SLC7A4 and Dystonia: 2006; Çalışkan et al. 2011). Our results also showed an overexpression of cat‐4 gene (ortholog of the human GTP cyclohydrolase I), which participates in C. elegans neurotransmitter biosynthesis (serotonin and dopamine) involved in movement, mating behavior, and cell migration; animals bearing a cat‐4 deletion reduces serotonin expression (Loer and Kenyon 1993) and causes dystonia in humans when mutated (Ichinose et al. 1994).