APP and amyotrophic lateral sclerosis: AEP has previously been reported to cleave aggregate-forming proteins, such as amyloid precursor protein (APP), microtubule associated protein tau (MAPT) and TAR-DNA binding protein 43 (TDP43) and is also implicated in an FTLD-related disorder, amyotrophic lateral sclerosis (ALS) [32, 48–51].