Polyoma nephropathy and progressive multifocal leukoencephalopathy in a renal transplant recipient.

Progressive multifocal leukoencephalopathy is a progressive and ultimately fatal white-matter disease of the brain that is associated with polyomavirus infection. It is uncommon in the general population, and even in the immunosuppressed patient, who is inherently at greatest risk for active infection with the virus, it is rare. The causative agent in progressive multifocal leukoencephalopathy, JC virus, has become increasingly important in recent years as its role in nephropathy in the renal transplant recipient has become better understood. We present a young renal transplant patient who developed nephropathy with renal biopsy changes consistent with polyomavirus lesions and then developed mental status changes and was diagnosed with progressive multifocal leukoencephalopathy.