Vitamin A is an essential dietary nutrient that is required to maintain good health. Vitamin A is particularly important during pregnancy, when the unborn child is developing. Our research is focused on the important role that vitamin A plays in the development of the diaphragm - the muscle required for breathing throughout life. We believe that mistakes in the way that vitamin A is used during development can cause problems with the way the diaphragm develops. When this occurs, the child is born with a condition called congenital diaphragmatic hernia, affecting its ability to breathe when first born. Many infants with this birth defect die early in life, while surviving children can have continuing problems with breathing and other developmental problems. Our research should provide a new way of understanding how vitamin A is important in diaphragm development, and has the potential to improve the lives of children born with this birth defect.