Genetics in Glaucoma Patients of African Descent, the GIGA Study

Glaucoma is a leading cause of blindness in the world, and is particularly prevalent among persons of African descent. Genetic studies are currently investigating the causes for this disease, but have thus far only been performed in persons of European and Asian descent. With this project, we aim to find the genetic causes for glaucoma in African populations. This will help us understand why glaucoma is so common in Africa, provide us with knowledge on the causes of glaucoma, and help create means to cure and prevent this disease.

Primary open angle glaucoma (POAG) is most common form of glaucoma, and its causes are still largely unknown. Family history and ethnicity are important risk factors, supporting a genetic basis for this disease. In the past years, my research group in Rotterdam has made substantial contributions to the discovery of > 25 genes for POAG, glaucomatous optic nerve, and eye pressure. Unfortunately, these genes explain only a small fraction of POAG cases, leaving a large part of the disease background unclear.

Mostly European and Asian populations were enrolled in the genetic studies. Considering their prevalence and severity of POAG, African populations are a better choice. The prevalence of POAG is three to five times higher in Africans, and the disease has a much more dramatic course with a higher risk of blindness. We believe that these characteristics will facilitate the identification of new genetic risk factors for POAG, and lead the way to important disease pathways.

In collaboration with hospitals from Tanzania and South Africa, we collected a total of 1,500 POAG cases and unaffected controls of African descent. We aim to identify new genetic causes of POAG using genome-wide exome array analysis. Since identification of novel genes will require very large study samples, we will form a consortium with other studies of Africans and analyze our genetic findings jointly. This strategy will help reveal the genetic causes of POAG, and may open up new avenues for therapy and prevention.