**4.3 Primary congenital glaucoma models**

Knockout of *Foxc1* and *Foxc2*, genes involved in embryonic and ocular development, in mice causes death during the embryonic or neonatal periods [66]. Heterozygous *Foxc1*+/*−* mice have defects in ocular drainage structures, but do not see elevation of IOP. Moreover*, Cyp1b1* KO animals develop ocular defects comparable to human congenital glaucoma, presenting with rudimentary Schlemm's canal, abnormalities in the trabecular meshwork, adhesion of the iris to the trabecular meshwork and peripheral cornea [15]. Another model was described in an albino quail population with a similar phenotype, but due to small size, limited availability, and difficult clinical translation, it is rarely used [11].
