Clinical features of a polymorphism of the beta(3)-adrenergic receptor gene in patients with type 2 diabetes mellitus - A study using a pin-point sequencing method

The human beta (3)-adrenergic receptor (beta (3)AR) is expressed specifical ly in adipose tissues, and its activation is activated in brown adipose tis sues during thermogenesis and in white adipose tissues during lipolysis. We investigated the relationship between a polymorphism of the beta (3)AR gen e and the clinical features of type 2 diabetes mellitus. Studies were condu cted in 30 type 2 diabetic patients (15 males and 15 females). Analysis of polymorphisms of the beta (3)AR gene was performed by a pin-point sequencin g method using the hair of the subjects. Preperitoneal (P-fat) and subcutan eous fat (S-fat) levels were determined by ultrasonography. We found a Trp( 64)Arg allele of the beta (3)AR gene in the hair of 27% of all patients. Th e patients with this mutation showed a significantly younger onset-age of d iabetes than those of tile wild type, The body mass index, serum GPT levels , fasting immunoreactive insulin (IRI) and daily urinary C-peptide reaction (CPR) in the mutation group were markedly higher than in the wild type gro up. The P-fat, serum cholesterol and leptin concentrations tended to be hig her in the mutation group. Patients in the mutation group had a significant ly higher prevalence of hypertension (80%) compared with those in the wild type group (20%). Conclusions: The present results Suggest that the clinica l features of diabetic patients with a missense mutation in the beta (3)AR gene are substantially distinct from those of tile wild type patients. Thes e specific features include obesity, hyperinsulinemia, hypertension, and an increase in preperitoneal fat.