P4HB and open-angle glaucoma: We identified SNPs associated with POAG in both the Salt Lake City and San Diego populations in PDIA5 (PDIR), a protein disulfide isomerase which facilitates the formation of disulfide bonds during protein folding and is associated with the UPR (Tables S3 and S4), and in BIRC6 (BRUCE, APOLLON), which encodes a ubiquitin ligase that protects against apoptosis (Tables S5 and S6) [21], [22].