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1.
J Clin Endocrinol Metab ; 82(12): 3926-9, 1997 Dec.
Article in English | MEDLINE | ID: mdl-9398689

ABSTRACT

Even with current so called physiologic doses of glucocorticoid replacement therapy, children with congenital adrenal hyperplasia (CAH) often show relative short stature and delayed bone maturation, an observation that suggests possible long-term effects on bone metabolism of daily transient post-absorptive hypercortisolemia. In 28 patients with 21-hydroxylase or 17 alpha-hydroxylase deficiency (16 females and 12 males, ages 4.9-22 yr) who had received oral cortisol 10-15 mg/M2/day for 4.7-22 yr, we studied cortisol bioavailability, growth, bone maturation, vertebral bone mineral density, and various markers of bone formation and resorption. Patients were grouped according to mean on-therapy serum 170H-progesterone or progesterone levels as tight control (170HP < 10 nmol/L), fair control (170HP 10-40 nmol/L or progesterone 1.0-1.5 nmol/L), or poor control (170HP > 40 nmol/L). There was no difference in peak post-absorptive serum cortisol or area under the concentration-time curve, and only three patients had a peak serum cortisol of more than 700 nmol/L. There was no difference in present height Z-score (-0.96; -0.24; -0.6), height Z-score at age 2 yr (-1.5; +0.4; -1.3), or current growth velocity Z-score (-0.1; +1.2; -2.2) between the groups, but bone maturation Z-score was significantly delayed (-1.63) in the tight control group and advanced (+0.8) in the poor control group. Present height was highly correlated (r = 0.8) with height at age 2 yr. Serum calcium, phosphorus, alkaline phosphatase, parathormone, and 25OH-vitamin D levels were all normal. There was no difference between the groups in age-corrected vertebral bone mineral density, and no difference in serum osteocalcin, procollagen peptide, or collagen C-terminal telopeptide, nor in urinary amino-terminal telopeptide. The data suggest that current methods of cortisol replacement do not significantly influence bone formation, resorption or density during childhood and therefore should not contribute to adult osteoporosis. The possibility remains that hypercortisolemia during infancy produces the short stature and delayed bone maturation that are present by the age 2 yr.


Subject(s)
Bone Density/drug effects , Bone Development/drug effects , Bone Remodeling/drug effects , Child Development/drug effects , Glucocorticoids/therapeutic use , Adolescent , Adrenal Hyperplasia, Congenital/drug therapy , Adrenal Hyperplasia, Congenital/metabolism , Adult , Biomarkers , Bone and Bones/metabolism , Child , Child, Preschool , Eating/physiology , Female , Humans , Hydrocortisone/blood , Male
2.
Biochim Biophys Acta ; 1299(2): 160-6, 1996 Jan 19.
Article in English | MEDLINE | ID: mdl-8555260

ABSTRACT

Fatty acid ethyl esters are a family of non-oxidative metabolites of ethanol present in many tissues after ethanol consumption. In this report we demonstrate the existence in human liver of an acyl-CoA:ethanol acyltransferase activity which may be responsible in part for the synthesis of these compounds in vivo. The effects of oleoyl-CoA and ethanol concentrations, presence or absence of bovine serum albumin and detergent, pH and enzyme concentration on this activity have been determined. Acyl-CoA:ethanol acyltransferase activity is localised in the membrane-bound fraction. Using inhibitors directed against related enzyme activities, it has been shown that the activity is not related to serine-dependent carboxylesterases or acyl-CoA:cholesterol acyltransferase, but tht it may be associated with acyl-CoA hydrolase activity. We have also compared acyl-CoA:ethanol acyltransferase activity with fatty acid ethyl ester synthase activity in microsomes and cytosol from the same liver. Our data indicate that these activities are comparable in vitro (on a unit/g liver basis), and suggest that both may be significant in vivo.


