BLOC1S3 and Leber congenital amaurosis: LCA is a genetically heterogeneous disease, and to date, 14 causative genes were identified for LCA (RetNet -- Retinal information Network1); one of these is RPGRIP1 (retinitis pigmentosa [RP] GTPase regulator interacting protein), which is responsible for approximately 5–6% of all LCA cases (Dryja et al., 2001; Gerber et al., 2001).