Gene/Protein Disease Symptom Drug Enzyme Compound
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Recent reports have thrown doubt on the role of measurements of plasma 5 alpha-androstane-3 alpha,17 beta-diol glucuronide (3 alpha-diolG) as a marker of peripheral androgen metabolism in women with polycystic ovarian syndrome and idiopathic hirsutism. It has been suggested that a plasma profile of C19 steroid glucuronides may be more informative. While preliminary data indicates that both 3 alpha-diolG and androsterone G (ADTG) may arise from adrenal steroid precursors, there have been no reports of C19 steroid glucuronides in women with non-classical, or late-onset congenital adrenal hyperplasia (NC-CAH), who constitute a significant proportion of the hirsute female population. We therefore measured plasma levels of 3 alpha-diolG, ADTG and dihydrotestosterone G (DHTG) before and following a standard Cortrosyn test in 15 symptomatic and 3 asymptomatic NC-CAH patients, 5 heterozygote carriers for 21-hydroxylase deficiency (NCHETS) and 18 normal women. The effects of chronic glucocorticoid (GCR) therapy (greater than 3 months) on the C19 steroid glucuronide profile in the symptomatic patients was also investigated. Baseline plasma levels of all 3 glucuronides were significantly (P less than 0.001) higher in symptomatic patients compared with either normals or NCHETS. However, the order of discrimination was ADTG greater than 3 alpha-diolG greater than DHTG. There were no significant differences between steroid glucuronide levels for NCHET and normal women and the C19 steroid glucuronide concentrations for the asymptomatic NC-CAH patients were greater than 2 SD above the normal means. Moderate clinical improvement was observed in all patients receiving oral GCR therapy and was accompanied by approx. 80% suppression of the plasma levels of all 3 C19 steroid glucuronides. This contrasts with a mean suppression of androstenedione of only 50%. However, plasma levels of the C19 steroid glucuronides were not significantly increased in response to a short ACTH stimulation test. This may be explained by the fact that the androgen glucuronides are thought to be peripherally formed metabolites derived from unconjugated glandular secreted androgen precursors and thus their synthesis at 60 min following adrenal stimulation may lag substantially behind that of their respective precursors. There were significant linear correlations between the levels of all 3 glucuronides, but neither correlated with Ferriman-Gallway scores, body mass index or 17-hydroxyprogesterone levels.(ABSTRACT TRUNCATED AT 400 WORDS)
J Steroid Biochem Mol Biol 1992 Apr
PMID:Plasma levels of C19 steroid glucuronides in pre-menopausal women with non-classical congenital adrenal hyperplasia. 131 40

Steroid 21-hydroxylase deficiency is the most common enzymatic defect causing congenital adrenal hyperplasia, an inherited disorder of cortisol biosynthesis. All mutations thus far characterized that cause this disorder appear to result from recombinations between the gene encoding the enzyme, CYP21B (CYP21), and the adjacent pseudogene, CYP21A (CYP21P). These are either deletions caused by unequal crossing-over during meiosis or apparent transfers of deleterious sequences from CYP21A to CYP21B, a phenomenon termed gene conversion. However, a small percentage of alleles do not carry such a mutation. We analyzed DNA from a patient with the mild, nonclassic form of 21-hydroxylase deficiency, who carried one allele that had no gene conversions detectable by hybridization with oligonucleotide probes. Sequence analysis revealed that this allele carried two missense mutations, R339H and P453S, neither of which has been previously observed in CYP21A or CYP21B. Each of these mutations was introduced into CYP21 cDNA which was then expressed in COS1 cells using a vaccinia virus system. Each mutation reduced the ability of the enzyme to 21-hydroxylate 17-hydroxyprogesterone to 50% of normal and the ability to metabolize progesterone to 20% of normal. Thus, each of these mutations represents a potential nonclassic 21-hydroxylase deficiency allele that is not the result of an apparent gene conversion.
Mol Endocrinol 1992 Aug
PMID:R339H and P453S: CYP21 mutations associated with nonclassic steroid 21-hydroxylase deficiency that are not apparent gene conversions. 140 9

