Hand flapping

Hand flapping

Flapping of the hands (usually both at once) is one of the most common signs of autism, and also appears in Angelman syndrome and Pitt–Hopkins syndrome, which are not believed to be related to autism. Whether hand flapping in these syndromes fits under a wider definition of stimming is a matter of terminology; the term stereotypy is often used in literature about Angelman syndrome, for example. Hand-flapping is also seen in fragile X syndrome patients; while fragile X syndrome correlates strongly with autism, hand flapping can also be seen in fragile X patients who do not meet the criteria for autism.