Subject(s)
Acyltransferases/chemistry , Acyltransferases/metabolism , Esters/metabolism , Fatty Acids/metabolism , Microsomes, Liver/metabolism , Acyl Coenzyme A/analysis , Acyltransferases/antagonists & inhibitors , Animals , Ethanol/analysis , Humans , Kinetics , Microsomes, Liver/enzymology , Oleic Acids/biosynthesis , Palmitoyl-CoA Hydrolase/metabolism , Rats
3.
Curr Opin Pediatr ; 5(4): 488-93, 1993 Aug.
Article in English | MEDLINE | ID: mdl-8374678

ABSTRACT

Female adolescence is normally accompanied by increased adrenal and ovarian production of androgens. Indeed it is not uncommon in early to midpuberty to see typical features of adult polycystic ovary syndrome, with luteinizing hormone-driven ovarian hyperandrogenism, hyperinsulinemia, acne, anovulation, oligomenorrhea, and large, multifollicular ovaries. Unfortunately, no single prospective test can differentiate girls in whom this maturational stage is self-limited from those in whom it will progress to adult polycystic ovary syndrome with hirsutism and anovular infertility. An occasional hirsute adolescent will prove by corticotropin testing to have a nonclassical variant of adrenal 21-hydroxylase deficiency and will benefit from glucocorticoid therapy. The prevalence or even the existence of mild 11 beta-hydroxylase or 3 beta-hydroxysteroid dehydrogenase deficiency is more problematic. Given these difficulties of exact diagnosis and prognosis, therapy for the adolescent with mild hirsutism, acne, or oligomenorrhea should be conservative.


Subject(s)
Androgens/biosynthesis , Endocrine System Diseases , Adolescent , Adrenal Glands/pathology , Endocrine System Diseases/metabolism , Endocrine System Diseases/physiopathology , Endocrine System Diseases/therapy , Female , Humans , Hyperplasia , Polycystic Ovary Syndrome/physiopathology , Puberty, Precocious/metabolism
4.
J Pediatr ; 122(2): 252-3, 1993 Feb.
Article in English | MEDLINE | ID: mdl-8429442

ABSTRACT

A 14-year-old boy was seen because of irritability, insomnia, lethargy, and profuse sweating, together with hypertension (blood pressure: 160/120 mm Hg), tachycardia, and a diffuse erythematous rash with desquamation of the palms and soles. Initial biochemical investigation suggested a diagnosis of pheochromocytoma, but subsequently a history of exposure to mercury vapor was obtained. This case emphasizes the clinical and biochemical similarities between mercury poisoning (acrodynia) and pheochromocytoma.


Subject(s)
Acrodynia/diagnosis , Adrenal Gland Neoplasms/diagnosis , Mercury Poisoning/diagnosis , Pheochromocytoma/diagnosis , Acrodynia/blood , Acrodynia/urine , Acute Disease , Adolescent , Diagnosis, Differential , Humans , Male , Mercury/blood , Mercury/urine , Mercury Poisoning/blood , Mercury Poisoning/urine
5.
Genomics ; 14(4): 1110-1, 1992 Dec.
Article in English | MEDLINE | ID: mdl-1478654

ABSTRACT

The gene for human P450(17 alpha) (CYP17) was previously mapped to chromosome 10 through analysis of somatic cell hybrids. Using a modified procedure of fluorescence in situ hybridization, this gene has now been visualized on simultaneously banded chromosomes and localized to a specific subband of chromosome 10 at q24.3. This precise assignment may facilitate the understanding of the molecular basis of 17 alpha-hydroxylase/17,20-lyase deficiency and the evolution of the CYP superfamily of genes.


