Heterozygous mutations in GBA, which cause the recessive lysosomal storage disorder (LSD) Gaucher disease, are a known risk factor for Parkinson disease (PD). Previous studies have investigated whether variants linked to other LSDs might increase the risk of PD but have, thus far, been insufficiently powered to reveal an effect. Now, a new report has analysed whole-exome sequencing data from 1,156 patients with PD and 1,679 non-neurodegenerative controls. The team found that the presence of an LSD-associated variant was linked to an increased risk of PD even when GBA was excluded from the analysis. More than half of the individuals with PD were found to have at least one gene variant associated with an LSD, and three specific loci — CTSD, SLC17A5 and ASAH2 — were newly implicated as risk factors for PD. The study supports the hypothesis that lysosomal dysfunction plays an important part in PD pathogenesis.