APOE and age-related macular degeneration: Homozygous APOE2-allele carriers are at increased risk for developing late AMD (recently confirmed in 20,000 subjects (McKay et al, 2011)) and are protected against Alzheimer's disease (AD), while the APOE4 allele protects against AMD and is a risk factor for AD (Mahley & Rall, 2000).