17 alpha-hydroxylase deficiency: mineralocorticoid hormone profiles in an affected family

The plasma concentrations of mineralocorticoid hormones, basal and after stimulation and suppression with ACTH, can identify the heterozygotes in a family with two siblings with 17 alpha-hydroxylase deficiency. Both parents and one sibling had elevated levels of plasma deoxycorticosterone, corticosterone, 18-hydroxydeoxycorticosterone, and 18-hydroxycorticosterone, but normal cortisol and aldosterone concentrations. Stimulation with ACTH effected additional increases in the elevated steroid and cortisol levels, but not in aldosterone, further increasing the discrepancy and the ratio between 18-hydroxycorticosterone and aldosterone. One sibling had normal steroid patterns and an 18-hydroxycorticosterone to aldosterone ratio. Suppression of ACTH restored the steroids to low normal levels. In addition, the ratio of the gas chromatographic analysis of the total major urinary metabolites of corticosterone to total metabolites of cortisol was greater, and the sum of urinary androsterone and etiocholanolone to total corticosterone and cortisol metabolites was less in the heterozygotes than in normal subjects. This identifies deficient 17-hydroxylation, which is required for the production of cortisol and C-19 steroids. These criteria appear unique for the 17 alpha-hydroxylase defect in the heterozygote.     

A case of male pseudohermaphroditism due to 17 alpha-hydroxylase deficiency and hormonal profiles in the nuclear family

A genetic male with 17 alpha-hydroxylase deficiency is described. The patient, raised as a female, was seen at 17 yr of age for impuberism. She presented all the features of the classical severe form of the disease: complete female phenotype; hypertension; hypokalemia; elevated levels of plasma progesterone, 11-deoxycorticosterone, corticosterone (B), and ACTH; and suppression of renin and aldosterone production. Levels of 17-hydroxyprogesterone, 17-hydroxypregnenolone, and all androgens were barely detectable. Hormone steroid patterns were determined in basal conditions and after acute ACTH stimulation in the parents and the two unaffected brothers in order to identify the heterozygotes. Subtle abnormalities in B and aldosterone secretion were observed in the male members of the family. On the basis of an increased ratio of B to aldosterone the two brothers were assumed to be heterozygotes. The mother had normal basal and stimulated levels of B, deoxycorticosterone, and aldosterone. In the parents and two brothers the progesterone responses to ACTH were exaggerated. The most striking finding in the father and both brothers was the observation of increased basal plasma 17-hydroxyprogesterone, unresponsive to ACTH stimulation, suggesting a partial Leydig cell 17,20-lyase deficiency in the male heterozygotes of this family. This study shows that a short ACTH test can help to identify the heterozygotes in affected families, but the abnormalities found are more heterogeneous than previously suggested.     

Comparison of two tests for heterozygosity in congenital adrenal hyperplasia (CAH).

The increase of plasma cortisol (F), androstenedione (A), 17 alpha-hydroxy-progesterone (17-OH-P) and testosterone (T) was measured after iv administration of ACTH in heterozygotes for CAH and in controls under two different conditions: Test 1: ACTH stimulation was performed without any particular preparation. Test 2: 1.5 mg of dexamethasone (dex.) was given the evening before the ACTH stimulation. Plasma F, A, 17-OH-P and T were measured by specific radioimmunoassays (RIA). Following ACTH stimulation, the increase of 17-OH-P was significantly higher in CAH-heterozygotes than in controls in both tests (P less than 0.0005). Heterozygotes were characterized by a 17-OH-P increase after ACTH stimulation exceeding the + 2 SD limit of the 17-OH-P increase found in controls. The detection of female heterozygotes was considerably improved by the administration of dex. before testing (test 2). In males, however, a better identification of heterozygotes was obtained without previous administration of dex. (test 1). By these tests, 100% of female (test 2) and 79% of male (test 1) CAH heterozygotes could be correctly identified. There were no significant differences in the levels of F, A and T between heterozygotes and controls except for decreased T levels in test 1 (2P less than 0.01) in most male heterozygotes after ACTH stimulation.     

