Aniridia is an eye disorder characterized by a complete or partial absence of the colored part of the eye (the iris). These iris abnormalities may cause the pupils to be abnormal or misshapen. Aniridia can cause reduction in the sharpness of vision (visual acuity) and increased sensitivity to light (photophobia). Aniridia may occur either as an isolated eye abnormality or as part of the Wilms tumor-aniridia-genital anomalies-retardation (WAGR) syndrome.
People with aniridia can also have other eye problems including increased pressure in the eye (glaucoma), clouding of the lens of the eye (cataracts), or underdevelopment of the structures that carry information from the eyes to the brain (optic nerves). Individuals with aniridia may also have involuntary eye movements (nystagmus) or underdevelopment of the region at the back of the eye responsible for sharp central vision (foveal hypoplasia). Many of these eye problems contribute to progressive vision loss in affected individuals. The severity of symptoms is typically the same in both eyes. Rarely, people with aniridia have behavioral problems, developmental delay, and problems detecting odors.
Aniridia may be caused by mutations in the PAX6 gene and is inherited in an autosomal dominant pattern. Source: Genetic and Rare Diseases Information Center (GARD), supported by ORDR-NCATS and NHGRI.