The development of autism may be related to abnormalities in parts of the brain responsible for processing language and sensory information. These abnormalities are caused by genetic errors or faults in fetal development. More investigation is needed as far as if environmental triggers can cause autistic behavior in autistic patients. Some studies show an over abundance or lack of neurotransmitters in the brain. Genes that control brain cell growth and function may also have defects in autistic children.