Clinical utility of adrenal steroid measurement by high-performance liquid chromatography in pediatric endocrinology.
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17-alpha-Hydroxyprogesterone↗
Biomedical subjects
M I New
Publications and source records attributed to M I New.
Pseudohypoaldosteronism: a review and report of two new cases.
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Adrenocorticotropic Hormone↗
Steroid 21-hydroxylase deficiency and the major histocompatibility complex.
Steroid 21-hydroxylase (21-OHase) deficiency is an HLA-linked recessive disorder of cortisol biosynthesis that can occur in several forms which differ in severity. Because they are in genetic linkage disequilibrium with different HLA antigens, the inheritance of these forms is consistent with the existence of several alleles at a single locus. When severe 21-OHase deficiency occurs in association with the HLA haplotype A3;Bw47;DR7, there is a simultaneous null allele at one of the C4 loci. This was hypothesized to result from a single deletion or rearrangement affecting the 21-OHase and C4 loci and perhaps the HLA-B gene as well. To test this hypothesis and identify the 21-OHase gene, a cDNA clone was isolated that encoded the cytochrome P450 specific for steroid 21-hydroxylation in the bovine adrenal gland. This clone hybridized to two genes in normal human DNA, but to only one gene in DNA from an individual homozygous for A3;Bw47;DR7. All individuals heterozygous for A3;Bw47;DR7 carry a heterozygous deletion of a cytochrome P450 gene. Cosmid clones have been used to locate the 21-OHase genes both in man and mouse. In both species, there are two 21-OHase genes each located immediately 3' of one of the two C4 genes, and oriented in the same direction as the C4 genes. In man, the gene located 3' of the C4B gene is deleted in 21-OHase deficiency on the Bw47 haplotype, but the gene 3' of the C4A gene is deleted in hormonally normal individuals on the A1;B8;C4AQ0, C4B1;DR3 haplotype. Thus the 21-OHase B gene is normally active in man, but the 21-OHase A gene is not.
Adrenal Hyperplasia, Congenital↗
Long-term endocrine sequelae after treatment of medulloblastoma: prospective study of growth and thyroid function.
Endocrine evaluations were performed prospectively in 22 patients with medulloblastoma (ages 2 1/2 to 23 1/2 years at diagnosis), after craniospinal radiation with or without adjuvant chemotherapy. The mean craniospinal hypothalamic-pituitary). and thyroid radiation doses were 3600 and 2400 rads, respectively. Fourteen (73%) of 19 patients who had not yet completed their growth experienced a decrease in growth velocity. However, only three of 10 of these children, who underwent growth hormone stimulation tests, had evidence of deficient growth hormone responses, suggesting that growth hormone secretory or regulatory dysfunction, rather than absolute growth hormone deficiency, is present in the majority of these children. Elevated thyroid-stimulating hormone levels were noted in 15 of 22 patients; one patient had hypothalamic hypothyroidism. Thus, the late effects of therapy for medulloblastoma include frequent endocrine morbidity involving hypothalamic-pituitary and thyroid dysfunction.
Adolescent↗
Resolution of the clinical features of tyrosinemia following orthotopic liver transplantation for hepatoma.
The clinical history before transplantation and subsequent clinical and biochemical course of 3 children and one adult with hereditary tyrosinemia treated by orthotopic hepatic transplantation is described. All four patients are now free of their previous dietary restrictions and appear to be cured of both their metabolic disease and their hepatic neoplasm.
Adult↗
Structure of human steroid 21-hydroxylase genes.
