progressive multifocal leukoencephalopathy

noun

: a progressive and often fatal demyelinating disease of the central nervous system that typically affects immunocompromised individuals and that is characterized especially by muscle weakness and loss of coordination with impairments in speech, vision, and cognitive function and that commonly progresses to paralysis and coma

Note: Progressive multifocal leukoencephalopathy is caused by reactivation in the body of a latent virus of the genus Polyomavirus (species JC polyomavirus) which destroys the myelin-producing oligodendrocytes of the central nervous system.