Six-year-old Ryan Ravellette is a happy and sociable child; he has a smile that can light up a room.
But his beaming smile both belies and reveals a genetic condition that will affect him for the rest of his life -- and make normal communication all but impossible for the upbeat little boy.
Ryan is one of a few thousand children in the United States who has Angelman syndrome, a condition associated with severe cognitive and developmental disorders, as well as seizures.
What sets this condition apart from many others is the unusually cheerful, gregarious disposition of the children who have it. This characteristic, along with the syndrome's effects on coordination, has earned it the nickname "happy puppet syndrome."
Ryan's mother Susan says doctors diagnosed her son with the condition in 2003, when he was 19 months old. But even before a formal diagnosis, she says she and her husband knew something was wrong.
"We noticed that he was not progressing like other kids were; he did not sit up when other kids did," she says. "We took that as a pretty serious red flag."
And even since the diagnosis, Ravellette says the condition has presented her family with uncommon hurdles.
"It's a tremendous challenge raising a child with Angelman syndrome, because they will be non-verbal, and there are many cognitive disorders associated with it," she says. "It is a pretty severe syndrome."
In the realm of genetic conditions, Angelman syndrome is a relative newcomer. It was first described as a unique syndrome in 1965 by English physician Dr. Harry Angelman, who, in particular, noted the stiff, jerky gait and absence of speech associated with the condition, as well as the excessive laughter and seizures the children exhibited.
Angelman syndrome researcher Dr. Charles Williams, a professor with the University of Florida department of pediatrics in Gainesville, says the condition is often misdiagnosed.
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