Showing papers on "Adrenocortical hyperfunction published in 2012"
TL;DR: Findings demonstrate striking variations in phenotypes and clinical outcome resulting from different mutations of the same amino acid in KCNJ5 and have implications for the diagnosis and pathogenesis of primary aldosteronism with and without adrenal hyperplasia.
Abstract: We recently implicated two recurrent somatic mutations in an adrenal potassium channel, KCNJ5, as a cause of aldosterone-producing adrenal adenomas (APAs) and one inherited KCNJ5 mutation in a Mendelian form of early severe hypertension with massive adrenal hyperplasia. The mutations identified all altered the channel selectivity filter, producing increased Na+ conductance and membrane depolarization, the signal for aldosterone production and proliferation of adrenal glomerulosa cells. We report herein members of four kindreds with early onset primary aldosteronism of unknown cause. Sequencing of KCNJ5 revealed that affected members of two kindreds had KCNJ5G151R mutations, identical to one of the prevalent recurrent mutations in APAs. These individuals had severe progressive aldosteronism and hyperplasia requiring bilateral adrenalectomy in childhood for blood pressure control. Affected members of the other two kindreds had KCNJ5G151E mutations, which are not seen in APAs. These subjects had easily controlled hypertension and no evidence of hyperplasia. Surprisingly, electrophysiology of channels expressed in 293T cells demonstrated that KCNJ5G151E was the more extreme mutation, producing a much larger Na+ conductance than KCNJ5G151R, resulting in rapid Na+-dependent cell lethality. We infer that this increased lethality limits adrenocortical cell mass and the severity of aldosteronism in vivo, accounting for the milder phenotype among these patients. These findings demonstrate striking variations in phenotypes and clinical outcome resulting from different mutations of the same amino acid in KCNJ5 and have implications for the diagnosis and pathogenesis of primary aldosteronism with and without adrenal hyperplasia.
252 citations
TL;DR: WGEP analysis revealed that not all cAMP activation is the same: adrenal lesions harboring PRKAR1A or GNAS mutations share the downstream activation of certain oncogenic signals but differ substantially in their effects on others.
Abstract: Context: The overwhelming majority of benign lesions of the adrenal cortex leading to Cushing syndrome are linked to one or another abnormality of the cAMP or protein kinase pathway. PRKAR1A-inactivating mutations are responsible for primary pigmented nodular adrenocortical disease, whereas somatic GNAS activating mutations cause macronodular disease in the context of McCune-Albright syndrome, ACTH-independent macronodular hyperplasia, and, rarely, cortisol-producing adenomas. Objective and Design: The whole-genome expression profile (WGEP) of normal (pooled) adrenals, PRKAR1A- (3) and GNAS-mutant (3) was studied. Quantitative RT-PCR and Western blot were used to validate WGEP findings. Results: MAPK and p53 signaling pathways were highly overexpressed in all lesions against normal tissue. GNAS-mutant tissues were significantly enriched for extracellular matrix receptor interaction and focal adhesion pathways when compared with PRKAR1A-mutant (fold enrichment 3.5, P < 0.0001 and 2.1, P < 0.002, respective...
62 citations
TL;DR: Lack of clinical and biochemical evidence of hyperandrogenism as well as the benign histology in spite of the large tumor size are some of the unique features of the patient.
Abstract: Bilateral macronodular adrenocortical disease as a part of McCune Albright Syndrome (MAS) is the most common cause of endogenous Cushing’s syndrome (CS) in infancy. Adrenocortical tumors causing CS in infancy are extremely rare. We report the case of a girl with CS who presented at age 4 months with obesity and growth retardation. Her 8 am paired cortisol and adrenocorticotropic hormone levels were 49.3 μg/dL and 7 cm diameter; 115 g) are some of the unique features of our patient.
Conflict of interest:None declared.
13 citations
TL;DR: The imaging characteristics of pediatric adrenocortical tumors are shown to show that in the absence of vascular infiltration and/or metastases it is difficult to differentiate between the two types by imaging and histology.
9 citations
TL;DR: Intraoperative hypotension occurred immediately after tumor removal and following postoperative adrenal insufficiency, which support that the tumor was hyperfunctioning.
Abstract: Cavernous hemangioma of the adrenal gland is a rare tumor, which does not usually have endocrinological function. We report to our knowledge, the third documented case of a functioning adrenal hemangioma. Interestingly, this tumor indicated glucocorticoid hypersecretion, whereas the two previous cases showed mineralocorticoid hypersecretion. The tumor was 5 cm in diameter with typical computed tomography and magnetic resonance imaging findings. Subclinical Cushing’s syndrome was diagnosed preoperatively, as there was insufficient suppression of cortisol by low-dose dexamethasone, a low adrenocorticotropic hormone (ACTH) concentration, and diminished ACTH and cortisol circadian rhythms without the typical clinical manifestation and symptoms of hypercortisolism. Intraoperative hypotension occurred immediately after tumor removal and following postoperative adrenal insufficiency, which support that the tumor was hyperfunctioning. The postoperative adrenal insufficiency had recovered completely by 12 months after the operation.
TL;DR: This is the first case of NF1 associated with clinical and biochemical features of Cushing’s secondary to ectopic ACTH due to MPNST in a plexiform neurofibroma and its resolution on treatment with imatinib.
Abstract: A 64-year-old male presented with neurofibromatosis 1 and Cushing's syndrome. Clinically he was over weight, depressed with extensive skin bruising and hypertension. His 24 hours urinary metanephrines, urinary 5HIAA, gut peptides and chromgranin levels were normal. His renal function and renal MRI scan was also normal. His cortisol failed to suppress on overnight dexamethsone suppression test. His low dose dexamethasone suppression with CRH stimulation showed failure of suppression of cortisol to < 50 nmol/L and ACTH was measurable at 10 ng/L on day 3. There was no response of ACTH or cortisol to CRH stimulation. His ACTH precursors were high at 126 pmol/L consistent with defective pro-opiomelanocortin (POMC) processing suggesting an ectopic source of ACTH production. The MRI scan of his pituitary and CT scan of the adrenal glands was normal. His octreotide scan was negative. The source of his ectopic ACTH was most likely a large retroperitoneal plexiform neurofibroma seen on CT abdomen that had undergone malignant peripheral nerve sheath tumour transformation on histology. He was a poor surgical risk for tumour debulking procedure. In view of the available literature and role of c-kit signalling in neurofibromatosis, he was treated with Imitinib. Four months after the treatment his Cushings had resolved on biochemical testing. After a year his plexiform neurofibroma has not increased in size. To our knowledge, this is the first case of NF1 associated with clinical and biochemical features of Cushing's secondary to ectopic ACTH due to MPNST in a plexiform neurofibroma and its resolution on treatment with imatinib.