[Monoamine and monoamine enzyme abnormalities in childhood autism]

According to monoaminergic hypothesis of psychosis, several symptoms observed in child autism may be related to anomalies of cerebral amines and/or synaptic dysfunctioning. The main amines concerned are serotonin and dopamine which are synthetized and catabolized following similar schemes. Methyl-indolamines production, mentioned in adult schizophrenia, has not been observed in child autism. Similarly, monoaminoxydase diminution has been observed in adults and not in children. Hyperserotoninemia does exist in some cases of child autism. Results concerning dopaminergic systems are more promising. The autistic behavioral syndrome suggests a dopaminergic dysfunctioning. Enhancement of homovanillic acid, the main metabolite of dopamine, has been found both in cerebrospinal fluid and in urines of some autistic children. Moreover, modifications of dopamine-beta-hydroxylase, an enzyme that changes dopamine into noradrenaline, have been mentioned in some cases of autism. A better definition of the autistic clinical syndromes associated with a more systematic study of monoamines plasmatic and urinary derivates will allow, in the near future, a better understanding of child autism and a clearer definition of therapeutic indications.