HTRA1 and age-related macular degeneration: iPSCs derived from the cells of patients with age-related macular degeneration allowed these scientists to analyze the downregulatory action of the age-related maculopathy susceptibility 2/high-temperature requirement A serine peptidase [ARMS2/HTRA1) risk alleles on superoxide dismutase 2 (SOD2) defense, which they found may be ultimately responsible for oxidative damage to the RPE [31].