Table 1. Observed genotype and allele frequencies for the TPH C → T SNP.

Cohort	Genotype			Allele
	CC	CT	TT	C	T
Migraine (n = 275)	0.39 (98)	0.44 (108)	0.17 (41)	0.62 (304)	0.38 (190)
Control (n = 275)	0.38 (89)	0.43 (100)	0.19 (45)	0.59 (278)	0.41 (190)

Observed genotype and allele counts shown in parentheses.