BMP4 and open-angle glaucoma: We hypothesize that sub-clinical mutations/polymorphisms in FOXC1, TGFβ2, and BMP4 may produce subtle and undetected abnormalities in anterior segment structure and function, which predispose to glaucomatous optic neuropathy through the effects of raised IOP and may be a significant susceptibility factor for the development of OHT and POAG.