BLK and BANK1 polymorphisms and interactions are associated in Mexican patients with systemic lupus erythematosus.

Objectives: The BLK and BANK1 genes have been consistently associated with systemic lupus erythematosus (SLE), primarily in European or Asian-derived populations. However, this finding has not been replicated in Latin-American patients.

Methods: Our study included 881 women from Mexico: 487 healthy controls and 394 SLE patients. The BLK rs13277113A/G-rs2736340T/C as well as BANK1 rs10516487G/A (R61H)-rs3733197G/A (A383T) single nucleotide polymorphisms (SNPs) were evaluated using a TaqMan SNP genotyping assay.

Results: Our data showed that the BLK rs2736340T/C and rs13277113A/G polymorphisms are associated with susceptibility to SLE (C vs T, OR 1.60, p = 2×10; G vs A, OR 1.53, p = 9 × 10, respectively). We also identified an association between the functional BANK1 R61H polymorphism and SLE (A vs G, OR 1.56, p = 0.002). In addition, we observed a genetic interaction between BLK (rs2736340T/C, rs13277113A/G) and BANK1 (R61H and A383T) associated with susceptibility to SLE.

Conclusion: This is the first study documenting an association between BLK and BANK1 and SLE in a Latin-American population. Our data confirm previous reports: BLK and BANK1 are factors associated with SLE. Thus, both genes are universal loci for this autoimmune disease.