Medically reviewed by Nicholas R. Metrus, MD Key Takeaways Mosaic Down syndrome has some cells with three copies of chromosome 21, and some with two instead of all three.Only about 1% to 2% of people ...

Nearly half of all babies born with Down syndrome face congenital heart defects, often involving serious malformations that require surgery in the first months of life. For decades, scientists have ...

After decades of mystery, researchers at Gladstone Institutes identify a gene that can derail heart formation—and show that fixing it prevents the problem in mice. SAN FRANCISCO—October 22, ...