The top-ranked DMP associated with persisting asthma (cg23603194, located downstream of the HLX gene) was consistently hypomethylated in asthma-affected twins compared with their unaffected co-twin (mean Δβ = −0.11, P = 6.87E-06, permuted empirical P = 0.0009). This evidence concerns the gene HLX and asthma.