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.