HTRA1 and age-related macular degeneration: One mode by which HTRA1 may modulate AMD pathogenesis is by compromising the integrity of the Bruch’s membrane,[26] which may lead to increased diffusivity of inflammatory or angiogenic factors across Bruch’s membrane.[40] In a normal eye, the choroidal vasculature is well-defined and is separated from the neural retina via Bruch’s membrane and the RPE.