"Aniridia" means "without an iris." The iris is the colored part of the eye, and is important for controlling how much light gets inside the eye. It is also important for functioning of the front of the eye, and when there is a problem with the iris other parts of the eye may also be affected. Eyes with aniridia are prone to glaucoma and clouding of the cornea. In addition, most people with aniridia have an abnormal fovea, the very center of the retina and the only place the eye can see detail. Some people have complete aniridia with all of these features and no iris at all. But others have just parts of the syndrome, and may have part of the iris. Most of the time aniridia is caused by mutations in the PAX6 gene. Sometimes it is caused by a deletion of the PAX6 gene which also includes deletion of a tumor suppressor gene next to it. People with this type of aniridia have a high risk of malignant kidney tumors, so genetic testing is important in aniridia. People with a known risk can have regular testing with treatment before there is a serious problem.
Vision for Tomorrow Foundation: Aniridia
Aniridia Foundation International
Research to Prevent Blindness
The John and Marcia Carver Nonprofit Genetic Testing Laboratory