There are many reasons why people gain different amounts of weight and why fat becomes stored in different parts of their bodies. Now, a cross campus group of Michigan faculty and staff — including the School of Public Health’s Dr. Goncalo Abecasis, chair of the Department of Biostatistics, and Dr. Michael Boehnke, the Richard G. Cornell Distinguished University Professor of Biostatistics — point to a genetic reason for a tendency to put on weight.
Their findings, part of the largest genome wide study, were published in two recent papers in the journal Nature.
By analyzing genetic samples for over half a million individuals as part of the GIANT research project, which aims to identify genes that regulate human body and size, researchers found more than 100 locations across the genome that play roles in various obesity traits.
Learning more about the genes and biological processes may guide the development of weight-loss therapies, and help doctors tailor the health advice they give to patients.
“Our work clearly shows that predisposition to obesity and increased body mass index is not due to a single gene or genetic change,” says senior study author Dr. Elizabeth Speliotes, assistant professor of internal medicine and computational medicine and bioinformatics at the University of Michigan Health System.
“The large number of genes makes it less likely that one solution to beat obesity will work for everyone and opens the door to possible ways we could use genetic clues to help defeat obesity,” she says.
Speliotes and colleagues at Broad Institute of MIT and Harvard and Mt. Sinai Health System investigated the genetic basis of body mass index (BMI), a common measure of overall obesity, in up to 339,224 individuals.
Across the genome, which is the full set of a person’s genes, they found 97 sites associated with obesity. The number triples the number of previously known regions, according to the published study.
Once better understood, these genetic mechanisms may not only help to explain why not all of those who are obese develop related metabolic diseases, such as type 2 diabetes and high cholesterol, but could lead to possible ways to treat obesity or prevent metabolic diseases in those who are already obese.
“Presently we have no way of knowing if obese individuals will develop these obesity-related metabolic diseases and if so which ones,” says Dr. Speliotes, who is also a gastroenterologist at the U-M Health System. “We envision using these genetic markers to help doctors decide which treatments would work best to keep patients healthy.”
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