HLA and hormonal studies in 5 patients with late-onset 21-hydroxylase deficiency syndrome (21OHDS)

Late-onset 21-hydroxylase deficiency (21OHD) presents biochemical evidence of 21OHD and virilization in peri-or postpubertal age; it has been demonstrated that late-onset 21OHD is linked to HLA system. We present the HLA typing, the baseline and the ACTH-stimulated hormonal levels in 5 patients with late-onset 21OHD and in their family members. We identified 3 HLA identical male sibs within their respective families, 2 sibs sharing one haplotype with the affected member and 2 homozygous normal sibs. We observed elevated baseline (greater than 4 ng/ml) and ACTH-stimulated 17-hydroxyprogesterone levels, increased baseline Androstenedione levels, slightly elevated or normal DHEA-S and Testosterone values and subnormal response of Cortisol levels to ACTH in patients and in the HLA-identical sibs, reduced SHBG levels in patients but not in their identical sibs. The heterozygous family members presented hyperresponsiveness of 17-hydroxyprogesterone but not of androgens after ACTH. We confirm that late-onset of 21OHD is an autosomal recessive disease linked to HLA-B; there is in fact biochemical evidence of mild 21OHD in patients and in their HLA identical sibs and 17-hydroxyprogesterone levels in the range of heterozygotes for classical 21OHD in parents and sibs predicted by HLA to be carriers. Thus HLA typing and hormonal data, particularly 17-hydroxyprogesterone, are useful, also in this form of congenital hyperplasia, in detecting heterozygotes.     

Increased plasma 21-deoxycorticosterone (21-DB) levels in late-onset adrenal 21-hydroxylase deficiency suggest a mild defect of the mineralocorticoid pathway

Plasma 21-deoxycorticosterone (21-DB) concentrations were measured before (basal) and 1 h after ACTH stimulation in a population of 34 normal subjects, 18 patients with the late-onset form of congenital adrenal hyperplasia (LO-CAH) due to 21-hydroxylase deficiency, and 19 LOCAH heterozygotes. For comparison, plasma 21-deoxycortisol (21-DOF) and 17-hydroxyprogesterone (17-OHP) were determined simultaneously in the same subjects. Plasma 21-DB concentrations as well as those of 21-DOF did not vary significantly as a function of age, sex, or phase of the menstrual cycle, in contrast to plasma 17-OHP. The mean plasma 21-DB concentrations in normal subjects (adult men, follicular and luteal phase women, and children) were 19.0 +/- 9.5 (+/- SD) pmol/L before and 73.2 +/- 31.0 after ACTH stimulation. In the LOCAH patient group, the mean post-ACTH plasma 21-DB concentration was 1736.0 +/- 1243.0 pmol/L, and all values were above the highest post-ACTH value (148.2 pmol/L) in the normal subjects. Similarly, in the LOCAH patients the post-ACTH plasma 21-DOF concentration was 33.7 +/- 20.3 nmol/L, and the post-ACTH plasma 17-OHP value was 134.0 +/- 70.6 nmol/L; all LOCAH patients had supranormal responses to ACTH. However, 38.9%, 11.2% and 16.7% of the basal plasma 21-DB, 21-DOF, and 17-OHP values in the LOCAH patients overlapped those in the normal subjects. There was a rather large overlap (63.2%) in post-ACTH plasma 21-DB levels between the LOCAH heterozygotes and the normal subjects; it was less than the overlap in plasma 17-OHP (74%) and more than the overlap in plasma 21-DOF values (5.2%) in these same 2 groups. There was moderate overlap (21%) in the post-ACTH plasma 21-DB levels between the LOCAH heterozygotes and LOCAH patients, but no overlap between these 2 groups for either 21-DOF or 17-OHP. The abnormally elevated post-ACTH plasma 21-DB levels found in all the LOCAH patients as well as in some LOCAH heterozygotes suggest the existence of minor 21-hydroxylase deficiency in the mineralocorticoid synthetic pathway in these patients in addition to the well known impairment in the glucocorticoid pathway demonstrated by the elevated post-ACTH 21-DOF and 17-OHP levels.     

