Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0042755 (masculinization)
 2,562 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The steroid 21-hydroxylase enzyme (P450c21) is a member of the cytochrome P450 gene superfamily and is essential in the synthesis of cortisol and aldosterone. Defects in the P450c21B gene cause congenital adrenal hyperplasia (CAH), a common genetic disorder leading to virilization of newborn females. To avoid the standard cloning of mutant P450c21 genes from genomic libraries, we amplified the full-length genomic P450c21 genes by polymerase chain reaction (PCR). The amplification was followed by cloning and sequencing of a defective P450c21B gene. The strategy described here is generally applicable, thus making a simple characterization of the complete P450c21B gene possible. The method was tested in one patient suffering from the simple virilizing form of CAH. The sequence of three independent clones originating from the defective P450c21B showed that Ile at position 172 in exon 4 was substituted by Asn. The identical mutation also has been found in other patients with CAH.
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PMID:Substitution of Ile-172 to Asn in the steroid 21-hydroxylase B (P450c21B) gene in a Finnish patient with the simple virilizing form of congenital adrenal hyperplasia. 193 74

Congenital adrenal hyperplasia, caused by any one of a number of inborn errors of steroidogenesis in which cortisol is not sufficiently produced by the adrenal cortex, is in most cases due to a deficiency of the enzyme steroid 21-hydroxylase. Classic 21-hydroxylase deficiency occurs in about 1 in 14,000 live births. In classic 21-hydroxylase deficiency, the most common cause of genital ambiguity in females, prenatal exposure to excess androgens results in virilization of the female fetus. Newborn males have normal genitalia. Postnatally, untreated females as well as males present with signs of androgen excess. Three fourths of classic 21-hydroxylase deficiency cases do not effectively synthesize aldosterone and are salt-wasting, a condition that is potentially fatal. An allelic variant of classic 21-hydroxylase deficiency, termed nonclassic 21-hydroxylase deficiency, is associated with a milder enzymatic defect and no genital ambiguity at birth, but postnatal virilization may be seen. The 21-hydroxylase enzyme, a cytochrome P450 hemeprotein (cytochrome P450c21), is encoded by the gene CYP21, which has a closely neighboring homologous pseudogene, CYP21P. Mutations in the CYP21 gene, causing 21-hydroxylase deficiency, are common and occur owing to two mechanisms: gene deletion and apparent gene conversion. Prenatal diagnosis is important to identify a fetus affected with 21-hydroxylase deficiency. Genital ambiguity in affected females can be prevented by proper administration of dexamethasone to the pregnant mother. Postnatally, the treatment of 21-hydroxylase deficiency is lifelong hormonal replacement. With carefully supervised medical treatment, congenital adrenal hyperplasia patients have the capacity for normal puberty and fertility.
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PMID:Steroid 21-hydroxylase deficiency (congenital adrenal hyperplasia). 782 36

To evaluate the heterogeneity of 21-hydroxylase deficiency with delayed symptoms, clinical and laboratory findings at presentation in 29 patients whose first symptoms occurred after three years of age were analyzed retrospectively. In 12 patients, these data were confronted with the results of molecular CYP21B gene analysis. Age at onset was 7 years on average and was comparable in boys and girls. Premature puberty was the most common presenting symptom [n = 24], whereas hirsutism, clitoral enlargement, and menstruation disorders were less frequent. Six cases were diagnosed as the result of routine studies of family members of index patients. The bone age over statural age ratio was greater than 1 in 19 of the 27 patients. Baseline 17-OH-progesterone levels were elevated in 22 of the 27 patients; magnitude of the elevation varied widely. Levels of 17-OH-progesterone after stimulation with immediate-action tetracosactide were closely correlated with baseline values and established the diagnosis in doubtful cases. Four patients had post-stimulation 17-OH-progesterone levels under 10 ng/ml, suggesting that were heterozygous for the disease. An important finding was that the magnitude of the devation in 17-OH-progesterone was not clearly correlated with clinical findings at presentation (age at onset, growth rate, advance in bone age). Molecular CYP21B gene analysis performed in 12 patients disclosed a homozygous 281 Val Leu mutation in 6 cases. This is the most commonly reported mutation in delayed onset forms. Two patients were heterozygous for the 281 Val Leu mutation and had an allele associated with severe disease, suggesting that the least severely affected chromosome governed clinical presentation of the disease. One boy had an allele associated with neonatal onset on both chromosomes; molecular analysis indicated a risk of antenatal masculinization of female fetuses in this family. This study showed that delayed onset 21-hydroxylase deficiency is a heterogeneous entity and that molecular analysis is essential to genetic counseling.
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PMID:[Late diagnoses of 21-hydroxylase deficiencies in children (after the age of 3 years]. 823 92

