LRRK2 and Parkinson disease: Genome-wide association studies (GWASs) have further underscored the association between the LRRK2 locus and IBD [37,38], with exome sequencing revealing shared LRRK2 alleles in CD and PD, including the gain-of-function variant N2081D within the LRRK2 kinase domain, suggesting excessive kinase activity might be crucial for the pathogenesis [39,40,41].