To assess the functional significance of the high‐risk allele composed of mutations in HTRA1/ARMS2 at 10q26, RPE from an AMD patient heterozygous (T‐in/del‐A; G‐wt‐G) at the 10q26 locus and a low‐risk homozygote (G‐wt‐G; G‐wt‐G) control at 10q26 locus was compared. The gene discussed is HTRA1; the disease is age-related macular degeneration.