Myocilin, also known as Trabecular meshwork-induced glucocorticoid response protein, MYOC and GLC1A, is a protein which contains one olfactomedin-like domain. Myocilin / MYOC may participate in the obstruction of fluid outflow in the trabecular meshwork. Myocilin / MYOC is expressed in large amounts in various types of muscle, ciliary body, papillary sphincter, skeletal muscle, heart and other tissues. Myocilin / MYOC is expressed predominantly in the retina. In normal eyes, it is found in the inner uveal meshwork region and the anterior portion of the meshwork. In contrast, in many glaucomatous eyes, it is found in more regions of the meshwork and appeared more intensively than in normal eyes, regardless of the type or clinical severity of glaucoma. Defects in Myocilin / MYOC may contribute to primary congenital glaucoma type 3A (GLC3A). Defects in MYOC may also contribute to this phenotype via digenic inheritance. GLC3A is an autosomal recessive form of primary congenital glaucoma (PCG). PCG is characterized by marked increase of intraocular pressure at birth or early choldhood, large ocular globes (buphthalmos) and corneal edema.