<p>Multiple sclerosis (MS) is the most common cause of severe disability in young adults in the UK. About one in 800 people have the disorder (Swingler and Compston 1988). Many of these people have partners and young families, so MS affects the lives of tens of thousands of people in this country.</p> <p>The cause of the disease is unknown, and it is incurable. However, recent studies discussed in this article suggest that it may be possible to alter the progression of MS.</p>