Individuals with AS show evidence of delayed development by 6–12 months of age. Eventually, this delay is recognized as severe mental retardation. Unlike some genetic conditions causing severe mental retardation, AS is not associated with developmental regression (loss of previously attained developmental milestones).
Severe speech impairment is a striking feature of AS. Speech is almost always limited to a few words or no words at all. However, receptive language skills (listening to and understanding the speech of others) and non-verbal communication are not as severely affected.
Individuals with AS have a balance disorder, causing unstable and jerky movements. This typically includes gait ataxia (a slow, unbalanced way of walking) and tremulous movements of the limbs.
AS is also associated with a unique "happy" behavior, which may be the best-known feature of the condition. This may include frequent laughter or smiling, often with no apparent stimulus. Children with AS often appear happy, excited, and active. They may also sometimes flap their hands repeatedly. Generally, they have a short attention span. These characteristic behaviors led to the original name of this condition, the "Happy Puppet" syndrome. However, this name is no longer used as it is considered insensitive to AS individuals and their families.
Jennifer Ann Roggenbuck MS, CGC, Thomson Gale, Gale, Detroit,