Through a collaboration between Emory University and the Sibley Heart Center at Children's Healthcare of Atlanta, families who have a child with Down syndrome and a specific type of congenital heart defect are being invited to participate in a research study. The study will help us to understand why some children born with Down syndrome also have a heart defect.

1. Families of children with Down syndrome who were born with a complete atrioventricular septal defect (or AV canal) with or without another major heart or birth defect are eligible to participate.
2. Participation of mothers is required and participation of fathers is encouraged.
3. Children must be living and born on or after 1/1/1989.

• Receiving an introductory letter and study description
• Reviewing and signing a consent form
• Signing a release of medical records for the child to document medical information directly related to Down syndrome
• Completing a telephone questionnaire (mothers and fathers only)
• Donating a small blood sample (parents and child - note that children's blood donation may be combined with a medically necessary draw).