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.
"It is rarely diagnosed under 2 years of age by either pediatric neurologists or pediatricians unless that physician for one reason or another knows something about the syndrome," Williams says. He adds that many with the syndrome may not be properly diagnosed until their teen or early adult years, despite the availability of a DNA test that can pick out between 80 and 85 percent of cases.
"I would estimate that about one-half of all children with Angelman syndrome have not been diagnosed at this point."
Eileen Braun, executive director of the Angelman Syndrome Foundation, says that, while her organization's database contains perhaps 1,200 individuals in the U.S. who have the condition, she believes that many more cases are missed.
"Many physicians are not aware of Angelman syndrome, and as a result, are unable to correctly diagnose it," says Braun, whose 18-year-old daughter Kaitlin was diagnosed at 21 months with the condition.
But whether it's properly diagnosed has little effect on the often devastating impact the condition has on parents.
"Probably the first thing they have to face is the reality that this is a condition where communication is going to be difficult -- where it's very unusual for any spoken words to be used in a meaningful way," Williams says. "For the family to adjust to that reality is a tough thing."