RXRA and Keratoconjunctivitis sicca: Du et al. reported the Pinkie mouse strain, with a loss of function RXRα mutation (I273N) (12) that alters ligand binding and heterodimerization resulting in a 90% decrease in ligand-inducible transactivation, develops signs of dry eye with aging, but the study did not evaluate the ocular surface disease and immunopathology (12).