In reality there are many different genes and many different enviornmental factors associated with asthma.
Asthma OMIM - OMIM search for genes realted to asthma susceptibility: Notice that it involves 9 chromosomes with multiple loci on the 5th and 6th chromosome
NCBI Sequence - ADAM33 protein sequence from NCBI
NCBI Blast - BLAST results of ADAM33
This figure was obtained from RSCB Protein Data Bank and is a depiction of ADAM 33 catalytic domain. ADAM33 consists of 22 exons coding a signal sequence domain, prodomain, catalytic domain, disintegrin domain, C-rich domain, EGF domain and a cytoplasmic domian with a long 3' untranslated region. A Ca binding site is located in the active site of the catalytic domain. Experimentally determined substrates include: Stem Cell factor, APP, Insulin B chain, and TRNANCE although it is worth nothing that enzymes kinetics of these studies suggest that none of them are natural substrates. Adam 33 is expressed in smooth muscle, fibroblasts and myfibroblasts. (1)