[Antenatal diagnosis and treatment of congenital adrenal hyperplasia due to 21-hydroxylase deficiency].
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Biomedical subjects
Publications and source records attributed to M G Forest.
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A mother at risk for 21-hydroxylase deficiency was treated with oral dexamethasone (0.5 mg 12 hourly) from early pregnancy, in an attempt to prevent in utero virilization in case of a female fetus. Fetal karyotype was 46,XX, and because of a possible intra HLA recombination, treatment was continued to term. The newborn had a modest virilization and hormonal studies confirmed the diagnosis of congenital adrenal hyperplasia (CAH). This observation and review of the literature suggest that efficient prenatal treatment of CAH requires a higher and more frequent dosage of dexamethasone.
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Total cortisol as well as percentage and absolute free cortisol values were determined in 75 full-term, 88 premature and 38 small-for-age (born at term) infants in the first 3 months of life. Equilibrium dialysis and radioimmunoassay were used to estimate the percentage value of the unbound fraction and the value of total cortisol from which absolute free cortisol level was calculated, respectively. A systematic decrease in the free cortisol value was observed in all the three groups of infants during the study period (in full-term infants from 32.3 to 19%, in prematures from 36.6 to 20.8%, and in small-for-age infants from 32.3 to 19.2%). A comparison between the percentage values of free cortisol in the groups studied revealed only slight differences which were not significant. The absolute free cortisol values in full-term infants were highest immediately after birth (4.05 micrograms/dl), then they fell to the lowest level of 0.67 micrograms/dl observed between the third and fifth days of life, and increased afterwards reaching the level of 1.89 micrograms/dl in the third month. The absolute free cortisol values in premature newborns at 3-5 days of life exceeded the values observed in full-term subjects. The pattern of free cortisol in the prematures seems to be 'delayed' as compared with that in full-term newborns. The absolute free cortisol values in small-for-age infants were much more similar to those found in the full-term subjects, than to those in premature babies.
Anti-Müllerian hormone (AMH), also called Müllerian-inhibiting substance or factor was measured by an interspecific enzyme-linked immunoassay in the serum of 218 normal children and adults of both sexes and in 110 boys with various developmental disorders. AMH levels were high [81.67 ng/ml +/- 7.44(SEM)] in normal males under 2 yr of age, fell progressively in older boys and, decreased sharply at puberty. Serum AMH was not detectable in adults or in females at any age, with very rare exceptions. AMH serum concentrations were significantly decreased in infants with disorders of sex differentiation, particularly testicular dysgenesis, and increased in patients with delayed puberty. In contrast, levels were not significantly affected by either cryptorchidism or chorionic gonadotropin stimulation. AMH shows promise as a marker of testicular function in infancy.
A genetic male with 17 alpha-hydroxylase deficiency is described. The patient, raised as a female, was seen at 17 yr of age for impuberism. She presented all the features of the classical severe form of the disease: complete female phenotype; hypertension; hypokalemia; elevated levels of plasma progesterone, 11-deoxycorticosterone, corticosterone (B), and ACTH; and suppression of renin and aldosterone production. Levels of 17-hydroxyprogesterone, 17-hydroxypregnenolone, and all androgens were barely detectable. Hormone steroid patterns were determined in basal conditions and after acute ACTH stimulation in the parents and the two unaffected brothers in order to identify the heterozygotes. Subtle abnormalities in B and aldosterone secretion were observed in the male members of the family. On the basis of an increased ratio of B to aldosterone the two brothers were assumed to be heterozygotes. The mother had normal basal and stimulated levels of B, deoxycorticosterone, and aldosterone. In the parents and two brothers the progesterone responses to ACTH were exaggerated. The most striking finding in the father and both brothers was the observation of increased basal plasma 17-hydroxyprogesterone, unresponsive to ACTH stimulation, suggesting a partial Leydig cell 17,20-lyase deficiency in the male heterozygotes of this family. This study shows that a short ACTH test can help to identify the heterozygotes in affected families, but the abnormalities found are more heterogeneous than previously suggested.
