Identify the association between polymorphisms of BLK and systemic lupus erythematosus through unlabelled probe-based high-resolution melting analysis

Systemic lupus erythematosus (SLE) is a complex immune disease. The genetic variation in the B lymphoid tyrosine kinase (BLK) gene was found to associate with SLE in Caucasian population. However, the association of rs13277113 and rs4840568 with SLE was not extensively studied in Chinese population. In this study, we aim to test the association of SNP rs13277113 and rs4840568 with the disease risk of SLE in Chinese mainland population. A total of 532 patients with SLE and 576 controls were recruited. Unlabelled probe-based high-resolution melting analysis (HRMA) was used in genotyping. HRMA with unlabelled probe successfully distinguished all genotypes. Significant differences were observed in both genotype and allele frequencies for rs13277113 and rs4840568. Minor alleles of rs13277113 (P = 4.2E-05, odds ratio [OR] 0.66, [95% CI 0.540.81]) and rs4840568 (P = 7.1E-05, OR 0.67, [95% CI 0.550.82]) were found to be protective against SLE. Polymorphisms of rs13277113 and rs4840568 in BLK gene were associated with SLE in Chinese population