Attenuated forms of congenital adrenal hyperplasia due to 21-hydroxylase deficiency

A variety of mild forms of congenital adrenal hyperplasia (CAH) due to partial 21-hydroxylase deficiency have recently been described. We report two families in whom members presented with CAH with various degrees of enzyme deficiency. In family A, two children had the classical salt-losing CAH. Their male sibling and mother presented a very mild asymptomatic form of CAH, characterized by elevated basal plasma levels of 17-hydroxyprogesterone (17-OHP) and exaggerated responses of progesterone and 17-OHP to ACTH stimulation. The Hormonal profile and HLA types of these two individuals suggested allelic compounds, having one mutant gene for classical CAH and another for a mild form. In family B, the proband presented an attenuated form of CAH, manifested by amenorrhea and hirsutism, elevated basal levels of plasma 17-OHP and androgens, as well as markedly increased ACTH response. Two of her four siblings had the same ad HLA type, elevated basal plasma 17-OHP levels, and increased ACTH response. Their father, their paternal aunt, and their paternal uncle had the ab HLA type and normal basal plasma 17-OHP but markedly increased ACTH response. The haplotypes a, b, and d were considered to be linked to a mutation resulting in mild 21-hydroxylase deficiency, the homozygotes with ab HLA type having a milder form of CAH than the homozygotes with the ad HLA type. The wide spectrum of clinical and hormonal characteristics among homozygotes for the 21-hydroxylase deficiency trait suggests that their is a continuum of degree of enzyme deficiency. Furthermore, it suggests that most nonclassical subjects are allelic compounds for variable degrees of severity in the mutation at the 21-hydroxylase locus. More specifically, the study of families A and B shows that the so-called cryptic and attenuated forms of CAH have the same pathophysiological basis.     

Recurrent mutations of the apolipoprotein A-I gene in three kindreds with severe HDL deficiency

Two siblings with high density lipoprotein (HDL) deficiency and no plasma apolipoprotein A-I (Apo A-I) were found to be homozygous for a cytosine deletion in exon 3 of Apo A-I gene (c.85 del C, Q5FsX11). This mutation causes a frameshift leading to a premature stop codon and abolishes the synthesis of Apo A-I. Although both siblings had corneal opacifications and planar xanthomas, only one of them had premature coronary artery disease, probably as the result of mildly elevated LDL levels. In two other unrelated subjects HDL deficiency was due to heterozygosity for a nucleotide substitution in exon 4 of Apo A-I gene (c.494 T>G, L141R). Both Apo A-I mutations were reported previously in an Italian kindred which included compound heterozygotes and simple heterozygotes. We investigated all carriers of these mutations in the three kindreds and in the one previously reported. Plasma Apo A-I and HDL-C levels were lower in the mutation carriers than in non-carrier family members. These levels, however, were lower in L141R carriers than in carriers of c.85 del C. Haplotype analysis performed using several polymorphisms suggested that both the c.85 del C and L141R are likely to be recurrent mutations.     

Impaired mineralocorticoid hormone responses to adrenocorticotropin stimulation: additional characterization of heterozygosity for the 21-hydroxylase deficiency type of congenital adrenal hyperplasia

In 12 obligate heterozygotes for the simple virilizing form of congenital adrenal hyperplasia (21-hydroxylase deficiency), basal and ACTH-stimulated levels of aldosterone, corticosterone, deoxycorticosterone, 18-hydroxycorticosterone, and 18-hydroxydeoxycorticosterone were examined. The responses to ACTH were significantly impaired (P less than 0.025 less than 0.001) compared with those of normal subjects. In addition to the often exaggerated stimulation by ACTH of the immediate precursor to 21-hydroxylation, 17 alpha-hydroxyprogesterone, the heterozygotes can now be characterized further by the impaired ACTH responses of mineralocorticoids distal to the block in the zona fasciculata; the ACTH-stimulated 17 alpha-hydroxyprogesterone/18-hydroxydeoxycorticosterone ratio was greater than normal in 94% of the heterozygotes. A limitation of 21-hydroxylation may also exist in the zona glomerulosa.     

Risk of disease in siblings of patients with hereditary hemochromatosis.

BACKGROUND: Parents of hereditary hemochromatosis (HH) homozygote patients, who are predominantly HH heterozygotes, have been found to have an increased risk of colonic neoplasia, diabetes, stroke death, stomach cancer and leukemia. The health histories of siblings of HH patients are reported. METHODS: Individuals homozygous for HH were mailed questionnaires concerning the health histories of their siblings. Spouses of the HH homozygotes were asked to complete accompanying questionnaires concerning their siblings. The frequencies of serious illness and, when specified, each reported disease were determined by zygosity, odds ratios and 95% confidence intervals estimated. RESULTS: Data were available for 279 siblings known to be HH homozygotes (HHs), and 1,265 other siblings of HH patients, who are predominantly hemochromatosis heterozygotes (HHhet). Controls consisted of 1,338 spouse siblings in whom only the general population prevalence of HH homozygosity and heterozygosity existed. Odds ratios comparing HH strata to controls were elevated for serious illness (1.12 in HHhet, 1.71 in HHs), diabetes (0.78, 2.45), arthritis (2.10, 1.69), and hepatoma (1.06, 11.96). CONCLUSIONS: There was a significant trend for increased risk of serious illness among siblings of HH patients with increasing exposure to the HH gene, especially for diabetes, arthritis and hepatoma.     

