In PAX6-related ocular disease, haploinsufficiency gives rise to a range of phenotypes; the majority of loss-of-function alleles result in classic aniridia (with full iris and foveal hypoplasia, nystagmus, cataract, glaucoma and corneal keratopathy [211]) and missense mutations in the DNA-binding paired domain result in a milder phenotype, such as dominant nystagmus with foveal hypoplasia and normal irides [212]. Here, PAX6 is linked to pathologic nystagmus.