This was just after the twins were born and we'd gotten home from the NICU: the phone rang and my husband Tom took the call. A few minutes later, he hung up. There was a dazed expression on his face.

"That was the pediatric cardiologist," Tom said. "He called to tell us the good news. We won't be taking a life flight to Seattle for emergency heart surgery. " He paused, letting the words hang in the air around us. "I didn't know," he said finally, "that such a thing was even a possibility."

I hadn't realized it, either. But there were so many things I was just beginning to understand, then. I thought back to my many ultrasounds with Tally, whose name always made me smile (each week she took a tally of our babies!) and the numerous, grainy black-and-white images of Bennett, the small bones in his back like a tiny string of pearls; or of Avery who, more often than not, was sucking his thumb.

Each measurement--of the bones in each baby's leg, or the width of each head, or the blood pumping through four chambers of each heart, was met with, "Everything looks fine," and despite what eventually followed--the twins' premature delivery and 5 days later, Avery's diagnosis of Down syndrome--I still had faith in those words. Why would anything be wrong with Avery's heart?

As it happens, babies with Down syndrome are 40-50% more likely to be born with a heart defect: some of the conditions are minor, and can be addressed with medication, but others require surgery. Hence, our cardiologist's comment to Tom, which was indeed, good news.

Since that time, I've learned even more things about being mother to a child with Down syndrome. I've learned that one of the more common problems in babies with Down syndrome is called atrioventricular septal defect (AVSD), sometimes called AV canal, a condition that affects the walls between the two upper chambers and the two lower chambers of the heart.

Which is how I came to have, in my hands, a white manila envelope from the Kennedy Krieger Institute, an internationally recognized facility dedicated to improving the lives of children and adolescents with disabilities. And though the institute is located in Baltimore, MD, and we're in Montana, I've agreed to participate in a collaborative research effort designed to help identify genetic and environmental factors related to congenital heart disease in Down syndrome.

My role in this study is minimal: since we don't have any heart issues, we'll be part of the comparison group. I need to fill out a medical questionnaire, and sign some release forms. I need to supply the team with a copy of Avery's karyotype, which is a profile of a person's chromosomes. In Avery's case, it shows 3 genes at the 21st chromosome instead of the usual 2, and was how we confirmed the diagnosis. And the researchers need a copy of the echocardiogram, the one that the cardiologist telephoned Tom about.

In a few weeks, I'll participate in a telephone interview too, answering questions about my medical history and my pregnancies. And Avery will donate 1/5 teaspoon of blood for DNA analysis--this will be, in fact, the most difficult part. Avery has his blood tested every year for TSH and T-4 Thyroid function, and we'll get the sample then. In the beginning, he'd approach these blood draws with his usual cheerfulness and good will, smiling at the nurses and even flirting a bit. It's happened often enough that now, just the sight of the medical clinic sets his chin to quivering, big teardrops already forming in the corners of his dark blue eyes.

Why would I consider such a thing? Before becoming Avery's mom, I probably wouldn't have. The world to me, then, seemed like something "out there" that was mostly none of our business. But having Avery made everything personal--the families in the NICU with us, the children we know at the CDC, the babies with heart surgeries, they are close to me, now. I'd once thought that having a child with a visible disability would isolate my family--but instead, most times, I've found the opposite to be true. Avery brings people together.

It's a small thing, our participation in the Kennedy Krieger Institute research, but it's what we can do.

When the twins were still babies, I used to sit with them in the rocking chair. I'd arrange them like the nurses in the NICU showed me, one in each arm, heads on my chest. The rhythm of the rocking chair reminded me of a heart beat, too--bump-bump. Bump-bump. And I'd feel it, then, our connectedness, all of our hearts beating as one.

For more information on the Kennedy Krieger Institute study contact Charnan Koller.