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Disease Profile

Progressive multifocal leukoencephalopathy

Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.


US Estimated

Europe Estimated

Age of onset

All ages





Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.


Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.


dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.


recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.


Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.


Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.


Not applicable


Other names (AKA)

Leukoencephalopathy, progressive multifocal; PML


Viral infections


Progressive multifocal leukoencephalopathy (PML) is a neurological disorder that damages the myelin that covers and protects nerves in the white matter of the brain. It is caused by the JC virus (JCV). By age 10, most people have been infected with this virus, but it rarely causes symptoms unless the immune system becomes severely weakened.[1][2] The disease occurs, rarely, in organ transplant patients; people undergoing chronic corticosteroid or immunosuppressive therapy; and individuals with cancer, such as Hodgkin’s disease, lymphoma, and sarcoidosis. PML is most common among individuals with acquired immune deficiency syndrome (AIDS).[3]


Currently, the best available therapy is reversal of the immune-deficient state. This can sometimes be accomplished by alteration of chemotherapy or immunosuppression. In the case of HIV-associated PML, immediately beginning anti-retroviral therapy will benefit most individuals.[3]

Learn more

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

  • MedlinePlus was designed by the National Library of Medicine to help you research your health questions, and it provides more information about this topic.
  • The National Institute of Neurological Disorders and Stroke (NINDS) collects and disseminates research information related to neurological disorders. Click on the link to view information on this topic.
  • The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.

In-Depth Information

  • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Progressive multifocal leukoencephalopathy. Click on the link to view a sample search on this topic.


  1. Dugdale DC, Jasmin L. Progressive multifocal leukoencephalopathy. MedlinePlus. 2010; https://www.nlm.nih.gov/medlineplus/ency/article/000674.htm. Accessed 3/3/2011.
  2. Koralnik IJ. Progressive Multifocal Leukoencephalopathy. National Organization for Rare Disorders (NORD). 2010; https://www.rarediseases.org/search/rdbdetail_abstract.html?disname=Progressive%20Multifocal%20Leukoencephalopathy. Accessed 3/3/2011.
  3. NINDS Progressive Multifocal Leukoencephalopathy Information Page. National Institute of Neurological Disorders and Stroke (NINDS). 2010; https://www.ninds.nih.gov/disorders/pml/pml.htm. Accessed 3/3/2011.

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