LRRK2 and Parkinson disease: This is a systemic problem in biomedical research and has resulted in billions of dollars wasted.61 To test the hypothesis that LRRK2 inhibitors might offer benefit to patients with PD or individuals at high risk for PD (e.g., G2019S-LRRK2 carriers), mere common sense dictates that verification of LRRK2 inhibition should be determined for individual subjects undergoing treatment.