**7. Amyloid plaques**

Even though amyloid plaques can be categorized into different groups depending on their structure, all types of -amyloid protein (A) are present in them. When APP is degraded proteolytically by - and -secretase, an amino acid peptide known as A is produced. The primary results of this cleavage are A1–40 and A1–42. The development of amyloid oligomers and fibrils, which come together to form amyloid plaques, is predisposed by a relative excess of A1–42. Since the generation, processing, and/or trafficking of amyloid is connected to the proteins encoded by APP, PS1, PS2, SorL1, and ApoE, this suggests that amyloid plays a significant role in the etiology of AD [37].
