Phenylketonuria (PKU) Disease
This happens because a necessary enzyme, phenylalanine hydroxylase, is deficient. Because of this, phenylalanine builds up in the bodys cells and causes nervous system damage. Phenylketonuria is a treatable disease that can easily be detected by a simple blood test. isayildiz / Getty Images (Screening for PKU in premature babies is different and more difficult for several reasons.) If PKU is present, the level of phenylalanine will be higher than normal in the blood....