(The Salt Lake Tribune) -- Utah geneticists say they have found the biological equivalent of the Rosetta stone for heart disease and overweight bodies: a single, inherited obesity gene.

Dubbed HOB1, for human obesity 1, identifying the gene is being hailed as a first step toward developing drugs to treat moderate to severe obesity and associated conditions, including heart disease and Type 2 diabetes, said Salt Lake City-based Myriad Genetics. The company announced its discovery Tuesday.

Observers sounded a more cautious note, saying too little information was released Tuesday to fully evaluate the significance. "Gee, I hope they're right, and we'll wait and see," said American Diabetes Association President Eugene Barrett when informed of the announcement.

"We think it's a significant breakthrough," said Steven Stone, one of Myriad's key geneticists specializing in metabolic disease. He said the discovery bolsters the view of obesity as partly a genetic disorder since changes in HOB1 are inherited and control important proteins that lead to obesity and diabetes.

Previous obesity-related genes have been found only in mice or other animal models.

In the past nine years, scientists have pinpointed a handful of genes that help regulate fatness in mice. The discoveries up to this point hold promise for making drugs or chemical compounds that could help overweight people reduce food cravings and feel sated by fewer calories. New fat-fighting medicines, though, have proven disappointing and sometimes lead to worsening medical conditions.

Myriad's announcement calls HOB1 "a highly druggable target" that opens up a new arena for treating a person's basic DNA in a way that would halt or slow bodily production of fat cells. Also, a genetic test of HOB1 alterations could help predict obesity and associated risks, Myriad said.

"There are numerous genes that people think are based on obesity models in animals, but in general that information has been brought into humans and researchers very rarely find anything," Stone said. "And here we have a gene that clearly contains inherited variations that predisposes people to obesity."

He said the company would announce in coming weeks an alliance with a separate pharmaceutical firm to begin developing an HOB1- targeting drug. There was no word Tuesday on when Myriad would publish the findings in a peer-reviewed medical journal or release the gene specifics to other researchers. HOB1's announcement came in a media release issued by the company and posted at www.myriad.com.

The Diabetes Association's Barrett said it is unlikely that obese people are defective in any one gene, since fat production and cardiovascular diseases are triggered by many environmental factors, such as physical activity and caloric intake. Yet he held out the hope that Myriad "was onto something with this discovery."

Scientists have known since the 1700s that eating too much food without expending enough energy can lead to added body weight -- a belief still held today. It wasn't until years later that researchers found DNA differences in the genetic makeup of different animal species also played a role in obesity.

That triggered a genetic race to beat fat, highlighted in 1994 with the discovery by Jeffrey Friedman of Rockefeller University in New York that an obesity gene is mutated in a strain of overweight mice.

The specific gene, shorted to the name "ob," was found to produce a hormone called leptin that could signal severely obese mice to lose weight. But experimental gene-based drugs designed on the leptin model have proven unconvincing, researchers say.

Myriad said it tackled the obesity question with the University Research Park company's own DNA-sequencing computers and the genetic history of about 900 Wasatch Front residents. That led to a discovery earlier this year by Myriad's Stone and other researchers nationwide, published in the American Journal of Human Genetics, that inherited obesity has something to do with a DNA "region" on the human chromosome 11.

Tuesday's finding maps that obesity inherited risk to a specific gene within the region, although Stone declined to describe exactly where HOB1 was located in the chromosome.

"Recently introduced prescription medications intended to help individuals manage their weight have demonstrated limited efficacy," a Myriad statement said. "The HOB1 gene appears to be a highly druggable target" the company hopes to use to fight obesity, diabetes and related disorders.

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