Open-angle glaucoma (OAG) is the most common type of Glaucoma. Glaucoma is a group of eye conditions that can damage the optic nerve which is responsible for transmitting images to the brain. Commonly such optic nerve damage is caused by increased pressure in the eye known as intraocular pressure. In OAG, the increase in pressure is often small and progresses slowly over time. The exact cause of the pressure increase in OAG remains unknown and usually cannot be felt by patients. The resulting damage to the optic nerve causes blind spots in the vision.
OAG tends to run in families, with an increased risk for individuals who have a parent or grandparent with the condition. Additionally, people of African descent are at a higher risk of developing the disease. Juvenile or early onset OAG is a rare type of primary open-angle glaucoma (POAG) that is caused by genetic variations. The MYOC gene, a gene heavily associated with early onset POAG encodes a protein called myocilin which is found in trabecular meshwork and the ciliary body, a structure in the eye that regulates the intraocular pressure.
Approximately 10-33% of individuals with early onset of POAG have variants in the MYOC gene. These variants can occur from genetic inheritance but also from external sources such as virus infection. MYOC gene variants have also been detected in some individuals with primary congenital glaucoma.
Mutations in the TMCO1 gene also appear to be associated with POAG in certain populations but not in others. Specifically how these genetic variations affect OAG remains unknown.
