The purpose of this study is to evaluate the safety, tolerability, pharmacokinetics, and pharmacodynamics of multiple oral doses of DNL201 in subjects with Parkinson's disease.

Key Inclusion Criteria:

• Body mass index (BMI) between 18 and 35.0 kg/m2, inclusive
• Clinical diagnosis of Parkinson's disease meeting UK Brain Bank criteria and H&Y Stage I, II, or III.
• sPD subgroup without a LRRK2 mutation; PD LRRK2 subgroup with LRRK2 mutation
• Screening dopamine transporter (DAT) SPECT scan with a DAT deficit consistent with Parkinson's disease
• Able to hold Parkinson's disease medications 8 hours (overnight) prior to specific study assessments

Key Exclusion Criteria:

• Any history of clinically significant asthma, chronic obstructive pulmonary disease, or emphysema within 5 years of screening, or other clinically significant pulmonary disease within 6 months of screening
• Abnormal Vitals including Respiratory Rate, Body Temperature, and Blood Pressure
• Pulmonary Function Tests (PFTs) (FVC <60% predicted, FEV1 <50% predicted, FEV1:FVC ratio <0.6, DLCO <70% predicted)
• Clinically significant neurologic disorder other than Parkinson's disease, including history of stroke, cognitive impairment, seizure within 5 years of screening, or head trauma with loss of consciousness within 6 months of screening
• Montreal Cognitive Assessment (MoCA) score of <24 at screening