Subject(s)
Chromosome Banding , Chromosomes, Human, Pair 10 , Cytochrome P-450 Enzyme System/genetics , In Situ Hybridization, Fluorescence , Steroid 17-alpha-Hydroxylase/genetics , Chromosome Mapping , DNA , Humans , Karyotyping
6.
Biochim Biophys Acta ; 1139(4): 275-9, 1992 Aug 25.
Article in English | MEDLINE | ID: mdl-1515452

ABSTRACT

The molecular defect in a reported case of isolated 17,20-lyase deficiency in a 46XY individual has been elucidated. The patient was found to be a compound heterozygote, carrying two different mutant alleles in the CYP17 gene. One allele contains a point mutation of arginine (CGC) to cysteine (TGC) at amino acid 496 in exon 8. The second allele contains a stop codon (TAG) in place of glutamine (CAG) at position 461 in exon 8 which is located 19 amino acids to the carboxy-terminal side of the P-450(17) alpha heme binding cysteine. COS-1 cells transfected with cDNAs containing one or the other of these mutations showed dramatically reduced 17 alpha-hydroxylase and 17,20-lyase activities relative to cells transfected with the wild type P-450(17) alpha cDNA. While the in vitro data in COS 1 cells can explain the patient's physical phenotype, with female external genitalia, it was somewhat discordant with the clinical expression of isolated 17,20-lyase deficiency with relative preservation of 17 alpha-hydroxylase activity in vivo. In addition to the expression studies of these two examples of mutants in the C-terminal region of cytochrome P-450(17) alpha, a third mutant cDNA construct containing a 4-base duplication at codon 480 previously found in patients with combined 17 alpha-hydroxylase/17,20-lyase deficiency was also expressed in COS-1 cells. This expressed protein was completely inactive with respect to both activities, supporting the biochemical findings in serum and in vitro biochemical data obtained using a testis from the patient. The results from these patients clearly indicate the importance of the C-terminal region of human P-450(17) alpha in its enzymatic activities.


Subject(s)
Adrenal Hyperplasia, Congenital , Aldehyde-Lyases/genetics , Cytochrome P-450 Enzyme System/genetics , Disorders of Sex Development/genetics , Mutation , Adolescent , Aldehyde-Lyases/deficiency , Amino Acid Sequence , Base Sequence , Cell Line , Cytochrome P-450 Enzyme System/deficiency , Disorders of Sex Development/enzymology , Heterozygote , Humans , Male , Molecular Sequence Data , Transfection
7.
J Clin Endocrinol Metab ; 74(3): 667-72, 1992 Mar.
Article in English | MEDLINE | ID: mdl-1740503

ABSTRACT

17 alpha-Hydroxylase deficiency is characterized by defects in either or both the 17 alpha-hydroxylase/17,20-lyase activities. We have, for the first time, elucidated the molecular basis of the deficiency in a male pseudohermaphrodite with ambiguous external genitalia resulting from partial combined deficiency of both activities. The patient is found to be a compound heterozygote, carrying two different inherited mutant alleles in the cytochrome P45017 alpha (CYP17) gene. One allele, from his mother, contains a stop codon (TGA) in place of arginine (CGA) at amino acid position 239 in exon 4. Because this occurs at the N-terminal side of the heme binding sequence, the putative resultant truncated protein is nonfunctional. The second allele, from his father, contains a missense mutation encoding the substitution of proline (CCA) by threonine (ACA) at position 342 in exon 6. Reconstruction of this mutation by site-directed mutagenesis into human P45017 alpha cDNA followed by expression in COS 1 cells leads to the same amount of immunodetectable P45017 alpha protein as found with expression of the normal P45017 alpha cDNA, although both the 17 alpha-hydroxylase and 17,20-lyase activities are found to be reduced to 40-45% of those of the normal enzyme. The presence of ambiguous external genitalia in this 46 XY individual indicates that greater than 20% of the total normal 17,20-lyase activity is required for complete virilization in the male.


