eLife Assessment
This important work compares the strain properties of a-synuclein fibrils isolated from LBD and MSA patient samples with the resulting amplified fibrils following SAA. Using orthogonal biochemical and structural approaches to strengthen their analyses, the authors provide solid evidence that the SAA-amplified fibrils do not recapitulate the disease-relevant strains present in the patient samples. CryoEM would further strengthen this data but it is outside the scope of the work. This work should be considered in the widespread applications of SAA in synucleopathies and its potential limitations.