Decoding Alzheimer's disease through down syndrome: insights from a genetically defined population.

Area of Science:

• Neurology
• Genetics
• Biomarker Research

Background:

• Down syndrome (DS) individuals invariably develop Alzheimer's disease (AD) neuropathology by age 40.
• DS provides a genetically defined model for studying AD pathogenesis.
• Understanding DS-AD informs broader Alzheimer's disease research.

Purpose of the Study:

• To review Alzheimer's disease (AD) in individuals with Down syndrome (DS).
• To examine the genetic basis, epidemiology, biomarker trajectories, and clinical trial innovations in DS-AD.
• To highlight how DS research informs broader AD pathogenesis, early detection, and therapeutic strategies.

Main Methods:

• Longitudinal biomarker studies (e.g., ABC-DS) tracking amyloid, tau, and neurodegeneration.
• Analysis of plasma and CSF biomarkers (Aβ42, p-tau, NfL, GFAP).
• Utilizing neuroimaging modalities (amyloid/tau PET, MRI) for early change detection.

Main Results:

• Biomarker trajectories in DS-AD align with clinical staging, showing early changes decades before dementia.
• Revised AD diagnostic criteria now include Stage 0 for DS individuals from birth.
• Comparative analyses reveal shared features but distinct timing/distribution of pathology between DS-AD, dominant AD, and sporadic AD.

Conclusions:

• DS-AD research offers unique insights into AD natural history, genetic drivers, and therapeutic targets.
• The genetically defined nature of DS-AD facilitates precise staging and early intervention strategies.
• Findings from DS-AD research can be translated to sporadic and familial AD, advancing personalized treatment approaches.