Overcoming a Bad Gene

This is the story of the unraveling of a profound medical mystery. It started 70 years ago in Norway, where Mrs Egeland was searching for a physician who could treat her two young children. At birth, both children appeared to be healthy, but they soon developed signs of severe mental retardation. Her search ended when she found Dr. Fölling, who determined that the retardation was caused by a new genetic disease, later named phenylketonuria (PKU), that blocks the oxidation of the amino acid phenylalanine. Later, others devised an inexpensive test for PKU and an effective treatment- the low phenylalanine diet. Although these developments came too late to help Mrs. Egeland's children, they have helped thousands of other PKU children live normal lives. This is one of the great success stories of modern medicine. There is one painful legacy from PKU that occurs when a woman who is unaware that she has PKU becomes pregnant. Infants born to such women, estimated to be about 6.5 million, will likely be damaged in utero, a condition called Maternal PKU. To prevent this damage, these women must be tested for PKU and, if positive, go on a low phenylalanine diet before they become pregnant.