Movements in autistic disorder.

Autistic disorder, an extremely disabling syndrome with onset in early childhood, is associated with multiple comorbid conditions. Although autistic disorder is heterogeneous in its manifestations, there is a subgroup of individuals with autistic disorder who display movements that appear to be unique for the disorders. Hand flapping and a variety of movements termed stereotypies may be pathognomonic of autistic disorder. Therefore, identification of a movement disorder characteristic of autistic disorder may imply that the individual has autistic disorder.