February/March 2018

At the UTRGV South Texas Diabetes and Obesity Institute, Research is a Family Affair

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By Susan Kirtz, MPH
Managing Editor, Texas Health Journal
Director of Special Projects, Center for Health Communication
The University of Texas at Austin


When Sarah Williams-Blangero and her team at the Texas Biomedical Research Institute Department of Genetics were recruited by the UTRGV School of Medicine, they packed up 3,500 family members and brought them along. In October 2014, they transported a biorepository filled with specimens and data about more than 3,500 people than 200 miles from San Antonio to the Rio Grande Valley, establishing the South Texas Diabetes and Obesity Institute (STDOI).

The STDOI works to address some of the most critical public health issues in the Rio Grande Valley region through their study of the genetic determinants of risk for diabetes and obesity. Dr. Williams-Blangero explains, “In any population, you see many people living in the same environment, eating the same food, and having similar exercise patterns, and yet some people develop diabetes and others don’t. So what is it that makes those people different – that makes them particularly susceptible to disease?”

The STDOI relies on large family studies to find genes influencing diabetes, obesity, and a variety of other health issues in the population. In San Antonio, they enrolled over 3,500 Mexican Americans from more than 80 families, with whom they’ve worked for over two decades. They also work with 2,000 people in Brazil (1,700 of whom are from one large family), and 2,600 people in Nepal. In exchange for their participation, participants receive small financial incentives, screening for diabetes and other diseases, and assistance with access to treatment, if necessary. Williams-Blangero describes it as a “collaborative, long-term relationship.”

These studies of large extended families allow STDOI researchers to identify genes in the causal pathways that influence disease. The results of their research are used to develop new drugs for treating diabetes, obesity, and related disorders. These studies also identify measurable biomarkers that can be developed into future screening tools to determine if someone is at particularly high risk for a disease like diabetes. Early screening facilitates aggressive prevention plans.

 STDOI freezer farm

STDOI freezer farm

The University of Texas Rio Grande Valley campus lies less than 20 miles from the border of Mexico, in a region where diabetes, obesity, and associated health issues are reaching crisis levels. About 10% of the US population has type 2 diabetes, which is now the 7th leading cause of death in the US. However, rates are higher in minority populations, with an estimated prevalence of 16% in Hispanic populations. Epidemiological studies in the Rio Grande Valley have estimated that the prevalence of diabetes among Mexican Americans living in the region is about 28%.  

Through their research, the STDOI is committed to reducing health disparities in the Rio Grande Valley by contributing to a broad understanding of why Mexican Americans are at particularly high risk. “Our ultimate goal is to make scientific discoveries that inform new treatment and prevention plans to reduce the rates of diabetes and obesity in Mexican Americans,” says Williams-Blangero.

Both genes and environmental factors act together to cause diabetes. Genetic factors primarily work by altering a person’s probability of having the disease. Other factors besides genetics, such as individual behaviors (diet and exercise) and the surrounding environment (access to healthy food, barriers to physical activity, etc.), also affect the likelihood of developing diabetes. The type of research undertaken by the STDOI team allows them to distinguish between genetic and environmental effects on diabetes risk.

 The STDOI has a unique 11,000 processor computer cluster located at its facility in Brownsville.  Name MEDUSA, it is one of the world’s largest clusters dedicated to human genetic analysis.

The STDOI has a unique 11,000 processor computer cluster located at its facility in Brownsville.  Name MEDUSA, it is one of the world’s largest clusters dedicated to human genetic analysis.

“Genetics is something that you can know completely because we can fully sequence the individuals and know how they vary across the chromosomes,” explains Williams Blangero. “That genetic component is known and when it segregates in families you know how much genetic information is shared between all your family members. Social determinants and environmental factors cannot mimic that known pattern of variation that’s attributable to genetics.” This approach also allows researchers to control for genetics and look at the impact of environmental factors on disease.

STDOI researchers will continue to work with the participants and data from San Antonio, but they also plan to begin recruitment in their new community. “Many of the 3500 participants who have collaborated with us in our studies have relatives in the Rio Grande Valley. Now we have a great opportunity to expand our study families through new recruiting efforts here,” says Williams-Blangero.

On Thursday, March 1, the Knapp Community Care Foundation announced a $1.98 million grant awarded to UTRGV to establish a major genomic research effort in the mid-Valley. The grant will support the STDOI in screening high-risk Mexican American families for diabetes, leading to new approaches to diabetes prevention and treatment. Williams-Blangero reports that “the Knapp Foundation has given us an incredible opportunity to bring genomic science to the study of diabetes risk in the Rio Grande Valley. We are extremely excited about this new recruitment effort that will be initiated in the late spring.”