Table 2. SNPs associated with C3 and C4 levels from two-stage GWAS study in Chinese population.

SNPs	Chr (Position)a	Genes	Gene regions	Minor Allele/Major Allele	First Stage (N = 1999)					Second Stage (N = 1496)					Combined (N = 3495)
					MAF	Mean levels (g/L)			P valuec	MAF	Mean levels (g/L)			P valuec	β(SE)c	P valuec
						aab	Aa	AA			aa	Aa	AA
C3
rs3753394	1(194887540)	CFH	promoter	C/T	0.43	1.16	1.13	1.08	5.79×10−13	0.44	1.31	1.26	1.20	1.08×10−3	−0.05(0.01)	7.33×10−11
rs3745567	19 (6641771)	C3	intron	T/C	0.06	0.93	1.06	1.13	9.32×10−9	0.07	1.07	1.16	1.26	3.58×10−4	0.09(0.01)	1.83×10−9
C4d
rs1052693	6 (30984131)	HLA-A	3′	G/A	0.36	0.28	0.31	0.34	3.26×10−10	0.34	0.29	0.31	0.35	7.48×10−22	0.10(0.01)	3.01×10−48
rs11575839	6 (31665770)	HLA-C	5′	A/G	0.05	0.47	0.40	0.31	9.70×10−35	0.06	0.41	0.41	0.32	2.55×10−20	−0.23(0.01)	1.22×10−54
rs2075799	6 (31886508)	C4	5′	T/C	0.20	0.40	0.36	0.30	1.08×10−49	0.20	0.47	0.36	0.30	2.53×10−48	−0.17(0.01)	5.62×10−97
rs2857009	6 (32127724)	C4	3′	G/C	0.20	0.28	0.31	0.33	3.46×10−24	0.21	0.28	0.31	0.34	3.04×10−10	0.08(0.01)	1.43×10−22
rs2071278	6 (32273422)	HLA-DRA	5′	G/A	0.27	0.38	0.34	0.30	3.48×10−29	0.28	0.41	0.35	0.30	7.86×10−39	−0.13(0.01)	4.25×10−72
rs3763317	6 (32484766)	HLA-DRB	5′	C/T	0.37	0.28	0.31	0.35	1.88×10−17	0.38	0.28	0.32	0.38	2.10×10−32	0.12(0.01)	9.21×10−66
rs9276606	6 (32844673)	HLA-DQB	3′	T/A	0.15	0.39	0.34	0.31	2.33×10−14	0.15	0.39	0.35	0.32	2.90×10−10	−0.09(0.01)	3.19×10−22
rs241428	6 (32912048)	HLA-DQB	3′	G/T	0.08	0.22	0.26	0.33	3.64×10−12	0.09	0.18	0.27	0.34	6.99×10−39	0.23(0.01)	9.12×10−83

^a. Genomic position is based on NCBI build 36.

^b. aa indicates serum complement levels for homozygous carriers of minor alleles, Aa indicates for heterozygous carriers, and AA indicates for homozygous carriers of major alleles.

^c. P values andβ-coefficient are based on multi-linear regression analysis for an addictive effect, and adjusted for age, smoking, and logBMI. The combined P s are calculated based on the regression model, adjusting for the covariates and stage information.

^d. The presented C4 levels were back-transformed.