happy-puppet syndrome

hap·py-pup·pet syndrome

(hăp′ē-pŭp′ĭt)
n.
A congenital syndrome of unknown cause that is characterized by mental retardation, ataxic movements, hypotonia, epileptic seizures, prolonged and easily provoked spasms of laughter, prognathism, and an open-mouthed facial expression.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.