To investigate the functional significance and tissue localization of the HtrA1 protein in human retinas form healthy subjects and AMD patients, we used Immunohistochemistry to re-confirm that HTRA1 is expressed intracellularly in the RPE layer and in the BM (Figs. 1A and S1) (Yang et al., 2006). This evidence concerns the gene HTRA1 and age-related macular degeneration.