APP and Alzheimer disease: For instance, the group led by Michel Goedert, who used MALDI-TOF mass spectrometry and LC-MS/MS to resolve the cryo-EM structure of Aβ42 filaments from human brains, recently indicated that Aβ3pE-42 was a minor variant in the brains of AD patients and App knock-in (KI) mice (Yang et al, 2022).