17-Hydroxyprogesterone responses to adrenocorticotropin in children with premature adrenarche

The adrenal secretory response to an iv bolus dose of ACTH was measured in 10 girls (4-8 yr of age), 5 boys (4-9 yr) with premature adrenarche (PA), and 20 normal children. The evening before the ACTH test, each subject took dexamethasone (1 mg at bedtime) to suppress the early morning surge of ACTH. The next morning, 2 serum samples were obtained before the administration of ACTH (Cortrosyn; 0.25 mg), and 2 samples were collected 30 and 45 min after ACTH administration. All samples were assayed for cortisol, dehydroepiandrosterone (DHEA), DHEA sulfate, 17-hydroxyprogesterone (17-OHP), and androstenedione. There was no significant difference in the dexamethasone-suppressed steroid levels between the children with PA and the normal children. After ACTH injection, cortisol, DHEA, 17-OHP, and androstenedione increased significantly. There was no significant change in DHEA sulfate. The mean 17-OHP response to ACTH in girls with PA was significantly higher than that in girls and women whose pubertal development was normal. This response was similar in magnitude to that in a group (n = 5) of obligate heterozygotes for congenital adrenal hyperplasia (CAH). These data suggest that many girls with PA have a mild adrenal steroid secretory defect that resembles the response in adult obligate heterozygotes for CAH due to 21-hydroxylase deficiency. In contrast to the girls, none of the boys with PA had an exaggerated 17-OHP response to ACTH. Thus, these boys had no evidence for an adrenal steroid secretory defect. In summary, although the clinical presentation of boys with PA is similar to that of girls with PA, there is a significant difference in the adrenal steroid secretory response to ACTH. Thus, the biochemical events that cause PA in boys may be different from the corresponding events in girls.     

Identification of nonclassical 21-hydroxylase deficiency in girls with precocious pubarche.

Recent studies have described mild adrenal enzymatic defects in patients presenting with precocious pubarche. In order to identify these defects we have evaluated basal and ACTH- (25 IU iv) stimulated serum adrenal steroid levels in 19 girls, 2- to 8.3-year-old, with precocius pubarche (pubic hair Tanner II-III). Two patients had clitorial enlargement. Bone age was moderatly advanced in 10 patients and 2 to 3.7 yr in four others. Four patients had high basal serum levels of 17-hydroxyprogesterone (17OHP) (525 + 202 ng/dl, mean +SD), compatible with the diagnosis of nonclassical congenital adrenal hyperplasia due to 21-hydroxylase deficiency (NCCAH-21OH), which was confirmed by an increased response of 17OHP to ACTH (3425 +/- 953 ng/dl). Fifteen patients had moderately elevated basal 17OHP levels (56 + 38 ng/dl) but a normal 170HP response (191 +/- 71 ng/dl) to ACTH, compatible with the diagnosis of idiopathic precocious pubarche (IPP). The cortisol response to ACTH was normal in both groups. Basal values of DHEA-S were 651 +/- 256 and 506 + 462 ng/ml and of DHEA 380 +/- 24 ng/dl and 205 +/- 102 ng/dl, in NCCAH-210H and IPP, respectively. We conclude that: i) clinical findings and baseline levels of DHEA-S and DHEA in IPP can be indistinguishable from the late onset 21 hydroxylase deficiency; ii) baseline levels of 17OHP are sufficient for the diagnosis of NCCAH-21OH; iii) the ACTH stimulation test is indicated only when baseline levels of 17OHP are moderately elevated (100-300 ng/dl).     

17-alpha-hydroxylase deficiency in three siblings: short- and long-term studies.

