Overcoming a Bad Gene: the Story of the Discovery and Successful Treatment of Phenylketonuria, a Genetic Disease That Causes Mental Retardation

This is the story of theunraveling of a profound medical mystery. It started 70 years ago in Norway,where Mrs Egeland wassearching for a physician who could treat her two young children. At birth,both children appeared to be healthy, but they soon developed signs of severemental retardation. Her search ended when she found Dr. Flling,who determined that the retardation was caused by a new genetic disease, laternamed phenylketonuria (PKU), thatblocks the oxidation of the amino acid phenylalanine. Later, others devised aninexpensive test for PKU and an effective¿ treatment- the low phenylalanine diet. Although these developments came too late to help Mrs. Egeland'schildren, 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 fromPKU 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 bedamaged in utero,a condition called Maternal PKU. To prevent this damage, these women must betested for PKU and, if positive, go on a low phenylalanine diet before they become pregnant.