We have determined the structure of cDNA and two genomic genes encoding steroid 21-hydroxylase [21-OHase; steroid 21-monooxygenase; steroid, hydrogen-donor:oxygen oxidoreductase (21-hydroxylating); EC 1.14.99.10]. If this cytochrome P-450 enzyme is defective, cortisol cannot be synthesized, resulting in congenital adrenal hyperplasia. The cDNA encoding this enzyme is 2.0 kilobases long, and the encoded protein is predicted to contain 494 amino acid residues with a molecular weight of 55,000. This enzyme is at most 28% homologous to other P-450 enzymes that have been studied. The 21-OHase genomic genes, which are located in the HLA major histocompatibility complex on chromosome 6, each contain 10 exons. This structure is distinct from other characterized P-450 genes, which contain 7 or 9 exons. Studies of individuals with homozygous deletions of the 21-OHase A or B genes suggest that only the B gene encodes an active enzyme. This is confirmed by the finding that the A gene has an 8-base deletion within codons 110-112, resulting in a frameshift that brings a stop codon into the reading frame at codon 130. A second frameshift and a nonsense mutation occur downstream. In contrast, the sequence of the exons of the B gene is identical to the cDNA sequence. The 21-OHase A gene is, therefore, a pseudogene.
Amino Acid Sequence↗
Microfilter paper method for antipyrine determination in whole blood by high pressure liquid chromatography.
A method for measuring antipyrine in whole blood collected on filter paper is described. A 6.2-mm diameter disc (1/4 in) is punched out, eluted with distilled water, and then extracted with 5 ml of dichloromethane/pentane (50:50, vol/vol). After reconstitution of the dried residue, reverse-phase high pressure liquid chromatography is used to quantitate antipyrine using an internal standard. A mixture of 15% acetonitrile in 0.006 M phosphate buffer pH 7.2 was used as the mobile phase. Chromatography was carried out under isocratic conditions for 15 min. The retention time of antipyrine was 3.6 min. Intra- and interassay coefficients of variation were 3.1% and 7.2%, respectively. The limit of sensitivity was 6 ng/injection. The amount of blood in a 6.2-mm filter paper disc was calculated to be 8.4 +/- 0.8 (SD) microliter. Antipyrine half-lives, apparent volumes of distribution, and metabolic clearance rates measured from the filter paper concentrations or directly from plasma were virtually identical. Antipyrine was stable on filter paper for less than or equal to 6 weeks at room temperature. The method reported is convenient; requires a small amount of blood, which can be easily obtained by fingerstick; and readily permits the measurement of antipyrine clearance in the pediatric as well as adult populations.
Adult↗
Antipyrine clearance in congenital adrenal hyperplasia.
Antipyrine (AP) metabolism was studied in four adult patients with congenital adrenal hyperplasia (CAH) due to classical 21-hydroxylase deficiency and in four (adult) patients with CAH due to non-classical 21-hydroxylase deficiency. This investigation was prompted by the known biochemical and functional similarities between drug- and steroid-metabolizing enzymes. We hypothesized that a common genetic mechanism may regulate the expression and activity of both the adrenal and hepatic cytochrome P450 enzymes. AP half-lives (T1/2, mean +/- SD) were 10.7 +/- 2.1 h in classical CAH patients, 10.1 +/- 0.4 h in the nonclassical CAH patients and 10.9 +/- 2.2 h in the control group, suggesting that there was no significant difference in AP metabolism among the three groups. Similarly, no significant differences were found in the AP apparent volume of distribution (aVd) and metabolic clearance rate (MCR) among the three groups. These results indicate that despite the deficiency of adrenal cytochrome P450 in patients with 21-hydroxylase deficiency CAH, these individuals have normal hepatic drug metabolizing activity for the biotransformation of AP.
Adrenal Hyperplasia, Congenital↗
Is salt-wasting in congenital adrenal hyperplasia due to the same gene as the fasciculata defect?
Clinical studies in patients with 21-hydroxylase deficiency congenital adrenal hyperplasia (CAH) were designed to ascertain the genetics of the salt-wasting component of the disorder. The gene controlling aldosterone biosynthesis may not be the same gene that controls 21-hydroxylase in the adrenal zona fasciculata. This we infer from the following clinical observations: (1) concordance for salt-wasting is not observed in all HLA-identical sibs with CAH; (2) the defect in aldosterone biosynthesis does not persist throughout life as does the fasciculata defect; (3) there is a significantly increased gene frequency of B40 and Bw47 in salt-wasting CAH; (4) obligate heterozygote parents of patients with salt-wasting CAH do not express a partial defect in aldosterone biosynthesis, as they do in the fasciculata. These observations cast doubt on the accepted concept of the autosomal recessive transmission of the glomerulosa 21-hydroxylase deficiency.
