This may help to explain the earlier onset of macular abnormalities, which are known to be associated with PRPH2 mutations, in patient 9,472; at age 20, a bull's eye maculopathy with significant abnormalities of the retinal pigment epithelium was observed, whereas his sibling 12,273 at age 22 did not show any significant macular abnormality. The gene discussed is PRPH2; the disease is Bull's eye maculopathy.