For example, purinergic receptors are found on cells within the retinal pigment epithelium (Tovell and Sanderson, 2008; Wan et al., 2011), and death or dysfunction of RPE cells could also lead to photoreceptor loss as is observed in other models of retinal degeneration such as sodium iodate (NaIO3) phototoxicity (Enzmann et al., 2006). The gene discussed is P2RX7; the disease is retinal degeneration.