Subject(s)
Adrenal Hyperplasia, Congenital , Aldehyde-Lyases/deficiency , Cytochrome P-450 Enzyme System/deficiency , Disorders of Sex Development/genetics , Heterozygote , Mutation , Steroid 17-alpha-Hydroxylase/genetics , Aldehyde-Lyases/genetics , Aldehyde-Lyases/metabolism , Alleles , Amino Acid Sequence , Animals , Arginine , Base Sequence , Blotting, Southern , Cell Line , Child , Cytochrome P-450 Enzyme System/genetics , Cytochrome P-450 Enzyme System/metabolism , DNA/blood , DNA/genetics , DNA/isolation & purification , Disorders of Sex Development/enzymology , Humans , Leukocytes/enzymology , Male , Molecular Sequence Data , Oligodeoxyribonucleotides , Polymerase Chain Reaction , Proline , Restriction Mapping , Steroid 17-alpha-Hydroxylase/metabolism , Threonine , Transfection
9.
Clin Endocrinol (Oxf) ; 34(2): 107-14, 1991 Feb.
Article in English | MEDLINE | ID: mdl-1850671

ABSTRACT

Allgrove syndrome (isolated glucocorticoid deficiency, achalasia and alacrima) was found in eight members of an inbred French Canadian/North American Indian pedigree. The high degree of consanguinity supports an autosomal recessive mode of inheritance for this disorder. Six patients presented with hypoglycaemia and other evidence of cortisol deficiency between 2.5 and 8 years of age; however, two others became cortisol deficient after initial testing showed normal cortisol responses to ACTH, evidence that the glucocorticoid insufficiency of this syndrome may not be congenital, but may develop as late as the third decade. No evidence of mineralocorticoid deficiency has been found during 65 patient-years of follow-up. Alacrima was the earliest and most consistent clinical sign of Allgrove syndrome. Other manifestations of peripheral or autonomic neuropathy were found in four patients. The patients showed similar facial features, and three had significant velo-pharyngeal incompetence. All showed oesophageal dysmotility even in the absence of symptomatic dysphagia. In-vitro studies of lymphocyte ACTH binding showed no differences from normal controls. If such lymphocyte binding, as has been suggested, reflects adrenal ACTH receptor activity, these data would suggest that the glucocorticoid deficiency of Allgrove syndrome is not the result of a defect in that receptor. However, the observation that ACTH does not elicit increased adenylate cyclase activity even in normal lymphocytes casts considerable doubt on the physiological significance of ACTH binding to lymphocytes. It seems likely, therefore, that true ACTH receptors are not expressed on peripheral lymphocytes, and any conclusions regarding a possible receptor defect in Allgrove syndrome must await studies of receptor expression on adrenal cell membranes.


Subject(s)
Adrenocorticotropic Hormone/metabolism , Esophageal Achalasia/genetics , Hydrocortisone/deficiency , Lacrimal Apparatus Diseases/genetics , Adult , Child , Child, Preschool , Consanguinity , Esophageal Achalasia/metabolism , Female , Genes, Recessive , Humans , Lacrimal Apparatus Diseases/metabolism , Lymphocytes/metabolism , Male , Pedigree , Syndrome
11.
Endocrinology ; 127(4): 1904-9, 1990 Oct.
Article in English | MEDLINE | ID: mdl-2169407

ABSTRACT

Studies using cultured bovine adrenocortical cells now demonstrate that the cytokines interleukin-1 (IL-1) alpha and beta, contrary to previous reports, can stimulate cortisol secretion in vitro in a dose- and time-dependent fashion. However detectable levels of IL-1 receptor could not be demonstrated in adrenal cortical, medullary, or capsular cells by membrane displacement of iodinated IL-1 alpha by unlabeled IL-1 beta, a technique that readily demonstrates specific IL-1 alpha-binding sites on 3T3 fibroblasts. The stimulatory effect of IL-1 on cortisol secretion could be totally blocked by indomethacin, an indication that this effect might be mediated indirectly via local release of prostaglandins (PGs). Subsequent investigations have confirmed that IL-1 does enhance the conversion of [3H]arachidonate to PGs by cultured adrenal cells, and that some of these PGs (PGD2, PGF2 alpha, and PGE2), in turn, can stimulate cortisol production. Taken together these observations suggest that IL-1-induced stimulation of cortisol secretion is mediated through local release of PGs by a small subpopulation of cells within the adrenal gland.


