APP and epilepsy: Analysis of the published data indicates that Aβ peptides in the brain in ASD, epilepsy, and self-injurious behavior are probably involved in several pathomechanisms, including (1) modulation of transcription—which result in increased APP and Aβ production; (2) induction of oxidative stress, and (3) tilting the excitatory and inhibitory balance in the neuronal networks through (a) activation and alteration of membrane receptors’ signaling; (b) formation of calcium channels causing hyper-activation of neurons and (c) reduction of the inhibitory GABAergic signaling.