The Gordon Wilson Lecture. Congenital adrenal hyperplasia.
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Adrenal Hyperplasia, Congenital↗
Biomedical subjects
M I New
Publications and source records attributed to M I New.
Bilateral adrenal uptake of gallium-67 citrate in a patient with congenital adrenal hyperplasia.
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Adrenal Glands↗
Prenatal diagnosis and treatment of adrenogenital syndrome (steroid 21-hydroxylase deficiency).
Prenatal treatment of pregnancies at risk for congenital adrenal hyperplasia due to 21-hydroxylase deficiency was carried out in conjunction with chorionic villus sampling (CVS) in the first trimester for analysis of restriction fragment length polymorphisms. Dexamethasone administration to the pregnant woman was initiated at a mean gestational age of 7 weeks (range 4-10 weeks) before testing to determine whether the fetus was affected with 21-hydroxylase deficiency, and CVS was performed at a gestational age of 8-10 weeks. Two affected female fetuses were identified by molecular genetic techniques among this group. The duration of unnecessary prenatal dexamethasone treatment for unaffected or male fetuses was substantially reduced in the CVS group compared with a cohort of 8 prenatally treated pregnancies where amniocentesis was performed in the early second trimester. No major morbidities were observed in the treated pregnancies. Postnatal confirmation of CVS diagnosis was obtained in all cases where DNA from an affected sibling was available for comparative analysis with the DNA from chorionic villus tissue. The external genitalia of the affected females who were treated prenatally appeared normal. Based on these data we conclude that the benefit:risk ratio is favorable for prenatal administration of dexamethasone in pregnancies at risk for 21-hydroxylase deficiency. Treatment should be initiated during the first trimester in conjunction with diagnosis by CVS/molecular genetic techniques. Long-term postnatal surveillance is recommended for all offspring of dexamethasone-treated pregnancies.
Adrenal Hyperplasia, Congenital↗
Prevalence of nonclassical steroid 21-hydroxylase deficiency based on a morning salivary 17-hydroxyprogesterone screening test: a small sample study.
Early morning salivary 17 alpha-hydroxyprogesterone (17-OHP) determination differentiates patients with non-classical 21-hydroxylase deficiency (NC21OHD) from those who are not affected. Using this test, we have conducted a trial screening study for NC21OHD and have compared the study results with previously reported figures for the frequency of this disorder. Testing was performed on 258 subjects recruited from among the medical students and employees of the New York Hospital-Cornell Medical Center. In 2 of the 249 admissible subjects, the 0700-0900 h salivary 17-OHP level was within the range for NC21OHD patients (0.72-6.7 nmol/L; n = 8). These 2 individuals were subsequently confirmed to be affected by ACTH testing. Of the subjects with morning salivary 17-OHP levels below the cut-off point of 0.72 nmol/L, 29 were recalled for ACTH testing and were confirmed to be unaffected. Prevalence of NC21OHD in the test population was determined according to ethnic group. Our study gives a prevalence by screening of 1.14% among caucasians, which agrees with values of 0.81% and 1.06% obtained by different analytical methods. Further, both affected subjects were Ashkenazi Jews, and the prevalence of 3.23% among study members from this group concurs with increased rates of 3.64% and 4.97% already reported. On the basis of a small population sample, screening so far confirms the claim that NC21OHD is the most common autosomal recessive human disorder. Using values from ACTH-proven unaffected subjects (n = 47) and NC21OHD patients (n = 10), we establish preliminary normative data for morning salivary 17-OHP levels of 0.172 nmol/L for unaffected subjects (95% confidence interval, 0.05-0.54 nmol/L) and 1.76 nmol/L for NC21OHD-affected subjects (95% confidence interval, 0.42-7.32 nmol/L).
17-alpha-Hydroxyprogesterone↗
Defective fasciculata zone function as the mechanism of glucocorticoid-remediable aldosteronism.
