Identification of novel genetic loci for intraocular pressure: A genomewide scan of the beaver dam eye study

Objective: To identify genetic loci that control intraocular pressure (IOP). Methods: We performed a genomewide scan of IOP, using 486 pedigrees ascertained through a populationbased cohort, the Beaver Dam Eye Study. Linkage analysis was performed using the modified Haseman-Elston regression models and variance components linkage analysis. Results: Seven regions of interest were identified on chromosomes 2, 5, 6, 7, 12, 15, and 19. The novel linkage region on chromosome 19p had an empirical multipoint P value of 6.1 × 10-5. Two of the regions (2 and 19) were especially interesting since each has been identified as a potential linkage region for blood pressure. Conclusions: The results of this genomewide scan provide evidence that a quantitative trait locus may influence elevated IOP and may colocalize with blood pressure loci. These loci may control systemic pressure reflected in the eye and vascular system. Clinical Relevance: Glaucoma is a leading cause of blindness in the world, and the identification of genes that contribute to this disease is essential. Elevated IOP is a principal risk factor for primary open-angle glaucoma and an intriguing quantitative trait that may strongly influence the development of disease.