Subject(s)
Adrenal Cortex/metabolism , Hydrocortisone/metabolism , Interleukin-1/pharmacology , Prostaglandins/physiology , Adrenal Cortex/drug effects , Adrenocorticotropic Hormone/pharmacology , Animals , Arachidonic Acid , Arachidonic Acids/metabolism , Cattle , Cell Line , Dinoprost/pharmacology , Dinoprostone/pharmacology , Fibroblasts/metabolism , Indomethacin/pharmacology , Mice , Prostaglandin D2/pharmacology , Recombinant Proteins/pharmacology
12.
Am J Med Genet ; 37(2): 265-7, 1990 Oct.
Article in English | MEDLINE | ID: mdl-2123375

ABSTRACT

A 2.8-year-old girl was investigated for early breast development and delayed psychomotor development. Chromosome analysis showed a fragile site at Xq27. Skeletal maturation was advanced. Computerized tomography of the head was normal. Pelvic ultrasonography showed ovaries and uterus enlarged for age. Basal serum gonadotropins were within the normal prepubertal range, but serum luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels rose during sleep and following stimulation by gonadotropin-releasing hormone (GnRH), consistent with true precocious puberty. The occurrence of precocious puberty in this girl, and macro-orchidism in affected males may be a reflection of an underlying disturbance of hypothalamic-pituitary-gonadal function in fragile X patients.


Subject(s)
Fragile X Syndrome/complications , Puberty, Precocious/complications , Breast/growth & development , Child, Preschool , Female , Follicle Stimulating Hormone/blood , Gonadotropin-Releasing Hormone , Humans , Luteinizing Hormone/blood
13.
Acta Paediatr Scand ; 79(1): 57-63, 1990 Jan.
Article in English | MEDLINE | ID: mdl-2316361

ABSTRACT

We have analyzed the lower leg growth using a knemometer and the height growth using a stadiometer of 90 healthy children aged 3-16 years, for one year. The intra- and inter-individual monthly lower leg growth varied up to 4-fold, which was not accounted for by age or sex. The correlation between short term and annual lower leg growth rates increased with longer observation periods. There was no month-to-month consistency in the ratio of lower leg growth and height growth. There was no correlation between 1 month lower leg growth and annual height growth. The correlation increased with time. The 6-month observation interval was the interval with the highest predictive value for annual lower leg growth (R2 = 0.727) and annual height growth (R2 = 0.732). We conclude that growth of different parts of the skeleton and variable interval growth rates limits the ability of knemometry to predict long term growth.


Subject(s)
Anthropometry/instrumentation , Body Height , Leg/growth & development , Adolescent , Child , Child, Preschool , Female , Humans , Male , Predictive Value of Tests , Time Factors
16.
Hum Genet ; 82(3): 285-6, 1989 Jun.
Article in English | MEDLINE | ID: mdl-2786493

ABSTRACT

During the course of studies to characterize mutations of the CYP17 gene that cause the 17 alpha-hydroxylase-deficient form of congenital adrenal hyperplasia we have discovered two ostensibly unrelated Mennonite families in which affected individuals are homozygous for the same mutation. The defect is a four-base duplication in exon 8 of the CYP17 gene, which alters the reading frame encoding the C-terminal 26 amino acids of cytochrome P450(17 alpha).


