Objective: SAPHO syndrome (synovitis, acne, pustulosis, hyperostosis, and osteitis) is an autoimmune disease of unknown etiology that seriously affects patients' daily lives. Family-based investigations support genetic contributions toward disease susceptibility. The present study evaluated whether the previously reported autoimmune disease-associated single nucleotide polymorphisms (SNPs) have any genetic overlap with SAPHO syndrome.
Method: Genomic DNA was obtained from 71 SAPHO patients and 104 healthy controls. The SNP genotypes of each patient were determined with polymerase chain reaction and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Genotype, allele, and haplotype frequencies were analyzed with SPSS software.
Results: Three SNP sites (rs10889677 and rs2201841 of interleukin [IL]-23R, and rs2243248 of IL-4) showed significant correlation with the occurrence of SAPHO syndrome in additive and dominant genetic models, while rs7517847 of IL-23R showed substantial correlation with SAPHO in the dominant genetic model. The G allele of rs2243248 (IL-4) was a high risk factor for SAPHO (P = 2.41e-5, odds ratio [OR] =7.79, 95% CI: 2.59-23.3). The haplotype (A-G-C-G-T), comprising 5 SNPs of the IL-23R gene, had a significantly higher frequency in the SAPHO cohort than in the controls (P = .011, OR = 2.05, 95% CI: 1.12-3.60).
Conclusion: Variants rs10889677, rs2201841, and rs7517847 of IL-23R, and variant rs2243248 of IL-4, showed strong associations with SAPHO syndrome. Patients carrying the A-G-C-G-T haplotype of IL-23 are significantly more likely to develop SAPHO syndrome.
Keywords: CDKAL1; IL-23R; IL-4; SAPHO syndrome; SNPs.
© 2019 Asia Pacific League of Associations for Rheumatology and John Wiley & Sons Australia, Ltd.