Abstract
Psychiatric diagnosing in mentally retarded patients is notoriously difficult and routine application of current taxonomies is of very limited use. Although psychotic disorders in general can be satisfactory grouped on a descriptive level, the aetiology is most probably very heterogeneous. In this case report a female patient is described who presented with mild mental retardation and recurrent affective psychotic episodes. Chromosome analysis showed a female karyotype with a de novo translocation (2;10)(p23;q22.1). Biochemical evaluation demonstrated a persistently increased taurine and decreased methionine in plasma, suggesting a disturbed one-carbon metabolism. Treatment with risperidone in combination with valproic acid resulted in prevention of further relapses and stabilisation of mood. An imbalance of chromosomes 2 and 10 was excluded by array CGH. A disruption of the PCBD gene could not be demonstrated by FISH.
