• Scientists have not yet identified the specific inherited causes of autistic disorder. Therefore, it is not possible to test whether an individual's autistic disorder is caused by an inherited trait or whom that trait might have been inherited from. Once the specific genes that contribute to the development of autistic disorder are identified, testing such as this may become available, but it is important to note that in some families multiple genes may be involved, and therefore testing may be quite complicated.

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.