Supplement 5: Correlation of the genotypes with the IFN score

Among the SSc cases, the presence of the GG or GT genotypes of IFNAR2 rs7279064 were significantly associated with higher IFN score (p=0.008), which remained significant after correction for ethnicity (p=0.032). The IFN score did not vary significantly by the investigated SNP in the control group. The mean difference ± SE of the IFN score between SSc patients with TT/GT versus GG genotype was 7.34±0.9 whereas the mean difference ± SE in the control group was only 0.37 ± 1.06.

Other SNPs (IFNAR2 rs4986956 , STAT1 rs1914408, STAT4 rs11889341, rs6752770, IRF7 rs1061502, IFNAR1 rs17875834, rs2257167, IRF5 rs729302, rs2004640 and rs752637) did not correlate with the IFN score among the SSc patients or controls (table 2). We did not investigate the correlation of these SNP’s with the IFN score among the SLE patients because the small sample size precluded us from a meaningful statistical analysis.

Table 2: Correlation of the investigated genotypes with the IFN score

 

Gene	SNP	Study Group	Minor Allele Frequency (%)	P-Value ‡
IFNAR1
	rs17875834	SSc*	A=0.08	1.0
		Control†	A=2.4	1.0
	rs2257167	SSc	C=41.5	0.136
		Control	G=35.7	0.248
IFNAR2
	rs4986956	SSc	C=4.6	1.0
		Control	C=16.7	1.0
	rs7279064	SSc	G=27.3	0.008
		Control	G=42.9	0.482
STAT1
	rs1914408	SSc	A=22.3	0.573
		Control	A=28.6	0.06
STAT4
	rs11889341	SSc	A=25	0.806
		Control	A=15	0.544
	rs6752770	SSc	C=28	0.52
		Control	C=28.6	0.509
IRF5
	rs2004640	SSc	A=48.4	0.55
		Control	A=50
	rs729302	SSc	C=30.8	0.121
		Control	C=19	1.0
	rs752637	SSc	A=44.6	0.054
		Control	A=42.9	0.763
IRF7
	rs1061502	SSc	G=34.6	0.305
		Control	G=26.2	0.207

*Genomic DNA was available on 66 (91.7%) SSc patients
†Genomic DNA was available on 21 (100%) healthy controls
‡Recessive Model