Congenital heart valve defects appear in 2 percent of all live births, making them the most common type of birth defect. While some of these defects have been linked to specific genetic mutations, the majority have no clearly definable genetic cause, suggesting that epigenetic factors - changes in gene expression versus an alteration in the genetic code—play an important role. Now researchers from the Perelman School of Medicine at the University of Pennsylvania have found that the force, or shear, of blood flow against the cells lining the early heart valve sends signals for heart "cushion" cells to become fully formed valves. Their findings are published in Developmental Cell.
↧