Multiple sclerosis is an autoimmune disease where the immune system attacks the protective myelin sheathing around nerve cells in the brain and spinal cord. This damage to myelin interrupts signals from the brain and causes various symptoms such as fatigue, numbness, vision problems, and more. There are four types of multiple sclerosis and while it is not usually fatal, it can cause disability. The causes of MS involve both genetic and environmental factors such as genetics, infectious agents like Epstein-Barr virus, low vitamin D levels, and smoking. Currently there is no cure for MS but treatments can help reduce relapses and manage symptoms.