These PAX6 target genes give rise to diverse ocular phenotypes when mutated in humans: missense mutations in SIX3 cause microphthalmia, coloboma and holoprosencephaly (MIM #157170); FOXC1 mutations cause anterior segment dysgenesis (MIM #601631), and alpha A-crystallin (CRYAA) mutations cause cataract (MIM #604219). Here, CRYAA is linked to holoprosencephaly.