Chorea and developmental regression associated with human herpes virus-6 encephalitis.

We report a 14-month old child with multiple episodes of febrile status epilepticus, followed by chorea and developmental regression, caused by human herpes virus-6 encephalitis. Chorea has been described as a complication of relapsing herpes simplex virus I infection, but not as a manifestation of human herpes virus-6 infection. It is uncertain whether the chorea was an autoimmune phenomenon or a direct effect of the virus.