A number of studies have reported variable findings regarding the CSF levels of MMPs and TIMPs in patients with AD, such as increased or decreased levels of MMP-3 [8,32,41,42], increased or undetectable levels of MMP-9 and MMP-10 [42,54], increased or decreased levels of TIMP-1 [32,42], and increased levels of TIMP-2 [55] compared to controls. This evidence concerns the gene MMP9 and Alzheimer disease.