There is much to find out about this fascinating and complex molecule in relation to the development and progression of asthma. Added to it are three further new asthma/allergy genes identified by positional cloning: PDH Finger Protein II (PHF11) on chromosome 13q14, which encodes NY-REN-34 a protein first described in patients with renal cell carcinoma [67]; Dipeptidyl diptidase 10 (DDP10) on chromosome 2q14 [68]; and G protein-coupled receptor for asthma susceptibility (GPRA) on chromosome 7p [69]. For each of these genes, as is the case for ADAM33, determining their normal function(s) and how these become disordered in asthma is the future challenge.