Christina Applegate multiple sclerosis diagnosis: What are the warning signs?

Actress Christina Applegate revealed a recent multiple sclerosis diagnosis to fans on Monday, but what is the chronic disease and what are the warning signs?

MS is a chronic autoimmune disease without a cure, and while the cause is unknown, it is believed to be a combination of environmental and genetic factors. The disease is unpredictable and can manifest differently in each patient depending on the extent of nerve damage; while some see a mild course of disease, others can lose their ability to walk and speak. When patients are diagnosed, about 90% will have a so-called relapsing-remitting form of disease defined by symptoms like fatigue, numbness, tingling, blurred vision and weakness lasting for days or weeks before partially resolving.