There are how many types of Autism? Usually we call Autism as ASD, which is Autism Spectrum Disorder. This means that it is actually a “spectrum” and you can find different kinds of people along this spectrum, from severe to mild, from low functioning (low IQ) to high functioning (high IQ). Therefore it is very difficult to clearly categorize them into different types.

But there are some other disorders which have similar symptoms as autism, like:

• Asperger's syndrome These children don't have a problem with language -- in fact, they tend to score in the average or above-average range on intelligence tests. But they have the same social problems and limited scope of interests as children with autistic disorder.
• Pervasive developmental disorder or PDD also known as atypical autism. This is a kind of catch-all category for children who have some autistic behaviours but who don't fit into other categories.
• Rett syndrome Known to occur mainly in girls, children with Rett syndrome start developing normally but begin to lose their communication and social skills. Beginning at the age of 1 to 4 years, repetitive hand movements replace purposeful use of the hands.
• Childhood disintegrative disorder This is a very rare condition. These children develop normally for at least two years and then lose some or most of their communication and social skills.