The most common cause of aniridia is pathogenic variants in the PAX6 gene, accounting for up to 90% of cases (Hingorani et al., 2012), with FOXC1, PITX2, and a few other genes explaining some of the remaining cases (Hall et al., 2019; Hingorani et al., 2012) but still leaving about 5%–10% of aniridia genetically unexplained. The gene discussed is PITX2; the disease is aniridia.