LRRK2 and Cowden disease: Additional translational studies are needed to fully understand the normal function of LRRK2 in the context of human immune cells, as well as the potential pathogenic role of LRRK2 mutations in immune cells, both of which should be possible with greater access to LRRK2 PD and CD patient blood samples and/or via utilization of human induced pluripotent stem cell-derived macrophages, monocytes, and microglia from LRRK2 PD and CD patients80,81.