PRKN and Parkinson disease: We excluded from this analysis those patients who were carriers of mutations in other PD-related genes: 62 in the non-carrier group, and 4 in the GBA-carrier group (LRRK2-p.G2019S, n = 2; LRRK2-p.R1441C, n = 1; and homozygous deletion of exon 3 in parkin gene, n = 1).