Parkinson disease (PD) is the second most common neurodegenerative disorder and a leading cause of morbidity worldwide. The World Health Organization1 has recognized PD as a major global public health problem and has issued an urgent call to action. The pathology leading to PD begins years before the disease becomes clinically manifest. Disease-modifying interventions have been ineffective in patients with clinically manifest PD, when the pathology is already advanced, but could be effective in earlier stages. Individuals at an increased risk of PD can now be accurately identified based on genetic risk factors or prodromal features.2 This at-risk population is a prime candidate for early interventions to prevent or delay manifest PD.3