Memory and Plasma pTau217 Refine Prognosis in Down Syndrome.

Individuals with Down syndrome (DS) are at high risk for Alzheimer's disease (AD), yet accessible tools for routine clinical screening of AD in individuals with DS remain limited. Using data from the Alzheimer Biomarker Consortium-Down Syndrome (ABC-DS), we show that integrating plasma pTau217 with performance on the modified cued recall task identifies a subgroup of cognitively stable individuals at markedly elevated risk of developing clinical impairment in the next 7 years. This low-burden, multimodal framework improves prognosis, supports more informed clinical management and efficient trial enrichment in Down syndrome. ANN NEUROL 2026.