In this recently published study, investigators in Montreal, Canada conducted a study "To test the association between Tourette syndrome (TS) and genetic variants in genomic loci MEIS1, MAP2K5/LBXCOR1, and BTBD9, for which genome-wide association studies in restless legs syndrome and periodic limb movements during sleep revealed common risk variants. Case-control association study."

"Movement disorder clinic in Montreal. We typed 14 single-nucleotide polymorphisms spanning the 3 genomic loci in 298 TS trios, 322 TS cases (including 298 probands from the cohort of TS trios), and 290 control subjects. Clinical diagnosis of TS, obsessive-compulsive disorder, and attention-deficit disorder. The Study provided 3 single-nucleotide polymorphisms within BTBD9 associated with TS (chi(2)=8.02 [P=.005] for rs9357271.), with the risk alleles for restless legs syndrome and periodic limb movements during sleep overrepresented in the TS cohort. We stratified our group of patients with TS according to presence or absence of obsessive-compulsive disorder and/or attention-deficit disorder and found that variants in BTBD9 were strongly associated with TS without obsessive-compulsive disorder (chi(2)= 12.95 [P <.001] for rs9357271). Furthermore, allele frequency of rs935727.1. inversely correlated with severity of obsessive-compulsive disorder as measured by the Yale-Brown Obsessive Compulsive Scale score," wrote J.B. Riviere and colleagues, University of Montreal (see also Obsessive-Compulsive Disorder).

The researchers concluded: "Variants in BTBD9 that predispose to restless legs syndrome and periodic limb movements during sleep are also associated with TS, particularly, TS without obsessive-compulsive disorder."

Riviere and colleagues published their study in Archives of Neurology (Association of Intronic Variants of the BTBD9 Gene With Tourette Syndrome. Archives of Neurology, 2009;66(10):1267-1272).

For additional information, contact G.A. Rouleau, University of Montreal, Hopital St. Justine, Research Center, 1560 Rue Sherbrooke Est, De Seve Pavill, Room Y-361, Montreal, PQ H2L 4M1, Canada.

The publisher of the journal Archives of Neurology can be contacted at: American Medical Association, 515 N State St., Chicago, IL 60610-0946, USA.