We have studied a family (12 members) with 3 patients (2 adult females and 1 pubertal-aged genotypic male) affected by congenital adrenal hyperplasia due to 17-alpha-hydroxylase deficiency, all of whom presented as phenotypically female subjects with lack of sexual development and with hypokalemic hypertension. The baseline hormonal pattern revealed low glucocorticoid levels (17-hydroxyprogesterone, plasma and urinary cortisol, cortisol secretion rate), as well as androgen (testosterone and dehydroepiandrosterone sulfate) and estrogen (17-beta-estradiol) levels, since the defect is present at both adrenal and gonadal levels. As a consequence ACTH, LH, and FSH concentrations were high. Otherwise steroids not requiring 17-alpha-hydroxylation, such as deoxycorticosterone, corticosterone and their 18-hydroxylated compounds, were secreted in excess with the exception of aldosterone whose levels were undetectable; baseline plasma renin activity levels were suppressed. Short-term dexamethasone treatment normalized potassium and reduced blood pressure and the abnormal mineralocorticoid levels. During chronic ACTH suppression with low doses of glucocorticoids (8 years), electrolyte disturbances were corrected, blood pressure was normalized in 2 cases but only reduced in the third; plasma renin activity returned to normal range within four years in all the patients, while urinary aldosterone was normalized only after 8 years of therapy and became partially responsive to posture, ACTH, angiotensin II, and furosemide. The other mineralocorticoids were reduced but remained above the normal range. The HLA-genotyping in all the family members revealed that the gene responsible for 17-alpha-hydroxylase deficiency was not linked to the HLA system. Measurement of plasma steroids (deoxycorticosterone, corticosterone, aldosterone) in this family revealed that the heterozygotes were different from the control population only in their ACTH-stimulated corticosterone levels.     

Identification of steroid biosynthetic defects in genotype‐proven heterozygous individuals for 17α‐hydroxylase/17,20‐lyase deficiency

Objective P450c17 deficiency (17α‐hydroxylase/17,20‐lyase deficiency, 17OHD) is a rare form of congenital adrenal hyperplasia caused by CYP17A1 gene mutations. The D487_F489 deletion in exon 8 and Y329fs in exon 6 are relatively frequent mutations of the CYP17A1 gene in China that completely abolish the enzyme activity of P450c17. However, little remains known about steroid biosynthetic functions in carriers with these mutations in a single allele of the CYP17A1 gene, who are assumed to have 50% P450c17 activity. We investigated adrenal steroidogenic function in genotype‐proven heterozygotes carrying such mutations in the CYP17A1 gene in vivo. Patients and design Eight patients and fourteen family members from five families with 17OHD were recruited. The mutations of the CYP17A1 gene in these individuals were screened by sequencing. The hormonal response to cosyntropin (ACTH) was evaluated in the 14 genotype‐proven carriers and 45 age‐ and gender‐matched normal controls. Results Fourteen carriers of the CYP17A1 mutation – seven with the D487_F489 deletion, six with Y329fs and one with H373L – were identified from the five families with 17OHD. Compared with normal controls, carriers showed lower basal and ACTH‐stimulated cortisol levels but higher ACTH‐stimulated corticosterone levels. The ratios of corticosterone to cortisol in the genotype‐proven heterozygotes were higher than those of the normal controls at the baseline and after cosyntropin stimulation. Similarly, the progesterone levels and the ratios of progesterone to 17‐hydroxyprogesterone in the male heterozygotes were also higher than those of the normal controls, both before and after ACTH stimulation. Conclusion Genotype‐proven carriers of the CYP17A1 mutation who lack apparent clinical symptoms exhibit decreased adrenal 17α‐hydroxylase activity and altered adrenal gland reserve for steroid biosynthesis.     

Heterozygosity for ABCA1 gene mutations: effects on enzymes, apolipoproteins and lipoprotein particle size