In order to test the hypothesis of a role of thyroid hormones on the circulating levels of sex steroid binding protein (SHBG) in children, SHBG levels were determined in 15 infants with congenital hypothyroidism at diagnosis and during the first 18 months of T4 therapy and in a separate group of 13 children with congenital hypothyroidism (7.1 +/- 0.5 yr, mean +/- SD), treated before 1 month of age, both during adequate L-T4 therapy and 4 weeks after withdrawing therapy. SHBG levels were significantly lower in hypothyroid infants than in controls (48.2 +/- 6.5 vs. 77.8 +/- 7.9 nmol/L; P less than 0.01), and significantly lower in infants with athyreosis compared to those with ectopic or eutopic glands (P less than 0.05). In patients with low values at diagnosis, SHBG increased rapidly and remained normal during LT4 therapy. After 1.5-18 months of treatment, a positive correlation (P less than 0.01) was found between SHBG, FT4, and FT3 levels. In older hypothyroid children, 4 weeks after withdrawal of therapy a significant (P less than 0.05) decrease in SHBG concentrations was observed. Analysis of these results as well as previous reports in adults, indicates that thyroid hormones influence SHBG concentrations in infants and children. This study also indicates that thyroid hormones may play a role in the physiological postnatal increase of SHBG.
A familial form of incomplete androgen insensitivity syndrome (AIS) is reported. The index case was first seen at 9 months of age for ambiguous genitalia. Diagnosis of AIS, suspected but first discarded on the basis of an androgen sensitivity test, was finally made at puberty on the discordance between poor virilization and elevated levels of both testosterone and LH, a florid gynecomastia, and the exclusion of any enzymatic defect in testosterone biosynthesis of 5 alpha-reductase deficiency. Androgen receptors in public skin were within the limits of normal for total number, with normal affinity. Familial occurrence included 2 first cousins born 7 and 10 years later, a maternal grand-uncle with similar ambiguous genitalia, and a maternal uncle with the gynecomastia-preserved fertility syndrome. This case report illustrates the heterogeneity of AIS in a given family and the difficulty of and early positive diagnosis in a newborn presenting with sexual ambiguity.
We have previously reported that anti-Müllerian hormone (AMH), also known as Müllerian-inhibiting substance, the testicular glycoprotein involved in regression of the Müllerian ducts of the male fetus, induces the formation of seminiferous cord-like structures in fetal ovaries exposed to it in organ culture. We have now investigated the effect of bovine AMH, purified to homogeneity, on ovarian endocrine differentiation. Ovine fetal ovaries exposed to AMH release testosterone instead of estradiol, an endocrine sex reversal due to suppression of aromatase activity. AMH dramatically decreases the conversion rate of testosterone to estradiol and also decreases total aromatase activity, as measured by the tritiated water technique. AMH acts by decreasing aromatase biosynthesis rather than by blocking enzyme activity, as suggested by the relatively long period of AMH exposure required to produce an effect. In the rabbit fetal ovary, aromatase activity is AMH-responsive during the whole gestational period. The basal steroidogenic activity of rat fetal ovaries is extremely low but can be markedly increased by cAMP. AMH completely blocks the effect of cAMP. Taken together, our results suggest that AMH plays a pivotal role in both morphological and endocrine gonadal sex differentiation.
A multicentric study of prenatal treatment of congenital adrenal hyperplasia (CAH) resulting from 21-hydroxylase deficiency in 43 pregnancies at risk for CAH is presented. The mothers were given dexamethasone per os, 0.5 mg either 12-hourly or 8-hourly. From the analysis of the results obtained in the present study and review of the literature, it would appear that the first condition for successful prevention of female virilization in utero (a total of 6 cases) is to start treatment as early as possible, no later than the 7th week. The dose of dexamethasone should be related to maternal size: 20 micrograms/kg/day (in 2 or 3 fractioned) doses would seem to be both efficient and safe. Adrenal suppression of both maternal and fetal adrenal function should be controlled by appropriate hormonal determinations. Finally, the advantages of early prenatal diagnosis or no prenatal diagnosis are discussed.
