On screening these patients for mutations in myocilin (MYOC), another glaucoma-associated gene, using denaturing high-performance liquid chromatography followed by sequencing, we identified a patient who was double heterozygous at CYP1B1 (c.1103G>A; Arg368His) and MYOC (c.144G>T; Gln48His) loci, suggesting a digenic mode of inheritance of PCG.