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[IP] Scientists Link Gene to Diabetes
this just out on AP:
By MALCOLM RITTER
NEW YORK (AP) - A previously unknown gene appears to influence the risk of
developing diabetes, particularly in Mexican-Americans, researchers say.
Some scientists called the work a landmark in the effort to find genes
involved in common illnesses such as heart disease and schizophrenia. For
diabetes, the work might lead to better prevention and treatment.
The rate of diabetes among Hispanic adults in the United States is nearly
double that of white adults. Mexicans account for about two-thirds of all
Hispanics in the United States. The study focused on type 2 diabetes, the
most common kind, which generally shows up in adults and affects about 15
million Americans. If untreated, the disease can lead to blindness, kidney
failure, heart attacks, stroke and amputations.
Other genes have been implicated before in type 2 diabetes. But the newfound
gene is from a class that had not been linked to diabetes before, so it
reveals a biological pathway to the disease that scientists didn't know about.
Further studies may provide insights that could lead to better treatments,
said Graeme Bell of the University of Chicago and the Howard Hughes Medical
Institute. Bell presented the study with co-authors in the October issue of
the journal Nature Genetics.
If confirmed, the finding might also help doctors identify susceptible people
who might be able to delay or avoid the disease through exercise, weight
control and perhaps other measures.
The gene tells the body how to make a protein called calpain-10. Such
proteins cut other proteins, which either activates or inactivates them.
Like other genes, the calpain-10 gene comes in subtly different forms. The
research indicates a heightened risk of diabetes in people who inherit one
particular form from one parent and another particular form from the other
The researchers calculated that this combination could roughly triple the
risk of diabetes. They estimated that it played a role in 14 percent of cases
in a sample of Mexican-Americans from Texas, but only 4 percent of cases in a
European sample from Finland and Germany. The combination was less common in
this European sample.
Experts called the study important, but some said the statistical evidence
does not prove the gene really affects the risk of diabetes.
``It's not an open-and-shut case,'' said geneticist Leonid Kruglyak of the
Fred Hutchison Cancer Center in Seattle.
Dr. Steve Elbein, who studies diabetes genetics at the University of Arkansas
for Medical Sciences in Little Rock, called the statistical results ``really
quite convincing. These investigators have done nearly everything that one
can do to prove this gene alters diabetes risk.''
Still, the study conclusion is puzzling from a biological point of view for a
variety of reasons, Elbein said, and ``I have a hard time judging the
biological importance of these data.''
Kruglyak called the work groundbreaking in terms of the more general
challenge of finding susceptibility genes for common disorders like diabetes,
heart disease or schizophrenia.
These genes are hard to find because their effect is so subtle; rather than
causing disease outright, they merely tip the scale of susceptibility. And
different people can be affected by different susceptibility genes.
Bell and colleagues used a technique called ``positional cloning.'' It relies
on statistical analysis and landmarks along chromosomes to zero in on target
genes, without any prior knowledge about what the genes normally do.
Up until now, this technique hasn't identified any genes that make people
more susceptible to common forms of widespread, genetically complex
disorders, Kruglyak said. The researchers in the latest study have at least
come closer than other scientists to identifying a gene with this technique,
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