GRoningen Early-PD Ambroxol Treatment (GREAT)

Inclusion Criteria: Diagnosis of Parkinson's disease, according to Movement Disorders Society (MDS) criteria (27) Disease duration of 10 years or less at time of inclusion PD patients carrying a GBA1 mutation Able to write written informed consent, understanding study protocol and perform protocol related actions Willing and able to self-administer oral ambroxol or placebo medication Exclusion Criteria: The refusal to be informed about an unforeseen clinical finding Use of an implanted Deep Brain Stimulation (DBS) system Confirmed dysphagia that would preclude self-administration of ambroxol or placebo tablets History of known sensitivity to the study medication Pregnant or breastfeeding women Participants of childbearing potential that would not use adequate birth control, consisting of a negative pregnancy test at the screening visit and use of accepted contraceptive methods defined as highly effective while participating in the study MRI incompatible implants in the body Any clinically significant or unstable medical or surgical condition that in the opinion of the principal investigator may put the participant at risk when participating in the study or may influence the results of the study or affect the participant's ability to take part in the study, as determined by medical history, physical examinations, electrocardiogram (ECG), or laboratory tests. Such conditions may include: Impaired renal function (a positive urine dipstick test, and laboratory values below or above: a eGFR <45 ml/min 1,73M2, Sodium 135-145 mmol/L, Potassium 3.5-5.0 mmol/L, Urea 2.5-7.5mmol/L). Moderate/severe hepatic impairment (laboratory values below or above: ASAT 0- 80U/L, ALAT0-90 U/L, GGT > 80 U/L, Alkaline Phosphatase 35-210 U/L).