Increased level of Rho was found in postmortem brains of patients with Huntington’s disease and Alzheimer’s disease.19,20 Cdc42 G12V and Q61L mutations, found in the same positions as RAS hotspot mutations, result in constitutively active proteins that exhibit oncogenic activities.229 Cdc42 is especially important in migration of tumor cells. Here, CDC42 is linked to early-onset autosomal dominant Alzheimer disease.