Nonclassical Steroid 21-hydroxylase Deficiency Research Articles

Steroid 21-hydroxylase deficiency, the most frequent cause of congenital adrenal hyperplasia

Congenital adrenal hyperplasia is a group of genetic diseases due to the disablement of 7 genes; one of them is steroid 21-hydroxylase deficiency. The genes of congenital adrenal hyperplasia encode enzymes taking part in the steroidogenesis of adrenal gland. Steroid 21-hydroxylase deficiency is an autosomal recessive disorder caused by mutations of the steroid 21-hydroxylase gene. The mutations of steroid 21-hydroxylase gene cause 95% of the congenital adrenal hyperplasia cases. Although the non-classic steroid 21-hydroxylase deficiency with mild symptoms is seldom diagnosed, the classic steroid 21-hydroxylase deficiency may lead to life-threatening salt-wasting and adrenal crises due to the insufficient aldosterone and cortisol serum levels. The classic type requires life-long steroid replacement which may result in cushingoid side effects, and typical comorbidities may be also developed. The patients' quality of life is decreased, and their mortality is much higher than that of the population without steroid 21-hydroxylase deficiency. The diagnosis, consequences and the patients' life-long clinical care require a multidisciplinary approach: the specialists in pediatrics, internal medicine, endocrinology, laboratory medicine, genetic diagnostics, surgery, obstetrics-gynecology and psychology need to work together. Orv Hetil. 2018; 159(7): 269-277.

Nonclassic Steroid 21-Hydroxylase Deficiency due to a Homozygous V281L Mutation in CYP21A2 Detected by the Neonatal Mass-Screening Program in Japan

Since 1989, neonatal mass screening for congenital adrenal hyperplasia (CAH) has been carried out in Japan. The mass screening has detected not only the patients with the classic form of steroid 21-hydroxylase deficiency (21-OHD), but also those with the nonclassic (NC) form of 21-OHD, and the molecular basis in these patients has been elucidated. However, the homozygous V281L mutation in CYP21A2, the common mutation in the NC form in Caucasians, has not been described in Japanese patients, implying at least two possibilities; 1) the V281L mutation itself might be very rare in Japanese, and 2) nonclassic 21-OHD patients bearing the V281L mutation might be barely detectable by the mass-screening program, hence overlooked in Japan. In the present study, we describe a Brazilian girl with the NC form of 21-OHD, who was pointed out to have mildly elevated 17 alpha-hydroxyprogesterone in blood by the mass screening in Japan. Genetic analysis revealed that the patient was homozygous for the V281L mutation, and that the parents were heterozygous for the V281L mutation. Thus, the NC patients due to the homozygous V281L mutation can be detectable by the mass-screening program for CAH in Japan, and further accumulation and analysis of the NC patients should elucidate the frequency of the V281L allele in Japan.

Genotype-phenotype associations in non-classical steroid 21-hydroxylase deficiency.

To evaluate whether genotype differences can explain the clinical variability of non-classical steroid 21-hydroxylase deficiency (NC21-OHD) and to determine if genotype is related to ethnic origin. Genotyping for mutations in the steroid 21-hydroxylase (CYP21) gene was performed in 45 unrelated Israeli Jewish patients (nine males) with NC21-OHD (60min 17-hydroxyprogesterone (17-OHP), 45-386nmol/l) who were referred for evaluation of postnatal virilization or true precocious/early puberty. Eleven siblings diagnosed through family screening were genotyped as well. Patients were divided by genotype into three groups: (A) homozygous or compound heterozygous for the mild mutations (V281L or P30L) (n=29; eight males); (B) compound heterozygous for one mild and one severe mutation (Q318X, I2 splice, I172N) (n=12; no males); (C) mild mutation detected on one allele only (n=4; one male; peak 17-OHP 58-151nmol/l). We then related the genotype to the ethnic origin, clinical phenotype and hormone level. Since group C was very small, comparisons were made between groups A and B only. At diagnosis, group B tended to be younger (5. 8+/-3.0 vs 8.1+/-4.3 years, P=0.09), had greater height SDS adjusted for mid-parental height SDS (1.6+/-1.1 vs 0.7+/-1.4, P=0.034), tended to have more advanced bone age SDS (2.9+/-1.5 vs 1.7+/-2.1, P=0.10) and had a higher peak 17-OHP level in response to ACTH stimulation (226+/-92 vs 126+/-62nmol/l, P<0.01). Group B also had pubarche and gonadarche at an earlier age (5.1+/-2.4 vs 7.4+/-2.2 years, P<0.01 and 7.4+/-1.8 vs 9.9+/-1.4 years, P<0.001, respectively) and a higher rate of precocious puberty (50 vs 17%, P=0.04). Stepwise logistic regression analysis (excluding males) yielded age at gonadarche as the most significant variable differentiating the two groups, with a positive predictive value of 86% for a cut-off of 7.5 years. The findings suggest that genotype might explain some of the variability in the phenotypic expression of NC21-OHD. Compound heterozygotes for one mild and one severe mutation have a higher peak 17-OHP associated with pubarche and gonadarche at an earlier age and more frequent precocious puberty. Hence, the severity of the enzymatic defect might determine the timing and pattern of puberty.

