Polymorphisms of the ADRβ2 gene for the β2-adrenergic receptor can influence clinical response to β agonists. For the ADRB2, single nucleotide
polymorphisms (SNPs) have been defined at codons 16 and 27. The normal, or wild-type, pattern is arginine-16-glycine and glutamine-27-glutamic acid, but SNPs have been described with homozygous pairing (e.g., Gly16Gly, Arg16Arg, Glu27Glu, and Gln27Gln). The frequency of these polymorphisms is the same in the normal population as in asthmatics. Presence of a gene variant itself does not appear to influence baseline lung function.