The most common enzymatic defect of steroid synthesis is adrenal steroid 21-hydroxylase deficiency. Inhibited formation of cortisol causes increased pituitary release of ACTH, driving the adrenal cortex to overproduce androgens, whose synthesis does not involve the 21-hydroxylase enzyme. This hormonal setting is established in the embryonic period and affects development of genetic females, misdirecting differentiation of the external genitalia toward male type. At birth, the genitalia are visibly ambiguous (enlarged clitoris, fused labia) or in some cases even male in appearance (phallus with urethral opening, rugated scrotal sac), leading to wrong sex assignment. Adrenal steroid 21-hydroxylase deficiency is the most common basis of female pseudohermaphroditism. These females, however, have normal fertility and potential for gestation (gonads are functional and the internal duct-derived structures are well-formed), thus the sex of rearing should always be female. Management is by life-long hormonal (glucocorticoid) replacement, with surgical correction of the genital ambiguity. Prenatal diagnosis of 21-hydroxylase deficiency, first possible by steroid assay of the amniotic fluid, has utilized HLA typing for identification of loci (antigens B and DR) in close linkage with the 21-hydroxylase gene, and now increasingly relies on DNA analysis for linked HLA or C4 genes or for mutant 21-hydroxylase alleles directly by molecular genetic techniques. The most recent clinical advance is a program of combined prenatal diagnosis with karyotyping and suppression of fetal androgen production in genetic females by steroid administration to the mother. This is the first instance of an inborn metabolic error to be prenatally treated. A series of 85 managed pregnancies is reported on, including accuracy of diagnosis, response of the mother to steroid treatment, and outcome for treated and untreated male and female fetuses (of 77 born by 6/91). Prenatal diagnosis by current techniques is accurate. Normal growth and development patterns postnatally suggest that dexamethasone treatment is safe.
J Steroid Biochem Mol Biol 1992 Mar
PMID:Prenatal diagnosis/treatment in families at risk for infants with steroid 21-hydroxylase deficiency (congenital adrenal hyperplasia). 156 17

While hypertension is observed in only two of the three major subtypes of congenital adrenal hyperplasia (CAH), 11 beta- and 17 alpha-hydroxylase deficiencies, deoxycorticosterone (DOC) production is increased in all. The elevated zona fasciculata (ZF) DOC produces mineralocorticoid hypertension with suppressed renin and reduced potassium concentrations. The DOC levels in 21-hydroxylase deficiency are in part produced by renin stimulation of the Zona glomerulosa (ZG) along with aldosterone. Assessment of the mineralocorticoid hormones of the ZF and ZF (17-deoxy steroids) provides additional unique characteristics of each subtype. Dissociation of DOC from cortisol is not unique to CAH. This dissociation is seen in other disorders and contrived conditions. There is a strong suggestion of a non-ACTH regulator of 17-deoxy steroids (DOC) that may contribute significantly to DOC production in general and effect DOC levels in CAH.
J Steroid Biochem Mol Biol 1991
PMID:Mineralocorticoids in congenital adrenal hyperplasia. 195 51

The molecular pathology of steroid 21-hydroxylase deficiency is attributable to unequal crossover-mediated gene deletion or to large- or small-scale replacement of the functional CYP21B gene sequence by a copy of the analogous CYP21A pseudogene sequence. Because the pathological point mutations originate from the pseudogene which shows only a small number of differences from the functional CYP21B gene sequence, the total number of different pathological point mutations is likely to be small. Mutant P450c21 enzymes carrying specific amino acid substitutions seen in patients with 21-hydroxylase deficiency exhibit activities that correlate with the clinical severity of the disease and with biochemical abnormalities such as 17-hydroxyprogesterone levels after ACTH (corticotropin) stimulation.
J Steroid Biochem Mol Biol 1991
PMID:Molecular pathology of steroid 21-hydroxylase deficiency. 195 56

The mild nonclassic form of steroid 21-hydroxylase deficiency is one of the most common autosomal recessive disorders in humans, occurring in almost 1% of caucasians and about 3% of Ashkenazi Jews. Many patients with this disorder carry a Val-281----Leu missense mutation in the CYP21 gene. This and most other mutations causing 21-hydroxylase deficiency are normally present in the CYP21P pseudogene and have presumably been transferred to CYP21 by gene conversion. To identify other potential nonclassic alleles, we used recombinant vaccinia virus to express two mutant enzymes carrying the mutations Pro-30----Leu (normally present in CYP21P) and Ser-268----Thr (considered a normal polymorphism of CYP21). Whereas the activity of the protein carrying the Ser----Thr mutation was indeed indistinguishable from the wild type, the enzyme with the Pro----Leu substitution had 60% of wild-type activity for 17-hydroxyprogesterone and about 30% of normal activity for progesterone when assayed in intact cells. When kinetic analysis of the latter mutant enzyme was performed in cellular lysates, the first order rate constants (maximum velocity/dissociation constant) for both substrates were reduced 10- to 20-fold compared with those for the wild-type enzyme. Pro-30 is conserved in many microsomal P450 enzymes and may be important for proper orientation of the enzyme with respect to the aminoterminal transmembrane segment. The Pro----Leu mutation was present in 5 of 18 patients with nonclassic 21-hydroxylase deficiency, suggesting that this mutation indeed acts as a nonclassic deficiency allele.
Mol Endocrinol 1991 May
PMID:A mutation (Pro-30 to Leu) in CYP21 represents a potential nonclassic steroid 21-hydroxylase deficiency allele. 207 28

