Brain Res Brain Res Rev 2000 Mar

agents which are capable of cellular infection and subsequent integration into

the host genome.  Retroviruses can exist in an endogenous form in which

viral sequences are integrated into the human germline and are vertically

transmitted in a  Mendelian fashion.  The transcriptional activation

of these viral sequences in cells within the central nervous system can affect

the transcriptional regulation of adjacent genes and result in alterations of

neural functioning.  This report discusses evidence for a possible role of

endogenous retroviruses in the etiopthogenesis of schizophrenia and other human

brain diseases.  Evidence of endogenous retrovirus activity is manifested

by the identification of viral sequences in the brains and cerebrospinal fluids

of affected individuals.  In addition, affected individuals display

evidence of increased activity of virally-encoded reverse transcriptase. 

The identification of a retroviral component of schizophrenia would be

consistent with genetic, environmental, and neurodevelopmental aspects of the

disease process.  The delineation of a role for retroviruses in disease

pathogenesis might lead to new methods for the diagnosis and treatment of