Glucocorticoid-remediable aldosteronism is characterized by unusual sensitivity of aldosterone secretion to ACTH. Suppressibility by glucocorticoid and continued stimulability by exogenous ACTH has provided the basis for diagnosis and treatment of the disorder. A qualitative biochemical abnormality consisting of marked overproduction of the products of the cortisol C-18 oxidation pathway, 18-hydroxycortisol and 18-oxocortisol, has been examined in 10 patients with the disorder and compared to the normal C-18 oxidation products of corticosterone, aldosterone, and 18-hydroxycorticosterone. The technique, based on stable isotope dilution mass fragmentography, measured the tetrahydro urinary metabolites of aldosterone, 18-hydroxycorticosterone, and 18-oxocortisol and unmetabolized 18-hydroxycortisol. All 4 C-18 oxygenated corticosteroids were markedly elevated in the untreated state and showed rapid parallel suppression with low doses of glucocorticoid. The proportional changes in C-18 oxygenated cortisols together with aldosterone and 18-hydroxycorticosterone suggested the mechanism of a common catalytic site of a cytochrome P450 methyl oxidase serving both cortisol and corticosterone substrates. The ACTH-dependent secretion of the C-18 oxidation products of both corticosterone and cortisol in the disorder is attributed to the acquisition of methyl oxidase activity by the fasciculata zone, where there are abundant pools of these precursors.
Adolescent↗
Clinical and genetic characterization of nonclassic 21-hydroxylase deficiency.
Nonclassic steroid 21-hydroxylase deficiency is a frequent, relatively mild disorder of cortisol biosynthesis characterized by variable signs of postnatal androgen excess. It is inherited as an allelic variant of the CYP21B gene encoding the 21-hydroxylase enzyme. CYP21B is located in the HLA histocompatibility complex, and a nonclassic allele is often associated with characteristic HLA antigens: B14;DR1. A CYP21B gene from a HLA-B14;DR1 homozygous patient with nonclassic 21-hydroxylase deficiency was cloned and analyzed. Five deviations from the normal sequence of CYP21B were found, but only one appeared likely to affect the functional integrity of the protein: codon 281, GTG, encoding valine, was changed to TTG, leucine. An oligonucleotide probe was constructed corresponding to the mutant sequence surrounding codon 281 and hybridized with DNA samples digested with restriction endonuclease Taq I. Samples from 8 nonclassic 21-hydroxylase deficiency patients carrying HLA-B14;DR1 contained a hybridizing fragment 3700 base-pairs long, indicating presence of the val-281 mutation in the CYP21B gene. In contrast, unaffected individuals and one patient who lacked HLA-B14;DR1 showed no evidence of the val-281 mutation in CYP21B. We conclude that the codon 281 mutation is a consistent molecular genetic marker for nonclassic 21-hydroxylase deficiency associated with HLA-B14;DR1.
Adrenal Hyperplasia, Congenital↗
Emerging trends in child abuse and neglect.
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Child↗
Growth and final height in classical and nonclassical 21-hydroxylase deficiency.
Final height was evaluated in 47 patients with classical 21-hydroxylase treated since diagnosis, and in 29 patients with nonclassical (NC) 21-hydroxylase deficiency who had never been treated before reaching final adult height. Classical patients achieved final heights consistently below the mean for the general population, and in all but four cases these patients also failed to attain the individual height expectation based on midparental height. Analysis of these results with regard to (1) clinical form (i.e. salt-wasting [SW] or simple virilizing [SV]) and (2) degree of hormonal control (i.e. good or poor) indicates that neither factor seems to affect the height outcome. Final height in NC patients, while significantly greater than for classical patients, was below the general population mean, and individual final heights were also significantly below expectation based on midparental height. In another group of NC patients who were still growing, some of whom were on courses of treatment and some under observation only, height at the time of diagnosis was compared with the most recent height prediction. Reduction of growth potential appeared to be somewhat lessened in the treated group, from which we tentatively suggest that treatment should be considered in NC patients even in the absence of clinical signs of androgenism.
Adolescent↗
An inherited defect in aldosterone biosynthesis caused by a mutation in or near the gene for steroid 11-hydroxylase.