Prenatal diagnosis of 21-hydroxylase deficiency, the most common cause of congenital adrenal hyperplasia (CAH), has benefited from the advances in endocrinologic and molecular genetic studies. In 1976, prenatal diagnosis of the disease was first attempted by measuring 17-hydroxyprogesterone in the amniotic fluid in the second trimester of pregnancy. Discovery of a close linkage between HLA and the disease gave a second approach for prenatal diagnosis, the latter being made by linkage study of the haplotypes of the index case in a given family. Diagnosis was later made directly by molecular biology. Currently, the studies of the C4-CYP21B gene locus by Southern blotting and the CYP21B gene mutations by PCR methods simplify the diagnostic procedure of an early and accurate prenatal diagnosis in the first trimester. In these conditions all families are now informative. Moreover, using a direct genetic analysis associated with the possibility of detecting the heterozygotes in a non-related CAH population, a prenatal diagnosis can be done in a family without a previously CAH affected child. From our results in a series of 274 pregnancies at risk for CAH in whom prenatal diagnosis has been made by these different approaches, it can be concluded that steroid analysis in the amniotic fluid is an accurate method but provides only a late (second trimester) diagnosis, while an early and accurate diagnosis now relies on adequate molecular genetic studies on chorion villus biopsies. In the aim to prevent the virilization of the external genitalia in CAH female fetuses, prenatal treatment was instituted in our group in 1979 by giving dexamethasone to the mother. This prenatal treatment appears safe for the fetus and the child and is effective in preventing virilization of CAH affected females. Although the degree of prevention is not always complete in all cases, the advantages of prenatal treatment are prevailing over the complications observed in a few mothers.
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PMID:Prenatal diagnosis and treatment of 21-hydroxylase deficiency. 848 54

Congenital adrenal hyperplasia (CAH) is an inherited metabolic disease caused by the deficiency of one of the enzymes necessary for cortisol synthesis. Deficiency of 21-hydroxylase (21-OH) accounts for 95% of affected patients There are two forms of the disease. The first is classic, which may be incomplete (simple virilizing) or complete (salt wasting). The second is nonclassic, which may be symptomatic or asymptomatic. In classic 21-OH deficiency which occurs in 1:10000-15000 live births, prenatal exposure to excess androgens results in virilisation of female fetus. Newborn males have normal genitalia. Postnatally, untreated females as well as males present with signs of androgen excess. Three fourths of classic 21-OH deficiency cases do not effectively synthesize aldosterone and are salt wasting, a condition that is potentially fatal. Nonclassic 21-OH deficiency, allelic variant of classic 21-OH deficiency is associated with a milder enzymatic defect and no genital ambiguity at birth, but postnatal virilization may be seen. A subset of individuals with nonclassic 21-OH deficiency are asymptomatic, despite high levels of androgens (cryptic form of disease). The 21-OH enzyme, a cytochrome P450 hemoprotein (cytochrome P450 c21) is encoded by the gene CYP21, which has a closely neighboring homologous pseudogene, CYP21P. Mutations in the CYP21 gene, causing 21-OH deficiency, are common and occur owing to two mechanisms: gene deletion and apparent gene conversion. Prenatal diagnosis is important to identify a fetus affected with 21-OH deficiency. Genital ambiguity in affected females can be prevented by proper administration of dexamethasone to pregnant mother. Postnatally, the treatment of 21-OH deficiency is lifelong hormonal replacement. With carefully supervised medical treatment. CAH patients have the capacity for normal puberty and fertility.
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PMID:[Congenital adrenal hyperplasia due to 21-hydroxylase enzyme deficiency]. 875 1

Long term follow-up studies of children with congenital adrenal hyperplasia have documented less than desirable outcomes, including reduction in final adult height, obesity, virilism, and decreased fertility. We have proposed that children with the most severe forms of congenital adrenal hyperplasia would be better off if their adrenals were removed at an early age. We report here on our experience with prophylactic bilateral adrenalectomy in a 3-yr-old girl with a double null mutation of the CYP21 gene. The results of sodium balance studies, performed preoperatively on our patient and her unaffected fraternal twin sister, and hormonal data are presented as well. In contrast to her twin, who markedly increased her sodium retention in response to ACTH, our patient showed increased natriuresis, suggesting a deleterious effect of her adrenals on sodium homeostasis. Adrenalectomy was carried out at the time of necessary genital repair. No surgical or postsurgical complications were encountered.
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PMID:Prophylactic adrenalectomy of a three-year-old girl with congenital adrenal hyperplasia: pre- and postoperative studies. 932 62

