In humans, the retinoic acid synthesis pathway including the genes ALDH1A3 (aldehyde dehydrogenase 1 family, member A3; OMIM 600463), RARB (retinoic acid-binding receptor B; OMIM 601972) and STRA6 (stimulated by retinoic acid 6; OMIM 610745) was discussed being one of the major causes of microphthalmia or even anophthalmia (Williamson and FitzPatrick 2014). This evidence concerns the gene RARB and microphthalmia.