In a genetic analysis of obese individuals, researchers have narrowed the search for the genes associated with obesity and related metabolic disorders to a small area on chromosome-3, according to a report in the Proceedings of the National Academy of Sciences for December 19.
A metabolic cluster consisting of glucose intolerance, dyslipidemia and hypertension, is also "a strong predictor of obesity-related morbidities and premature mortality," Dr. Ahmed H. Kissebah, from the Medical College of Wisconsin in Milwaukee, and colleagues explain. A close interaction between this metabolic cluster and patterns of abdominal fat, total body adiposity and insulin resistance has also been noted.
To further explore the genetic basis of these associations, Dr. Kissebah's team performed a genome-wide scan of 2209 subjects, who represented 507 Caucasian families. The study participants were recruited from Take Off Pounds Sensibility (TOPS) clubs.
The results of their analysis demonstrate that a "quantitative trait locus on chromosome-3 (3q27) [is] strongly linked to six traits representing these fundamental phenotypes," they write. These six traits included body mass index, waist circumference, weight, and insulin and leptin levels.
According to Dr. Kissebah, "This area on chromosome-3 is fascinating because six features of obesity are clustered on this area and nobody had looked at this area before."
In addition, they found that the quantitative trait locus found on chromosome-3 has a possible epistatic interaction with a quantitative trait locus found on chromosome-17 (17p12), which, according to Dr. Kissebah's team, is "strongly linked to plasma leptin levels."
The genes "involved on these two chromosomes seem to belong to the same pathway subserving those biological mechanisms leading to the obesity-related features," Dr. Kissebah commented in a university statement.
"We have the potential of creating new remedies for obesity, by targeting these two genetic pathways," said Dr. Kissebah. "Also, we will be able to identify individuals who have this genetic makeup, so that they can be taught the importance of living a healthy lifestyle. We are not there yet, but we have laid the foundation."