COL2A1, WDPCP and HMX1 are linked with syndromic and systemic retinopathy and autosomal dominant or recessive retinal degeneration; CRB1 is linked to early onset Leber congenital amaurosis (LCA8), and a severe form of autosomal recessive retinitis pigmentosa (RP12); and EFEMP1 mutations affect RPE cells and are associated with both Malattia Leventinese and Doyne honeycomb retinal dystrophy. The gene discussed is HMX1; the disease is retinitis pigmentosa 12.