SLC6A4 and Tremor: Furthermore, results from studies in patients with Parkinson's disease show a correlation between 5‐HT1A/SERT binding sites and tremors (Caretti et al., 2008; Doder, Rabiner, Turjanski, Lees, & Brooks, 2003; Loane et al., 2013; Qamhawi et al., 2015) as well as a relationship between post‐mortem SERT binding and dyskinesia‐free survival time (Rylander et al., 2010).