Congenital adrenal hyperplasia (CAH) is caused by disorders of the P450c21B gene, which, with the P450c21A pseudogene, lies in the HLA locus on chromosome 6. The near identity of nucleotide sequences and endonuclease cleavage sites in these A and B loci makes genetic analysis of this disease difficult. We used a genomic DNA probe that detects the P450c21 genes (A pseudogene, 3.2 kb; B gene, 3.7 kb in Taq I digests) and the 3' flanking DNA not detected with cDNA probes (A pseudogene, 2.4 kb; B gene, 2.5 kb) to examine Southern blots of genomic DNA from 68 patients and 165 unaffected family members in 57 families with CAH. Of 116 CAH-bearing chromosomes, 114 could be sorted into five easily distinguished haplotypes based on blots of DNA digested with Taq I and Bgl II. Haplotype I (76 of 116, 65.6%) was indistinguishable from normal and therefore bore very small lesions, presumably point mutations. Haplotype II (4 of 116, 3.4%) and haplotype III (8 of 116, 6.9%) had deletions and duplications of the P450c21A pseudogene but had structurally intact P450c21B genes presumably bearing point mutations; point mutation thus was the genetic defect in 88 of 116 chromosomes (75.9%). Haplotypes IV and V lack the 3.7-kb Taq I band normally associated with the P450c21B gene. Haplotype IV (13 of 116, 11.2%) retains all other bands, indicating that the P450c21B gene has undergone a gene conversion event, so that it is now also associated with a 3.2-kb band. Haplotype V (13 of 116, 11.2%) lacks the 2.4-kb Taq I fragment and the 12-kb Bgl II fragments normally associated with the P450c21A pseudogene, as well as lacking the 3.7-kb Taq I fragment, indicating deletion of approximately 30 kb of DNA, resulting in a single hybrid P450c21A/B gene. Most (114 of 116, 98%) CAH alleles thus can easily be classified with this new probing strategy, eliminating many ambiguities resulting from probing with cDNA.
Congenital adrenal hyperplasia (CAH) can be caused by a variety of defects in the functional gene encoding 21-hydroxylase (P450c21), which lies in the midst of the human leukocyte antigen (HLA) locus on chromosome 6. As a result, Mendelian genetics permit clinically distinct forms of CAH to be traced genetically by HLA and complement typing of family members. The recent cloning of probes for P450c21 now permits tracing of the affected gene directly. A consanguineous family had three members affected with three clinically distinct forms of CAH. Two of these individuals had identical extended haplotypes, including nine HLA and complement loci. Despite this extensive identity, the patterns of genomic DNA fragments digested with endonuclease EcoRI and detected by a P450c21 cDNA probe differed greatly in these two individuals. Thus, the DNA diagnosis of allelic variation was much more sensitive than the HLA diagnosis. Genomic DNA digested with endonuclease TaqI and probed with P450c21 cDNA revealed the 3.2-kilobase (kb) band, which is generally associated with the nonfunctional P450c21 A pseudogene, in all family members, and also revealed the 3.7-kb band associated with the functional P450c21 B gene in all family members except the severely affected index case. Probing of the same blots with a genomic probe also permitted examination of the adjacent downstream TaqI fragments, showing retention of both the 2.4-kb (A pseudogene) and 2.5-kb (B gene) fragments. Similarly, BglII-digested genomic DNA from all individuals contained both the 12-kb (A pseudogene) and 11-kb (B gene) bands. These data indicate that the basis of 21-hydroxylase deficiency in the index case was due to a homozygous gene conversion event and not to gene deletion. These results show that the DNA in and around the 21-hydroxylase gene is genetically very active, so that the usual generalization concerning linkage and inheritance may yield incorrect conclusions and diagnoses.
