available after analysis and unlimited.

Authorized users within the participating organizations.