Autism: the paediatric neurologist's tale.

Neurologists use the term 'autistic' to describe a quality of social behaviour and communication rather than 'autism' as a diagnosis. It has an organic basis and is commonly, and increasingly, found to be associated with specific medical diagnoses. Epilepsy is as common as in severely mentally handicapped children but whereas in the latter it is often evident in the early years it commonly emerges in adolescence in autistic children. There is a genetic component to autism and in the absence of a specific diagnosis an empirical recurrence risk of 1-2% is given. Fragile-X chromosome disorder is a relatively common explanation but the investigation is expensive and subject to restriction in spite of the enormous implications for affected families. The male preponderance and the neurological explanation for autism have not yet been explained.