CTLA4 and vitiligo: Genome-wide association studies (GWAS) have identified more than 50 genetic risk variants for vitiligo, including genes related to cytolysis (GZMB, CTLA4, FOXP3) (Birlea et al. 2011; Jin et al. 2016, 2010) and melanocyte function (TYR, MC1R, XBP1) (Jin et al. 2012, 2007; Ren et al. 2009).