𝐂𝐚𝐬𝐞 𝐬𝐭𝐮𝐝𝐲 𝟏𝟕𝟐 - 𝘗𝘳𝘰𝘨𝘳𝘦𝘴𝘴𝘪𝘷𝘦 𝘮𝘶𝘭𝘵𝘪𝘧𝘰𝘤𝘢𝘭 𝘭𝘦𝘶𝘬𝘰𝘦𝘯𝘤𝘦𝘱𝘩𝘢𝘭𝘰𝘱𝘢𝘵𝘩𝘺⁣ ⁣ Progressive multifocal leukoencephalopathy (PML) is a rare and often fatal viral disease that progressively damages the brain’s white matter in multiple locations. It’s caused by the JC virus (JCV), which is usually inactive and controlled by the immune system. However, in people with weakened immune systems, JCV can develop into PML. PML is progressive, meaning it worsens over time