USH2A and retinitis pigmentosa 1: Intriguingly, almost two thirds of the solved cases of pericentral RP (i.e. 14 out of 22) harbored putatively pathogenic mutations in genes involved in ciliary development and function, such as BBS2 (one case), CEP290 (two cases), RP1 (two cases) and USH2A (nine cases) (Figure 2c).