Nonclassical 21-hydroxylase Deficiency Research Articles

21-Hydroxylase Deficiency: Disease-Causing Mutations Categorized by Densitometry of 21-Hydroxylase-Specific Deoxyribonucleic Acid Fragments*

The types of disease-causing mutations were studied in 43 unrelated patients with 21-hydroxylase deficiency. Densitometry of Southern blots after cleavage with the restriction enzymes TaqI, PvuII, and BglII was used to measure the ratio of the copy-number of the 21-hydroxylase gene (CYP21) to the copy-number of its pseudogene (CYP21P). DNA from 16 unrelated patients showed equal hybridization intensities of the 2 genes, indicating that point mutations caused the enzyme deficiency. One of the 2 haplotypes in 7 patients showed evidence of a large gene conversion between the CYP21 and the CYP21P gene without loss of the total number of 21-hydroxylase genes. Deletion of at least 1 21-hydroxylase gene was found in 11 patients. DNA from 8 of these patients had relative hybridization intensities compatible with a deletion of the active 21-hydroxylase gene, CYP21. Two patients with the salt-wasting form of the disease showed homozygous loss of DNA fragments that are specific for the 5' end of the active 21-hydroxylase gene. Nine patients showed relative 21-hydroxylase hybridization intensities compatible with duplication of the gene in 1 or both haplotypes. In conclusion, point mutations, gene conversions, or CYP21 gene deletions are the typical mutations in patients with the simple virilizing and salt-wasting forms of the disease, while duplications of the locus are overrepresented in patients with nonclassical 21-hydroxylase deficiency.

Congenital adrenal hyperplasia family studies using the short ACTH test.

Because of the increasing use of 17-hydroxyprogesterone (17OHP) levels with the short adrenocorticotrophic hormone (ACTH) test in the detection of 21-hydroxylase deficiency, the diagnostic efficiency of the test was evaluated in patient and family studies of congenital adrenal hyperplasia due to 21-hydroxylase deficiency and of congenital adrenal hyperplasia due to 11-hydroxylase (11OH) deficiency (the latter disorder now overlaps basally with the milder non-classical 21-hydroxylase deficiency [NC-CAH]). Stimulated 17-hydroxyprogesterone level (17OHP30), 17-hydroxyprogesterone increase (delta 17 OHP) and the ratio 17-hydroxyprogesterone increase to cortisol increase (delta 17OHP/delta cortisol) were the parameters from the short ACTH test derived for assessment. 17-OHP30 provided complete differentiation of NC-CAH from the controls and heterozygotes, but overlap between NC-CAH and 11-OH occurred. Complete differentiation of NC-CAH from 11-OH was achieved using delta 17OHP. The heterozygotes showed best differentiation from the controls using delta 17OHP/delta cortisol with a diagnostic accuracy of 70%, however marked overlap of heterozygotes and NC-CAH with 11-OH was found. The short ACTH test proved to be a valuable technique with the further detection of homozygotes (n = 3) and heterozygotes (n = 5) in the 13 families studied. However, when interpreting the short ACTH test a careful choice of parameters should be made. It should be kept in mind that mild NC-CAH patients can only be differentiated from 11OH patients by using delta 17OHP.

Absence of Nonclassical Congenital Adrenal Hyperplasia in Patients with Precocious Adrenarche

