Mutations in CRX cause a spectrum of retinal disease phenotypes (Sohocki et al., 1998), including dominant CRD (Freund et al., 1997; Swain et al., 1997), RP and dominant as well as recessive LCA, in which marked retinal degeneration is already evident at birth (Rivolta et al., 2001; Swaroop et al., 1999). The gene discussed is CRX; the disease is Leber congenital amaurosis.