Clinically silent adrenal adenomas - their relation to the metabolic syndrome and to GNB3 C825T gene polymorphism

Objectives: Aim of the study was to assess the prevalence of C825T GNB3 gene polymorphism in patients with adrenal incidentaloma (AI) as well as its relation to the metabolic syndrome (MS) and cortisol status. Subject and methods: Alltogether 82 subjects (50 patients with AI, mean age 57.9 +/- 15 years and 32 subjects without AI, mean age 53.8 +/- 6.9 years) were included in this study. Parameters of glucose and lipid metabolism, serum adiponectin and the single nucleotide polymorphism C825T in GNB3 gene using PCR-RFLP method were examined. To detect subclinical Cushing syndrome an overnight dexamethason test was performed in all patients with AI. Results: Patients with AI had signifcantly higher BMI, HOMA, triacylglycerols (p < 0.05) and significantly lower serum adiponectine (p < 0.05) than controls. There were no significant differences in metabolic parameters between group with and without subclinical Cushing syndrome (SCS). The prevalence of T allele of GNB3 gene in patients with AI was not significantly higher as compared with control group (32% vs. 47%). No significant differences in serum glucose and lipids between carriers of T and C alleles were detected. However carriers of T allele had significantly lower serum adiponectin than those with allele C (p < 0.01). Conclusion: We conclude that patients with AI had significantly higher cardiovascular risk factors that is not related to the presence of SCS. Moreover patients with AI and TC or TT genotype have significantly lower serum adiponectin which may be an early symptom of metabolic syndrome in patients with AI.