A genomewide scan identifies novel early-onset primary open-angle glaucoma loci on 9q22 and 20p12

Glaucoma is a leading cause of blindness worldwide. The disease is characterized by a degeneration of the optic nerve, which is usually associated with elevated intraocular pressure. The common form of adult-onset primary open-angle glaucoma is inherited as a complex trait, whereas the rarer early-onset juvenile open-angle glaucoma (JOAG) exhibits autosomal dominant inheritance. Of all cases of JOAG, approximately 10%-20% are caused by mutations in the myocilin gene. We have identified 25 pedigrees that are affected with typical JOAG and that demonstrate autosomal dominant inheritance. We sequenced the myocilin gene in probands from each family and found mutations in 8% of this population. To identify novel genes responsible for JOAG, we used families that did not have myocilin mutations for a genomewide screen. Markers located on chromosomes 9q22 and 20p12 showed evidence for linkage, identifying two novel loci for early-onset open-angle glaucoma.