News & Research

    University of California, San Francisco, San Francisco, California

Molecular Genetics of Human Obesity

General Research Subject: Type 2 Diabetes

Focus: Obesity\Pathogenesis

Type of Grant: Mentor Based Postdoctoral Fellowship

Project Start Date: July 1, 2008

Project End Date: June 30, 2012

Research Description

By dramatically raising the rate of diabetes, obesity has become a major public health concern for the 21st century. Both environmental and genetic factors are involved in the onset and progression of weight gain. Our long-term objective is to identify gene mutations that predispose humans to obesity and to understand how they cause obesity.

We have already found that mutations in genes such as the Melanocortin-4 receptor can predispose to severe obesity and to early childhood onset obesity. This gene is expressed in the brain and is part of a pathway that matches food intake to energy expenditure. One of our objectives is to extend the study of this gene to better understand how these mutations cause obesity and how patients carrying such mutations differ from other severely obese patients. Another objective of our studies is to test if gene variations in the same molecular pathway than MC4R can also predispose humans to severe obesity. The final objective of our studies is to develop new approaches to find other pathways in which gene variations could predispose human to severe obesity.

Reseacher Profile

Mentor: Christian Vaisse, MD, PhD   Postdoctoral Fellow: Ivy Aslan, MD

What area of diabetes research does your project cover?  What role will this particular project play in preventing, treating and/or curing diabetes?

Obesity, and in particular severe obesity, is a major predisposing condition for type II diabetes. Although obesity has been long known to run in families, it is not until recently that genes causing obesity in humans have been discovered. One of these genes is the Melanocortin-4 Receptor (MC4-R). This gene encodes a protein that is implicated in the regulation of food intake by the brain. We have previously demonstrated that mutations in the MC4R gene account for 1 to 6% of cases of severe obesity cases.

This project is aimed at determining if patients with MC4R have a better or worse outcome after bariatric surgery. Bariatric surgery is currently the best treatment for severe obesity, which can also successfully treat type 2 diabetes in these patients. For this study we will systematically determine the presence of an MC4R mutations in 2400 patients undergoing bariatric surgery and determine if patients with these mutations fare better or worse than patients without such mutations.

If a person with diabetes were to ask you how your project will help them in the future, how would you respond?

Obesity and in particular severe, is the most common and rapidly growing nutritional problem in westernized countries. Obesity is the major risk factor for type II diabetes. By understanding what genes contribute to obesity and how these genes contribute to obesity, we hope to better understand the underlying causes of the obesity epidemic and help prevent the rise in type II diabetes.

Why is it important for you, personally, to become involved in diabetes research?  What role will this award play in your research efforts?

Our long-term scientific objectives are to identify gene mutations causing obesity or type II diabetes in humans, to understand their pathogenic effects and to determine if these mutations influence the outcome of therapeutic interventions. This research award will allow us to directly address the later in the specific case of MC4R mutation carriers.

In what direction do you see the future of diabetes research going?

Although numerous major advances are underway in the treatment of this condition, we are faced with the reality that the number of  people diagnosed with diabetes, both type I and type II, is increasing steadily. Understanding the reasons for this increase as well as developing strategies to prevent it will be the major challenge for future diabetes research.