Beta 3-adrenoreceptor gene polymorphism and leptin. Lack of relationship in type 2 diabetic patients.
BACKGROUND
The beta 3-Adrenergic receptor (beta 3AR) and leptin are molecules involved in the regulation of energy balance. Recently, a mutation in the beta 3AR 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 beta 3AR gene in Type 2 diabetic patients, its relationship with leptin levels, and its role in microangiopathic complications.


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 beta 3AR 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 beta 3AR 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.
Vendrell
J
J
Endocrinology Unit, University Hospital Joan XXIII of Tarragona, Spain. jvo@galenics.com
Gutierrez
C
C
Broch
M
M
Fernandez-Real
J M
JM
Aguilar
C
C
Richart
C
C
D000368:Aged; D000483:Alleles; D001794:Blood Pressure / Q000235:genetics; D015992:Body Mass Index; D016022:Case-Control Studies; D003924:Diabetes Mellitus, Type 2 / Q000235:genetics / Q000378:metabolism*; D003928:Diabetic Nephropathies / Q000235:genetics / Q000378:metabolism; D003930:Diabetic Retinopathy / Q000235:genetics / Q000378:metabolism; D005260:Female; D006801:Humans; D020738:Leptin; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic; D011506:Proteins / Q000378:metabolism*; D011943:Receptors, Adrenergic, beta / Q000235:genetics*; D022702:Receptors, Adrenergic, beta-3; D054411:Receptors, Leptin; D018709:Statistics, Nonparametric
C515448:LEPR protein, human; D020738:Leptin; D011506:Proteins; D011943:Receptors, Adrenergic, beta; D022702:Receptors, Adrenergic, beta-3; D054411:Receptors, Leptin