These abilities include things like memorizing huge amounts of information, a great musical or art ability, or counting thousands of something accurately in seconds. The official cause of autism is still unknown but a variety of things seem to be related. Prenatal causes include diseases to the mother such as rebulla, tuberous sclerosis, and Cornelia de Lange's syndrome. Chromosomal abnormalities like Fragile X, Angelman's syndrome, and Down's Syndrome can also be prenatal causes of autism. A final prenatal abnormality that can cause autism is a problem in the brain such as hydrocephalus.
Research shows that perinatal effects have very little if any effect on the development of autism.
Postnatal problems that can cause autism are untreated phenylketonuria, infantile spasms, herpes, or a focal brain lesion. For these to lead to autism, they must occur right after birth. None of these problems are considered unique to autism. One part of autism that is being researched currently has to do with the effect of having a fever on a child who is autistic. For reasons that are currently unknown, autistic children appear, to on occasions, be normal when they have a high fever.