New studies dispute claim of single-gene link for alcoholism


A recent claim that a single gene predisposes some people to alcoholism was apparently wrong, scientists said this week.

Two new studies -- involving larger groups of people and using different research techniques -- have found no association between the suspect gene and alcoholism.

"The finding is not reproduced," said Dr. David Goldman, chief of the genetics section at the National Institute of Alcohol Abuse and Alcoholism in Maryland. "We looked at 40 alcoholics, a large number of controls, over a hundred, and two families," and found no link between the gene and alcoholism.

Goldman declined to discuss details of his study because it is awaiting publication in a medical journal. But another geneticist, who asked not to be identified, said that Goldman "has in fact repeated the (alcoholism gene) study using well-classified alcoholics and non-alcoholics in a lot larger sample than the original study. It suggested very clearly that there is no effect."

The second study, run by Dr. Robert Cloninger, head of psychiatry at the Washington University School of Medicine in St. Louis looked at genes from 250 people in 24 families, and a similar-size control population, comparing alcoholics to non-alcoholics.

Both studies aimed to verify a report last April in the Journal of the American Medical Association by pharmacologist Kenneth Blum, at the University of Texas, San Antonio, and Ernest Noble, director of the Alcohol Research Center at the University of California, Los Angeles.

Blum, Noble and their colleagues saw evidence in brain cells from 35 alcoholics that "suggests that a gene that confers susceptibility to at least one form of alcoholism is located on the q22-q23 region of chromosome 11." Seventy per cent of these alcoholics seemed to carry the mutant gene in their cells.

The researchers were careful, however, not to claim that the gene causes alcoholism; only that it predisposes for the disorder.

The suspect gene identified by Blum and Noble makes a special protein called a dopamine receptor. Dopamine, a natural brain chemical, is intimately involved in communication among brain cells. And dopamine seems important in normal functioning of the brain's "pleasure center."

Drinking too much coffee

can cause hip fractures

People who drink more than two cups of coffee or four cups of tea a day could be increasing their risk of hip fracture in old age, according to a new study.

The study, published in the October issue of the American Journal of Epidemiology, is the first to link caffeine consumption with the hip fractures that occur in older people whose bones have weakened. A hip fracture often marks an elderly person's final decline into dependency or death.

Dr. Douglas Kiel, a professor of medicine at Brown University, and his colleagues looked at how much coffee or tea 3,170 people reported drinking over 14 years. Then they looked to see which ones fractured their hips, a sign that bones had become brittle. They found that heavy caffeine drinkers were 53 per cent more likely to suffer hip fractures.

Caffeine has long been suspected of draining calcium from the bones, because people who consume it have higher levels of calcium in their urine. Loss of calcium leads to osteoporosis, the brittle-bone condition that afflicts many elderly people -- most of them women.

"This is a preliminary study," Kiel said. "If you're going to make any personal adjustments, use moderation. It's not unreasonable to have a couple of cups a day."

Growth hormone can cause

spread of breast cancer

Scientists have identified a substance that "turns on" cells of the most aggressive forms of breast cancer, causing them to proliferate and spread.

The researchers said they believe they soon will be able to interfere with the way the substance works and therefore halt the deadly spread of the disease in the bodies of its victims.

Animal studies aimed at testing the effect of antibodies to the substance, described as a growth-promoting protein, would begin within a month, they said.

Scientists with other institutions said the discovery was an exciting piece of a large puzzle -- but warned that translating it into a way to treat cancer could be years away.

In addition to breast cancers, the newly discovered material, which was being called "gp30," appears to be active in the development of some ovarian and gastric tumors, said researchers from Georgetown University.

"We cannot overemphasize the prognostic and diagnostic implications of this work for breast and ovarian cancers," said Dr. Ruth Lupu, a biochemist and a member of the team of scientists who identified the tumor-promoting material.

She estimated that within two to five years, the discovery would lead to development of new drugs for the two diseases.