Aniridia is a congenital, bilateral ocular malformation defined as iris aplasia or hypoplasia. It can be either isolated or accompanied by other ocular defects. Aniridia is caused by decreased dosage of the PAX6, a master regulatory gene that induces eye formation in a broad range of animals. Recently, it has been reported that aniridia is also caused by heterozygous mutations in the ELP4 gene and TRIM44 gene.
