For most of the genomic era, the search for the causes of congenital heart defects has focused on one place: the roughly 2 percent of DNA that codes for proteins. The researchers knocked out EnhTBX1 in embryonic stem cells and grew blood vessel organoids, three-dimensional lab-grown tissue that recapitulates vascular development. Where This Fits in a Broader ShiftThe work sits at the heart of a genuine change in how congenital heart disease genetics is being done. Families with a child affected by a congenital heart defect should discuss genetic testing options with a cardiologist or clinical geneticist rather than drawing conclusions from a single mechanistic study. It occurs in roughly 3 of every 10,000 live births and is the most prevalent cyanotic congenital heart defect.