NPTX2 and Alzheimer disease: SST decorrelated at the transcript layer (0.51 → 0.30) while over-correlating modestly at the RNA–protein layer (0.31 → 0.37); separation increased from D = 0.86 to D = 0.99, moderate to moderate-to-strong, indicating lower SST RNA together with lower NPTX2 protein in AD (Fig. 3H and 3I).