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 population-based 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 x 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.