MiR-146a polymorphism is associated with asthma but not with systemic lupus erythematosus and juvenile rheumatoid arthritis in Mexican patients.

Extensive research has shown that aberrant expression of microRNAs ( miRNAs) plays an important role in innate and adaptive immune responses. The rs2910164 polymorphism has been identified as a functional variant, which affects the transcription and expression level of miR-146a and, thereby, contributes to the pathogenesis of several inflammatory and autoimmune diseases. To investigate whether the rs2910164 G/C polymorphism was associated with asthma, systemic lupus erythematosus ( SLE) or juvenile rheumatoid arthritis ( JRA), we performed an association study in a pediatric Mexican cohort. We included 979 pediatric patients (asthma: 402, SLE: 367 and JRA: 210) and 531 control subjects without inflammatory or immune diseases. Genotyping was performed using the 5′ exonuclease technique. The genotype distribution of the rs2910164 polymorphism was in Hardy-Weinberg equilibrium in each group. No significant differences were detected in the distribution of this polymorphism between cases and controls ( P = 0.108, 0.609 and 0.553 for subjects with asthma, JRA and SLE, respectively). However, stratification by gender showed a statistically significant difference between asthmatic and control females, where the C allele was significantly associated with protection to asthma (odds ratio = 0.694, 95% confidence interval 0.519-0.929, P = 0.0138). Our results provide evidence that rs2910164 may play a role in the susceptibility to childhood-onset asthma, but not SLE or JRA in Mexicans. Further association studies may contribute to determining the role of miR-146a single-nucleotide polymorphisms in immune-mediated diseases. [ABSTRACT FROM AUTHOR]