Mice, Men & Mongolism

Twice in every 1,000 births, some unhappy mother finds that she has borne a child suffering from an affliction which has been misnamed "Mongolian idiocy." In the 85 years since mongolism was defined, authorities have disagreed widely as to its cause. No speculation seemed too absurd. Mongolism, said some, looking at the slanted eyes of its victims, was racial evidence of "the Mongol in our midst." Others, more responsible, argued that it was caused by "advanced maternal age," exhaustion of the womb, ovarian disorders, an upset gland (any gland would do) or, finally, heredity.

Last week, a keen-minded Harvard physician offered the most convincing explanation yet of mongolism. It seems, said Dr. Theodore H. Ingalls at the New York Academy of Medicine, to be the result of an injury or shock to the fetus at about the eighth week of pregnancy. This does not mean that the cause is always the same type of injury or shock. In fact, said Dr. Ingalls, the trouble with researchers who have been looking for a single, simple cause is that they were like the three blind men describing an elephant: one found it all foot, another all trunk, the third all tail.

Eyes, Ears & Nose. All victims of mongolism have three things in common: 1) mental deficiency, 2) short heads, 3) faces which seem to have been flattened (actually, growth is arrested). Besides these constants, other defects are found so often in mongolism that Dr. Ingalls got a vital clue from analyzing them: the ears are usually malformed, there may be opacities in the eye lens, one of the nasal bones is usually absent, and the middle phalanx of the fifth finger is generally stunted. The clue: all these signs affect tissues which develop at about the eighth week of fetal life. In mongolism victims, the body structures formed earlier than that are usually normal, said Dr. Ingalls, and so are those formed later.

"The fetus," suggested Dr. Ingalls in explanation, "has been blighted by what might be called intrauterine drought . . . [It may be] a metabolic drought, a biochemical upset, transient vitamin or enzyme deficiency, or oxygen lack." The likelihood that oxygen shortage may be the villain in many cases is heightened, said Dr. Ingalls, by the fact that mongolism often results from a pregnancy marked by early vaginal bleeding, and this bleeding might starve the fetal brain of oxygen.

Skull, Lip & Palate. To test his theory, Dr. Ingalls and colleagues at Harvard's School of Public Health took 300 mice in batches of 20, subjected them to oxygen lack (artificial "high altitude") for five hours on certain days of their pregnancies. Mice, unlike men, do not suffer from mongolism. But Dr. Ingalls found skull defects (actually worse than mongolism) in about a third of the litters which had been starved of oxygen on the eighth day of development. Lack of oxygen on the twelfth day gave them harelip, on the 14th day, cleft palate.

Even if Dr. Ingalls' challenging theory is proved right, a greater challenge will face doctors and public-health workers in putting the theory into practice and preventing mongolism. Heredity may still be a predisposing factor, he believes, but not a decisive one. And that is the basis for hope. Says Dr. Ingalls: "The important consideration is the prenatal environment. It is man's environment that is susceptible to manipulation, not his genes and chromosomes."

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