5 April 2002
STUDY QUESTIONS MANY GENE-DISEASE LINKS
1. Study questions many gene-disease links
2. Norman Mailer lends weight to US anti-cloning coalition
1. Study questions many gene-disease links
NEW YORK, Apr 02 (Reuters Health) - In recent years, a growing number of studies have reported possible links between genes and diseases, raising hopes of finding a cure for everything from Alzheimer's disease to cancer.
But according to a recent review, only a handful of these studies have been corroborated by subsequent reports.
Researchers reviewed medical studies involving 133 diseases or genetic traits and found that just six associations were supported by the results of at least three different studies. In the most widely corroborated association--between ApoE4 and Alzheimer's disease—the relationship was stronger in whites than in blacks and Hispanics.
The finding underscores the importance of duplicating the results of a single study since correct associations "would have tremendous importance for the prevention, prediction, and treatment of most common diseases," the researchers explain in the March/April issue of Genetics in Medicine.
Gene studies generally determine the frequency with which a specific gene occurs in people with and without a disease. The majority of diseases, including heart disease and cancer, are influenced by both genes and environmental factors. Identifying key genes and finding ways to manipulate them can therefore have profound implications for health.
To avoid generating false hope, the authors suggest that future reports on possible genetic associations be pooled into a database so that the results can be interpreted in the context of a larger body of research.
"Until complete (literature reviews) can be performed using data from multiple large studies, we will be left with a scenario in which the majority of reported associations are in genetic purgatory, neither convincingly confirmed or refuted, awaiting future judgment," Dr. Joel N. Hirschhorn and colleagues conclude.
Hirschhorn, from the Whitehead Institute/MIT Center for Genome Research in Cambridge, Massachusetts, and his co-authors cite several reasons why study findings are not replicated. For one, statistical fluctuations can lead to findings that are essentially a fluke. Differences in ethnic groups studied, accidental associations with nearby genes and interactions between genes and environmental factors could also account for different findings.
SOURCE: Genetics in Medicine 2002;4:45-61.
2. Norman Mailer lends weight to US anti-cloning coalition: Veteran author joins forces with women's and religious groups
by Geoff Dyer
Financial Times (London) April 3, 2002
In more than half a century at the centre of American literary life, Norman Mailer has picked fights with just about everyone - not all of them verbal. In the 1970s he was poking fun at feminists, for whom he became a hate-figure. A recent novel about Jesus infuriated the churches. So it might come as a surprise to see him sharing a political platform with women's rights advocates and conservative religious groups. The issue uniting these unlikely bedfellows is human cloning. Mr Mailer is one of more than 60 prominent figures from the left who have signed a letter supporting a proposed ban on cloning embryos. "My feeling is that science is now trying to appropriate many of the functions of the Creator. Humankind cannot be trusted to proceed in this area," says Mr Mailer. "Let's just slow up a little."
The Senate is due to vote this month on a bill seeking to ban embryo cloning. Analysts say it could go either way.
Still writing at 78, Mr Mailer illustrates how the debate over cloning defies easy categorisation, especially in the US. Anti-abortion groups have long opposed research on human embryos. Echoing the anti-globalisation movement, critics from the left fear the experiments could open the door to "commercial eugenics". "Cloning is opening a new era in US political history," says Jeremy Rifkin, a prominent critic of the biotechnology industry who organised the letter. "The left has seen that they have something in common with the right, and we're working together to make sure that cloning embryos to harvest body parts is not allowed."
For Mr Mailer, even the medical benefits from the research will aggravate inequalities. "Only the very wealthiest people - who are often the worst - would get the benefits of these new treatments. The rest of society would be left out," he says. The US scientific community sees cloning as an important tool in the emerging area of "regenerative medicine". Researchers hope to develop treatments that use stem cells - immature cells that can be directed to form any type of tissue - to repair organ damage. Human embryos are one of the most promising sources of those stem cells.
If the cells were derived from an embryo that had been cloned with a patient's own DNA, the risks of rejection by the body's immune system would be reduced. So while few scientists support the cloning of babies, many believe research on these embryos could be important. "We are still at an early stage but it could be that each type of stem cell, including from cloned embryos, has a use in different treatments," says Austin Smith of Edinburgh university, a leading researcher in the area. The debate boils down to whether governments can keep scientists in check.
Researchers want the leeway to do limited experiments. Opponents fear research on cloned embryos would be a step on the way to designer babies. Mr Mailer says: "Like the rest of humankind, scientists are a mixture of the good and the bad. It would be folly upon folly to think that politicians can control scientists if we open the door to this type of research."
The US has already had a bruising debate over embryonic stem cells, which resulted in strict limits being placed on research in the public sector. In private industry, however, scientists face no such restraints. The controversy in the US has prompted not a little schadenfreude in the UK, which has just approved rules for research on cloned embryos. "The US is in a real muddle," says Sir Paul Nurse, the cancer researcher who won last year's Nobel Prize for medicine. "What sort of signal does it send out when the private sector can do anything and the public sector is restricted? How can you take such legislation seriously?" While research into embryonic stem cells has opponents in the UK, two years of debate in parliament have taken the heat out of the issue. All research on embryonic stem cells requires a licence from a government agency. The situation is a mirror image of the debate over genetically modified food, where scientists in the UK claim the enormous public hostility has held back research. But Britain is on its own. The European Parliament has approved a ban on funding research into cloned embryos. The issue is most controversial in Germany, where it rouses memories of Nazi experiments. Scientists say we have been here before. Procedures such as in vitro fertilisation prompted outrage at first, but are now widely accepted. They hope therapeutic cloning will follow the same path. "The UK has often led the way in these debates about embryology and I think this issue will be the same," says Michael West, chief executive of ACT, the US company that claimed to have cloned a human embryo last year. For Mr Mailer, public disapproval will hem in the scientists.
"What is going to happen with the politics is that we will eventually reach a compromise. But I suspect that if a referendum were held (on the cloning of embryos) most people would vote it down." Additional reporting by Victoria Griffith ..
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