A person is diagnosed with PDD-NOS (Pervasive Development Disorder Not Otherwise Specificed) often called Atypical Autism, if they have some behaviors seen in autism but don’t meet the full criteria for having an Autistic Disorder.
Not all children with PDD-NOS have the same symptoms. PDD-NOS symptoms can be mild, with the child exhibiting only a few symptoms while in school or at home. Other children may have a more severe form of PDD-NOS and have difficulties in all areas of their lives. (nationalautismresources.com)