Familial glucocorticoid deficiency: New genes and mechanisms.

Familial Glucocorticoid deficiency (FGD), in which the adrenal cortex fails to produce glucocorticoids, was first shown to be caused by defects in the receptor for ACTH (MC2R) or its accessory protein (MRAP). Certain mutations in the steroidogenic acute regulatory protein (STAR) can also masquerade as FGD. Recently mutations in mini chromosome maintenance-deficient 4 homologue (MCM4) and nicotinamide nucleotide transhydrogenase (NNT), genes involved in DNA replication and antioxidant defence respectively, have been recognised in FGD cohorts. These latest findings expand the spectrum of pathogenetic mechanisms causing adrenal disease and imply that the adrenal may be hypersensitive to replicative and oxidative stresses. Over time patients with MCM4 or NNT mutations may develop other organ pathologies related to their impaired gene functions and will therefore need careful monitoring.