Big hips, big belly? It's in your genes, Joslin-led s...( abdomen -- are much higher risk for dia...)

While recent studies at Joslin and elsewhere have shed light on the role of appetite and energy expenditure (physical activity) in obesity, little has been known about the role of genes in fat distribution or the association of genes in metabolic disorders like type 2 diabetes.

To investigate this question the researchers examined the genetic makeup of fat samples from around internal organs and under the skin of both mice and almost 200 human subjects ranging from normal to very obese, and including people with mostly abdominal obesity and people with subcutaneous and intra-abdominal obesity. Theorizing that fat distribution patterns -- and perhaps obesity itself -- may originate in the genes involved in control of development, the researchers found that as many as 12 developmental genes may play a role in different fat depots and that at least three of these seemed to be especially important in obesity.

The researchers compared levels of activity for these three genes --Tbx15, Gpc4, and HoxA5 -- in intra-abdominal and subcutaneous fat taken from individuals of normal weight versus overweight or obese individuals. "The differences we found in gene expression were so distinct," said Dr. Gesta, "that we could identify the body mass index (level of obesity) and the waist/hip ratio (whether the fat is in the abdomen or under the skin) in the overweight population by the expression level of these genes. This finding suggests that the expression of these genes could be related to the pathogenesis of obesity."

These results also suggest that different fat cell precursors are responsible for where the body stores fat. "While we don?t know yet whether this genetic activity is a cause or an effect of obesity," said Dr. Gesta, "these data do suggest that dif
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10-Apr-2006