A cohort of 13 female and 14 male heterozygotes for ATP binding cassette A1 (ABCA1) gene defects was directly compared with 13 and 14 unaffected female and male family members of almost exact same age. The activities of three proteins that play key roles in HDL metabolism were measured in addition to extensive lipid and (apo) lipoprotein subfraction analysis. Compared to controls, LCAT activity was reduced by 15% in affected subjects (P < 0.001) while PLTP activity was unaffected. Interestingly, CETP activity was elevated by 50% in the heterozygote siblings of one kindred but was unaffected in heterozygotes of the three other families. With respect to lipids, the heterozygotes had normal total cholesterol (TC), and LDL-cholesterol concentrations but presented with a trend towards increased triglyceride levels (13%; P = 0.08). HDL metabolism, by contrast, was severely affected as illustrated by 40% reductions in HDL-cholesterol (P < 0.001) with concomitant reductions in apoAI (25%; P < 0.001) levels and in lipoprotein subfraction LpAI (28%; P < 0.001), LpAI:AII (24%; P=0.014), and LpCIII:nonB (34%; P < 0.001) concentrations. We furthermore observed reduced average HDL particle size (5%; P = 0.004; 16% in female and 3.6% in male) and reduced plasma apoCIII concentration (15%; P = 0.006) while apoAII, apoAIV, apoE and apoB levels were unchanged. In conclusion, heterozygosity for ABCA1 defects was associated with reduced LCAT activity in absence of effects on PLTP activity. Of special interest was our finding that the effects of compromised ABCA1 function on HDL were more pronounced in women than in men.     

Comparison of basal and adrenocorticotropin-stimulated plasma 21-deoxycortisol and 17-hydroxyprogesterone values as biological markers of late-onset adrenal hyperplasia

Plasma 21-deoxycortisol (21-DOF) and 17-hydroxyprogesterone (17-OHP) concentrations were assayed before (basal) and 1 h after ACTH stimulation in 4 groups of normal subjects (35 follicular phase women, 22 luteal phase women, 33 adult men, and 15 prepubertal children) and in a group of 31 patients with the late-onset form of congenital adrenal hyperplasia (LOCAH) due to 21-hydroxylase deficiency as well as in 31 LOCAH) heterozygotes. The mean basal plasma 21-DOF concentrations in each of the 4 groups of normal subjects were between 8 ng/dL (0.23 nmol/L) and 11 ng/dL (0.31 nmol/L), and they increased significantly after ACTH stimulation to between 36 ng/dL (1.04 nmol/L) and 44 ng/dL (1.27 nmol/L). There were no differences in basal or ACTH-stimulated plasma 21-DOF levels in these 4 groups, whereas their basal and post-ACTH plasma 17-OHP levels did vary. Among the LOCAH patients, 83.8% had basal plasma 21-DOF levels and 61.2% had basal plasma 17-OHP levels higher than the highest basal 21-DOF [30 ng/dL (0.86 nmol/L)] and 17-OHP [450 ng/dL (13.61 nmol/L)] concentrations in the normal subjects, and all individual 21-DOF and 17-OHP levels after ACTH stimulation [greater than or equal to 404 ng/dL (11.67 nmol/L) and greater than or equal to 1040 ng/dL (31.47 nmol/L), respectively] were markedly higher than the highest 21-DOF [76 ng/dL (2.19 nmol/L)] and 17-OHP [580 ng/dL (17.55 nmol/L)] levels in the normal subjects. The mean post-ACTH/basal plasma level ratios among the LOCAH patients were 19.75 for 21-DOF and 8.03 for 17-OHP. In LOCAH heterozygotes, basal 21-DOF values were higher than normal in 48.3%, and post-ACTH values were higher than normal in 93.5% of the cases. In contrast, basal plasma 17-OHP levels were similar in LOCAH heterozygotes and normal subjects, and only 16.1% of the LOCAH heterozygotes had post-ACTH plasma 17-OHP levels higher than the highest normal value. If sex and phase of the menstrual cycle are taken into account, along with the incremental responses (post-ACTH minus baseline value) of plasma 21-DOF and 17-OHP, to compare LOCAH heterozygotes and normal subjects, the discriminating power for detection of heterozygocity was somewhat increased for 21-DOF (to 100%) and appreciably increased for 17-OHP (to 30%).(ABSTRACT TRUNCATED AT 400 WORDS)     

基因型明确的17 α-羟化酶/17,20-裂解酶缺陷症杂合子肾上腺皮质功能的研究

目的 明确携带CYP17A1基因突变的杂合子个体肾上腺类固醇激素合成功能.方法 对17α-羟化酶和17,20-裂解酶缺陷(17OHD)5个家系的8例患者和14例家系成员,通过PCR产物直接测序的方法来鉴定CYP17A1基因突变,并测定CYP17A1基因突变携带者与45名年龄、性别匹配的正常个体在ACTH兴奋前后肾上腺皮质激素的变化.结果 发现5个家系14例CYP17A1基因突变的携带者中,7例为D487_F489del,6例为Y329fs,1例为H373L.杂合携带者基础和ACTH刺激后的皮质醇水平均低于正常对照,而兴奋后的皮质酮水平高于正常.杂合子的皮质酮与皮质醇的比值在ACTH兴奋前后皆高于正常对照.而男性杂合子在ACTH兴奋前后孕酮水平以及孕酮与17-羟孕酮比值也均都高于正常对照.D487_F489del和Y329fs两组杂合子之间的激素水平无显著差异.结论 与CYP21A2基因突变的携带者体内的21-羟化酶活性轻度受损相类似,CYP17A1基因突变杂合携带者的肾上腺类固醇激素合成已有异常.     

