Glucocorticoid receptor polymorphism BclI with increased glucocorticoid sensitivity has a positive influence on Quality of Life in Endogenous Cushing's syndrome in remission

CONTEXT

Patients with endogenous Cushing's syndrome (CS) may suffer from a wide range of neuropsychiatric symptoms leading to impaired quality of life (QoL).

OBJECTIVE

Glucocorticoid receptor (GR) polymorphisms are associated with increased (BclI and N363S) or decreased (A3669G and ER22/23EK) GR sensitivity.

HYPOTHESIS

GR genotypes may modulate and affect QoL and recovery after remission differently via GR sensitivity.

METHODS

295 patients with endogenous CS (81 active, 214 in remission) from 3 centers of the German Cushing's Registry were included for the cross-sectional analysis. All subjects were assessed with three questionnaires (CushingQoL, Tuebingen CD-25, SF-36). For the longitudinal part 120 patients of them were analyzed at baseline and after 1.5 ± 0.9 yrs of follow-up. DNA samples were obtained from peripheral blood leukocytes for GR genotyping.

RESULTS

Patients in remission scored significantly better than patients with active CS in the CushingQoL questionnaire and in the SF-36 sub-categories physical and social functioning, role-physical, bodily pain and vitality. In cross-sectional analysis, no differences in QoL between minor allele and wildtype carriers were detected for all polymorphisms in active or cured CS. In longitudinal analysis, however, carriers with BclI minor allele showed significant improvement in SF-36 sub-categories vitality (p = 0.038) and mental health (p = 0.013) compared to wildtype carriers (active CS at baseline vs. CS in remission at follow-up). The outcome of the two questionnaires CushingQoL and Tuebingen CD-25 improved significantly in both wildtype and minor allele carriers.

CONCLUSION

BclI minor allele carriers initially had the lowest QoL but recovered better from impaired QoL than wildtype carriers.

Glucocorticoid receptor polymorphism in obesity and glucose homeostasis

Glucocorticoid receptor (GR) activity plays a significant role in the etiology of obesity and is essential for glucose homeostasis, the development of hyperinsulinaemia and subsequent increased fat deposition. Several polymorphisms in the GR gene have been described, and at least three of them seem to be associated with altered glucocorticoid sensitivity and changes in glucose homeostasis, and other metabolic parameters. The N363S polymorphism has been associated with increased sensitivity to glucocorticoides, increased insulin response to dexamethasone and increased plasma glucose level. BclI polymorphism is associated with increased abdominal obesity, hyperinsulinaemia and increased insulin resistance. Another polymorphism, ER22/23EK, in contrast to the others, is associated with relative resistance to glucocoricides actions and more beneficial metabolic profile-lower insulin resistance level, decreased lower cardiovascular risk and subseuent prolongation of life time. More research is still needed to understand the mechanisms behind these associations at the molecular level.