Putting this information together, the researchers hypothesized that a defect in CD36 might cause the characteristic retinal atrophy (by preventing the phagocytosis of worn-out photoreceptor outer segments) and choroidal involution (by preventing the induction of COX2 expression and consequently the maintenance of the blood vessels in the choroid) of dry AMD. Here, PTGS2 is linked to dry age related macular degeneration.