We studied 31 patients (28 girls and 3 boys), ranging in age from 3.2-7.9 yr, with precocious adrenarche defined by the presence of early sexual hair development, no signs of virilization, and bone age within +3 SD of the mean for chronological age. To determine if this symptom complex stemmed from any form of nonclassical (late-onset) congenital adrenal hyperplasia, an ACTH stimulation test was performed on each patient using a standard 0.25-mg dose of Cortrosyn, given as an iv bolus. Twelve pubertal children (7 girls and 5 boys) and 18 prepubertal children (11 girls and 7 boys) served as normal controls. Baseline and stimulated 17-hydroxypregnenolone (17-OHPreg), 17-hydroxyprogesterone, (17-OHP), 11-deoxycortisol, dehydroepiandrosterone, androstenedione, testosterone, and cortisol levels were measured. Using published nomogram standards for serum 17-OHP response to ACTH, no child with precocious adrenarche was diagnosed as having nonclassical 21-hydroxylase deficiency. Eight girls, however, had a stimulated 17-OHP value that exceeded the mean response for pubertal and prepubertal controls by more than +2 SD [range, 295-670 ng/dL (8.94-20.3 nmol/L)]. Stimulated 11-deoxycortisol values [less than 400 ng/dL (11.6 nmol/L)] ruled out any cases of nonclassical 11 beta-hydroxylase deficiency. No patient had nonclassical 3 beta-hydroxysteroid dehydrogenase deficiency, as defined by both the stimulated 17-OHPreg and the 17-OHPreg/17-OHP ratio to be more than +2 SD above the mean for pubertal children [1354 ng/dL (41.0 nmol/L) and 10.4, respectively]. In conclusion, we could not provide any biochemical evidence for nonclassical congenital adrenal hyperplasia in a large group of children with precocious adrenarche.

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.

Screening for Non-classic 21-Hydroxylase Deficiency in an HLA-B14 Positive Population

MOTTA, P.; AIRAGHI, L.; CATANIA, A.; MANGONE, I.; ORSATTI, A.; TENCONI, L.; CANTALAMESSA, L.; ZANUSSI, C. Author Information

Screening for Non-classic 21-Hydroxylase Deficiency in an HLA-B14 Positive Population

To evaluate whether HLA-B14 positive individuals are at increased risk for non-classic 21-hydroxylase deficiency, the response of progesterone and 17-hydroxyprogesterone to ACTH stimulation test was studied in a group of 27 apparently normal, HLA-B14 positive, blood donors. Four of these subjects showed a response typical of 21-hydroxylase defect. In the present series, the enzymatic defect was found to have a considerably lower prevalence than in a previous study of smaller size (15% vs 66%); however, considering the low frequency of the gene coding for the defect in the general population (0.015-0.057), the present results confirm an increased risk for non-classic 21-hydroxylase deficiency in HLA-B14 positive individuals. Therefore, in these subjects, a screening for 21-hydroxylase deficiency may be indicated.

Defective antigen presentation and novel structural properties of DR1 from an HLA haplotype associated with 21-hydroxylase deficiency.

We have segregated DR1+ individuals into two categories according to whether or not their class II+ cells stimulated T lymphocyte clones specific for or restricted to DR1. In a majority of cases (87%), failure to stimulate was a property of cells having the B14;DR1 haplotype and/or nonclassical 21-hydroxylase deficiency. Absence of clonal proliferation could not be explained by release of an intercellular suppressor factor or by stimulator cell absorption of interleukin 2. Homozygous cells inheriting both stimulatory (DR1n) and nonstimulatory (DR1x) haplotypes did not successfully mediate clonal expansion, implying that a trans acting factor operates intracellularly to modify both DR1 alleles or their products. Other DR alleles did not appear to be affected as evidence by normal proliferative responses of T lymphocyte clones restricted to DR2 or DR7 and stimulated by DR1x,2 and DR1x,7 cells, respectively. By two-dimensional gel analysis, we have further identified a 50-kD surface glycoprotein contained in anti-DR immunoprecipitates of DR1x, but not DR1n or non-DR1 cellular lysates. This 50-kD structure had antigenic and peptide identity to DR alpha and beta chains but was resistant to dissociation under conditions that normally separate DR alpha and beta (8 M urea plus 5% 2-mercaptoethanol); boiling in sodium dodecyl sulfate was required to segregate the component polypeptides of the 50-kD heterodimer. We postulate that a product of a novel combinatorial association between constitutive chains of DR may interfere with or compete for normal T cell receptor recognition of DR1 as both an alloantigen and a restricting element. We further propose that gene abnormalities within the class III region of a haplotype associated with nonclassical 21-hydroxylase deficiency may extend into the DR subregion of the major histocompatibility complex with consequent aberrations in DR1 presentation.

