Low CSF APP refines diagnosis for <i>p</i> ‐tau negative Alzheimer‐like dementia

Individuals with low APP levels (APP positive) or elevated p-tau181 (p-tau181 positive) had the highest prevalence of AD-like dementia, with the risk being greatest in those positive for both markers. These results reveal a unique biological profile for T- status in clinically diagnosed AD, who are a complex and under-explored patient group, and highlight opportunities for enhancing diagnostic refinement. Given that APP influences neuronal plasticity, memory, synaptogenesis, and maintenance of neuronal iron homeostasis, our findings suggest that disruptions in APP production and processing may contribute to disease progression.