VMAT2 is a protein localized at the vesicular membrane and is involved in transporting monoamine transmitters from the cytosol into the synaptic membrane and storing neurotransmitters in human brain neurons.426 Patients with PD presented a reduction in VMAT2 expression in the brain striatum, which enables the diagnosis of PD and other disorders based on the abnormal VMAT2 density determined using VMAT2-targeting PET tracers. This evidence concerns the gene SLC18A2 and Parkinson disease.