NPTX2 and Alzheimer disease: SCG2 displayed a broader weakening across layers: transcript correlation decorrelated from 0.57 to 0.36 and RNA–protein correlation fell from 0.28 to 0.25; separation rose from D = 0.72 to D = 1.04, reflecting strong group separation and joint reductions of SCG2 RNA and NPTX2 protein in AD (Fig. 3J and 3K).