A phenomenon observed in Alzheimer’s disease (AD) and Parkinson’s disease (PD), where amyloid-associated proteins propagate within the neuronal system of patients (amyloid-β-peptide (Aβ) and tau for AD, and alpha-synuclein for PD) (Banerjee et al, 2024; Duyckaerts et al, 2019). This evidence concerns the gene MAPT and Parkinson disease.