Hereditary aniridia results from a dysfunction of the regulatory gene PAX6. In aniridia 1 (106210) the PAX6 gene (a transcription regulator) gene itself contains mutations. In anirdia 2 (617141) the mutation occurs in the ELP4 gene, whose product is a cis-regulatory enhancer of PAX6.
Aniridia 3 results from heterozygous mutations in the TRIM44 gene (11p13). The TRIM44 gene is a negative regulator which normally suppresses the expression of PAX6 and the reported missense mutation (p.G155R) enhances its activity.