Association of STAT6 variants with asthma risk: a systematic review and meta-analysis.

A large number of studies have reported that the genetic variants in STAT6 gene may be implicated in susceptibility to asthma, but with inconsistent results. Therefore, the aim of this meta-analysis was to determine the likelihood of developing asthma for the individuals with different STAT6 variants. The database including Pubmed, Embase and CNKI (Chinese National Knowledge Infrastructure) were searched to find the relevant papers. Data were extracted by two independent reviewers and the odds radios (ORs) were pooled with 95% confidence intervals (CIs), using random effect or fixed effect models as appropriate, to indicate the risk of asthma for different STAT6 variants. The heterogeneity and bias were tested for each pooled result. Data from 19 studies were pooled that reported associations of rs324015, rs71802646 and rs324011 in STAT6 gene with asthma risk. The results demonstrated that 13GT and short GT in rs71802646 were both associated with increased risk of asthma in overall analysis (OR=1.26 for 13GT and 1.30 for short GT). Further, subgroup analysis showed an increased risk of asthma in Asian population with 13GT (OR=1.21), 14GT (OR=1.97) and short GT (OR=1.27). Besides, 13GT, 14GT and short GT all contributed to higher risk of atopic asthma, with OR 1.50, 2.21 and 1.65 respectively. However, rs324015 (G>A) appeared to be associated with decreased risk for atopic asthma (with OR=0.83, 0.68 and 0.79 for A, AA and AA+AG respectively). Both overall and subgroup analyses indicated no effect of rs324011 on asthma risk. In conclusion, our meta-analyses suggest that short GT repeats of rs71802646 in STAT6 contribute to higher risk for asthma, while rs324015 may have a protective effect on atopic asthma.