Stereotypy due to Huntington Disease (Q101236)

Repetitive stereotyped voluntary movements in the setting of Huntington Disease, an autosomal dominant disorder caused by a CAG repeat expansion in the huntingtin gene. Movement abnormalities are subtle at first until becoming progressively more pronounced until the entire musculature is implicated with chorea. The frequency of blinking is increased and voluntary protrusion of the tongue, like other attempts at sustained posture, is constantly interrupted by unwanted darting movements.