HTRA1 and atrophic macular degeneration: However, while increased HTRA1 protein has been identified in iPSC-RPE cells from donors with homozygous risk at the 10q26 locus with AMD pathogenesis [18], as well as in aqueous humor of nAMD patients [65], and inhibition of HTRA1 with an anti-HTRA1 antibody has been suggested as a therapeutic avenue in geographic atrophy [66], a recent study using donor tissues showed that mRNA levels for HTRA1 are reduced in the RPE, but not in the retina or choroid of donors with homozygous risk at the 10q26 locus.