Glucocorticoid resistance due to mutations in the gene for the glucocorticoid receptor has been suggested to be more common than is thought at present, owing to the relative mildness of its symptoms and the difficulty of its diagnosis. To investigate the prevalence of mutations in the glucocorticoid receptor gene responsible for relative insensitivity to glucocorticoids, we carried out polymerase chain reaction/single-strand conformation analysis of the glucocorticoid receptor gene in a group of 20, otherwise healthy, persons with a reduced response in a dexamethasone suppression test and in 20 controls. We did not find mutations or polymorphisms associated with a reduced sensitivity to glucocorticoids. However, we identified five novel polymorphisms in the gene for the human glucocorticoid receptor, which may be useful in analyzing whether loss of (part of) the glucocorticoid receptor gene plays a role in glucocorticoid-resistant malignancies. Although relative resistance to glucocorticoids seems to be rather frequent in otherwise healthy persons, it is not usually associated with mutations or polymorphisms in the glucocorticoid receptor gene.
Primary (partial) cortisol receptor resistance was previously reported in a total of 7 patients and 14 asymptomatic family members. Its occurrence is considered to be extremely rare. In the present study we report on 6 patients (2 males and 4 females) with the syndrome. The first male patient presented with mild hypertension. Hydrochlorothiazide therapy resulted in life-threatening hypokalemia. The second male patient had slight hypertension without hypokalemia. All four female patients presented between the age of 20-30 yr with acne, hirsutism, and irregular menstruations. Low dose dexamethasone therapy (1-1.5 mg/day) was of clinical benefit in these patients. All patients showed insufficient suppression of serum cortisol concentrations in the overnight 1-mg dexamethasone test. The diurnal rhythm of ACTH and cortisol was intact, albeit at an elevated level. There was a normal increase in ACTH, cortisol, and GH (except in one obese patient) in response to insulin-induced hypoglycemia, while cortisol production was elevated in three patients. Circulating adrenal androgen levels were increased in all patients. Glucocorticoid receptors were investigated in a whole cell dexamethasone binding assay in mononuclear leukocytes. In the first male patient, the number of receptors was very low, while the affinity was lower than that in controls. A lowered affinity to dexamethasone was found in one female patient, while a lowered number of receptors was found in three patients. In the second male patient, no abnormalities were found. As a bioassay for glucocorticoid action we also measured dexamethasone suppressibility of mitogen-stimulated incorporation of [3H]thymidine in mononuclear leukocytes. In the male patient with normal receptor status, dexamethasone suppressibility of [3H]thymidine incorporation was significantly lower than that in healthy controls with respect to both maximal suppression and IC50. Partial cortisol receptor resistance might be less rare than previously thought. In the six patients presented, at least three different forms can be recognized. Therapy with dexamethasone was successful in female patients with acne and hirsutism, as the secondary increase in the production of adrenal androgens was effectively controlled.
We identified one SNP, which was associated with increased salivary cortisol levels at nadir as well as higher androstenedione levels. Moreover, this SNP was also associated with a higher risk of an incident depression. This suggests that 11β-HSD1 is implicated in human HPA axis regulation and susceptibility to depression.
It has been shown that an appreciable percentage of patients presenting with primary, apparently sporadic phaeochromocytomas may in fact have von-Hippel-Lindau (VHL) disease. In order to investigate this, we retrospectively screened 68 patients, who had been operated on for phaeochromocytomas, for the presence of germline mutations in the vhl gene. DNA was isolated from peripheral-blood leukocytes and used to screen the entire coding sequence and the intron-exon boundaries of the vhl gene for mutations, using a PCR-based SSCP strategy. When an abnormal pattern was found in the SSCP analysis, sequence analysis was carried out. We found SSC variants in the vhl gene in 8 of the 68 patients. Of 6 patients, 2 turned out to be related (an uncle and his nephew), and they carried the same mis-sense mutation: R64P. In 4 other patients, mis-sense mutations, P25L, L63P, G144Q and I147T, were also identified. None of these mutations has been described, and 3 of them (P25L, L63P and R64P) are located closer to the N terminus of the vhl protein than any reported vhl mutation. In the remaining 2 cases, the mutations were localized not in the coding sequence but in the intronic sequence (but not within splice-sites), adjacent to the exon, so they were probably not related to the disease. Our results show that a relatively high proportion (6/68, or 8.8%), though not as high as the 20% reported earlier, of patients with apparently sporadic phaeochromocytomas may carry germline mutations in the vhl gene. Int.
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