Autism: Basics and Causes
What is autism? What forms of autism are there? When can the first symptoms occur? More in this chapter.
Early childhood autism begins as early as the first three years of life. In some cases, parents notice at the end of their first year that something is wrong. More often, this form of autism is discovered later, in infancy.
The exact cause of autism is not yet fully understood. First, over 100 genes are known that may be related to autism spectrum disorder. That there are so many forms of autism could be due to the fact that there are many different combinations of genetic aberrations that lead to autism.
Atypical autistic individuals do not fit into the typical picture of neonatal autism. Either her autistic behavior does not begin until after the third year of her life - ie later, as it is characteristic of early childhood autism. Or they do not show all the typical symptoms of neonatal autism. Or both.