Interestingly, linkage analysis of genes associated with essential tremor identified four loci: chromosome 3q13 (ETM1) (Gulcher et al., 1997), 2p22-p25 (ETM2) (Higgins et al., 1997), 6p23 (ETM3) (Shatunov et al., 2006), and 5q35 (Hicks et al., 2016), among which ETM1 contains the DRD3 gene encoding D3 receptors (Gulcher et al., 1997). This evidence concerns the gene DRD3 and essential tremor.