Screening for non-classic 21-hydroxylase deficiency in an HLA-B14 positive population.

To evaluate whether HLA-B14 positive individuals are at increased risk for non-classic 21-hydroxylase deficiency, the response of progesterone and 17-hydroxyprogesterone to ACTH stimulation test was studied in a group of 27 apparently normal, HLA-B14 positive, blood donors. Four of these subjects showed a response typical of 21-hydroxylase defect. In the present series, the enzymatic defect was found to have a considerably lower prevalence than in a previous study of smaller size (15% vs 66%); however, considering the low frequency of the gene coding for the defect in the general population (0.015-0.057), the present results confirm an increased risk for non-classic 21-hydroxylase deficiency in HLA-B14 positive individuals. Therefore, in these subjects, a screening for 21-hydroxylase deficiency may be indicated.

Morning salivary 17-hydroxyprogesterone is a useful screening test for nonclassical 21-hydroxylase deficiency.

A screening test for nonclassical 21-hydroxylase deficiency (NC 21-OHD) has been established based on early morning salivary 17-hydroxyprogesterone (17-OHP) measurements. Saliva and serum samples were collected simultaneously between 0700 and 1100 h from 57 normal subjects (37 women and 20 men) and from 15 untreated patients (6 women and 9 men) with NC 21-OHD. The salivary (mean +/- SD, 524 +/- 508 pg/mL) and serum (10,548 +/- 5,998 pg/mL) 17-OHP concentrations in all 15 patients were unequivocally higher than the levels in normal subjects (saliva, 51 +/- 24 pg/mL; serum, 1,564 +/- 787 pg/mL). Salivary 17-OHP levels in patients with NC 21-OHD were significantly higher at 0700-0900 h (828 +/- 653 pg/mL) than at 0900-1100 h (314 +/- 227 pg/mL), while no such change was found in normal subjects. The salivary 17-OHP concentration was 1.3-6.9% of its serum concentration, and there was an excellent correlation (r = 0.93) between salivary and serum concentration in both normal subjects and patients with NC 21-OHD. In conclusion, early morning salivary 17-OHP measurement is an excellent screening test for the diagnosis of NC 21-OHD, since it accurately reflects serum 17-OHP levels, and sample collection is easy and noninvasive. We propose that salivary 17-OHP determination be used in population screening programs for NC 21-OHD to establish the true frequency of this disease.

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.

Basic and clinical aspects of congenital adrenal hyperplasia

Defective steroid 21-hydroxylation is the most common of the biochemical defects causing hyperplasia of the adrenal cortex. The genetic mode of transmission of all enzyme abnormalities seen in cortisol biosynthesis is autosomal recessive. Steroid 21-hydroxylase deficiency has three currently accepted forms: the simple virilizing and salt-wasting variants of the classical deficiency, and the nonclassical (attenuated) form, which shows a wide clinical range of effects and whose characterization emerged from co-ordinated hormonal testing and family studies. More recent molecular genetic studies have started to identify specific mutations altering 21-hydroxylase activity. Defects in the other enzymes occur more rarely and are less well known, although initial work with abnormal 11β-hydroxylase and 3β-hydroxylase indicates that allelic gene defects may be correlated with different clinical phenotypes seen for these disorders also. The gene for the enzyme steroid 21-hydroxylase, a cytochrome P-450, is situated within the major histocompatibility complex on the p arm of human chromosome 6, proximal to the HLA-B antigen locus. Linkage disequilibria between certain B and DR alleles and classical and nonclassical 21-hydroxylase deficiency permit the use of HLA genotyping in conjunction with hormonal evaluation for diagnosis of this disorder and for identification of carrier haplotypes in population studies. Test programs have shown the feasibility of neonatalscreening for 21-hydroxylase deficiency by blood-spot hormonal assay for elevated 17-hydroxyprogesterone. Prenatal detection of disease currently depends on HLA serotyping of cultured aminocytes jointly with measurement of amniotic 17-hydroxyprogesterone (13–18 week gestation); molecular genetic techniques with more specific nuclear probes will improve the specificity of this test and will in addition permit even earlier definitive fetal genotyping by chorionic villus biopsy (6–10 week gestation).

