Ever heard of it? I nannied this weekend for a three year old (4 in nov) that has been diagnosed with this disorder. Only abnormal developments I observed were that he was probably at 18 months give or take verbally and he would shake hands at side when very excited. Parents told me they say he's autistic to get more cooperation from the medical community.
(I won't touch on the fact that this family's house was a complete disaster- disguistingly dirty, this child had no scheule, routine, or discipline. I don't think a normal child would have progressed in this home let alone one with special needs. But, I wanted to just ask ya'll about PDD, because I hadn't heard of it.)