Study of genetics in African Americans with glaucoma targets better care

By Cheryl Guttman Krader

Las Vegas-The Primary Open-Angle African American Glaucoma Genetics (POAAGG) study is an ongoing 5-year NIH-funded study designed to elucidate the genetic architecture and comorbidities associated with POAG in African Americans, said Joan M. O’Brien, MD.

Dr. O’Brien provided an update on the POAAGG study at the 2015 meeting of the American Academy of Ophthalmology.

Ultimately, the investigators hope that it will lead to the identification of genetic pathways that can be targeted in a precise manner in order to improve screening of patients at risk and allow application of targeted therapies to appropriate patient subsets, explained Dr. O’Brien, William F. Norris and George E. DeSchweinitz, professor and chairman, Department of Ophthalmology, University of Pennsylvania, Philadelphia.

As an ophthalmologist specializing in oncology, she explained her vision of the impact of the study in terms of managing breast cancer.

“I think glaucoma represents many different genetic diseases,” Dr. O’Brien said. “If I see someone with breast cancer metastasis to the eye, I would not just say, how should we treat this patient with breast cancer? Instead, I would say how should we treat this patient who has infiltrating intraductal breast cancer that is estrogen receptor positive, HER2 positive and has 2 out of 23 positive nodes.

“I think that someday, we will be deciding on treatment for glaucoma in exactly the same way,” she said.

To date, the POAAGG represents the largest genetic study of POAG in an African American population. It has an intended enrollment of 7,765 subjects, including 3,000 cases and 47,65 controls, although Dr. O’Brien said that target may be exceeded.

The study population consists of self-identified blacks, ages 35 years and older, identified from the Scheie Eye Institute and its research affiliates in Philadelphia.

All subjects undergo a complete glaucoma examination and interview by a glaucoma specialist. Cases, suspects, and controls are determined by fellowship-trained glaucoma specialists based on specific criteria. Glaucoma is defined as optic nerve disease that is glaucomatous in nature and that correlates with visual field defect.

The specific aims of the study are to conduct a comprehensive genetic analysis of POAG in African Americans, including genome-wide and exome-wide association analysis, admixture analysis, and mapping.

In addition, it will conduct a comprehensive genetic analysis of quantitative traits that are associated with POAG to better understand the role of genetic factors in the development of POAG in African Americans.

As of April 2015, 1,503 cases and 1,149 controls had been enrolled. Of the cases, more than 95% had bilateral glaucoma, almost two-thirds were using glaucoma medications, and one-third had a history of glaucoma surgery.

A second control group of African American patients from the Penn Medicine Biobank has been added.