Subject(s)
Adrenal Hyperplasia, Congenital , Aldehyde-Lyases/deficiency , Ethnicity , Steroid Hydroxylases/deficiency , Adrenal Hyperplasia, Congenital/enzymology , Adrenal Hyperplasia, Congenital/genetics , Aldehyde-Lyases/genetics , Canada , Cytochrome P-450 Enzyme System/genetics , Exons , Homozygote , Humans , Mutation , Steroid 17-alpha-Hydroxylase/genetics
17.
Hum Biol ; 61(2): 263-9, 1989 Apr.
Article in English | MEDLINE | ID: mdl-2767674

ABSTRACT

Using the Valk knemometer, lower leg length (LLL) was assessed relative to changes in the positioning of the upper leg. Lowering the chair height of the knemometer resulted in a more acute angle between the upper and lower leg and a decrease in LLL. This decrease in measurement was attributed to changes in the anatomical surface of the knee underlying the measuring platform as a result of increasing the acuity of the leg angle. Based on four different leg positions, the average change in LLL per centimeter change in chair height was 0.607 mm in a child sample of 50, and 0.655 mm in an adult sample of 20. The difference in chair height with the leg angle at 90 degrees and the lowest chair height possible, ranged from 12.3 to 30.3 mm, relative to lower leg length. This meant the longest leg in the study had a LLL measurement differing by 19.8 mm between these two positions. Due to the effect of leg position, we advised the use of a standard method of measuring LLL with respect to leg angle. Given the difficulties in accurately measuring leg angle with current available tools, we advise the most acute angle.


Subject(s)
Anthropometry/instrumentation , Human Development , Leg/growth & development , Adolescent , Anthropometry/methods , Child , Humans
18.
J Pediatr ; 114(3): 400-4, 1989 Mar.
Article in English | MEDLINE | ID: mdl-2784166

ABSTRACT

In a retrospective analysis of 24 cases of congenital adrenal hyperplasia (CAH) in neonates born in the province of Manitoba during the last 20 years, we set out to determine whether patients, in particular male infants with salt-losing CAH, were being missed by the usual forms of clinical ascertainment. Although the overall incidence of 1/14,500 live births was similar to that found in several screening surveys, a skewed female/male sex ratio of 2.2:1 suggested probable death among male infants with unrecognized adrenal insufficiency. These results led to a prospective analysis of 17 alpha-hydroxyprogesterone (17-OHP) levels in 1194 neonatal blood specimens by a solid-phase direct radioimmunoassay procedure to determine whether this method would be suitable for CAH screening. In 1103 neonates weighing greater than 2500 gm at birth, all 17-OHP values were less than 30 nmol/L (approximately 1000 ng/dl), with a mean of 8.2 nmol/L; values in male infants were slightly higher than in female infants. In 89 neonates with a birth weight less than 2500 gm, 17-OHP values were skewed, with nine having levels greater than 30 nmol/L and two greater than 50 nmol/L. Postnatal age (1 to 24 days) at the time of specimen collection had no effect on 17-OHP levels, although higher values occur during the first 24 hours. One unsuspected case of CAH in a male infant was discovered during the trial period. We conclude that neonatal CAH screening can permit diagnosis and therapy of affected male infants who are being missed by normal clinical evaluation. This radioimmunoassay method is relatively simple and inexpensive, and it has the specificity and sensitivity necessary to provide such mass screening.


Subject(s)
Adrenal Hyperplasia, Congenital/blood , Hydroxyprogesterones/blood , 17-alpha-Hydroxyprogesterone , Adrenal Hyperplasia, Congenital/epidemiology , Age Factors , Cohort Studies , Female , Humans , Infant, Low Birth Weight , Infant, Newborn , Male , Manitoba , Mass Screening , Prospective Studies , Radioimmunoassay , Retrospective Studies
19.
J Clin Endocrinol Metab ; 68(2): 309-16, 1989 Feb.
Article in English | MEDLINE | ID: mdl-2493025