17-alpha-Hydroxyprogesterone↗
Genetics of adrenal steroid 21-hydroxylase deficiency.
Impairment of 21-hydroxylation is the most common enzymatic deficiency resulting in the syndrome of CAH, which may present either in the classical form in infants or in the nonclassical form in older individuals. Variable signs and symptoms of androgen excess are common to both types of the disorder, which are transmitted as autosomal recessive traits linked to HLA. Virilization begins in the second month of gestational life in classical 21-OHD, but postnatally in the nonclassical form. Salt wasting is a feature of the disease in a large number of classical patients; in the simple virilizing form aldosterone biosynthesis, a function of the adrenal zona glomerulosa, is intact. Additionally, no patient with nonclassical 21-OHD has been found to have salt wasting. Levels of precursor hormones are less markedly elevated in nonclassical 21-OHD, reflecting a less severe enzyme deficiency; coordinates of basal and stimulated 17-OHP are plotted on a nomogram to ascertain diagnostic category within a family. Confirmatory evidence of heterozygosity within the family of an affected proband is found by performing HLA typing. Specific linkage disequilibria exist for the classical and nonclassical forms of 21-OHD. Frequency of the classical disease is 1/5,000-1/15,000 in Caucasians, whereas the nonclassical disease is found in approximately 1/100 individuals in the Caucasian population, placing the latter disorder among the most common autosomal recessive disorders in man. A deletion of the active 21-hydroxylase gene has been detected in some classical patients; further investigations are in progress to elucidate the molecular genetics of this disease.
Adrenal Cortex↗
The syndrome of apparent mineralocorticoid excess: its association with 11 beta-dehydrogenase and 5 beta-reductase deficiency and some consequences for corticosteroid metabolism.
We describe the metabolism of cortisol (F) in three children, two of them siblings, with apparent mineralocorticoid excess (AME). As with prior patients with AME, oxidation of F to cortisone (E) was impaired, but reduction of E to F was not. We propose that this metabolic defect is caused by deficient 11-dehydrogenase associated with unimpaired 11-reductase. The following supporting observations were made: urinary C21 11-hydroxy metabolites exceeded C21 11-oxo metabolites: ratio of urinary cortols to cortolones, 6.6 +/- 2.8 (+/- SD; normal, 0.47); tetrahydrocortisol (THF) and alloTHF to tetrahydrocortisone, 14.6 +/- 5.6 (normal, approximately 1); normal subjects oxidized [11 alpha-3H]F with transfer of 3H to water; the patients did not; 11-hydroxy, but not 11-oxo, C19 steroids were excreted into the urine; and fibroblasts from patients had 5 times more 11-reductase activity than normal subjects, though fibroblasts from neither group had 11-dehydrogenase activity. Other defects of cortisol metabolism not directly associated with 11-dehydrogenase deficiency were found: impaired conversion of tetrahydro to hexahydro neutral steroids, indicating defective reductive metabolism of the side chain; depressed F production rate and increased half-life of circulating F, resulting in normal blood levels of F; increased excretion of unconjugated F metabolites; and decreased excretion of THF relative to alloTHF, consistent with a 5 beta-reductase defect. Excretion of acidic metabolites of F (cortoic acids) was within the normal range. However, little or no 20 beta-hydroxy acids were excreted, while the level of urinary 20 alpha-hydroxy acids was increased. The 11-hydroxy to 11-oxo ratio of acid metabolites was similar to values in normal subjects. The proportion of cortoic acids relative to neutral hexahydro metabolites was increased (0.37 to 1.27 in patients; 22 in normal subjects). We conclude that children with AME have multiple defects in the conversion of F to neutral metabolites, while metabolism to cortoic acids was less extensively affected. How the defects in cortisol metabolism and the symptoms of AME are related remains to be determined.
11-beta-Hydroxysteroid Dehydrogenases↗
The effect of treatment of final height in classical congenital adrenal hyperplasia (CAH).
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Adrenal Hyperplasia, Congenital↗
Molecular genetics and the characterization of steroid 21-hydroxylase deficiency.
