A newly discovered variant in a brain gene that controls appetite may partly explain why some ethnic groups are more overweight than others, according to a study in Native Americans. The results will be presented Wednesday, June 18, at The Endocrine Society’s 90th Annual Meeting in San Francisco.

Investigators from the National Institutes of Health (NIH), which funded the research, studied more than 3,500 Native Americans living near Phoenix, Arizona.

“This Native American community has a very high prevalence of type 2 diabetes and is, on average, more obese than other populations,” said the study principal investigator, Leslie Baier, PhD, of the NIH’s National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).

The NIH research team identified a candidate gene for obesity, called HCRTR2. This gene produces a brain receptor that regulates food intake in animals. A variation in a sequence of this gene is highly associated with a person’s body weight, Baier said.

“People who have this variant are, on average, about 20 pounds heavier than people who do not have it,” she said.

The gene variant is common among Native Americans, occurring in 48 percent of this population, the study showed. It does not occur in whites, however, and occurs in only 12 percent of people of Chinese heritage and four percent of people of African heritage, according to Baier. About 28 percent of Japanese have the gene variant.

Dr. Baier’s colleague—Dr. Rong Rong, MD, PhD, also of NIDDK—and other researchers found the gene variant on chromosome 6, after searching all of the human chromosomes using a genome-wide association analysis. This molecular genetics technique is a way of finding what region of a chromosome is associated with a particular disease and then all of the genes in that particular chromosomal region are studied, Baier explained. This is done by analyzing inherited variations in the DNA, called SNPs (pronounced SNIPs), to see which were highly associated with body mass index, a measure of body weight.

The finding opens the possibility that scientists can one day develop drug therapies that specifically target the physiologic pathway affected by this gene variant, Baier said.

“In the meantime, it can help these people understand why they are driven to eat,” she said.

Baier said it is likely that other gene variants, not yet found, also are tied to obesity.

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Founded in 1916, The Endocrine Society is the world's oldest, largest, and most active organization devoted to research on hormones and the clinical practice of endocrinology. Today, The Endocrine Society's membership consists of over 14,000 scientists, physicians, educators, nurses and students in more than 80 countries. Together, these members represent all basic, applied, and clinical interests in endocrinology. The Endocrine Society is based in Chevy Chase, Md. To learn more about the Society, and the field of endocrinology, visit our web site at www.endo-society.org.