Retinal tissues (including retina, retinal pigment epithelium, and choroid) were punched from the macula of fresh frozen eyes retrieved within 24 hours of death from 24 unrelated white subjects (mean [SD] age, 76.4 [14.5] years) without any known eye diseases, and RNA was extracted with the RNeasy lipid tissue kit (Qiagen Inc, Valencia, California). The RNA was also extracted from whole blood samples of 52 white subjects including 46 cases (mean [SD] age, 79.0 [7.5] years; 50% female) and 6 controls (mean [SD] age, 72.7 [10.5] years; 67% female) using the PAXgene Blood RNA System Kit (PreAnalytiX, Venlo, the Netherlands). Procedures for recruitment, requests for medical records, and consent forms were approved by the University of Miami, Miller School of Medicine Institutional Review Board. Quantitative polymerase chain reaction was performed using an ABI HP7900 (Applied Biosystems, Carlsbad, California). Each sample was repeated 3 times at different locations in the plate. After the polymerase chain reaction run was complete, quantitative gene expression data were acquired and analyzed using the ABI Prism 7900HT Sequence Detection System (RQ manager) (Applied Biosystems). The overall experiment was repeated twice. The t test was applied to compare the difference in the HTRA1 level between the genotypes at rs11200638.