Classical 21-hydroxylase deficiency congenital adrenal hyperplasia is a monogenic autosomal recessive disorder that has been conclusively shown by family HLA-typing studies to be in close genetic linkage with the human major histocompatibility complex. More recently recognized is the nonclassical disorder, an attenuated form of 21-hydroxylase deficiency characterized variably by late onset or absence of symptoms. Certain of the mild 21-hydroxylase deficiency allotypes involved in the nonclassical disorder have also been shown to be genetically linked with HLA, exhibiting distinct (B and B,DR) antigen associations. The nonclassical disorder is now also known to result from different genotypes: two mild 21-hydroxylase defects in conjunction, or a mild defect occurring with a sever (classical) defect. Restriction mapping and hybridization analysis have located two highly homologous base sequences, one structural gene coding for 21-hydroxylase and one pseudogene, in the Class III region of the MHC in tandem with the A and B genes for C4, the fourth component of complement. Current work documenting and characterizing gene abnormalities, as well as elucidating the molecular genetic basis of the mutations that have arisen, is aimed at developing better cDNA probes for prenatal diagnosis by amniocentesis and chorionic villus biopsy. In addition, because of the close association of the C4 and 21-hydroxylase genes, coordination of data on C4 variants and null alleles with altered 21-hydroxylase activity is improving understanding of the genetic mechanisms generating disease alleles of this enzyme crucial for normal endocrine function.
17-alpha-Hydroxyprogesterone↗
Apparent mineralocorticoid excess causing hypertension and hypokalemia in children.
Cortisol 11 beta-hydroxysteroid dehydrogenase (11 beta-HSD) deficiency was observed in four patients with apparent mineralocorticoid excess. The 11 beta-HSD deficiency was demonstrated by a markedly decreased urinary tetrahydrocortisone/tetrahydrocortisol (THE/THF) ratio (less than 1 in normal children) during infusion of ACTH and administration of hydrocortisone. We propose that in these patients the 11 beta-HSD deficiency impairs the metabolism of cortisol to cortisone, resulting in a prolonged cortisol half-life, suppression of ACTH, and normal serum cortisol. The 11 beta-HSD deficiency protects the patient from adrenal insufficiency despite the low cortisol secretion; the prolonged half-life of cortisol may contribute to the hypertension and hyporeninemia observed in this disorder. Continuous intravenous hydrocortisone administration resulted in increased blood pressure and decreased serum potassium. Addition of spironolactone during continued administration of 20 mg per day of hydrocortisone resulted in a decrease in blood pressure and a rise in serum potassium. These studies suggest that an abnormality in cortisol action or metabolism results in cortisol behaving as a potent mineralocorticoid. These findings may account for this syndrome of apparent mineralocorticoid excess.
11-beta-Hydroxysteroid Dehydrogenases↗
Percutaneous transluminal renal angioplasty in the treatment of renovascular hypertension in children.
We report five young patients who underwent percutaneous transluminal renal angioplasty (PTRA) for the treatment of hypertension related to renal artery stenosis. Four had fibromuscular disease and one had probable Takajasu's arteritis; two had solitary kidneys. Following PTRA, a prompt decrease in blood pressure was observed in all patients. Further, four of five patients long after PTRA remained normotensive, and in all patients plasma renin levels declined. These results indicate that PTRA can be a safe and effective alternative to surgery in the treatment of renovascular hypertension in childhood.
Adult↗
Frequent deletion and duplication of the steroid 21-hydroxylase genes.
Congenital adrenal hyperplasia due to 21-hydroxylase (21-OHase) deficiency is an HLA-linked disorder resulting from a mutation in the 21-OHase B gene encoding the adrenal cytochrome P450 specific for steroid 21-hydroxylation. To identify polymorphisms associated with 21-OHase deficiency, DNA samples from 22 unrelated patients with this disorder were examined with a human cDNA clone encoding the enzyme. Deletions of the active 21-OHase gene were found in almost one-fourth of classical 21-OHase deficiency alleles. In contrast, mild, "nonclassical" 21-OHase deficiency is associated with a duplicated 21-OHase gene.
