happy-puppet syndrome

[ hăpē-pŭpĭt ]

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® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.