Table 1.

Characteristics of the included studies.

Author	Year	Country	Ethnicity	Genotyping Method	MAF		Sample Size
					Control_1	Control_2	Case	Control
Van Heel [18]	2007	UK	European	The Illumina Infinium II assay	0.174	0.123	778	1422
Hunt [6]	2008	UK	European	Infinium assay	0.188	0.127	719	1561
–	–	Ireland	European	GoldenGate assay	0.187	0.130	416	957
–	–	Netherlands	European	GoldenGate assay	0.189	0.124	508	888
Romanos [16]	2009	Italy	European	Taqman probe	0.166	0.067	538	598
Coenen [14]	2009	Netherlands	European	Taqman probe	0.190	0.120	795	1683
Dubois [15]	2010	UK1	European	Illumina Hap300v1-1	0.182	0.118	737	2596
–	–	UK2	European	Illumina 670-QuadCustom_v1	0.173	0.121	1849	4936
–	–	Finland	European	Illumina 670-QuadCustom_v1	0.143	0.101	647	1829
–	–	Netherlands	European	Illumina 670-QuadCustom_v1	0.188	0.118	803	846
–	–	Italy	European	Illumina 670-QuadCustom_v1	0.169	0.067	497	543
–	–	USA	American	Illumina GoldenGate	0.162	0.118	973	555
–	–	Hungary	European	Illumina GoldenGate	0.158	0.113	965	1067
–	–	Ireland	European	Illumina GoldenGate	0.182	0.133	597	1456
–	–	Poland	European	Illumina GoldenGate	0.151	0.133	564	716
–	–	Spain	European	Illumina GoldenGate	0.188	0.095	550	433
–	–	Italy	European	Illumina GoldenGate	0.180	0.078	1010	804
–	–	Finland	European	Illumina GoldenGate	0.162	0.113	259	653
Sperandeo [17]	2011	Italy	European	Taqman probe	0.178	0.077	637	711
Plaza-Izurieta [7]	2011	Spain	European	TaqMan probe	0.199	0.094	1094	540

MAF: minor allele frequency; Control_1: controls for RGS1 rs2816316; Control_2: controls for IL12A rs17810546.