DEXAMETHASONE TREATMENT OF CONGENITAL ADRENAL HYPERPLASIA IN UTERO: AN EXPERIMENTAL THERAPY OF UNPROVEN SAFETY

Congenital adrenal hyperplasia (CAH) due to steroid 21-hydroxylase deficiency is a common cause of genital virilization in female infants resulting from inappropriate fetal adrenal androgen secretion. Some investigators have advocated treating pregnant women who are at risk for carrying a CAH fetus with dexamethasone to suppress fetal adrenal androgen synthesis. Experience to date shows that this treatment can be effective in ameliorating the genital virilization in female fetuses. However, the doses used are supraphysiological, the mechanism of dexamethasone action in the fetus is unclear and no long-term followup studies have been done. To be effective the treatment would need to be started by week 6 of gestation but the genetic diagnosis cannot be made until week 12. If the mother has had a previous CAH child, only 1 in 4 pregnancies will be affected and only the female fetuses stand to benefit from treatment, thus, 7 of 8 fetuses will be treated needlessly. In view of these and other concerns, the prenatal treatment of CAH remains an experimental therapy and, hence, must only be done with fully informed consent in controlled prospective trials approved by human experimentation committees at centers that see enough of these patients to collect meaningful data.

Mutations of the CYP21 gene in nonclassical steroid 21-hydroxylase deficiency in Japan.

To determine whether nonclassical steroid 21-hydroxylase deficiency in Japan has the same molecular basis as in western countries, we have characterized the mutations of the CYP21 gene in 7 Japanese patients with nonclassical (NC) steroid 21-hydroxylase deficiency. In the Japanese NC cases the P30L was present in one allele in 5 of the 7 patients and on both alleles in one patient. By contrast, the V281L mutation, which was present in about 60% of NC cases in western countries, was not identified in any patient. Among our 7 cases, 4 were detected through neonatal mass screening by a mild increase in serum 17-hydroxyprogesterone (without any symptoms of CAH) at birth, but the 2 cases who were diagnosed as adults were born before nationwide neonatal screening was instituted, so that the Japanese neonatal screening program does detect some cases of NC steroid 21-hydroxylase deficiency. We suggest that P30L mutation is more frequent in Japanese NC CAH than V281L and that the frequency of the mutations causing NC steroid 21-hydroxylase deficiency in Japan might be different from that in western countries.

Molecular Basis of Nonclassical Steroid 21-Hydroxylase Deficiency Detected by Neonatal Mass Screening in Japan

Molecular Basis of Nonclassical Steroid 21-Hydroxylase Deficiency Detected by Neonatal Mass Screening in Japan

Molecular basis of nonclassical steroid 21-hydroxylase deficiency detected by neonatal mass screening in Japan.

Since 1989, neonatal mass screening for congenital adrenal hyperplasia (CAH) has been performed in Japan, and the frequency of the classical form of 21-hydroxylase deficiency was found to be nearly identical to that in other countries. However, it has not yet been determined whether our mass screening program can detect the nonclassical (NC) form. From 1991 to 1994, about 4,500,000 infants underwent CAH mass screening in Japan. During this period, we identified by screening 2 siblings and 2 unrelated patients who had mild elevation of serum 17-hydroxyprogesterone levels at 5 days of age, but who revealed no symptoms of CAH. They were diagnosed as having probable NC steroid 21-hydroxylase deficiency. To clarify the molecular basis of NC CAH detectable by neonatal screening in Japan, the steroid 21-hydroxylase (CYP21) genes from these cases were analyzed. The 2 siblings (patients 1 and 2) had I172N and R356W mutations in 1 allele and in the other allele had local gene conversion, including the P30L mutation in exon 1. Patient 3, who was unrelated, had gene conversion encoding the same P30L mutation in 1 allele and in the other allele had an intron 2 mutation (668-12 A-->G), causing aberrant ribonucleic acid splicing, and the R356W mutation. Patient 4, also a compound heterozygote, had the R356W and 707del8 mutations. The estimated rate of detection of the NC form by mass screening (1:1,100,000) seemed low compare to the established detection rate for the classical form (1:18,000). As all of our 4 patients were compound heterozygotes with at least 1 allele bearing 1 or more mutations associated with classic CAH, it may be difficult to detect NC cases carrying only NC-associated alleles using our current neonatal mass screening methods.

