APP and Alzheimer disease: Other studies have investigated amyloid precursor protein (APP) and its glycosylation pattern and specificity in AD considering that one of the big hallmarks of this multifactorial disease is the accumulation of the β-amyloid peptide (Aβ) within the brain (Zhang et al., 2011), Aβ being the end product of sequential cleavages of APP that occur in the amyloidogenic pathway.