Diagnosis and therapy surveillance in Addison's disease: rapid adrenocorticotropin (ACTH) test and measurement of plasma ACTH, renin activity, and aldosterone.

The rapid ACTH injection test is an indirect screening test for adrenocortical insufficiency. As a supplement to this test, we evaluated the practicability of single measurements of plasma cortisol, ACTH, aldosterone, and PRA as a definitive diagnostic test of primary adrenocortical insufficiency (PAI). We also tested the value of PRA measurements during treatment with hydro- and fludrocortisone (HC and FC) as a guide for correct mineralocorticoid substitution. In 45 patients with PAI, results of the rapid ACTH test and single measurements of the four hormones (all tests between 0800-0900 h) were compared. Single hormone measurements were also made in 55 normal subjects and 46 patients with pituitary disease (cortisol and ACTH only), most of them with mild to severe secondary adrenocortical insufficiency (SAI). The rapid ACTH test was abnormal in 100% of 41 patients with PAI tested. Plasma ACTH, PRA, and the ratios of ACTH/cortisol and PRA/plasma or urinary aldosterone were clearly elevated in 100% of the patients with PAI. The ACTH/cortisol ratio also distinguished 100% of patients with PAI from those with SAI, but not always control subjects from those with SAI. Thus, dynamic tests (CRH or insulin tests) are indicated if SAI is suspected. PAI and involvement of zona fasciculata and glomerulosa function can be diagnosed with high reliability by measuring cortisol, ACTH, aldosterone, and PRA either together with the rapid ACTH test or later, after a short interval of steroid substitution. PRA measurements during treatment with HC and FC correlated better with the mineralocorticoid dose than plasma potassium and sodium levels. PRA measurement is a valuable guide for FC replacement therapy. It should be titrated into the upper normal range to avoid under- and overtreatment.     

Measurement of urinary CDH and CTH by tandem mass spectrometry in patients hemizygous and heterozygous for Fabry disease

Summary Fabry disease is an X-linked disorder of glycosphingolipid metabolism resulting from a deficiency of the lysosomal enzyme α-galactosidase A. This deficiency leads to the progressive accumulation, in lysosomes of visceral tissues and in body fluids of hemizygotes, of the glycosphingolipids globotriaosylceramide (CTH, Gb₃ or GL-3) and galabiosylceramide (CDH) and to a lesser extent the blood group AB and B related glycolipids. Elevated levels of the glycosphingolipids are found in the urine of hemizygous males with the classic phenotype, but it is not known whether all symptomatic or asymptomatic heterozygotes have elevated levels. We have therefore measured CTH and CDH quantitatively in a multiplex assay using tandem mass spectrometry in urine from a large cohort (44) of genetically proven or obligate heterozygotes including four with the N215S mutation, from classic hemizygotes (28), from cardiac variant hemizygotes with the N215S mutation (6) and from normal controls. The levels of CTH and CDH were related to both creatinine and sphingomyelin. Urinary CTH was elevated in all 28 classic hemizygotes but only in 4/6 of the cardiac variants. The level was within or just above the normal reference range in the four individuals heterozygous for the N215S mutation but was elevated in 38/40 of the other heterozygotes. Similar results were obtained for CDH, except that only 34/40 heterozygotes had an elevated level. The level of CDH was not elevated in the four heterozygotes and 4/6 of the hemizygotes for the N215S mutation. Combining the levels of CTH and CDH did not improve the discrimination of heterozygotes from controls. The ratio of CDH to CTH was higher in heterozygotes than in hemizygotes. Measurement of urinary CTH gave the best discrimination of heterozygotes from controls.     

Pituitary-adrenal responses to corticotropin-releasing hormone in different degrees of adrenal 21-hydroxylase deficiency.

