In abdominal aortic aneurysm (AAA), often described for its wide degradation of the aortic wall matrix, remodeling and further rupturing of the wall, Qin et al. (9) in a murine model, provide evidence of cathepsin S’s role in the formation of AAA and suggest cathepsin S as a new therapeutic target for preventing AAAs in humans. The gene discussed is CTSS; the disease is achalasia-alacrima syndrome.