Gene protecting against age-related macular degeneration

Age-related macular degeneration (ARMD) is the most common cause of blindness in the elderly in Europe and in the United States ARMD is a multifactorial disease process corresponding to a thinning or scarring of the center of the retina, the macula. Some risk factors that have been associated with ARMD include less skin pigmentation, cigarette smoking, systemic hypertension, low intake of antioxidants and family history The main clinical retinal markers of ARMD are drusen, which are composed of protein and lipid deposits within the Bruch's membrane. The lipid composition of drusen and the possible influence of genetic susceptibility risk factors prompted us to consider the gene coding for a protein involved in lipid transport, apolipoprotein E (APOE), as an interesting candidate risk factor for ARMD occurrence. In a case control study, we compared patients with exudative ARMD to controls of similar age and gender. We observed a lower frequency of the APOE epsilon 4 allele in patients with exudative ARMD. For non APOE epsilon 4 allele bearers, the relative risk of developing exudative ARMD was almost five-fold higher than for APOE epsilon 4 allele bearers. This intriguing protective effect of the APOE epsilon 4 allele, which is commonly known to be deleterious for the vascular system and cognitive performance, opens up several questions related to disease origin, gene evolution and genetic testing.