21-hydroxylase (21-OH) deficiency accounts for the vast majority of nonclassic (NC) forms of congenital adrenal hyperplasia (CAH), and is associated with symptoms detectable either in childhood (precocious puberty) or sometimes only later in adulthood (hirsutism, acne, amenorrhea). While the severe forms of the disease responsible for salt wasting or simple virilization have been extensively studied, the NC 21-OH deficiency is less well characterized, especially in adults. We studied the 21-OH gene (CYP21) in a population of 69 unrelated hyperandrogenic subjects suspected to be homozygous or heterozygous for NC 21-OH deficiency, based on basal and adrenocorticotrophin (ACTH)-stimulated plasma 17-hydroxyprogesterone (17-OHP, 17-OHPSI) and 21-desoxycortisol (21-DOF, 21-DOFSI) levels. To identify all mutations involved, determination of the whole gene sequence, including exons, exon-intron junctions, and promoter region, was performed, followed by a study of large rearrangements and identification of compound heterozygotes. Alterations were identified in at least one allele of 55 hyperandrogenic subjects. Two NC alterations, Val282Leu and Pro454Ser, were detected in 68% and 7% of the affected alleles, respectively, whereas mutations involved in severe forms were identified in 21% of them. These results document the utility of a molecular diagnosis in hyperandrogenic women suspected of being either heterozygous or homozygous for NC 21-OH deficiency and clearly indicate the importance of genetic counseling in such a population.
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PMID:Exhaustive screening of the 21-hydroxylase gene in a population of hyperandrogenic women. 938 70

The physiological importance of adrenal 21-hydroxylase cytochrome P450 (CYP21) expression is clearly demonstrated by 21-hydroxylase deficiency, which results in adrenal hyperplasia and over-production of C19 steroids, leading to virilization. The mechanisms regulating normal expression of this key enzyme in human adrenocortical cells are ill defined. Herein we examine the role of the calcium, protein kinase C, and protein kinase A signaling pathways in the expression of CYP21 messenger ribonucleic acid (mRNA) using the H295R human adrenocortical cell model. Forskolin (10 mumol/L) treatment caused a progressive increase in CYP21 mRNA levels (maximum, 4-fold; P < 0.05) over 36 h of treatment, whereas angiotensin II (AII; 10 nmol/L) produced a smaller, biphasic rise (maximum, 1.8-fold at 12 h; P < 0.05). K+ (14 mmol/L) also induced a time-dependent (maximal, 1.5-fold at 12 h; P < 0.05) and dose-dependent (P < 0.05 12 mmol/L or above at 20 h) rise in CYP21 mRNA levels. The action of forskolin was reproduced by dibutyryl cAMP, confirming the involvement of cAMP in this response. The action of AII was greater than that of K+ or the calcium channel agonist BAYK8644, suggesting that AII action was not solely through the Ca2+ signaling pathway. The action of AII was reproduced and indeed exceeded by the protein kinase C activator 12-O-tetradecanoylphorbol 13-acetate (TPA; 10 nmol/L; 5.5-fold increase; P < 0.05). The actions of forskolin alone were not significantly increased by combined treatment with AII, suggesting neither synergy nor attenuation of the effects of protein kinase A activation. This was further demonstrated at the level of mRNA and 21-hydroxylase activity by the observation that the effect of forskolin and TPA in combination did not exceed that of TPA alone. Inhibition of protein synthesis with cycloheximide blocked induction of CYP21 as well as type II 3 beta-hydroxysteroid dehydrogenase (3 beta HSDII) mRNA expression in response to AII, forskolin, and dibutyryl cAMP, but had no effect on 17 alpha-hydroxylase cytochrome P450 (CYP17) or cholesterol side-chain cleavage cytochrome P450 (CYP11A) mRNA. Together, these findings were remarkably similar to those of our previous studies regarding mechanisms regulating 3 beta HSDII expression and underline the existence of a subset of steroidogenic enzymes regulated positively (CYP21 and 3 beta HSDII) as opposed to negatively (CYP17 and CYP11A) by the protein kinase C signaling pathway. The additional finding of a small induction of CYP21 expression in response to increased Ca2+, as previously reported for CYP17, but not 3 beta HSDII, expression, also demonstrates that the mechanisms of control of CYP21 and 3 beta HSDII are not identical. This latter finding may also relate to how CYP21 as well as CYP17 expression continues in the zona reticularis after adrenarche, whereas 3 beta HSD expression declines.
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PMID:Protein kinase A, protein kinase C, and Ca(2+)-regulated expression of 21-hydroxylase cytochrome P450 in H295R human adrenocortical cells. 958 61

