Table 2.

Comparison of genotypes of significant results from the main-effect analyses of previously implicated SNPs in relation to lifetime tic severity

SNP	Genotype	N	Initial sample					Replication sample
			Lifetime tic severity Mean (SD)a	β	Standard error	T	Pb,c (Genotype)	N	β	Standard error	T	P b, c (Genotype)
rs7123010	GG	129	17.5 (7.75)					373
	AG	131	15.5 (7.77)	− 1.76	0.87	− 2.02	0.045	341	0.47	0.61	0.78	0.44
	AA	26	21.6 (7.11)	3.92	1.49	2.62	0.009	64	− 1.10	1.10	− 1.01	0.31

SNP single-nucleotide polymorphism

^aLifetime worst-ever tic severity was assessed based on a modified version of the Yale Global Tic Severity Scale (Dietrich et al. 2015)

^bAnalyses were corrected for age, sex, and socioeconomic status

^cMajor allele homozygous genotype was used as the reference genotype