Antipyrine clearance in congenital adrenal hyperplasia.

Antipyrine (AP) metabolism was studied in four adult patients with congenital adrenal hyperplasia (CAH) due to classical 21-hydroxylase deficiency and in four (adult) patients with CAH due to non-classical 21-hydroxylase deficiency. This investigation was prompted by the known biochemical and functional similarities between drug- and steroid-metabolizing enzymes. We hypothesized that a common genetic mechanism may regulate the expression and activity of both the adrenal and hepatic cytochrome P450 enzymes. AP half-lives (T1/2, mean +/- SD) were 10.7 +/- 2.1 h in classical CAH patients, 10.1 +/- 0.4 h in the nonclassical CAH patients and 10.9 +/- 2.2 h in the control group, suggesting that there was no significant difference in AP metabolism among the three groups. Similarly, no significant differences were found in the AP apparent volume of distribution (aVd) and metabolic clearance rate (MCR) among the three groups. These results indicate that despite the deficiency of adrenal cytochrome P450 in patients with 21-hydroxylase deficiency CAH, these individuals have normal hepatic drug metabolizing activity for the biotransformation of AP.

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.

Late-onset adrenal steroid 3 beta-hydroxysteroid dehydrogenase deficiency. I. A cause of hirsutism in pubertal and postpubertal women.

To investigate the adrenal cause of hyperandrogenism in peri- and postpubertal hirsute women, baseline and ACTH-stimulated serum concentrations of delta 5-17-hydroxypregnenolone (delta 5-17P), dehydroepiandrosterone (DHEA) and its sulfate, 17-hydroxyprogesterone (17-OHP), cortisol, delta 4-androstenedione, and testosterone were determined in 116 women with hirsutism or acne of peri- and postpubertal onset with or without menstrual abnormalities. The results were compared with the same steroid concentrations in 30 normal age-matched women. Sixteen of the 116 women with hirsutism whose ACTH-stimulated 17-OHP levels (mean +/- SD, 5404 +/- 3234 ng/dl; normal, 334 +/- 194) were markedly elevated while their ratios of delta 5-17P to 17-OHP (0.4 +/- 0.2; normal, 3.4 +/- 1.5) were low were diagnosed as having nonclassical symptomatic 21-hydroxylase deficiency. Seventeen other hirsute women, including 3 siblings, had very high responses of delta 5-17P (2276 +/- 669 ng/dl; normal, 985 +/- 327) and DHEA (2787 +/- 386 ng/dl; normal, 1050 +/- 384) to ACTH stimulation, with significantly elevated ratios of delta 5-17P to 17-OHP (11 +/- 2.0; normal, 3.4 +/- 1.5) and DHEA to delta 4-androstenedione (7.5 +/- 2.3; normal, 4.6 +/- 1.5). In these hirsute women, the morning serum delta 5-17P and DHEA concentrations were elevated, had a diurnal variation, and were suppressed with dexamethasone administration. We propose that partial adrenal 3 beta-hydroxysteroid dehydrogenase deficiency is the cause of hirsutism in these women. This may represent an allelic variant at the genetic locus for 3 beta-hydroxysteroid dehydrogenase deficiency similar to that reported for symptomatic nonclassical 21-hydroxylase deficiency producing peripubertal excess androgen syndrome.

