Most autism spectrum disorders are characterized by marked difficulties in social interactions, challenges involving communication or the functional and social use of language, and atypical or repetitive behaviors.
Pervasive Developmental Disorder: Commonly called PDD or atypical autism, this type of autism is generally given to children who have autistic symptoms but do not fit well within the other categories.
Inherited conditions include too many or too few teeth, too much or too little space between teeth, irregular mouth and jaw size and shape, and atypical formations of the jaws and face, such as a cleft palate.
Although each person experiences autism differently, the atypical autism symptoms generally focus on the three areas of impairment - social skills, language development and imaginative expression.
Additional disorders that fall under the autism umbrella term are Rett syndrome, Asperger syndrome, and pervasive developmental disorder not otherwise specified (PDD-NOS) or atypical autism.