A<unk>  (Including atypical autism) <unk>  is one of the four autistic disorders (AD) in the DSM-5 and also was one of the five disorders classified as a<unk>  developmental disorder (PDD) in the DSM-IV. According to the DSM-4,<unk>  is a diagnosis that is used for "severe or<unk>  impairment in the development of reciprocal social interaction and/or verbal and nonverbal communication skills, or when stereotyped behavior, interests, and/or activities are present, but the criteria are not met for a specific PDD" or for several other disorders.<unk>  includes atypical autism, because the criteria for autistic disorder are not met, for instance because of late age of onset, atypical symptomatology, or subthreshold symptomatology, or all of these. Even though<unk>  is considered milder than typical autism, this is not always true. While some characteristics may be milder, others may be more severe.
Pervasive developmental disorder not otherwise specified
Multiple complex developmental disorder
Zellweger spectrum disorders
Zellweger syndrome
Asperger syndrome
Childhood schizophrenia
Childhood disintegrative disorder
Tardive dysmentia