Pervasive Developmental Disorder is short for Pervasive Developmental Disorder Not Otherwise Specified. That means that a child has characteristics of Autism Spectrum Disorders but doesn’t exactly fit in any of the other categories. He may not be severely enough impaired in communication or social skills to fit Autism. She may not have a special , repetitive interest to fit Asperger’s. Or, the child just may be very young and the person doing the assessment has trouble testing some areas, such as language.

What are these other categories? Besides Asperger’s and Autism, which we have already discussed, there are two more. Both of these disorders are very rare. Both occur following a period of normal development in childhood. The child learns to walk and talk about the same rate as other children, and then something goes terribly wrong. Children with these last two disorders are almost always mentally retarded.

Rett Syndrome – is seen almost solely in girls. It is caused by a defect in the X chromosome. Boys with Rett Syndrome usually die very young. Girls with Rett Syndome develop normally at first. Usually by age four, they will have lost language skills and begin to show unusual behaviors with their hands such as repeated hand-washing or wringing their hands over and over. Girls with Rett Syndrome may also lose motor skills and become unable to walk, although some girls remain able to walk throughout their lives.

Please click here to see a video on Rett Syndrome. SCROLL down to the video RSRF: Urgency, passion, hope.
Click on the video that matches the video system you have on your computer (that is probably Windows Media Player).
RSRF is the Rett Syndrome Research Foundation.

Childhood Disintegrative Disorder – begins after age two. Children who have been toilet-trained, walking and speaking lose those skills. CDD is very rare. What little we know about it is that it is similar to Autism, occurs mostly in boys and children do not usually regain those skills they have lost. There is no cure for CDD, no medication for it and no known cause. Behavioral therapy is effective less often than for children with Autism.