Only BSCs transduced with WT and A53T α-syn with the addition of PFFs showed detectable Thiazin Red positivity and similar to p62, only in a small proportion of cells (Fig. 3c), with staining absent in BSCs transduced with Dendra2 or without PFFs, suggesting the detection of structural features common to later stage Lewy bodies in human PD. Here, SQSTM1 is linked to Parkinson disease.