Hyperasparaginemia in a schizophrenic patient.

A man with a chronic schizophrenia-like psychotic disorder had fasting plasma asparagine concentrations that were consistently 4 to 8 SD above the normal level. Asparagine levels were also high in his cerebrospinal fluid (CSF) and erythrocytes. Ornithine, proline, and glutamate concentrations were irregularly high in fasting plasma, and gamma-aminobutyric acid (GABA) concentrations were elevated in CSF. Whether or not these biochemical abnormalities were related to the psychotic disorder is unclear. However, increased asparagine concentrations, possibly due to an enzymatic deficiency of asparaginase, could lead to deregulation of polyamine biosynthesis and to excessive production of GABA from putrescine. These biochemical changes could in turn cause disordered brain function. A search in mentally ill patients for metabolic abnormalities involving asparagine, or other amino acids, might hasten elucidation of the biochemical basis of the schizophrenias.