Clinical and biochemical impact of BCL1 polymorphic genotype of the glucocorticoid receptor gene in patients with adrenal incidentalomas.

Background: Adrenal incidentaloma (AI) is a common clinical problem. Subtle hormonal abnormalities are present in a substantial proportion of patients. BCL1 gene polymorphism of the glucocorticoid receptor (GR) is associated with increased sensitivity to glucocorticoid action. The genotype-phenotype associations of this polymomorphism in patients presenting with AI has not been extensively investigated. Aim: A cross-sectional study in secondary/tertiary care centers. Subjects/methods: Ninety-five subjects with AI were genotyped for the BCL1 GR gene polymorphism. Patients underwent an oral glucose tolerance test and a dexamethasone suppression test (DST). The presence of subclinical hypercortisolism, features of metabolic syndrome, and osteoporosis/osteopenia were also assessed. Results: No significant differences in markers of adrenal function between BCL1 carriers and non-carriers were revealed. Also, no difference was found in the features of metabolic syndrome, as well as in bone metabolism and density between these 2 groups. However, DST suppressor patients belonged more frequently to the BCL1 carriers group (41 out of 69 patients, 59.4% vs 9 out of 26 patients, 34.6%, p=0.0039), had smaller total adenoma size (2.4±0.2 cm vs 3.5±0.4 cm, p=0.04), and lower incidence of bilateral adrenal masses (18.8% vs 46.2%, p=0.01). Conclusions: AI patients who also carry the polymorphic BCL1 variant exhibit smaller size adrenal nodules. Those AI patients with complete DST suppression had a higher incidence of the polymorphic BCL1 variant. However, this study failed to demonstrate any significant impact of BCL1 GR polymorphism on the frequency of cortisol-dependent co-morbidities in patients with AI.