DUSP4 maintained a stable transcript correlation with NPTX2 (0.59 vs. 0.58) but decorrelated at the RNA–protein layer (0.34 → 0.22); separation increased from D = 0.54 to D = 0.97, moving from little to moderate-to-strong, indicating joint reductions of DUSP4 RNA and NPTX2 protein in AD (Fig. 3B and 3C). Here, DUSP4 is linked to Alzheimer disease.