ABSTRACT

We studied in vivo and in vitro steroidogenesis in six phenotypic female children with 17-hydroxylase deficiency. The diagnosis was suspected as a likely cause of familial low renin hypertension and was confirmed by findings of reduced basal and ACTH-stimulated serum and urinary levels of cortisol and other 17-hydroxysteroids, together with hypergonadotropic hypogonadism in both 46,XY and 46,XX patients, and abnormally increased secretion of 17-desoxysteroids, such as progesterone, 11-deoxycorticosterone, and corticosterone. ACTH stimulation testing demonstrated a lesser degree of 17-hydroxylase deficiency in the obligate heterozygous parents; one father had increased basal serum 17-hydroxyprogesterone values, unresponsive to ACTH, suggesting partial Leydig cell 17,20-desmolase deficiency. In vitro kinetic analysis of testicular microsomal enzymes in the affected 46,XY male pseudohermaphrodites confirmed that both 17-hydroxylase and 17,20-desmolase activities were less than 2% of those in age-matched normal subjects. However, in spite of this virtual absence of both enzymatic activities of cytochrome P450c17, Northern blot analysis demonstrated abundant amounts of RNA in these tests that hybridized to a cDNA specific for this P450 enzyme. Moreover, immunoblot analysis of sodium dodecyl sulfate-polyacrylamide gel electrophoresis-resolved testicular microsomes showed an apparently normal content of an immunoreactive protein with a mol wt similar to that of authentic P450c17. These results suggest that these patients have a point mutation in the gene for P450c17; the mutant gene is transcribed, but gives rise to a protein defective in normal 17-hydroxylase and 17,20-desmolase activities.


Subject(s)
Adrenal Hyperplasia, Congenital , Aldehyde-Lyases/deficiency , Cytochrome P-450 Enzyme System/deficiency , Cytochrome P-450 Enzyme System/metabolism , Steroid Hydroxylases/deficiency , Adult , Aldehyde-Lyases/genetics , Blotting, Northern , Child , Child, Preschool , Cytochrome P-450 Enzyme System/genetics , Female , Genes, MHC Class II , Heterozygote , Humans , In Vitro Techniques , Male , Microsomes/enzymology , Nucleic Acid Hybridization , Pedigree , Steroid 17-alpha-Hydroxylase/genetics , Testis/analysis , Testis/enzymology
20.
Mol Endocrinol ; 2(6): 564-70, 1988 Jun.
Article in English | MEDLINE | ID: mdl-2843762

ABSTRACT

Steroid 17 alpha-hydroxylase (cytochrome P-450 17 alpha) catalyzes both 17 alpha-hydroxylation of pregnenolone and progesterone and 17,20-lysis of 17 alpha-hydroxypregnenolone and 17 alpha-hydroxyprogesterone. In the course of undertaking detailed investigation of the structure-function relationships which exist within this enzyme we have begun to elucidate the molecular basis of human deficiencies in either or both of these activities. Consequently we have determined the exonic structure of the human P-450 17 alpha gene as well as the sequences at the exon/intron boundaries and at the site of initiation of transcription. A single gene in the human genome encodes this protein, being the sole member of a unique gene family (P450XVII) within the P-450 supergene family. A protocol for exonic sequencing of the P-450 17 alpha gene has been established which permits structural analysis of the gene from patients having 17 alpha-hydroxylase and/or 17,20-lyase deficiency. This procedure has been applied to the mutant gene from one individual having combined 17 alpha-hydroxylase/17,20-lyase deficiencies. A four-base duplication is found in exon 8 producing a protein with an altered C-terminal amino acid sequence which results in loss of both enzymatic activities.


Subject(s)
Aldehyde-Lyases/deficiency , Cytochrome P-450 Enzyme System/deficiency , Steroid 17-alpha-Hydroxylase/genetics , Steroid Hydroxylases/genetics , Adrenal Hyperplasia, Congenital , Amino Acid Sequence , Base Sequence , DNA/genetics , DNA Restriction Enzymes , DNA, Recombinant , Exons , Humans , Introns , Molecular Sequence Data , Mutation , Nucleic Acid Hybridization , Structure-Activity Relationship
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