Asperger syndrome is a form of autism characterised by normal or above average intelligence.
The fifth edition of the Diagnostic and Statistical Manual of Mental Disorders, published in 2013, eliminates Asperger syndrome as a formal diagnosis by dissolving it and other subtypes of autism into one diagnosis called autism spectrum disorder.
The 10th edition of the International Classification of Diseases and Related Health Problems, published in 2010, states that Asperger syndrome is
'A disorder of uncertain nosological validity, characterized by the same type of qualitative abnormalities of reciprocal social interaction that typify autism, together with a restricted, stereotyped, repetitive repertoire of interests and activities. It differs from autism primarily in the fact that there is no general delay or retardation in language or in cognitive development. This disorder is often associated with marked clumsiness. There is a strong tendency for the abnormalities to persist into adolescence and adult life. Psychotic episodes occasionally occur in early adult life.'
Please see our detailed entry on Asperger Syndrome