According to the Centers for Disease Control (CDC), over 3 million people in the U.S. currently have glaucoma, and the disease costs the economy over $2 billion in losses in productivity losses and direct costs. Scientists are studying this disease to understand its causes and progression, as well as ways to detect it before symptoms appear. Two research projects, one at the University of Pennsylvania Perlman School of Medicine and the other at University of Wisconsin-Madison, are examining these aspects of the disease.
A study done at the University of Pennsylvania Perlman School of Medicine found that people of African ancestry are five times more likely than others to develop glaucoma and almost 15 times as likely to experience blindness as a result. Yet, previous research on glaucoma has mostly used data from people of European ancestry. Researchers at the University of Pennsylvania Perlman School of Medicine conducted a study that focused on people of African descent, identifying three gene variants that may contribute to this group’s susceptibility to developing and experiencing blindness from glaucoma.
This study involved over 11,000 people of African ancestry and identified two variants associated with the most common form of the disease, primary open-angle glaucoma, which is the leading cause of blindness worldwide. The variants associated with primary open-angle glaucoma are rs1666698, linked to the gene DBF4P2, and rs34957764, linked to the gene ROCK1P1. A third variant, rs11824032, linked to the gene ARHGEF12, is associated with the cup-to-disc ratio, a measure of glaucoma severity.
As of 2019, only two percent of all genome-wide studies have involved individuals of African descent. So, this study is significant because it aims to define subgroups of glaucoma, enable early screening, and determine pathways for personalized treatments. One advantage researchers had in this study was access to the Penn Medicine BioBank, a collection of biological samples linked to health records donated by Penn Medicine patients. These samples allow scientists to study new methods for disease detection, treatment, and prevention. Having access to this information allowed the researchers to validate the genetic effects they found in the group they studied.
“Without our focus on this specific ancestry group, these unique and critical insights might have remained lost,” said first author Shefali Setia Verma, PhD, an assistant professor in Pathology and Laboratory Medicine. “And we would not have been able to substantially enhance our understanding of the genetics behind primary open-angle glaucoma in this overaffected population.”
In Part Two, we’ll explore research focused on detecting glaucoma before symptoms occur. One area scientists are examining for early signs of glaucoma is the macula.