Developing the ATX(N) classification for use across the Alzheimer disease continuum

Area of Science:

• Neuroscience
• Biomarkers
• Alzheimer's Disease Research

Background:

• Alzheimer disease (AD) is shifting from a symptom-based definition to a clinical-biological construct.
• Fluid and neuroimaging biomarkers are crucial for this transformation.
• The AT(N) system categorizes AD pathophysiology using amyloid-β (Aβ), tau, and neurodegeneration markers.

Purpose of the Study:

• To describe the conceptual framework and clinical importance of the AT(N) and evolving ATX(N) systems.
• To summarize the use of these biomarker systems in AD clinical trials and practice.
• To discuss challenges and provide an outlook on the real-world application of the AT(N) system.

Main Methods:

• Review of current literature on AD biomarkers and classification systems.
• Analysis of the AT(N) and ATX(N) frameworks.
• Discussion of potential applications and challenges in clinical settings.

Main Results:

• The AT(N) system provides a biomarker-based classification of AD.
• The ATX(N) system expands this framework to include novel pathophysiological mechanisms.
• These systems offer potential for improved AD diagnosis, monitoring, and clinical trial design.

Conclusions:

• The AT(N) and ATX(N) systems represent a significant advancement in understanding and classifying Alzheimer disease.
• Further validation and standardization are needed for widespread clinical adoption.
• These biomarker frameworks hold promise for future AD clinical practice and research.