We have previously established a viable colony of cats with a spontaneously occurring, recessively inherited feline congenital glaucoma (FCG),13,14 which is an ortholog of human primary congenital glaucoma (PCG) at the GLC3D locus (Online Mendelian Inheritance in Man #613086) due to a mutation in LTBP2, a gene encoding latent transforming growth factor-β binding protein 2 (LTBP2).15 Here, LTBP2 is linked to primary congenital glaucoma.