The final step in aldosterone biosynthesis, an oxidation at position 18 of 18-hydroxycorticosterone, is catalyzed by an enzymatic activity termed corticosterone methyl oxidase II (CMO II). This activity is mediated in vitro by P450c11 (steroid 11-hydroxylase), a cytochrome P-450 enzyme that also catalyzes the preceding two steps of 11-hydroxylation and 18-hydroxylation. CMO II deficiency, an inherited defect in the 18-oxidation step, impairs aldosterone biosynthesis and thus leads to a clinical syndrome of salt wasting. To test the hypothesis that CMO II deficiency results from a mutation affecting the structural gene for P450c11, we examined 11 affected and 21 unaffected members of six families with this disorder. After DNA samples were digested with the restriction endonuclease MspI (thereby cutting the DNA at specific sites) and hybridized with a P450c11 DNA probe, a unique DNA fragment in the P450c11 structural gene was detected in subjects with the deficiency. The DNA fragment and the disease trait were inherited together in each family, demonstrating that CMO II deficiency is caused by a mutation in or very near the structural gene for P450c11 on chromosome 8. We conclude that the metabolic diseases of CMO II and 11-hydroxylase deficiency, which have distinct clinical symptoms, may be caused by different mutations in the single gene for a multifunctional enzyme.
Aldosterone↗
Molecular genetic analysis of nonclassic steroid 21-hydroxylase deficiency associated with HLA-B14,DR1.
Nonclassic steroid 21-hydroxylase deficiency is a frequent, relatively mild disorder of cortisol biosynthesis, characterized by variable signs of postnatal androgen excess. It is inherited as an allelic variant of the gene designated CYP21B, which encodes 21-hydroxylase. CYP21B is located in the HLA histocompatibility complex, and a "nonclassic" allelic variant is often associated with characteristic HLA antigens--B14,DR1. We cloned and analyzed the CYP21B gene from a patient homozygous for HLA-B14,DR1 who had nonclassic 21-hydroxylase deficiency. Five deviations from the normal genetic sequence of CYP21B were found, but only one appeared likely to affect the functional integrity of the protein: codon 281, GTG, encoding valine, was changed to TTG, leucine. We constructed an oligonucleotide probe corresponding to the mutant DNA sequence surrounding codon 281 and hybridized the probe with DNA samples digested with the restriction endonuclease Taql. Samples from eight patients with nonclassic 21-hydroxylase deficiency who had the haplotype HLA-B14,DR1 contained a hybridizing fragment 3700 base pairs long, indicating the presence of the valine-281 mutation in the CYP21B gene. In contrast, unaffected subjects and one patient with nonclassic deficiency who did not have HLA-B14,DR1 had no evidence of this mutation. We conclude that the mutation in codon 281 is a consistent molecular genetic marker for nonclassic 21-hydroxylase deficiency associated with HLA-B14,DR1.
Adrenal Hyperplasia, Congenital↗
Immunohistochemical localization of cytochrome P-450C21 in human adrenal cortex and its relation to endocrine function.
Cytochrome P-450C21 was successfully demonstrated in the human adrenal glands by a peroxidase-antiperoxidase method. All three cortical layers were stained in the normal adrenal glands, particularly the zonae glomerulosa and reticularis. Well-stained and faintly stained cells were intermingled in the zona fasciculata, suggestive of intrazonal variations. The immunoreactivity was particularly intense at the site of ACTH action, i.e., cells in micronodules and cells around myelolipomatous lesions in adrenocortical hyperplasia of Cushing's disease and sites of regeneration in the normal adrenal glands. In adrenocortical adenomas with Cushing's syndrome and primary aldosteronism, cells with large nuclei were generally stained well. In the adrenocortical tissue adjacent to a functioning adenoma, the immunoreactivity was observed only in the zona glomerulosa, especially in cases of primary aldosteronism. This finding is consistent with morphologic observations.
Adenoma↗
Molecular genetics of congenital adrenal hyperplasia.
