Aim: The beta 3-adrenergic receptor (beta 3-AR) is suspected to play a key role in the regulation of energy balance by increasing lipolysis and thermogenesis. A mutation in the beta 3-AR gene (Trp64Arg) has been associated with the capacity of weight gain and with early onset of noninsulin dependent diabetes mellitus (type 2 diabetes). In this study we investigated the prevalence of the two beta 3-AR alleles in a Caucasian population and studied the association between the beta 3-AR genotype and metabolic disorders (obesity and type 2 diabetes).
Methods: Genomic DNA extracted from peripheral blood leucocytes of 200 Caucasian subjects (137 subjects with and 63 subjects without type 2 diabetes). The MvaI polymorphism of beta 3-AR, which detects the Trp64Arg mutation, was determined by polymerase chain reaction (PCR). We studied the correlation between the Trp64Arg mutation and the body mass index (b.m.i. kg/m2).
Results: There was no significant difference between the patients with type 2 diabetes and control subjects in the frequency of the Arg64 allele (5.5% and 4.8%, respectively). Within the group of type 2 diabetes patients were 14 subjects with the Trp64Arg mutation (b.m.i., mean +/- s.d.: 31 +/- 8.5 kg/m2) and 123 without the mutation (b.m.i. 29 +/- 4.8). There was no association between the beta 3-AR gene polymorphism and sex, obesity, blood pressure, glycohaemoglobin concentration, proteinuria.
Conclusion: Our results suggest that the Trp64Arg mutation is not a major determinant of metabolic disorders (type 2 diabetes, obesity) and chronic complications of type 2 diabetes in a Dutch population.