Table I.

Data of methylenetetrahydrofolate reductase (MTHFR) polymorphisms included in this study.

Authora	Year of publication	Country	Test methods	MTHFR genotype	HWE of control	Cases (n)	Controls (n)	Source of controls	Refs.
Ma et al	2012	China	PCR-RFLP	C677T	0.83	120	60	Hospital-based	(11)
Kiyohara et al	2011	Japan	PCR-RFLP	C677T	0.62	379	462	Hospital-based	(12)
				A1298C	0.63
Cui et al	2011	China	Real-time PCR	C677T	0.48	641	438	Population-based	(13)
Cheng et al	2011	China	PCR-RFLP	C677T	0.77	178	180	Population-based	(14)
Cui et al	2011	Korean	PCR-RFLP real-time PCR	C677T	0.14	1,700	3,938	Population-based	(15)
Yang et al	2010	China	DNA MassArray	C677T	0.52	120	165	Population-based	(16)
Liu et al	2009	China	PCR-RFLP	C677T	0.67	716	358	Population-based	(17)
				A1298C	0.49
Liu et al	2008	China	SNP gene chips	C677T	0.48	517	500	Hospital-based	(18)
				A1298C	0.62
Suzuki et al	2007	Japan	Real-time PCR	C677T	0.17	1,030	515	Hospital-based	(19)
				A1298C	0.51
Jin et al	2007	China	PCR-RFLP	C677T	0.83	100	100	Population-based	(20)
				A1298C	0.73
Zhang et al	2005	China	PCR-RFLP	C677T	0.15	500	505	Population-based	(21)
				A1298C	0.01a
Shen et al	2005	China	Real-time PCR	C677T	0.12	C677T	C677T	Population-based	(22)
				A1298C	0.51	111	116
						A1298C	A1298C
						109	114
Jeng et al	2003	China	PCR-RFLP	C677T	0.44	232	59	Population-based	(23)

HWE, Hardy-Weinberg equilibrium; PCR-RFLP, polymerase chain reaction-restriction fragment length polymorphism; SNP, single nucleotide polymorphism.