Inheriting Bad Health

Less common than come-and-go infectious diseases, but far more insidious and likely to cause lifelong handicaps, are the defects humans are born with. The majority of congenital defects, it is currently believed, come when something goes wrong in the womb--typically, cataracts in a child resulting from the fact that the mother had German measles (TIME, Aug. 1, 1960). The rest are hereditary, dating from the instant that a sperm and an ovum, one or both defective, join to make a defective cell. In the subdividing process that starts at once, every newly created cell carries in its genes the defect, ready to misguide the fetus toward abnormal development--malformation, for example, or mental retardation.

So little was once known of the molecular structure of genes that the defects they cause could not be identified or treated. Now, in the baby science of "molecular medicine," chiefly conceived by Chemist Linus Pauling, both problems are beginning to be solved. Last week in Los Angeles, at a conference co-sponsored by the National Foundation and the University of Southern California, Dr. Pauling and others told of their progress.

Treatment for PKU. Basil O'Connor, head of the National Foundation (the old March of Dimes group), pointed out that at least two inborn errors can now be treated. In phenylketonuria (PKU), an infant is unable to metabolize phenylalanine (one of the basic components of many proteins) and is in danger of severe mental retardation. Treatment consists simply of giving the child foods that are specially processed to remove phenylalanine. In galactosemia. the inability to convert galactose (which the body derives from milk) to glucose, untreated infants are prey to fulminating, fatal infections, and survivors suffer severe physical and mental retardation and blindness. The answer is to cut out milk, or anything containing the galactose molecule.

While PKU is rare (once in 25,000 births) and galactosemia is probably even rarer, one in every 16 U.S. infants is born with some defect, many of which, untreated, may be handicapping or fatal, said O'Connor. And the scientists are closing in on other disorders suspected of being transmitted by genes, the giant molecules of heredity: diabetes, gout, some forms of mongolism, cretinism, cystic fibrosis, muscular dystrophy, the inability to make protective antibodies against bacteria, and many other disorders of the blood, besides obvious physical defects.

Dr. Pauling is especially interested in molecular malformations in the blood. At the California Institute of Technology, where his work on molecule structure got him a 1954 Nobel Prize, he and Dr. Harvey Itano have gone far to explain sickle-cell anemia, which is usually debilitating and may be fatal, and afflicts many U.S. Negroes and vast numbers in Africa. The disease got its name because the deoxygenated red cells in the veins lose their globular shape (they look normal in the arteries) and take a crescent or sickle form. The Pauling team found that this was because of a minute, submolecular abnormality in the hemoglobin.

4-to-1 Odds. The sickling defect is transmitted by genes in such a way that if only one parent has the trait, three children will be normal, but one will carry on the trait. But if both parents have it, one child will be normal, two will be carriers, and one will have overt disease. Said Dr. Pauling: "We should begin now by requiring by law that the simple blood test to detect carriers of sickle-cell anemia be performed before a marriage license is issued.'' Then, he suggested, it would be up to a couple contemplating marriage to decide whether to go ahead, and whether to have children.

The heartening news about sickle-cell anemia is that a test exists to identify it. Less sharply defined but also threatening are the "Mediterranean anemias," which afflict whites (but spare Negroes) around much of the Mediterranean basin. And there are strange hybrid anemias between the Mediterranean and sickle-cell types. As simple tests for these and other molecular diseases are developed, said Dr. Pauling, they also should be made mandatory before marriage.

This file is automatically generated by a robot program, so reader's discretion is required.