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Familial glucocorticoid deficiency (FGD) is an autosomal recessive syndrome with hereditary adrenocortical unresponsiveness to ACTH. After the cloning of ACTH receptor or melanocortin-2 receptor (MC-2R) cDNA, several kinds of mutations in the receptor genes have been reported. However, the apparently normal ACTH receptor gene in some affected children suggests that the etiology of FGD is heterogeneous. In this short review, we describe the recent advances in the molecular biology of ACTH receptor genes, its post-receptor signal transduction in the adrenocortical cells, and the molecular genetics of the FGD and a related syndrome, Allgrove syndrome. We also discuss that this kind of work will help us to understand better about the molecular mechanism of the glucocorticoidogenesis in the human being.

Recent studies have revealed the presence of four subtypes for the melanocortin receptor (MC-R). Among these MC-Rs, MC2-R is considered to be an adrenocorticotropin (ACTH) receptor because its expression is almost localized in the adrenal cortex. Five Japanese patients with ACTH unresponsiveness were examined as to whether they have mutations in the putative ACTH receptor. Among these patients, there are two groups of siblings, each of which consists of two individuals. The coding region of the ACTH receptor gene was amplified by polymerase chain reaction and directly sequenced on both strands, however, no point mutation was found in any of the five patients, suggesting that familial glucocorticoid deficiency, caused by the mutated ACTH receptor, may be rare.