• Autistic disorder is a complex genetic disorder. Genetic studies suggest that autistic disorder is caused by a combination of genetic and environmental factors. Genetic models predict that in any given individual with idiopathic autistic disorder, between 2 and 15 genes may be interacting with each other or environmental factors to cause autistic disorder. There may be as many as 30 different genes that contribute to autistic disorder in different individuals.

Asperger Disorder
Individuals with Asperger disorder do not have a delay in spoken language development, but can have serious deficits in social and communication skills.

Pervasive Developmental Disorder Not Otherwise Specified (PDD/NOS)
Is a diagnosis often considered for children who show some signs of autistic disorder, but who do not meet the specific diagnostic criteria for the other PDDs.

Rett Disorder
Rett disorder is among the most common genetic cause of profound intellectual and physical disability in girls, occurring more commonly than 1 in 10,000 female births.

Childhood Disintegrative Disorder
Children with childhood disintegrative disorder develop normally for a relatively prolonged period before developing a condition that resembles autistic disorder.