PAX6 and isolated aniridia: For example, most cases of hereditary aniridia are caused by heterozygous LOF coding variants within PAX6. However, hereditary aniridia can also be caused by SNVs within a PAX6 enhancer located 150 kb downstream of the PAX6 promoter that disrupt a PAX6 autoregulatory element, causing loss of enhancer activity and subsequent loss of PAX6 transcription (Bhatia et al. 2013).