Screening for Non-classic Steroid 21-Hydroxylase Deficiency in Japanese Women with Infertility and/or Hyperandrogenism

To identify patients with nonclassic steroid 21-hydroxylase deficiency, 137 Japanese women who visited our clinics because of infertility and/or hyperandrogenism were tested with adrenocorticotropin (ACTH) stimulation. In women with serum 17α-hydroxyprogesterone (17 OHP) values 60 min after ACTH administration higher than 5 ng/mL, ratios of 17-hydroxypregnanolone (5α) (17OH-PO) (5α) to the sum of tetrahydrocortisone (THE) and tetrahydrocortisol (THF) in 24-hour urine after ACTH-Z administration were determined. None of the women investigated showed any evidence of having the nonclassic form of this deficiency.

Enzyme-Linked Immunosorbent Assay (ELISA) Method for Screening of Non-Classical Steroid 21-Hydroxylase Deficiency

Morning salivary 17-hydroxyprogesterone (17-OHP) determination is a useful method to diagnose non-classical 21-hydroxylase deficiency (NC 21-OHD). In ethnic groups with high frequency of NC 21-OHD, mass screening is thought to be necessary. A pilot screening test for NC 21-OHD was performed by measuring morning salivary 17-OHP by enzyme-linked immunosorbent assay (ELISA). Two individuals were found NC 21-OHD from 230 subjects. Results of this ELISA were well correlated with those of established radioimmunoassay. ELISA can be performed in any laboratory because of non-radioactivity and the procedure is very easy by the use of a microplate. This ELISA is suitable for large scale population studies. We conclude that morning salivary 17-OHP determination by ELISA is a useful method for NC 21-OHD screening test.

Insulin insensitivity in adrenal hyperplasia due to nonclassical steroid 21-hydroxylase deficiency.

To determine whether hyperandrogenism caused by an inborn error of adrenal steroidogenesis could produce insulin resistance, we examined insulin sensitivity in females with 21-hydroxylase deficiency. Minimal modelling was used to analyze the results of tolbutamide-modified, frequently sampled, iv glucose tolerance testing. Insulin sensitivity [Si; (min-1) (microU/mL)-1] was plotted against body mass index (BMI; defined as kilograms per m2). Six patients with nonclassical 21-hydroxylase deficiency (mean age, 27 yr; mean BMI, 23.2) underwent testing. None of these patients was in active puberty, nor was any patient being treated with glucocorticoids at the time of the study. Twelve eumenorrheic nonhyperandrogenic young adult female control subjects (mean age, 27 yr; mean BMI, 22.4) were also tested. The basal 17-hydroxyprogesterone concentration, but not the total serum testosterone level, was significantly different in the two groups (mean +/- SEM, 11,987 +/- 2,761 vs. 4,059 +/- 802 pmol/L; P < 0.05). As a group the patients' Si values were significantly lower than those of the controls (mean +/- SEM, 4.1 +/- 0.6 vs. 9.7 +/- 1.2; P < 0.05). There was no correlation between Si and basal serum 17-hydroxyprogesterone, testosterone, delta 4-androstenedione, or dehydroepiandrosterone. We conclude that chronic hypersecretion of androgen precursors due to an inborn error of metabolism can induce a reduction in insulin sensitivity.

Insulin insensitivity in adrenal hyperplasia due to nonclassical steroid 21-hydroxylase deficiency

Insulin insensitivity in adrenal hyperplasia due to nonclassical steroid 21-hydroxylase deficiency

Pro-453 to Ser mutation in CYP21 is associated with nonclassic steroid 21-hydroxylase deficiency

Pro-453 to Ser mutation in CYP21 is associated with nonclassic steroid 21-hydroxylase deficiency

Pro-453 to Ser mutation in CYP21 is associated with nonclassic steroid 21-hydroxylase deficiency.

Steroid 21-hydroxylase deficiency is the leading cause of impaired cortisol synthesis in congenital adrenal hyperplasia (CAH), with the nonclassic form (NC) comprising approximately 1% of the Caucasian population. The structure of the CYP21 gene was studied in 13 unrelated NC-CAH patients, three affected siblings, and 55 blood donors using polymerase chain reaction. In addition to the Leu-281 and Leu-30 mutations previously associated with NC-CAH, the finding of a Pro-453 to Ser mutation in exon-10 of CYP21 in the NC-CAH patients is reported. Ser-453 was found in 46.2% of unrelated NC-CAH patients, but only 7.7% and 3.6% of salt-wasting CAH patients and blood donors, respectively. In contrast to the Leu-281 and Leu-30 mutations, Ser-453 has not been previously detected in the CYP21 pseudogene (CYP21P) and, therefore, has not likely arisen by gene conversion.

