One study in postmortem tissue described a positive correlation between SERT binding densities and the development of dyskinesia (Rylander et al., 2010); however, subsequent studies in postmortem samples or patients did not find any correlation between 5-HT or SERT in the striatum and dyskinesia (Politis et al., 2014; Cheshire et al., 2015). The gene discussed is SLC6A4; the disease is drug-induced dyskinesia.