Endocrine Abstracts

Background: The alpha2B adrenoceptor gene, a candidate gene for essential hypertension, harbours a functional insertion/deletion (I/D) polymorphism of three glutamate residues.

Objectives: The aim of this study was to investigate whether the presence of the D allele is associated with hypertension in Greek patients with type 2 diabetes mellitus (T2DM).

Patients-methods: One hundred and twenty-nine hypertensive (64 male, mean age: 66.5±9.3, mean diabetes duration: 11.9±8) and 70 age-matched normotensive (32 male, mean age: 65.8±9.6, mean diabetes duration: 10.7±9.2) T2DM subjects were included in the study. Hypertension was defined as known or newly diagnosed hypertension according to current guidelines (JNC7). All patients included were normoalbuminuric with normal renal function. The I/D polymorphism was determined by polymerase chain reaction (PCR). Differences in the genotype and allele frequencies in the study and control groups were analyzed by use of Yates-corrected chi square-test.

Results: Alpha2B adrenoreceptor I/D genotypes were distributed in T2DM hypertensive patients as follows: 81 (62.8%) II, 40 (31%) ID, 8 (6.2%) DD. The distribution was similar in T2DM nortotensives: II in 62.9% (44), ID in 31.4% (22), and DD in 5.7% (4). There was no statistically significant difference in genotypic and allelic frequencies of the I/D polymorphism between the hypertensive and normotensive diabetic patients (Yates-corrected chi-square =0.814, P=0.36 for the allelic frequencies). In T2DM hypertensive patients, those carrying the D allele showed significantly higher diastolic blood pressure (P=0.002). Total cholesterol and atheromatic index were also higher in this group of patients (P=0.033 and P=0.004 respectively).

Discussion: The D variant of the alpha2B-adrenoceptor gene was not associated with hypertension in T2DM patients. However, diabetic hypertensive patients carrying the D allele are probably prone to diastolic hypertension.