The proposed staging system delineates the entire continuum of Parkinson ’ s . Stages correspond with earliest signs of risk , diagnosis and functional impairment ranging from slight to severe . An individual ’ s stage is premised on their personal biological profile , including their genetic risk factors and the presence or absence of abnormal alpha-synuclein in spinal fluid as well as dopamine degeneration in the brain .
Biological staging frameworks for other diseases have led to treatment breakthroughs . For example , the biological classification of Alzheimer ’ s disease in living people combined with a staging system for biomarker and symptom severity has led to better clinical trial designs and , recently , the first FDA-approved treatments , such as lecanemab , that slow clinical symptoms and demonstrate functional benefit to patients . Similarly , a biological staging system for type 1 diabetes established a scientific roadmap for intervention prior to symptom onset and has yielded the first FDA-approved treatment to delay the onset .
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