Glaucoma is a leading cause of blindness that involves loss of retinal ganglion cells and degeneration of the optic nerve [1]. Glaucoma is usually associated with high intraocular pressure (IOP) that results from an increased resistance to drainage of the ocular fluid [1]. Developmental disorders of the ocular anterior segment, including Axenfeld-Rieger syndrome, are often associated with elevated IOP and glaucoma [1,2]. The developmental sequence and structure of the human and mouse ocular drainage structures are similar [3], and the same genes are known to cause anterior segment dysgenesis (ASD) in humans and mice. Known genes that cause anterior segment dysgenesis code for developmentally important transcription factors. These genes include PITX2, PITX3, PAX6, FOXC1 (previously known as FKHL7 and FREAC3), Foxc2 and FOXE3[4-9]. Activity levels for these transcription factors normally associated with diploid gene dosage are important for normal ocular development, with heterozygosity for null mutations in most of these genes causing anterior segment dysgenesis. For FOXC1 and PAX6, both haploinsufficiency and increased gene dosage due to gene duplication result in abnormal ocular development [10-13]. Similarly, a mutation in PITX2 that results in increased transcriptional transactivation causes ASD [14].