Relapsing-remitting multiple sclerosis (RRMS) is a form of multiple sclerosis characterized by episodes of neurological symptoms (relapses) followed by periods of partial or complete recovery (remissions). It is the most common type of multiple sclerosis, affecting approximately 85% of people with the condition. The cause of RRMS is unknown, but it is believed to involve an abnormal immune response that damages the protective covering of nerve fibers, leading to impaired nerve function.