Demyelinating Diseases In Brief

Demyelinating diseases are those in which myelin is the primary target. They fall into two main groups: acquired diseases (i.e., multiple sclerosis) and hereditary neurodegenerative disorders (i.e., the leukodystrophies). Although their causes and etiologies are different, they have the same outcome: CNS demyelination. Without myelin, nerve impulses are slowed or stopped, leading to a constellation of neurological symptoms.

Acquired Diseases

The most common of these is multiple sclerosis (MS), which usually manifests itself between the 20th and 50th years of life. Current estimates are that approximately 2.5 million people worldwide have MS, with between 250,000 and 350,000 cases in the United States, 50,000 cases in Canada, 130,000 cases in Germany, 85,000 cases in the United Kingdom, 75,000 cases in France, 50,000 cases in Italy, and 11,000 cases in Switzerland.

MS attacks the white matter of the central nervous system (CNS). In its classic manifestation (90% of all cases), it is characterized by alternating relapsing/remitting phases with periods of remission growing shorter over time. Its symptoms include any combination of spastic paraparesis, unsteady gait, diplopia, and incontinence.