β3‐adrenoreceptor gene polymorphism and leptin. Lack of relationship in type 2 diabetic patients

The β 3 ‐Adrenergic receptor (β 3 AR) and leptin are molecules involved in the regulation of energy balance. Recently, a mutation in the β 3 AR gene (Trp64Arg) has been reported to be associated with features of insulin resistance, weight gain and early onset of Type 2 Diabetes Mellitus. The aim of this study was to determine the frequency and clinical characteristics of the Trp64Arg mutation in the β 3 AR gene in Type 2 diabetic patients, its relationship with leptin levels, and its role in microangiopathic complications. SUBJECTS AND METHODS 187 Type 2 diabetic patients and 100 unrelated non‐diabetic subjects were studied. There was no difference between the diabetic and nondiabetic subjects in the frequency of the Trp64 and Arg64 alleles (92.5% vs . 92.3% and 7.5% vs . 7.7%, respectively). Type 2 diabetic patients were divided into two groups according to the presence ( n  = 27) or absence of the mutation ( n  = 160). RESULTS Mutation of the β 3 AR gene was not associated with any differences either in the clinical and metabolic parameters or microangiopathic complications. Type 2 diabetic patients carrying the Arg64 allele tended to have a lower diabetes duration, but this was not statistically significant. Plasma leptin levels were not different according to the β 3 AR genotype. CONCLUSIONS The Trp64Arg mutation is not a major determinant of Type 2 diabetes and its microangiopathic complications. Moreover, this mutation was not clinically relevant in leptin regulation.