Congenital adrenal hyperplasia results from a deficiency in any of the five enzymes necessary to synthesize cortisol from cholesterol: cholesterol desmolase (P450scc), 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD), 17-hydroxylase (P450c17), 21-hydroxylase (P450c21) and 11-hydroxylase (P450c11). P450scc and P450c11 are structurally-related mitochondrial cytochrome P450 enzymes, whereas P450c17 and P450c21 are microsomal enzymes. The P450scc gene, CYP11A, is located on chromosome 15, and the P450c17 gene, CYP17, is on chromosome 10. The P450c21 gene, CYP21B, and a pseudogene, CYP21A, are located in the HLA major histocompatibility complex on chromosome 6p, while the P450c11 gene, CYP11B, is on chromosome 8q along with a second related gene of unknown function. Thus, despite common regulation by ACTH, there is no clustering of the genes for steroidogenic enzymes. CYP11A and CYP11B have an identical intron-exon organization, and CYP17 and CYP21B have similar gene structures, but the two pairs of genes encoding mitochondrial and microsomal P450 enzymes resemble each other poorly. More than 90% of cases of congenital adrenal hyperplasia result from 21-hydroxylase deficiency, and most of the remainder are caused by 11-hydroxylase deficiency. About one-quarter of 21-hydroxylase deficiency alleles are associated with a deletion of all or part of CYP21B. Most of the remaining mutant alleles result from transfers of deleterious mutations from the CYP21A pseudogene to CYP21B, a process termed gene conversion. These mechanisms provide an explanation for the relatively high frequency of 21-hydroxylase deficiency. The clinical severity of various forms of 21-hydroxylase deficiency may be roughly correlated with particular mutations.
Adrenal Cortex Hormones↗
Characterization of frequent deletions causing steroid 21-hydroxylase deficiency.
Steroid 21-hydroxylase deficiency is caused by mutations in the CYP21B gene. This gene and a highly homologous pseudogene, CYP21A, alternate with the C4A and C4B genes encoding the fourth component of complement. Classical deficiency alleles are frequently caused by deletions of CYP21B or by gene conversions that transfer deleterious mutations from the CYP21A pseudogene to CYP21B. Gene conversions involving restriction enzyme sites that distinguish CYP21A [e.g., 3.2-kilobase (kb) Taq I fragment] and CYP21B (3.7-kb Taq I fragment) might be confused with actual deletions of CYP21B. To determine the incidence of this type of gene conversion, 15 chromosomes (in 13 families) with absent 3.7-kb Taq I fragments were studied. When hybridized with a 21-hydroxylase probe, all of these chromosomes were associated with absent 2.9-kb Kpn I fragments, 14 of 15 were associated with absent 2.4-kb Bgl II/EcoRI fragments, and 13 of 15 were associated with absent 10-kb Bgl II/EcoRI and 12-kb EcoRI fragments. Thirteen of 15 chromsomes had absent 6.0- or 5.4-kb Taq I fragments when hybridized with a C4 probe. Thus, 2 of 15 chromosomes do not carry deletions and may represent gene conversions; 13 of 15 chromosomes studied have a deletion of approximately equal to 30 kb, leaving behind the C4A gene and a single CYP21A-like gene. Hybridization with specific oligonucleotide probes showed that in all 13 cases this remaining CYP21 gene carried an 8-base-pair deletion, typical of CYP21A, that prevents synthesis of a functional protein. Thus, gene conversions are rarely confused with deletions as a cause of 21-hydroxylase deficiency.
Adrenal Hyperplasia, Congenital↗
Mutation in the CYP21B gene (Ile-172----Asn) causes steroid 21-hydroxylase deficiency.