An update on the frequency of nonclassic deficiency of adrenal 21-hydroxylase in the Yugoslav population

Nonclassic steroid 21-hydroxylase deficiency is an attentuated adrenal enzyme defect that is commonly the basis of hyperandrogenic syndromes. Inherited as an autosomal recessive trait, it is known to occur with high frequency in the general population and with increased frequency in a number of ethnic groups, including the Yugoslav population. Following expansion of the original data on 21 families in Croatia to a total of 49 Croatian and Serbian families, we establish that this enzymatic disorder is increased in this Slavic population and provide an updated estimate for the gene frequency of 0.092 (0.035-0.149). Also in keeping with earlier reports, we continue to note the absence of association between nonclassic 21-hydroxylase deficiency occurring among Yugoslavs and HLA-B14; DR1.

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).

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.

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.

Genotype and hormonal phenotype in nonclassical 21-hydroxylase deficiency.

In nonclassical steroid 21-hydroxylase deficiency, the genotype may be represented as a homozygous mild (nonclassical) form of the 21-hydroxylase defect or as a compound heterozygote, with one severe (classical) and one mild (nonclassical) 21-hydroxylase deficiency allele. We examined hormone levels in patients with nonclassical 21-hydroxylase deficiency in whom pedigree analysis and/or HLA linkage disequilibrium allowed unequivocal identification of the respective haplotypes as either classical or nonclassical. The results indicated that compound heterozygotes (21-OH defsevere/21-OH defmild) have an ACTH-stimulated 17-hydroxyprogesterone (17-OHP) response significantly greater than that of mild homozygotes (21-OH defmild/21-OH defmild): at 60 min, 8,131 +/- 4,205 (+/-SD) (n = 17) vs. 4,468 +/- 2,123 ng/dl (n = 31) for the respective groups (P less than or equal to 0.01); at 360 min, 11,067 +/- 5,582 (n = 17) vs. 5746 +/- 1565 (n = 8, P less than or equal to 0.01). Since serum cortisol levels were the same in both groups, the ratio of 17-OHP to cortisol was higher in the former group. Sixty minute ACTH-stimulated serum delta 4-androstenedione levels also were significantly higher in compound heterozygotes than in mild homozygotes. Serum dehydroepiandrosterone and its sulfate were not significantly different between the two groups. Notably, compound heterozygotes were no more likely to have signs of androgen excess than were homozygotes for the mild gene defect. Stimulated levels of serum 17-OHP, 17-OHP/cortisol, delta 4-androstenedione and dehydroepiandrosterone and its sulfate did not differ significantly between heterozygotes for the classical (21-OH defsevere/21-OHnormal) and nonclassical (21-OH defmild/21-OHnormal) 21-hydroxylase deficiency alleles. Thus, the presence of a single normal 21-hydroxylase allele is sufficient to obscure the difference between a severe and a mild 21-hydroxylase deficiency allele on the opposite haplotype. We conclude that the compound heterozygous patients as a group have a significantly higher response of 21-hydroxylase precursors to ACTH stimulation than do patients with the homozygous mild 21-hydroxylase deficiency state.

High Frequency of Nonclassical Steroid 21-Hydroxylase Deficiency

SPEISER, PHYLLIS W.; DUPONT, B O; RUBINSTEIN, PABLO; PIAZZA, ALBERTO; KASTELAN, ANDRIJA; NEW, MARIA I. Author Information

861 THE MOST FREQUENT HUMAN AUTOSOMAL RECESSIVE DISEASE

Nonclassical steroid 21-hydroxylase deficiency (nc21OHD) is an autosomal recessive disease which results in a phenotypically variable syndrome of postnatal hyperandrogenism. Its prevalence is unknown because basal serum 17-OHP levels are not sufficiently elevated for detection with the microfilter paper technique used in screening for classical 21-OHD. We therefore ascertained the frequency of the nc21OHD gene using ethnic group-specific HLA-B-nc21OHD associations in conjunction with ACTH testing in obligate heterozygote parents. Confirmation of this approach was obtained by the affected sib pair method of Thomson and Bodmer. The gene frequency for nc21OHD was highest in Ashkenazi Jews (19.1%) and was also high in Hispanics (13.6%), Yugoslavs (12.5%), and Italians (5.8%). In other Caucasians studied it was 0.1%. Disease frequencies were 1/27 for Ashkenazi Jews, 1/53 for Hispanics, 1/63 for Yugoslavs, 1/333 for Italians, and 1/1000 for other Caucasians. Carriers of the HLA-B14 marker had a 32-fold increased risk of nc21OHD compared to controls. Linkage disequilibrium betweeen HLA-B14 and nc21OHD was significant in Ashkenazi Jewish, Hispanic, and Italian patients, but not in Yugoslavs or other Caucasians.Conclusion: It appears that nc21OHD is the most frequent autosomal recessive genetic disorder in man.