In a sepharad family from Morocco, 2 children out of 4 had congenital adrenal hyperplasia with 11 beta-hydroxylase deficiency. The index case had a very severe genital masculinization (Prader V), diagnosed at 18 months of age. For the fourth pregnancy, dexamethasone was given from the 8th to the 24th week of amenorrhea, in order to prevent the virilization of a female fetus. The treatment was interrupted for 5 days, at the 20th week, because of amniocentesis. As the amniotic steroid concentrations were normal, the treatment was stopped. Nevertheless the neonate also has severe virilization of the external genitalia and postnatal hormonal studies confirmed the diagnosis of congenital adrenal hyperplasia due to 11 beta-hydroxylase deficiency. The reasons for the failure of the treatment are analyzed.
In 13 and 14-day old fetal rat ovaries maintained 3 to 10 days in organ culture, purified bovine anti-Müllerian hormone (AMH) (1.5 to 3 micrograms/ml) induced a characteristic freemartin effect. Gonadal volume and germ cell number were significantly reduced, compared to control ovaries cultured in anhormonal medium, and epithelial cells with large clear cytoplasm linked by interdigitations differentiated in the gonadal blastema. These cells resembling rat fetal Sertoli cells became polarized and formed seminiferous cord-like structures delineated by a basal membrane containing laminin and fibronectin as is the case of testicular seminiferous cords at the first step of their differentiation. These data indicate that AMH is probably the testicular factor responsible for the morphological modifications of bovine freemartin gonads and suggest that this hormone could also be involved in normal morphological differentiation of the testis. In contrast, in fetal rat ovaries, AMH did not trigger the testosterone production which occurs in freemartin gonads at an early stage of the gestation.
This presentation reports the effects of androgens, glucocorticoids and some pituitary hormones on plasma sex steroid-binding protein (SBP). The latter was measured by a solid phase method after desteroidation of the plasma. An hCG test (1500 I.U. every other day X 7) was given to 60 boys. In the children with a normal testosterone (T) rise, plasma SBP decreased (% of basal values) either significantly (38.3 +/- 9.3%, group A; n = 29), or moderately (13.4 +/- 4.4%, group B; n = 9) or did not change (-1.6 +/- 6.4%, group C; n = 10). In the 3 infants tested at an age when SBP normally rise sharply, hCG partially prevented this rise. The administration of either fluoxymesterone (10 mg/m2 for 10 days) or depot-T (4 I.M. injections of 100 mg/m2 every 2 weeks) induced a significant drop (about 2-fold) in plasma SBP in a control group of infants or children, but did not change SBP in 3 infants with the androgen insensitivity syndrome. A single injection of 0.25 mg of ACTH did not significantly alter SBP levels. In contrast, at the end of a 3-day ACTH test (0.5 mg/m2 12 hourly X 6) SBP levels had significantly decreased (mean 35% fall) with no age or sex differences, and with no correlation with the cortisol levels reached. However, the lowering effect of ACTH on SBP levels is likely mediated by glucocorticoids, since its effect was reproduced by high doses (8 mg/day for 3 days) of dexamethasone given at once or after 3 days of treatment at lower dose (20 micrograms/kg BW). It would appear that the depressive effect of ACTH and/or dexamethasone is observed for a threshold dose of glucocorticoids (greater than 5-fold physiological levels) and a certain time (greater than or equal to 3 days) of exposure. The mechanism by which androgens and glucocorticoids lower SBP levels in vivo is not yet understood. From recent experiments, showing that both stimulate the secretion of SBP in hepatoma cells in vitro, it would appear that both hormones may alter SBP metabolism. In a selected population of hyperprolactinemic women, with normal weight and no hirsutism, plasma SBP levels were found in the normal female range. The discrepancy with previous studies in the literature may be explained by differences in the degree of hyperprolactinemia and/or associated hyperandrogenim. This study further documents the multifactorial and intricated hormonal influences involved in the regulation of plasma SBP in vivo.