21-Hydroxylase congenital adrenal hyperplasia (21-OHCAH) involves a primary defect of the adrenal gland and a secondary involvement of ACTH secretion. The responses of the pituitary-adrenal axis to ovine CRH (oCRH, 1 micrograms/kg) were examined in subjects with different degrees of 21-OH deficiency. We studied 43 subjects: 7 classical and 6 nonclassical (NC) 21-OHCAH patients, 15 heterozygotes (HT) and 15 control subjects. Baseline plasma ACTH levels were higher in classical CAH than in NC-CAH, HT, and control subjects (mean +/- SEM, 66 +/- 14, 6 +/- 1.6, 4 +/- 0.5, and 5 +/- 0.5 pmol/L, respectively). The mean plasma ACTH response to oCRH in NC-CAH (17 +/- 3 pmol/L) was higher than in controls and HT (9 +/- 0.8 and 11 +/- 1.5 pmol/L). The highest ACTH responses to oCRH were obtained for classical CAH patients (126 +/- 29 pmol/L). Plasma cortisol rose after oCRH in control, HT, and NC-CAH patients but did not change in classical CAH. After oCRH, plasma 17-hydroxyprogesterone (17-OHP) were 4 +/- 0.5, 8 +/- 1.6, 93 +/- 28, and 359 +/- 110 nmol/L for controls, HT, NC-CAH, and classical patients, respectively. There was a significant correlation (r = 0.70) between 17-OHP and the ACTH responses to oCRH. The 17-OHP responses to oCRH were also correlated (r = 0.94) with the 17-OHP responses to the synthetic ACTH test. We conclude that the release of endogenous ACTH by oCRH result in graded 17-OHP responses on 21-OH deficiency. The present study also suggests that different degrees of adrenal biosynthetic defect may result in graded ACTH responses to oCRH.     

Dose effect of adrenocorticotropin on aldosterone and cortisol biosynthesis in cultured bovine adrenal glomerulosa cells: in vitro correlate of hyperreninemic hypoaldosteronism.

In some critically ill patients, aldosterone secretion is diminished despite hyperreninemia. These same patients demonstrate appropriately elevated plasma ACTH and cortisol levels. In addition, infusion of ACTH or angiotensin-II (AII) fails to elicit the normal aldosterone response, implying that the defect is at the level of the zona glomerulosa (ZG) cell. To test the hypothesis that elevated ACTH levels induce this defect, Percoll-purified bovine ZG cells were plated in serum-free defined medium and cultured for 5 days. On days 1-4, cells were exposed to various concentrations of ACTH for 1 h. On the fifth day of culture, half of the wells pretreated with ACTH were treated for 1 h with AII (10(-7) M); the other half of the wells received another dose of ACTH for 1 h. Additionally, cells were exposed to daily 1-h pulses of AII (10(-7) M) alone or in combination with ACTH (10(-8) M) for 5 days. Acutely dispersed bovine ZG cells showed dose-dependent increases in aldosterone when incubated with ACTH, potassium, or AII, with minimal cortisol production. Acutely dispersed bovine fasciculata cells produced no aldosterone, but demonstrated a dose-dependent cortisol response to ACTH and AII, but not potassium. On day 1 of culture, the ZG cells demonstrated a significant (P less than 0.001 in all cases) dose-related increase in aldosterone secretion in response to ACTH. However, continued daily pulsation with ACTH resulted in a dose-dependent decrease in aldosterone secretion, with a concomitant dose- and time-related rise in cortisol production. Indeed, ACTH-induced cortisol production in ZG became similar to ACTH-induced cortisol production in zona fasciculata cells. The addition of AII to the daily ACTH pulse did not significantly alter the aldosterone or cortisol response patterns to ACTH alone. In contrast, ZG cells treated with AII alone for 5 days showed a minimal change in cortisol production and no reduction in aldosterone production until day 4. Northern blot analysis of total RNA isolated from ZG cells pulsed with ACTH for 5 days demonstrated a parallel dose-dependent increase in 17 alpha-hydroxylase mRNA, which did not occur in cells pulsed with AII alone. These in vitro results suggest that elevated ACTH levels over time induce 17 alpha-hydroxylase activity in ZG cells, thereby shifting steroid biosynthesis from an aldosterone-producing to a cortisol-producing pathway. It is likely that the chronically elevated ACTH levels in critically ill patients induce a similar change in ZG cell biosynthesis, resulting in their hyperreninemic hypoaldosterone state.