- Association analysis of the dopamine D2 receptor gene in Tourette's syndrome using the haplotype relative risk method. Nöthen, M.M., Hebebrand, J., Knapp, M., Hebebrand, K., Camps, A., von Gontard, A., Wettke-Schäfer, R., Lisch, S., Cichon, S., Poustka, F. Am. J. Med. Genet. (1994)