Serum sulphates of 5-androstene-3 beta,17 beta-diol (5-ADIOL-S), 5 alpha-androstane-3 alpha,17 beta-diol (3 alpha-DIOL-S) and dehydroepiandrosterone (DHEA-S), as well as 5 alpha-androstane-3 alpha,17 beta-diol glucuronide (3 alpha-DIOL-G) and unconjugated androstenedione (AD) and testosterone (T), sex hormone binding globulin (SHBG), free androgen index (FAI) and 17 alpha-hydroxyprogester-one (17OHP) were measured by specific radioimmunoassays (RIA) in 14 women with late-onset 21-hydroxylase deficiency (LOCAH), and in normal women (n = 73). The diagnosis of LOCAH was made on the finding of a (17OHP) response level greater than 30 nmol/l following ACTH stimulation, and/or an elevation of urinary metabolites of 17OHP. Mean values for serum concentrations of all steroids measured and the free androgen index (100 X T nmol/l divided by SHBG nmol/l) were significantly elevated, and SHBG levels depressed in patients with LOCAH. These studies show that in LOCAH, in addition to the unconjugated steroids AD and T, the sulphoconjugated steroids DHEA-S, 5-ADIOL-S and 3 alpha-DIOL-S are increased, as is the glucuronide conjugate 3 alpha-DIOL-G and the index of bioavailable testosterone (FAI), and that mean SHBG levels are depressed. These data suggest that as well as AD, 5-ADIOL-S and DHEA-S may act as pro-hormones for more potent steroids (T and 5 alpha-dihydrotestosterone) in peripheral tissues, while 3 alpha-DIOL-S and 3 alpha-DIOL-G may both reflect peripheral androgen metabolism in patients with LOCAH.
J Steroid Biochem Mol Biol 1990 Nov 30
PMID:Serum levels of 5-androstene-3 beta,17 beta-diol sulphate, 5 alpha-androstane-3 alpha, 17beta-diol sulphate and glucuronide, in late onset 21-hydroxylase deficiency. 217 25

Steroid 21-hydroxylase deficiency is the leading cause of impaired cortisol synthesis in congenital adrenal hyperplasia (CAH). We have studied the structure of the CYP21B gene in 30 unrelated CAH patients using the polymerase chain reaction (PCR) to differentiate the active CYP21B gene from its highly related CYP21A pseudogene. The PCR approach obviates the need to distinguish the CYP21A and CYP21B genes by restriction endonuclease digestion and electrophoresis before analysis with labeled probes. Furthermore, direct nucleotide sequence analysis of CYP21B genes is demonstrated on the PCR-amplified DNA. Gene deletion of CYP21B, gene conversion of the entire CYP21B gene to CYP21A, frame shift mutations in exon 3, an intron 2 mutation that causes abnormal RNA splicing, and a mutation leading to a stop codon in exon 8 appear to be the major abnormalities of the CYP21B gene in our patients. These mutations appear to account for 21-hydroxylase deficiency in 22 of 26 of our salt-wasting CAH patients.
Mol Endocrinol 1990 Jan
PMID:Direct analysis of CYP21B genes in 21-hydroxylase deficiency using polymerase chain reaction amplification. 232 62

The results of measurement of 17-hydroxyprogesterone (17-OH-P) in 125 samples of amniotic fluid (AF) from early amniocenteses are presented. The fetuses from all pregnancies studied were unaffected by congenital adrenal hyperphasia caused by 21-hydroxylase deficiency. The AF 17-OH-P level increases slightly but significantly between the 11th and 15th week of gestation, with a maximum in the 14th week. There is no difference between the values measured in male and female fetuses. The AF 17-OH-P levels from the early gestation were compared with those from the 16th-22nd week of pregnancy (published previously). The overall differences of AF 17-OH-P concentrations when considered in all gestational age groups in the whole period 12-22 weeks were statistically insignificant. Thus, the biochemical prenatal diagnosis of congenital adrenal hyperplasia due to 21-hydroxylase deficiency and control of its early fetal treatment could be carried out starting from the end of the first trimester in the same way as at the later period of gestation.
J Steroid Biochem Mol Biol 1994 Dec
PMID:Amniotic fluid 17-hydroxyprogesterone in early pregnancy. 782 94

Congenital adrenal hyperplasia (CAH) results from an enzymatic block at any stage in the synthesis of cortisol. All enzyme defects causing CAH are autosomal recessive traits. It is a relatively common disease, occurring in 1 in 5000 to 1 in 15,000 births in most populations. Since the isolation of the gene responsible for steroid 21-hydroxylase deficiency (involved in about 90% of the cases of CAH) in 1984, knowledge of the specific mutations that cause the different forms of CAH has grown rapidly. Defects in the encoding gene have been confirmed as the basis of endocrine disease in the case of all but one of the adrenal steroidogenic enzymes. Analysis of DNA obtained by chorionic villus sampling in early pregnancy permits prenatal diagnosis and treatment of 21-hydroxylase deficiency CAH. The correlation between the clinical expression of endocrine disease and the mutations of the primary structural gene is not absolute. Clinicians cannot accurately predict the course of the disease or make therapeutic decisions based on the genotype alone. We will review the various forms of clinical presentation of 21-hydroxylase CAH, its etiology, diagnosis, molecular genetics, and treatment.
J Steroid Biochem Mol Biol 1994 Jan
PMID:21-hydroxylase deficiency congenital adrenal hyperplasia. 813 1


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