The association of the BLK gene with SLE was replicated in Chinese Han.

Systemic lupus erythematosus (SLE) is an autoimmune disease influenced by genetic and environmental factors. Recently, single nucleotide polymorphisms (SNPs) in the region of B lymphoid tyrosine kinase (BLK) have been shown to be associated with SLE in Caucasian population. In this paper, we genotyped SNP rs2248932 in 1,396 SLE patients of Chinese Han and 4,362 ethnically matched control subjects by using the Sequenom MassArray system. We confirmed that SNP rs2248932 in BLK gene was significantly associated with SLE (P = 1.41 x 10(-8) for the allele frequency, Odds ratio [OR] = 0.74, 95% confidence interval (CI): 0.66-0.82).The association of BLK in Chinese SLE patients was consistent with a dominant model (P = 8.88 x 10(-9), OR = 0.69, 95% CI: 0.61-0.79). In contrast to the Caucasian, this risk allele was the major allele in the Chinese Han; the risk allele frequency was higher in Chinese Han than in Caucasian. We did not find the association between this SNP and any subphenotype of SLE. The SNP rs2248932 was correlated to the expression of BLK mRNA. We conclude that the association of the BLK region with SLE was replicated in Chinese Han population living in mainland.