Primary open-angle glaucoma (POAG) affects 33 million individuals worldwide and is a leading cause of blindness. In a study of 54 families with autosomal dominantly inherited adult-onset POAG, we identified the causative gene on chromosome 10p14 and designated it OPTN (for "optineurin"). Sequence alterations in OPTN were found in 16.7% of families with hereditary POAG, including individuals with normal intraocular pressure. The OPTN gene codes for a conserved 66-kilodalton protein of unknown function that has been implicated in the tumor necrosis factor-alpha signaling pathway and that interacts with diverse proteins including Huntingtin, Ras-associated protein RAB8, and transcription factor IIIA. Optineurin is expressed in trabecular meshwork, nonpigmented ciliary epithelium, retina, and brain, and we speculate that it plays a neuroprotective role.

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We recently reported three truncating mutations of the cytochrome P4501B1 gene (CYP1B1) in five families with primary congenital glaucoma (PCG) linked to the GLC3A locus on chromosome 2p21. This could be the first direct evidence supporting the hypothesis that members of the cytochrome P450 superfamily may control the processes of growth and differentiation. We present a comprehensive sequence analysis of the translated regions of the CYP1B1 gene in 22 PCG families and 100 randomly selected normal individuals. Sixteen mutations and six polymorphisms were identified, illustrating an extensive allelic heterogeneity. The positions affected by these changes were evaluated by building a three-dimensional homology model of the conserved C-terminal half of CYP1B1. These mutations may interfere with heme incorporation, by affecting the hinge region and/or the conserved core structures (CCS) that determine the proper folding and heme-binding ability of P450 molecules. In contrast, all polymorphic sites were poorly conserved and located outside the CCS. Northern hybridization analysis showed strong expression of CYP1B1 in the anterior uveal tract, which is involved in secretion of the aqueous humor and in regulation of outflow facility, processes that could contribute to the elevated intraocular pressure characteristic of PCG.

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