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Aniridia is the clinical absence of the irides (although a circular stump of tissue is visible on gonioscopy) combined with severe amblyopia and nystagmus due to macular hypoplasia. Glaucoma is associated in 50% to 70% of cases, and usually occurs during the teenage years. Intraocular pressure should be measured yearly. Cataracts and altered corneas can also be seen. Aniridia caused by deletions in 11p, or type 2 aniridia, is sporadic in 15% of cases and is usually unilateral. In 20% of cases it is associated with nephroblastoma (Wilms tumor), especially when it is bilateral. Other congenital disorders such as genitourinary malformations and mental retardation are noted in 15% of cases, leading to diagnosis of the WAGR syndrome (Wilms, Aniridia, Genitourinary, Retardation). The genetically affected area is located on chromosome 11 (11p13), as is the PAX6 gene, a homeogene of the eye. When aniridia is diagnosed in a child, a genetic study including karyotyping and investigation of family history must be carried out to quickly determine whether the disorder is inherited or not. If the deletion in 11p13 is detected, annual sonograms are an absolute requirement. There is no specific treatment for aniridia. Treatment is adapted to each individual depending on the associated complications. |