CTLA4 and Vogt-Koyanagi-Harada disease: Since the risk genotype of rs733618 and rs231775, and the haplotype of rs4553808-rs5742909-rs231775-rs3087243 of CTLA-4 in PSS were completely different from those in VKH syndrome, we considered that CTLA-4 genetic background might be different between PSS and VKH syndrome (13).