To examine the relation among serum cholesterol, apolipoprotein E genotype (APOE), and the risk of early and late age-related macular degeneration (AMD).
To study the genotypes, allelic frequencies, and polymorphisms of apolipoprotein E (Apo E) in unrelated Japanese patients with polypoidal choroidal vasculopathy (PCV) or exudative age-related macular degeneration (AMD) and control subjects without macular degeneration.
Despite extensive genetic screening of candidate genes only two associations have been identified with AMD (Adenosine triphosphate (ATP)-binding cassette rim (ABCR) protein and apolipoprotein E gene-ApoE).
Our studies on candidate genes of eye diseases in the Chinese population in Hong Kong include MYOC and TISR for primary open angle glaucoma, RHO and RP1 for retinitis pigmentosa, ABCA4 and APOE for age-related macular degeneration, RB1 for retinoblastoma, APC for familial adenomatous polyposis with congenital hypertrophy of retinal pigment epithelium, BIGH3/TGFBI for corneal dystrophies, PAX6 for aniridia and Reiger syndrome, CRYAA and CRYBB2 for cataracts, and mtDNA for Leber hereditary optic neuropathy.
Apolipoprotein E is a common component of the extracellular plaques and deposits characteristic of these disorders, including drusen, which are a hallmark of age-related macular degeneration.
Age-related macular degeneration (ARMD), characterized by drusen containing lipids, was reported to show a lower frequency of the ApoE epsilon4 allele than control subjects.
This lower relative frequency of the epsilon4 allele supports the hypothesis that the ApoE gene is a genetic protective factor identified in age-related macular degeneration.