Arg(389)Gly beta(1)-adrenoceptor polymorphism varies in frequency among different ethnic groups but does not alter response in vivo

There are marked interethnic differences in beta (1)-adrenclceptor-mediated responsiveness, with sensitivity decreased in African-Americans and increa sed in Chinese compared with Caucasians, Therefore, the frequency of a comm on naturally occurring polymorphism of the human beta (1)-adrenoceptor gene (Arg(389)Gly), which has functional importance in vitro, was determined in 194 African-Americans, 316 Caucasian-Americans, 221 Hispanic-Americans and 142 Chinese. African-Americans were found to hare a significantly lower fr equency of the Arg(389) allele than the other three ethnic groups (all P < 0.01), In the populations studied, the order of the distribution of the Arg (389) allele was: Chinese (74%) > Caucasians (72%) > Hispanics (67%) > Afri can-Americans (58%). To determine the functional significance of the Arg(38 9)Gly beta (1)-adrenoceptsr polymorphism in-vivo heart rate responses to ex ercise were compared in healthy subjects homozygous for the Arg (n = 9) and Gly (n = 8) alleles, Heart rate response to exercise was not affected by g enotype (P = 0.4). Although ethnic differences in the frequency of the beta (1)-adrenoceptor Arg(389)Gly polymorphism exist, the polymorphism does Hot appear to have functional significance in healthy subjects and therefore m ay not contribute to ethnic differences in response to drugs acting through the beta (1)-adrenoceptor, Pharmacogenetics 11:191-197 (C); 2001 Lippincot t Williams & Wilkins.