Interestingly, in most samples, we could not detect phosphorylated Rab29 (T71), even in the presence of a signal boost reagent (SignalBoost Immunoreaction, Sigma; not shown), suggesting that within PBMCs, Rab29 is not a particularly prominent LRRK2 substrate, either in the healthy control population or in any of the PD cohorts; or that specific Rab29 phosphatases are particularly active in these cells. This evidence concerns the gene RAB29 and Parkinson disease.