Faith Kasparian, age 14, of Hattiesburg, Miss., for her question:

WHAT CAUSES MULTIPLE SCLEROSIS?

Multiple sclerosis is a disease that attacks the brain and spinal cord. The cause of the disease is not known. No cure for the disease has as yet been found.

The disease, sometimes called MS, strikes people between the ages of 20 and 40 most of the time. With the disease can come loss of sight or double vision, hand tremors, weakness of the arms and legs, tingling or numbness or pain, a slurring of speech and the loss of control over some body functions.

The symptoms sometimes show up and then disappear after only a short time. Then, often for many years, the symptoms show up and then disappear again time after time. Eventually the symptoms stay for longer periods of time. The person often becomes weaker and more clumsy as time goes on.

Sometimes the disease is slowly progressive instead of being intermittent and relapsing.