Polymorphisms of PXK are associated with autoantibody production, but not disease risk, of systemic lupus erythematosus in Chinese mainland population.

Systemic lupus erythematosus (SLE) is a complex immune disease. The genetic variation in the PXK gene was found to associate with SLE in Caucasian populations. However, the association of rs6445975 with SLE has not been extensively studied in a Chinese mainland population. A total of 288 SLE patients and 357 controls were recruited. Unlabeled probe-based high-resolution melting analysis (HRMA) was used in genotyping. HRMA with unlabeled probe successfully distinguished all genotypes. Neither genotype nor allele frequencies of SNP rs6445975 showed statistically significant differences between SLE patients and controls. The association of SNP rs6445975 with the diagnostic criteria of SLE was also examined. No obvious association was observed between rs6445975 and the incidence of clinical symptoms. However, the minor allele (G) of rs6445975 was found to significantly associate with increased abnormalities of anti-Smith (p = 0.004, odds ratio (OR) = 1.95, 95% confidence interval (CI) = 1.22-3.09), anti-Ro (p = 0.015, OR = 1.69, 95% CI = 1.10-2.58), anti-La (p = 0.008, OR = 1.86, 95% CI = 1.17-2.93) and C3C4 (p = 0.007, OR = 1.79, 95% CI = 1.17-2.74). Polymorphisms of rs6445975 in the PXK gene were associated with autoantibody production, but not disease risk, of systemic lupus erythematosus in a Chinese population.