GBA1 and Parkinson disease: Also, increased acetylcholinesterase activity, suggesting upregulation of cholinergic neurotransmission, has been reported in carriers of leucine repeat kinase 2 mutations with prodromal Parkinson’s disease.15,61 The expected heterogeneity of both Parkinson’s disease groups, besides GBA1 status, could be an important factor confounding the direct comparison between GBA-PD and non-GBA-PD.