Postoperative psychosis in homocystinuria.

Young homocystinuria patients suffering from lens dislocation frequently have to undergo eye surgery. We describe a 16-year-old girl with mild mental retardation who became psychotic-delirant immediately after the last of three lentectomia operations performed under general thiopental anaesthesia. Because methionine, homocysteine, its oxidation product homocysteate and cysteine are potent glutamate agonists, the disturbance of the sulphur containing amino acid (SCAA) metabolism in homocystinuria patients may alter the function of cerebral glutamatergic transmission. The chronic and acute neurological and psychiatric symptoms of homocystinuria patients offer a clue to studies of the neurotoxic but also antipsychotic potency of glutamate agonists like the SCAAs in humans.