PITX2 and Axenfeld-Rieger syndrome: Although both FOXC1 and PITX2 mutations in humans are associated with ARS phenotypes,13, –15 the ocular defects observed in NC-specific Pitx2 mutant mice are somewhat different from those seen in either single NC-Foxc or compound NC-Foxc1;NC-Foxc2 homozygous mutants.