Dyskinesia in Parkinson’s disease are associated with changes in long term neuroadaptation and neuronal synaptic plasticity which in turn are linked to dopamine transporters and receptors density, respectively at a presynaptic and a postsynaptic level.6 Based on this concept, both positron emission tomography (PET) and single photon emission computed tomography (SPECT) were used to assess changes in neurotransmitter pathways involved in dyskinesia and, subsequently, to identify imaging biomarkers for LID development. This evidence concerns the gene SLC6A3 and Parkinson disease.