Fifty-nine cases with infantile autism/autistic disorder were subclassified 
according to associated medical condition (fragile-X, tuberous sclerosis, 
neurofibromatosis, hypo-melanosis of Ito, Moebius syndrome, Rett syndrome, and a 
'new' syndrome associated with a marker chromosome). It was concluded that, even 
within a group of cases fitting currently accepted criteria for autism, there is 
considerable variation in symptom profile depending on the exact type of 
associated medical condition.