Progressive multifocal leukoencephalopathy (PML) is a rare and serious brain infection caused by the JC virus, which typically remains dormant in healthy individuals. It primarily affects people with weakened immune systems, such as those with HIV/AIDS, certain cancers, or those taking immunosuppressive medications. PML leads to the destruction of myelin, the protective covering of nerve fibers, resulting in neurological symptoms. Symptoms of PML can include confusion, weakness, vision problems, and difficulty with coordination. As the disease progresses, it can lead to severe disability and may be life-threatening. There is currently no specific treatment for PML, making early diagnosis and management of underlying conditions crucial.