Association of Glu 27 beta 2-adrenoceptor polymorphism with lower airway reactivity in asthmatic subjects.

Cells expressing the Glu 27 beta 2-adrenoceptor polymorphism show attenuated down-regulation of the receptor after long-term exposure to agonist. We studied beta 2-adrenoceptor genotype for the Gln/Glu 27 polymorphism and airway reactivity in 65 patients with mild to moderate asthma. Glu 27 homozygotes had a four-fold higher geometric mean methacholine PD20 (provocative dose) than individuals who were homozygous for the wild-type (Gln 27) form of the receptor; heterozygotes had an intermediate value (3.23, 0.86, 1.96 mumol, respectively). These data suggest that beta 2-adrenoceptor genotype is important in the establishment of the asthmatic phenotype.