FOXP3 and asthma: DNA methylation of the Foxp3, ACSL3, and ARG2 loci are associated with impaired regulatory T-cell function (Nadeau et al. 2010), increased asthma morbidity (Nadeau et al. 2010; Perera et al. 2009), and exhaled nitric oxide production, respectively (Breton et al. 2011a).