Variants in the human β1-,β2- and β3-adrenergic receptor genes are not associated with morbid obesity in children and adolescents

Aim:  β-adrenergic receptors (β-ARs) are of key importance for the regulation of lipolysis and thermogenesis by catecholamines. Genetic defects in expression or function of β1- β2- and/or β3-AR could affect energy homeostasis and predispose an individual towards the development of obesity. We therefore investigated the possible association of polymorphisms in the β-adrenergic receptor genes with early onset obesity. Methods:  Frequencies of the following variants were assessed in extremely obese children and healthy underweight controls: Gly/Ser in codon 49 and Arg/Gly in codon 389 of the β1-AR, Arg/Gly in codon 16 and Gln/Glu in codon 27 of the β2-AR, Trp/Arg in codon 64 of the β3-AR. Results:  The Ser49 allele in the β1-AR gene was found at a frequency of 0.131 in obese and 0.136 in lean subjects (p = 0.835), while the Gly389 allele in the β1-AR had a frequency of 0.319 in obese and 0.328 in lean subjects (p = 0.802). Gly16 in the β2-AR was found with a frequency of 0.590 in obese and 0.611 in lean subjects (p = 0.591) and the Glu27 allele in the β2-AR had a frequency of 0.380 in obese and 0.420 in lean subjects (p = 0.298). Conclusion:  We did not detect significant differences for allele and carrier frequencies of individual polymorphisms. Together with previously obtained data on genotype distribution of a β3-AR variant in the same study group, no significant differences were found between obese and lean subjects for the distribution of individuals with variants in none, one, two or all three β-ARs. Our data make it unlikely that polymorphisms in β-ARs are involved in the pathogenesis of early onset obesity.