While one small study reported increased plasma levels of IFN-γ, interleukin-1 beta, interleukin-2 and TNF-alpha in eight PDGBA patients24, two larger studies did not find any differences in blood and CSF levels between PD patients with versus without heterozygous GBA mutations which is in line with our findings25,26. This evidence concerns the gene GBA1 and Parkinson disease.