In humans, sex steroid-binding protein (SBP) is a protein from the liver which binds with high affinity sex steroid hormones. The plasma concentration of SBP is regulated in part by hormonal factors. It has been shown that estrogens and/or thyroid hormones increase the production of SBP by hepatoma cell lines. It is therefore assumed that the increase in SBP levels in patients given oral estrogens or thyroid hormones is the consequence of a direct stimulation of the liver production of SBP by these hormones. The effects of androgen, progestagen and glucocorticoid hormones are unclear or still a matter of controversy. Moreover, the regulation of the metabolic clearance rate of SBP and the influence of nonhormonal factors on the production of SBP are still speculative. Changes in SBP have been described in a few nonendocrine diseases. A slight hormonal dysfunction may be either the primary or the sole cause of the changes in SBP occurring in these diseases. As an example, elevated SBP levels have been reported in men with liver cirrhosis together with testicular hypofunction and increased estrogen levels. It is therefore difficult to demonstrate that the increase in SBP is due to the liver dysfunction rather than to the endocrinological side effects of cirrhosis. The aim of this review is to present some aspects of the nonhormonal regulation of SBP. There is accumulating evidence in the literature for a relation between SBP levels and body weight and fat distribution, energy balance, diet and physical activity, and lipid metabolism. Therefore, it is tempting to propose that SBP is an index which reflects the status of endocrine, metabolic and nutritional functions. Measurement of SBP may be considered of interest in the light of previous epidemiological studies and the preventive approach to diseases such as hormone dependent tumors, cardiovascular diseases and osteoporosis.
A randomized study of two protocols of human chorionic gonadotropin (hCG) treatment was performed in 183 prepubertal boys between 7 months and 12 years of age: protocol I, in which the boys were given 7 injections of 1,500 IU every other day, and protocol II consisting of 4 injections of 100 IU/kg at 4- to 5-day intervals. In both protocols, by the end of the test, testosterone had risen significantly to values within the normal adult male range. However, the amplitude of the rise was slightly but significantly lower using protocol II (4.08 +/- 2.07 ng/ml) than protocol I (5.16 +/- 2.73 ng/ml). It would thus appear that repetition of the hCG injection at intervals of less than 4 days is unnecessary, and that a total stimulation period of 2-3 weeks is sufficient. Although not correlated with testosterone levels, the success rates for treatment were similar in both protocols and comparable to rates reported in the literature.
Whether GnRH agonist treatment leads to reduced gonadotropin secretion and tumor volume in patients with gonadotropin-secreting pituitary adenomas is controversial. We studied the effect of GnRH analog treatment in two such patients, one with a recurrent FSH- and LH-secreting pituitary adenoma (patient 1) and one with a recurrent FSH- and alpha-subunit-secreting pituitary adenoma (patient 2). Patient 1 was treated with 200 micrograms Buserelin daily for 65 days, and patient 2 received three injections of 3 mg [D-Trp6]-LHRH formulated in microcapsules at 21-day intervals. In both patients, plasma FSH, LH (RIA), and alpha-subunit concentrations increased initially and remained above the pretreatment values throughout the treatment period. Plasma LH, measured by immunoradiometric assay, remained well above the detection limit. Plasma bioactive LH and testosterone became undetectable in patient 2, but did not change in patient 1. In neither patient did pituitary tumor size (determined by computed tomographic scan) change during treatment. We conclude that 1) the overall effect of GnRH analogs in patients with gonadotroph cell adenomas is stimulation of gonadotropin release by the tumor, although LH release varies according to how plasma LH is measured, possibly related to the origin of the hormone (normal or tumor gonadotroph cells), and 2) GnRH analog treatment does not reduce tumor size.