The frequency of MAFs of the genotyped SNPs was lower in GTS patients with Attention Deficit Hyperactivity Disorder (for rs9357271 and rs9296249, P=0.039 and rs4714156, P=0.040) and higher in GTS patients without comorbidities (for rs9357271 and rs9296249 P=0.021 and rs4714156 P=0.025).
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).