Are γ-secretase and its associated Alzheimer's disease γ problems?

Presenilins (PS1 and PS2) and the amyloid-β precursor protein (AβPP) are the only known proteins as causing monogenic Alzheimer's disease. AβPP is not the unique substrate of the γ-secretase complex. Presenilins are also implicated in the processing of Notch, an important developmental protein, which is thought to compete directly with AβPP for cleavage by γ-secretase.