The identified genes account for approximately 70%–80% of LCA/EOSRD cases (table 1, figure 1 and below), with GUCY2D, CEP290, CRB1, RDH12 and RPE65 being the most common.9 16–19 It has been possible to identify certain characteristic associated phenotypes (figure 2 and below): RDH12-associated disease, which gives rise to an EOSRD phenotype is characterised by early-dense intraretinal pigment migration pigmentation and maculopathy. The gene discussed is GUCY2D; the disease is Leber congenital amaurosis.