Multiple sclerosis (MS) is a disease of the central nervous system that can damage myelin sheaths and nerves. It causes problems with vision, balance, muscle control and other functions. In MS, the immune system attacks and damages myelin. Symptoms vary depending on location of nerve damage and include numbness, weakness, vision problems, tingling and fatigue. The cause is unknown but considered autoimmune, with the immune system destroying myelin. Diagnosis involves MRI, lumbar puncture and ruling out other diseases. While there's no cure, treatment focuses on recovery from attacks, slowing progression and managing symptoms.