We recently measured HSPA8 in cerebrospinal fluid (CSF) samples from patients with sporadic Parkinson’s disease (PD), PD patients carrying leucine-rich repeat kinase 2 (LRRK2) gene mutations, healthy control subjects carrying LRRK2 mutations, and healthy controls without LRRK2 mutations (Loeffler et al., 2016). This evidence concerns the gene LRRK2 and Parkinson disease.