Genetic polymorphisms of the beta-2 adrenergic receptor in Israelis with severe asthma compared to non-asthmatic Israelis.

Background: It has been argued that arginine replacement in locus 16 (Arg16) of beta 2 adrenergic receptor with glycin (Gly16) increases asthma severity, while glutamin replacement in locus 27 (Gln27) with glutamic acid (Glu27) decreases it. In addition, ethnic dependency of these polymorphisms has been described, but few studies investigated its relation to asthma severity in a non-anglosaxic population.

Objectives: To investigate non-anglosaxic ethnic influences on beta 2AR polymorphisms and its correlations to asthma severity.

Methods: Sixty-six Israeli Jewish and Arab asthmatics who had near-fatal asthma and/or severe nocturnal asthma and/or steroid-dependency were investigated for genetic polymorphisms of beta 2AR and compared to matched controls. The Jewish patients included both Ashkenazi (of European origin) and non-Ashkenazi (originating from the Middle East or North Africa). The results were compared with those of ethnically matched 113 non-asthmatic Israelis and non-asthmatic Anglo-Saxons described in the literature.

Results: We found no significant genetic differences between the asthmatics and their controls or between the various ethnic groups of our population. However, the prevalence of Glu27 was significantly lower in non-asthmatic Israelis compared to non-asthmatic Anglo-Saxons.

Conclusions: The genetic distribution of beta 2AR polymorphisms in severe Israeli asthmatics is not different from that of non-asthmatic Israelis and therefore its clinical impact on asthma is probably minimal.