Association Between SPARC Polymorphisms and Ankylosing Spondylitis and Its mRNA and Protein Expression in a Chinese Han Population: A Case–Control Study

Figures & data

Table 1 The Main Demographic and Clinical Characteristics of the AS Patients and Controls

Characteristic	AS Patients	Controls
Number of subjects	768	768
Gender (Men, %)	61.7	57.8
Age (mean ± SD, years)	35.7±9.8	37.1±8.7
HLA-B27 positive, %	95	–
Disease duration (mean ± SD, years)	8.6±4.1	–
ESR (mean ± SD, mm/h)	30.03±12.84	–
CRP (mean ± SD, mg/L)	24.36±9.62	–
BASDAI (mean±SD)	4.67±1.62	–
BASFI (mean±SD)	3.86±2.14	–

Abbreviations: AS, ankylosing spondylitis; SD, standard deviation; HLA-B27, human leukocyte antigen B27; ESR, erythrocyte sedimentation rate; CRP, C reactive protein; BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; BASFI, Bath AS Functional Index.

Table 2 The Basic Information of the Nine SNPs

SNPs	Genotyping Assay Part Number	Region
SPARC-rs3776959	C___2086343_10	Intron8
SPARC-rs4958279	C__28037505_10	Intron6
SPARC-rs7733793	C___2086331_20	Intron2
SPARC-rs2881558	C__16083139_10	Intron1
SPARC-rs2347128	C__15779576_10	Intron1
SPARC-rs4958485	C__27927153_10	Intron1
SPARC-rs17112187	C__34334451_10	Intron1
SPARC-rs4958487	C___2086329_10	Intron1
SPARC-rs1545030	C___8949874_10	5’flanking

Abbreviations: SNP, single nucleotide polymorphism; SPARC, Secreted protein acidic and rich in cysteine.

Table 3 Frequencies of Alleles and Genotypes of SPARC Polymorphisms in AS Patients and Controls

SNPs	Genotypes	AS n (%)	Controls n (%)	P values	OR (95% CI)	Pc values
rs3776959	G	870(56.6)	854(55.6)		1
	C	666(43.4)	682(44.4)	0.561	0.96(0.83–1.11)
	GG	234(30.5)	226(29.4)		1
	CC	132(17.2)	140(18.2)	0.829	1.10(0.81–1.48)
	CG	402(52.3)	402(52.3)		1.04(0.82–1.30)
rs4958279	G	925(60.2)	938(61.1)		1
	A	611(39.8)	598(38.9)	0.631	1.04(0.90–1.20)
	GG	278(36.2)	278(36.2)		1
	AA	110(14.3)	108(14.1)	0.841	0.94(0.69–1.29)
	AG	391(50.9)	382(49.7)		0.94(0.75–1.17)
rs7733793	T	888(57.8)	882(57.4)		1
	C	648(42.2)	654(42.6)	0.827	0.98(0.85–1.14)
	TT	250(32.6)	241(31.4)		1
	CC	130(16.9)	127(16.5)	0.826	1.07(0.85–1.34)
	CT	388(50.5)	400(52.1)		1.01(0.75–1.37)
rs2881558	G	890(61.7)	948(61.7)		1
	A	646(42.1)	588(38.3)	0.033	1.17(1.01–1.35)	0.299
	GG	270(35.2)	286(37.2)		1
	AA	148(19.3)	106(13.8)	0.016	0.68(0.50–0.91)	0.140
	AG	350(45.6)	376(49.0)		1.01(0.81–1.27)
rs2347128	C	872(56.8)	834(54.3)		1
	G	664(43.2)	702(45.7)	0.168	1.11(0.96–1.27)
	CC	258(33.6)	228(29.7)		1
	GG	154(20.1)	162(21.1)	0.258	1.19(0.90–1.58)
	GC	356(46.4)	378(49.2)		1.20(0.96–1.51)
rs4958485	C	1120(72.9)	1057(68.8)		1
	T	416(27.1)	479(31.2)	0.012	1.22(1.04–1.43)	0.112
	CC	404(52.6)	359(46.7)		1
	TT	52(6.8)	70(9.1)	0.040	1.51(1.03–2.23)	0.362
	TC	312(40.6)	339(44.1)		1.22(0.99–1.51)
rs17112187	C	1273(82.9)	1344(87.5)		1
	A	263(17.1)	192(12.5)	3.14E-4	1.45(1.18–1.77)	0.003
	CC	534(69.5)	584(76.0)		1
	AA	29(3.8)	8(1.0)	2.84E-4	0.25(0.11–0.56)	0.003
	AC	205(26.7)	176(22.9)		0.79(0.62–0.99)
rs4958487	A	1431(93.2)	1368(89.1)		1
	G	105(6.8)	168(10.9)	6.57E-5	1.67(1.30–2.16)	0.001
	AA	670(87.2)	614(79.9)		1
	GG	7(0.9)	14(1.8)	0.001	2.18(0.88–5.44)	0.005
	GA	91(11.8)	140(18.2)		1.68(1.26–2.23)
rs1545030	T	1171(76.2)	1220(79.4)		1
	C	365(23.8)	316(20.6)	0.033	1.20(1.01–1.43)	0.300
	TT	456(59.4)	482(62.8)		1
	CC	53(6.9)	30(3.9)	0.029	0.54(0.34–0.85)	0.258
	CT	259(33.7)	256(33.3)		0.94(0.75–1.16)

Abbreviations: AS, ankylosing spondylitis; SNP, single nucleotide polymorphism; OR, odds ratio; CI, 95% confidence interval; p_c was corrected by Bonferroni method; significance level p_c <0.05.

Table 4 The Haplotypes Between rs17112187 and rs4958487 Related to AS

Haplotype	Case (Freq)	Control (Freq)	p value	Global p	OR (95% CI)
AA*	232.66 (0.151)	153.92 (0.100)	2.31E-5		1.60 (1.28–1.98)
CA*	1198.34 (0.780)	1214.08 (0.790)	0.314		0.91 (0.76–1.09)
CG*	74.66 (0.049)	129.92 (0.085)	5.42E-5	1.90E-7	0.55 (0.41–0.74)
AG	30.34 (0.020)	38.08 (0.025)	0.344		0.793(0.49–1.28)

Note: *Haplotype with a frequency >3%. Significance level p <0.05.

Abbreviations: AS, ankylosing spondylitis; OR, odds ratio; CI, 95% confidence interval.

Figure 1 Comparison of SPARC mRNA expression levels in both PBMC (A) and granulocyte (B) between AS patients and healthy controls. The scatter-plot showed that the quantification levels of normalized mRNA. The p value refers to unpaired nonparametric comparison of the two groups (Mann–Whitney U-test).

Abbreviations: AS, ankylosing spondylitis; SPARC, secreted protein acidic and rich in cysteine; PBMC, peripheral blood mononuclear cell.

Figure 2 Comparison of serum SPARC protein levels between AS patients and healthy controls by ELISA analysis. The scatter-plot showed that the quantification levels of normalized serum levels of SPARC. The p value refers to unpaired nonparametric comparison of the two groups (Mann–Whitney U-test).

Abbreviations: AS, ankylosing spondylitis; SPARC, secreted protein acidic and rich in cysteine.