"Chloe loves people and relationships," says her mom, Johanna. "She can completely change a person's demeanor with one of her incredibly warm, wide smiles."

Now, Chloe's powerful smile is bringing together supporters and scientists to advance research on Williams syndrome, the rare genetic disorder she was born with 11 years ago. Williams syndrome can affect many parts of the body, including the heart and blood vessels. Children with Williams syndrome have mild-to-moderate intellectual disability, distinctive facial features and friendly personalities.

At only 6 weeks old, Chloe underwent open-heart surgery in New York to repair a life-threatening heart defect called supravalvular aortic stenosis — common in children with Williams syndrome. Soon after, Johanna and her husband Marshall switched all of their daughter's care to the Williams Syndrome Clinic at Boston Children's Hospital, which specializes in addressing the complex cardiovascular, physical, developmental and psychosocial challenges that children with Williams syndrome face.

Today, Chloe's days are full of family and friends and lots of smiles. With a steady stream of support from her parents and intervention at school, Chloe has made huge strides developmentally. She enjoys competing in basketball and swimming at the Special Olympics and riding horses — a kind of "real world" physical therapy, explains Johanna.

But her future is unclear. "We don't know what's ahead," says Johanna. "Things could stay the same, get better or worse — there's just such a wide range of outcomes possible." That's why she and Marshall, in collaboration with the Williams Syndrome Association, put together a joint donation to Boston Children's that will help researchers gain a deeper understanding of their daughter's condition and its long-term outcomes, as well as improve care in the near term.

Marshall admits that like many families facing their child's diagnosis, he and Johanna felt helpless at first. "But then you start to understand the condition, and you feel better. And then you meet the right people who are willing and able to do something to help, and you realize that if everyone bands together, we can make a difference."

It all starts with a smile.