Familial ACTH-independent Cushing's syndrome with bilateral macronodular adrenal hyperplasia clinically affecting only female family members

Primary adrenal hyperplasia, which may occur as a familial disorder, is a rare cause of ACTH-independent Cushing's syndrome. In most of these cases the underlying pathology is primary adrenocortical micronodular dysplasia. Very few cases of familial Cushing's syndrome due to primary macronodular adrenal hyperplasia have been described. We report a family with seven affected family members. The pedigree indicates an autosomal dominantly inherited disorder. Interestingly only female family members developed the clinically apparent syndrome. The only available obligatory male gene carrier failed to adequately suppress his plasma cortisol level on overnight dexamethasone suppression test. His adrenal glands showed nodular enlargement on abdominal computed tomographic imaging. Screening of the MEN 1 gene and genetic analysis of the hot spot regions of the GNAS 1 (codons 201 and 227) and GNAI 2 (codons 179 and 205) genes did not show any mutations in the constitutional DNA or the adrenal tissue DNA of the index patient. In conclusion, this family is the largest kindred reported in the literature with ACTH-independent Cushing's syndrome due to autosomal dominant inherited macronodular adrenocortical hyperplasia. Four currently alive and affected family members in two generations and further careful observation of the yet unaffected members of the third available generation might offer the opportunity to identify the still unknown gene defect in the future.