On the contrary, Parnetti et al. [32], in a study employing 90 MCI patients followed for up to 4 years, stated that the performance of the Aβ42/40 ratio was not superior to Aβ42 alone and that the Aβ42/p-tau ratio was the best parameter to predict conversion to AD in MCI patients. Here, MAPT is linked to Alzheimer disease.