Steroid 21-hydroxylase deficiency is the most common cause of congenital adrenal hyperplasia. It results from a deficiency in a specific cytochrome P450, P450c21 (P450XXIA). The gene encoding this protein (CYP21B) and a closely linked pseudogene (CYP21A) are located in the HLA complex on chromosome 6p. Many mutant alleles are associated with deletions of CYP21B; we report the cloning and characterization of a nondeleted mutant CYP21B gene. This mutant gene is expressed on transfection into mouse Y1 adrenal cells, producing mRNA levels similar to those seen after transfection of the normal CYP21B gene. In codon 172 of the mutant gene, the normal codon ATC, encoding isoleucine, has been changed to AAC, encoding asparagine. This mutation is normally present in the CYP21A pseudogene, so that it may have been transferred to the mutant CYP21B gene by gene conversion. Hybridization of oligonucleotide probes corresponding to this and two other mutations normally present in CYP21A demonstrated that 4 out of 20 patients carried the codon 172 mutation; in one of these patients, the mutation was present as part of a larger gene conversion involving at least exons 3-6. Gene conversion may be a frequent cause of 21-hydroxylase deficiency alleles due to the presence of six chi-like sequences (GCTGGGG) in the CYP21 genes and the close proximity of the CYP21A pseudogene, which has several potentially deleterious mutations.
Adrenal Hyperplasia, Congenital↗
Nonsense mutation causing steroid 21-hydroxylase deficiency.
We determined the sequence of a mutant CYP21B gene isolated from a patient with the severe, "salt-wasting" form of congenital adrenal hyperplasia due to steroid 21-hydroxylase deficiency. Codon 318 in this gene is changed from CAG, encoding glutamine, to TAG, a nonsense codon. This is predicted to result in a completely nonfunctional enzyme due to premature termination of translation. In addition, when the cloned mutant gene was transfected into mouse Y1 adrenal cells, the resulting mRNA levels were decreased compared with transfected normal CYP21B genes. This mutation was carried by 3 of 20 unrelated patients with 21-hydroxylase deficiency alleles as determined by hybridization with a specific oligonucleotide probe. This mutation is also seen in the normal CYP21A pseudogene, so that its presence in the abnormal CYP21B gene may be the result of a gene conversion event.
Adrenal Hyperplasia, Congenital↗
Immunohistochemistry of cytochrome P-450 21-hydroxylase: microscopic examination of the enzyme in the bovine adrenal cortex and kidney.
Cytochrome P-450 specific for steroid 21-hydroxylase (P-450C21) localized in bovine adrenal cortex and kidney was immunocytochemically observed by the peroxidase-antiperoxidase method using a specific antibody. P-450C21 was present in all three zones of the adrenal cortex. Immunoreactivity for P-450C21 was intense in the zona glomerulosa and inner reticularis and faint in the area between the zona glomerulosa and outer fasciculata, probably representing the zona intermedia. The positive stain was only observed in parenchymal cells. The immunoreactivity varied within each zone, especially in the zona reticularis. In the kidney, immunoreactivity for P-450C21 was exclusively localized in the distal and cortical and medullary collecting tubules. This corresponds to the site of mineralocorticoid action in the kidney. No immunoreactivity was observed in the liver and aorta.
Adrenal Cortex↗
Preclinical Creutzfeldt-Jakob disease discovered at autopsy in a human growth hormone recipient.
An adolescent girl with idiopathic hypothalamic dysfunction and hypopituitarism was treated with human growth hormone between 1969 and 1979, dying of parainfluenza pneumonia 2 months after her last hormone treatment. Although she had no signs of progressive neurologic disease, reexamination of autopsy material revealed a focus of spongiform change and astrogliosis in the corpus striatum. Thus, this growth hormone recipient, who died of intercurrent infection, was unexpectedly found to be in an early, preclinical phase of Creutzfeldt-Jakob disease.
Adolescent↗
Disorders of gonadal differentiation and congenital adrenal hyperplasia.
Ambiguity of the external genitalia may be based on disordered steroid biosynthesis or may arise from fundamental genetic and chromosomal abnormalities that produce failure of gonadogenesis. This article first discusses congenital adrenal hyperplasia and then considers the diverse abnormalities that cause disordered gonadal differentiation.
Adrenal Hyperplasia, Congenital↗