[Development of the iridocorneal angle and congenital glaucoma]

The trabecular meshwork originates from cells of the neural crest which migrate to the iridocorneal angle during embryonic and fetal development of the eye. Correct morphogenesis of trabecular outflow pathways requires the differentiation of the cells to a porous and lamellate meshwork as well as the ingrowth of Schlemm's canal and posterior movement of the iris root. A failure in these processes is responsible for primary congenital or infantile glaucoma which presents with increased resistance to aqueous humor outflow resulting in increased intraocular pressure. Most cases appear to be of a sporadic nature but hereditary cases are often caused by mutations in the CYP1B1 gene which encodes for the enzyme cytochrome P450 1B1. Mutations cause a reduction in enzymatic activity which probably leads to diminished turnover of an as yet unidentified metabolite taking part in the signaling processes essential for formation of the trabecular meshwork and Schlemm's canal. More rarely, mutations in latent transforming growth factor beta binding protein 2 (LTBP2) or in the transcription factor FOXC1 have been described as causative for primary congenital glaucoma.