Progressive multifocal leukoencephalopathy (PML) is a rare disorder that damages the material (myelin) that covers and protects nerves in the white matter of the brain.

PML

The JC virus (JCV) causes PML. By age 10, most people have been infected with this virus, but it hardly ever causes symptoms.

Anyone with a weakened immune system, however, are at greater risk of developing PML. Causes of a weakened immune system include:

• AIDS (less common now because of better AIDS treatments)
• Certain medications used to treat multiple sclerosis, rheumatoid arthritis, and related conditions
• Leukemia and lymphoma

Images

Gray and white matter of the brain

Leukoencephalopathy

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Progressive multifocal leukoencephalopathy Symptoms

Review Date: 02/06/2010
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; Luc Jasmin, MD, PhD, Department of Neurosurgery at Cedars-Sinai Medical Center, Los Angeles, CA, and Department of Anatomy at UCSF, San Francisco, CA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org)