Linear regression models with the global FDG-PET or PiB-PET signal to reference region (cerebrum to cerebellum or to pons or to thalamus ratios) as dependent variables with KLK6, KLK8 or KLK10 as independent variables, respectively, were calculated in a sub-cohort of 14 AD patients. This evidence concerns the gene KLK6 and Alzheimer disease.