Using ultrasound to help deliver an enzyme into the brain

Inclusion Criteria: * Men or women between age 35 and 80 years, inclusive. * Able and willing to give informed consent. * Diagnosis of PD satisfying MDS Clinical Diagnostic Criteria for PD * At least 2 years from initial diagnosis * Hoehn and Yahr Stage 1-3 on PD medication * Dopaminergic deficit by a positive DAT SPECT scan * On stable regimen of PD medications for at least 90 days prior to the study * American Society of Anesthesiologists (ASA) score 1-3 * Harbor at least one GBA mutation if enrolled in the GBA PD arm or two wild-type GBA alleles if enrolled in the idiopathic PD arm Exclusion Criteria: * Positive pregnancy test (for pre-menopausal women). * Contraindication to DEFINITY ultrasound contrast agent or perflutren (e.g. hypersensitivity, known left or bidirectional cardiac shunt) * Contraindication to MRI or gadolinium-DTPA (e.g. incompatible device, hypersensitivity) * Insulin-dependent diabetes mellitus that is not well-controlled or that in the Investigator's opinion precludes participation in the study. * Severely impaired renal function with estimated glomerular filtration rate \<30 mL/min/1.73m2 and/or on dialysis. * Currently participating in another clinical therapeutic trial * Patient receiving bevacizumab (Avastin) therapy * Subjects with evidence of cranial or systemic infection. * Cerebral or systemic vasculopathy. * Documented cerebral infarction within the past 12 months or TIA in the past 1 month. * Contraindication to GCase enzyme therapy, specifically previous hypersensitivity reaction to GCase enzyme therapy * Parkinsonism plus symptoms, secondary parkinsonism * Previous neurosurgical procedure for PD