A tremendous worldwide push for glaucoma research has yielded many exciting breakthroughs, including the discovery of new gene variants associated with primary open-angle glaucoma (POAG). This gives researchers hope that genetic screening can one day be used to identify and direct treatment for people who are at greatest risk of losing their sight. Together these studies have more than doubled the number of gene variants associated with POAG—the most common form of glaucoma disease.
What Studies Were Conducted?
One of the BrightFocus sponsored studies came out of Australia and was co-led by Jamie Craig, PhD. The study identified three genes as having a significant association with primary open-angle glaucoma (POAG), the most common form of glaucoma and one of the top causes of blindness worldwide.
A second study, also sponsored in part by BrightFocus and also co-authored by Craig and several Australian researchers, identified new genetic variations that can influence susceptibility to glaucoma in individuals of multiple ancestry.
The final study, this one conducted in China and unique for being the first large-scale study of POAG in an Asian population, associated the variants near two genes with a risk of glaucoma in people from China and Singapore.
What Did We Learn?
The objective of genome-wide association studies (GWAS) such as these is to examine common genetic variants among a large group of individuals to determine which variants, if any, are associated with different traits. In the case of the above studies, the goal was to look at genes that have previously been associated with various forms of glaucoma and then to look closely at the genetic coding to find subtle variations, technically known as “single-nucleotide polymorphisms” (SNPs), that exist between people with and without the disease.
In the Australian study, the discoveries by Craig et al came from comparing genetic information from a cohort of 1,555 patients enrolled in the Australian and New Zealand Registry of Advanced Glaucoma with that of 1,992 normal controls. Once the research team had identified possible SNPs associated with POAG, the findings were cross-checked with genetic data from two other study cohorts in Australia and two in the United States, altogether comprising more than 10,000 patients. The combined data showed the SNPs (sometimes referred to as “loci”) to be located near or within the three genes—ABCA1, AFAP1, and GMDS—all of which are expressed in three components of the human eye: the retina, optic nerve, and trabecular meshwork.
BrightFocus Vice President of Scientific Affairs Guy Eakin, PhD, characterized the results as a “huge win” in the glaucoma field. “Clearly, the investment we’ve made in these individual scientists is paying off in innovative, collaborative research,” he said. Eakin was especially interested to hear about the role of ABCA1, which is genetically associated with Alzheimer’s disease—another area of research that BrightFocus supports.
Initially, it’s likely that findings from all three studies will be used to develop “risk profiles” for people diagnosed with glaucoma. This will help clinicians and patients reach an informed decision about whether the disease should be treated aggressively at an earlier stage in order to preserve sight.
However, making use of the findings in this way will also take additional research. As Craig explained, “we are looking at ways to add up a genetic risk profile. If you've got a larger load of these variant genes, your risk is high.” As he indicated, additional research is required before it will be possible to apply these new findings in this way—but with these latest discoveries, the goal draws closer.
This Promising Science article is excerpted from a longer article by BrightFocus Health and Science Writer Martha Taggart, "Researchers ‘Strike Gold’ with Discovery of New Gene Variations Associated with Glaucoma."
BrightFocus is a foundation created to support continued research to advance the treatment of Alzheimer’s, glaucoma, and macular degeneration. If you’re interested in reading about more of the breakthroughs we’ve helped sponsor, visit the research we fund section.
This content was last updated on: June 29, 2015