RTN1 and Alzheimer disease: Many AD‐related molecules were on the top‐altered proteins, that is, the most altered molecules in clusters 1 and 4, such as synaptophysin (SYP), 14‐3‐3 protein zeta/delta (YWHAZ), reticulon‐1 (RTN1), and complement component C8 beta chain (C8B) (Figure 1D).