Inclusion Criteria:

• All groups of patients eligible to participate to the Observatoire Français de la Sclérose en Plaque (OFSEP), including :
• Definite Multiple sclerosis (MS) according to McDonald criteria
• Whatever the clinical course (single attack MS, relapsing-remitting MS, secondary progressive MS, primary progressive MS)
• Radiologically Isolated Syndromes (RIS) (will be validated by the RIS expert group)
• Clinically Isolated Syndromes (CIS)
• Neuromyelitis optica (NMO) and NMO spectrum disorders (will be validated by the "Neuro-optico-myélite aiguë de Devic et des syndromes neurologiques apparentés" (NOMADMUS) expert group)
• No age limit (patients under the age of 18 might be included, provided informed consent is obtained from the parents)
• Ongoing pregnancy: there will be no limit in the gestational age at inclusion. Women can be included at any time before delivery, but the gestational age at inclusion will be recorded and introduced in the analyses whenever pertinent. However, neurologists and patients will be encouraged to start the study as soon as pregnancy is diagnosed.
• Able to give informed consent
• Able to read and/or understand French

Exclusion Criteria:

• None