Mattsson et al., in a larger study, investigated the role of age in AD-related CSF biomarkers, i.e. Aβ42, T-tau and P-tau and concluded that there was an age-dependent effect on the levels of these biomarkers, complicating the differentiation between elderly patients with AD and the control group as compared to the younger patient/control group, since the normal ageing process and AD-related pathology presented similar changes [36]. This evidence concerns the gene MAPT and Alzheimer disease.