Although these and other published observations suggest that MMP9 is a compelling therapeutic target, previous efforts to target MMPs (including MMP9) utilized pan-specific or semi-selective inhibitors, and were unsuccessful due to dose-limiting side effects such as musculoskeletal syndrome (MSS) and/or to a general lack of clinical benefit [1, 17, 39, 82–84]. The gene discussed is MMP9; the disease is Marinesco-Sjogren syndrome.