HLA-DRB5 and Dystonia: Regarding sporadic dystonia, a number of genes have been linked to dystonia phenotypes including but not limited to TOR1A, b-cystathionine synthase (CBS), GTP cyclohydrolase1 (GCH1), dopamine D5 receptor (DRB5) and brain-derive neurotrophic factor (BDNF) genes [11–21].