PREMATURE ADRENARCHE RESULTING FROM SYMPTOMATIC NONCLASSICAL CONGENITAL ADRENAL HYPERPLASIA

Among 25 patients (19 girls and 6 boys) with premature adrenarche, 8 were diagnosed as having mild, asymptomatic, nonclassical 21-hydroxylase deficiency (21-OH def) based on elevated ACTH stimulated 17-hydroxyprogesterone (17-OHP) and decreased ratio of 17-hydroxypregnenolone (Δ5-17P)/17-OHP; 2 were suspected of having a partial adrenal 3β-hydroxysteroid dehydrogenase deficiency (3β-HSD def) based on high responses of Δ5-17P to ACTH stimulation and elevated ratio of Δ5-17P/17-OHP. Elevated morning Δ5-17P in a 5-year-old girl with 3β-HSD def revealed diurnal variation. In all 7 patients with suspected genetic steroidogenic defects who received dexamethasone (dex), there was prompt suppression of elevated hormone levels. The remaining 15 patients with premature adrenarche did not have abnormalities in steroidogenesis, although some androgen levels were elevated and suppressed with dex, and those were classified as idiopathic. In conclusion, we propose that premature adrenarche with excessive Δ5 and Δ4 steroid production in association with partial steroid enzyme defect is probably due to late-onset, nonclassical congenital adrenal hyperplasia, and this condition is probably more common than has been previously recognized.

ADRENAL SONOGRAPHY AND COMPUTED TOMOGRAPHY IN THE DIAGNOSIS OF CLASSICAL AND NONCLASSICAL 21-HYDROXYLASE DEFICIENCY CONGENITAL ADRENAL HYPERPLASIA

Adrenal sonogram and computed tomography (CT) studies were carried out as a part of the diagnostic workup either for evaluation of the cause of elevated androgen levels or to look for autonomously functioning adenomatous adrenal lesions in patients with proven classical or nonclassical steroid 21-hydroxylase deficiency (21-OH def) congenital adrenal hyperplasia (CAH). Sonograms revealed unequivocally hyperplastic adrenal glands in 2 neonates with female pseudohermaphroditism due to classical CAH and in 1 inadequately treated 9-year-old child with classical CAH.

Recent advances in 21-hydroxylase deficiency.

A deficiency of 21-hydroxylase in the adrenal cortex results in insufficient cortisol production. The salt-wasting form of 21-hydroxylase deficiency is characterized by inadequate aldosterone production, as well. Because the hypothalamic-adrenal negative feedback system is broken, excess adrenal androgens are produced. This disordered corticosteroid production causes hormonal and clinical symptoms, including pseudohermaphroditism in genetic females and disordered puberty in both males and females. There is a spectrum of the time of onset and the severity of these symptoms. This disorder is inherited in an autosomal recessive manner. The 21-hydroxylase deficiency is genetically linked to the human leukocyte antigen (HLA) complex; in addition, nonclassical and classical 21-hydroxylase deficiency have each been shown to be in genetic linkage disequilibrium with specific HLA-B antigens. This genetic linkage, used in conjunction with baseline and stimulated serum hormonal levels, is useful in the diagnosis of this disorder. Prenatal diagnosis of homozygote, heterozygote, and unaffected fetuses is also available. Adequate treatment with glucocorticoid and mineralocorticoid replacement resolves symptoms and enables a normal life.

Late-Onset, Cryptic and Classical 21-OH Deficiency: Allelic Variants

HLA genotyping and hormonal studies in 9 females with non-classical steroid 21-hydroxylase deficiency (AAH) indicate that this disorder is due to an autosomal recessive gene linked to HLA, similar to classical and cryptic 21-hydroxylase deficiency (21-OH def). They had normal genitalia at birth and presented between 9 mos to 16 yrs with varying degrees of virilization. Hormonal studies of the families revealed 2 fathers and their HLA identical sisters with 21-OH def. The remaining parents and the sibs sharing one HLA haplotype with the AAH patient responded to ACTH stimulation as heterozygotes for classical or cryptic 21-OH def. Five sibs who were HLA identical to their affected sib also had findings diagnostic of 21-OH def. The hormonal response to ACTH of the patients with AAH and their HLA identical sibs was similar to that of patients with cryptic 21-OH def. Thus, individuals with these non-classical forms of 21-OH def and similar hormonal findings present with a clinical spectrum ranging from an asymptomatic deficiency to precocious pubic hair, acne, tall stature and advanced bone age, hirsutism, clitoromegaly and menstrual irregularities. The results of these studies support the concept that AAH, similar to classical and cryptic 21-OH def is due to an HLA linked autosomal recessive gene and that these disorders are due to allelic variants at the locus of steroid 21-hydroxylase.