Adrenal Hyperplasia, Congenital↗
Two genes encoding steroid 21-hydroxylase are located near the genes encoding the fourth component of complement in man.
Two genes encoding steroid 21-hydroxylase [21-OHase; steroid 21-monooxygenase; steroid, hydrogen-donor: oxygen oxidoreductase (21-hydroxylating); EC 1.14.99.10], a cytochrome P-450 enzyme, have been located within the HLA major histocompatibility complex. Congenital adrenal hyperplasia due to 21-OHase deficiency is a common inherited disorder of cortisol biosynthesis which is in genetic linkage disequilibrium with certain extended HLA haplotypes. These haplotypes include characteristic serum complement allotypes. A series of cosmid clones was isolated from a human genomic library by using a probe encoding part of the fourth component of complement, C4. These clones also hybridized with a probe encoding most of human 21-OHase. Restriction mapping and hybridization analysis showed that there are two 21-OHase genes, each located near the 3' end of one of the two C4 genes. Hybridization with probes specific for the 5' and 3' ends of the 21-OHase gene showed that the 21-OHase and C4 genes all have the same orientation. The 21-OHase genes 3' to C4A and C4B carry T aq I fragments of 3.2 and 3.7 kilobases (kb), respectively. Both of these fragments are found in genomic DNA of most individuals. In DNA from an individual with the severe, "salt-wasting" form of 21-OHase deficiency who was homozygous for HLA-A3;Bw47;C4A*1;C4B*Q0(null); DR7, the 3.7-kb Taq I fragment is absent, whereas hormonally normal individuals homozygous for HLA-A1;B8;C4A*Q0;C4B*1;DR3 do not carry the 3.2-kb Taq I fragment. These data suggest that the 21-OHase "B" gene (3.7-kb Taq I fragment) is functional, but the 21-OHase "A" gene (3.2-kb Taq I fragment) is not.
Chromosome Deletion↗
Adrenal 21-hydroxylase cytochrome P-450 genes within the MHC class III region.
Genes encoding several serum complement components and the gene(s) for steroid 21-hydroxylase (21-OH) have been located in the class III region of the major histocompatibility complex (MHC). All these genes are highly polymorphic in man, and these polymorphisms have been used to draw conclusions about the structure and function of these genes. For example, electrophoretic polymorphisms of the fourth component of complement (C4) have been shown to be controlled by two closely linked genes, which also control expression of the red cell antigens Rodgers and Chido. Steroid 21-OH deficiency (D) can occur in several forms which differ in severity, and because of genetic linkage disequilibrium with different HLA antigens the inheritance of these forms is consistent with the existence of several alleles at a single locus. When severe 21-OH D occurs in association with the HLA haplotype A3;Bw47;DR7, there is a simultaneous null allele at one of the C4 loci. This was hypothesized to result from a single deletion or rearrangement affecting the 21-OH and C4 loci and perhaps the HLA-B gene as well. To test this hypothesis and identify the 21-OH gene, a cDNA clone was isolated which encoded the cytochrome P450 specific for steroid 21-hydroxylation in the bovine adrenal gland. This clone hybridized to two genes in normal human DNA, but to only one gene in DNA from an individual homozygous for A3;Bw47;DR7. All individuals heterozygous for A3;Bw47;DR7 carry a heterozygous deletion of a gene. These experiments showed that at least one structural gene for the cytochrome P450 specific for 21-hydroxylation is located in the MHC, probably very near the C4 genes, and a mutation in this gene results in 21-OH D. Cosmid clones have been used to locate the 21-OH genes both in man and mouse. In both species, there are two 21-OH genes, each located immediately 3' of one of the two C4 genes, and oriented in the same direction as the C4 genes. In man, the gene located 3' of the C4B gene is deleted in 21-OH D on the Bw47 haplotype, but the gene 3' of the C4A gene is deleted in hormonally normal individuals on the A1;B8;C4AQO;C4B1;DR3 haplotype. Thus the 21-OH B gene is normally active in man, but the 21-OH A gene is not.
Adrenal Glands↗