Autism is a developmental brain disorder characterized by impaired social interactions, communication problems, and repetitive behaviors. Symptoms usually appear before the age of three. The exact cause of autism is not known, however, it is likely influenced by genetics. Autism is one of a group of related developmental disorders called autism spectrum disorders (ASDs). Other ASDs include Asperger syndrome and Rett syndrome.
Autism is a developmental disorder that usually has onset in the first two or three years of life. It's characterized by problems in social interactions, particularly in communicating with other people, and is often also accompanied by various repetitive behaviors such as flapping of the hands. The exact cause of autism is not known, and partly that's because autism is probably not one specific condition but a family of conditions that have this similar kind of symptom. The role of genetics in autism is also, therefore, not clear, but it is clear that genes play a significant role in the causation of at least a fair bit of autism. There are some specific syndromes where conditions we know that can cause autism, but in most cases of autism we really don't understand the underlying cause. We know that autism in general happens more frequently in boys than in girls, but it can certainly be seen in boys and girls. The term autism was first used in the 1940s to describe a group of a handful of kids who were noticed to have sort of what was described as auto, and therefore self-centered, behaviors because they weren't really interacting with others in their environment very well. It was coined by a child psychiatrist at Johns Hopkins named Leo Kanner. I have to note one of Leo Kanner's other contributions, I hope, to science is that he introduced my parents to each other, so without the father of autism I wouldn't be here today myself.