PAX6 and isolated aniridia: Missense variants are usually linked with the autosomal inheritance form, while sporadic cases are more often caused by deletions or rearrangements of the PAX6 gene locus and, in some cases, may lead to WAGR syndrome (Wilms tumor, aniridia, genitourinary abnormalities, and mental retardation) or a Wilms tumor alone, due to the proximity of the WT1 tumor suppressor gene [40].