ARMS2 and age-related macular degeneration: In this study, we identified the transcription factors binding to the in/del of the 3′UTR region of ARMS2. We also observed that overexpression of these transcription factors induced HTRA1 transcription in iPSCs derived from AMD patients as well as in the blood of CNV mice ubiquitously overexpressing Htra1. Further study demonstrated a significant increase of HTRA1 protein concentration in blood in both GA and CNV AMD patients carrying the in/del sequence compared with age-matched controls, indicating that AMD is also associated with an increase of blood circulating HTRA1.