Understanding Autism -- the Basics
What Is Autism? continued...
Autism is just one syndrome that now falls under the heading of autism spectrum disorders. Disorders that are now classified as either ASD or a social communication disorder include:
Autistic disorder. This is what most people think of when they hear the word "autism." It refers to problems with social interactions, communication, and imaginative play in children younger than 3 years.
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 behaviors but who don't fit into other categories.
Childhood disintegrative disorder. These children develop normally for at least two years and then lose some or most of their communication and social skills. This is an extremely rare disorder and its existence as a separate condition is a matter of debate among many mental health professionals.
previously fell under ASD spectrum but it is now confirmed that Rett’s cause is genetic. It no longer falls under ASD guidelines. Children with Rett syndrome, primarily girls, start developing normally but then begin losing their communication and social skills. Beginning at the age of 1 to 4 years, repetitive hand movements replace purposeful use of the hands. Children with Rett syndrome are usually severely cognitively impaired.
What Causes Autism?
Because autism runs in families, most researchers think that certain combinations of genes may predispose a child to autism. But there are risk factors that increase the chance of having a child with autism.
Advanced age of the mother or the father increases the chance of an autistic child.
When a pregnant woman is exposed to certain drugs or chemicals, her child is more likely to be autistic. These risk factors include the use of alcohol, maternal metabolic conditions such as diabetes and obesity, and the use of antiseizure drugs during pregnancy. In some cases, autism has been linked to untreated phenylketonuria (called PKU, an inborn metabolic disorder caused by the absence of an enzyme) and rubella (German measles).