Background: Congenital adrenal hyperplasia (CAH) due to deficiency of steroid 21- hydroxylase (CYP21) is an autosomal recessive disease that is a major cause of ambiguous genitalia at birth in females. The milder late-onset form of the disease can cause mild virilization in women including hirsutism, infertility, and acne. Characterization of the causative mutations in a patient requires finding mutations on both chromosomes. Methods and Results: We use polymerase chain reaction (PCR) followed by restriction enzyme digestion (RED), among several other methods, to detect mutations in the CYP21 gene. The authors found two different point mutations in a patient with CAH, V281L and Q318X. Did we find two mutations in trans which would account for the disease, or two mutations in cis with a still unknown mutation(s) on the other chromosome? We devised a method to determine the cis/trans nature of the mutations using PCR amplification, digestion with a restriction enzyme (ApaL I) diagnostic for V281L, gel purification of the mutant band which lacks the cutting site, digestion with a second restriction enzyme (Pst I) which detects Q318X, and gel electrophoretic analysis of the products. Although the results initially supported a a cis orientation, consideration of the impact of heteroduplex formation during the PCR on the products of RED showed that the orientation was actually trans. Conclusions: When DNA that is heterozygous for a mutation is amplified using the PCR, four double-stranded DNA products can be formed: the two homoduplexes and two heteroduplexes. The heteroduplex DNA must be considered to ensure correct interpretation of the results of PCR-RED analysis.
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PMID:The Importance of Heteroduplexes in Interpreting the Results of PCR-RED Diagnostic Assays: Application to the Analysis of Mutations in the Steroid 21-Hydroxylase Gene in a Case of Congenital Adrenal Hyperplasia. 1002 63

On the basis of hormonal studies, the incidence of defective steroidogenesis in children with premature adrenarche (PA) in the various reports ranges from 0-54%. Molecular studies have not been reported to date. The aim of the present study was to search for defects in the CYP21 gene in children with PA and to detect possible correlations of the molecular defect to pertinent hormonal and clinical data. In 48 children with PA (40 females and 8 males) and without signs of virilization, a Synachten test and molecular studies were carried out. DNA analysis was performed using the Southern blot technique and allele-specific PCR. Synachten (0.25 mg) was given i.v., and 17-hydroxyprogesterone and cortisol were determined at 0 and 60 min. At baseline, delta4-androstenedione, dehydroepiandrosterone sulfate, and 11-deoxycortisol were also determined. Bone age was evaluated using the Greulich and Pyle atlas. Abnormal genotype was detected in 45.8% of the studied subjects; 8.3% were homozygotes, with genotypes concordant with the nonclassical phenotype of 21 hydroxylase deficiency, and 37.5% were heterozygotes for 9 different molecular defects of the CYP21 gene. The children with no detectable molecular defect were designated normal. The 60 min post-Synachten values in homozygotes (17.9 +/- 7.1 ng/mL) and heterozygotes (7.1 +/- 3.6 ng/mL) were significantly higher than that in normal subjects (3.3 +/- 1.5 ng/mL), but with significant overlapping of values. The mean difference between bone age and chronological age differed in the three groups with overlapping values. The basal delta4-androstenedione level was lower in the normal subjects (0.65 +/- 0.3 ng/mL) than in those with abnormal genotype (1.1 +/- 0.8 ng/mL). The data indicate that the incidence of molecular defects in PA is quite high. The CYP21 heterozygocity is clinically expressed in some subjects prepubertally. In a significant number of cases the genotype cannot be predicted by the age of onset of PA, the mean difference between bone age and chronological age, or the results of a Synachten test. Follow-up of these children through puberty is imperative and may reveal the clinical significance of the molecular defect, namely more hypertrichosis, intense acne, early puberty, possible abnormal menses, and/or fertility problems in the affected.
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PMID:High incidence of molecular defects of the CYP21 gene in patients with premature adrenarche. 1032 82


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