This decision was made due to the small number of APOE ε4+ individuals in the CU group, which could compromise the statistical power of the analysis. Furthermore, the correlation analysis between MMP-9, TIMP-1, and the MMP-9/TIMP-1 ratio with Ab42/40, p-tau, and t-tau was not conducted in AD patients compared to CU individuals. This evidence concerns the gene MMP9 and Alzheimer disease.