Alzheimer disease biomarkers and synucleinopathy

The vast majority of biomarker studies for Alzheimer disease (AD) and other neurodegenerative diseases such as Lewy body disease (LBD) are restricted to clinically diagnosed individuals, whether focused on CSF or PET. 1,2 However, data from clinical-pathologic studies find that mixed pathology, typically AD pathology plus another comorbid pathology, is the most common cause of dementia in older persons. 3 However, there are limited data examining the relation of antemortem AD biomarkers to mixed pathology because this is best accomplished by linking antemortem biomarker data with autopsies from the same persons. Such data exist for MRI 4 and PET 5 but not yet for CSF. In the current issue of Neurology®, Irwin et al. 6 examine the relation of CSF amyloid and tau to synucleinopathies with and without pathologic AD at autopsy conducted ≈5 years after CSF collection.