I told my brother that Pervasive Developmental Disorder is not rare, but my brother told me that I have PDD-NOS, and that doesn't mean that I am autistic, and that it's two different things. I so confused right now, because PDD-NOS, Asperger Syndrome, Rett Syndrome and CDD, and Autistic Disorder are forms of Pervasive Developmental Disorder.
My brother even time me that Asperger Syndrome is rare, but I don't think that is true, I think there are people with undiagnosed Asperger Syndrome or just undiagnosed ASD.