Our data extends these findings by demonstrating a graded decline, with reductions already evident at the MCI stage (NPTX2 RNA: p ≈ 0.07, NPTX2 protein: p ≈ 0.09) but more significant at AD stage (NPTX2 RNA: p ≤ 0.001, NPTX2 protein: ≈ 0.001). Here, NPTX2 is linked to Alzheimer disease.