Early diagnosis of congenital adrenal hyperplasia by measurement of 17-hydroxyprogesterone

Steroid 21-hydroxylase deficiency in congenital adrenal hyperplasia

Congenital adrenal hyperplasia (CAH) refers to a group of inherited genetic disorders involving deficiencies in enzymes that convert cholesterol to cortisol within the adrenal cortex. There are five key enzymes involved in the production of cortisol. Of these key enzymes, deficiency of 21-hydroxylase is the most commonly defective enzyme leading to CAH representing more than 90% of cases. The low adrenal cortisol levels associated with CAH affects the hypothalamic-pituitary-adrenal negative feedback system leading to increased pituitary adrenocorticotropic hormone (ACTH) production, which overstimulates the adrenal cortex in an attempt to increase cortisol production resulting in a hyperplastic adrenal cortex. The deficiency of enzyme 21-hydroxylase results from mutations or deletions in the CYP21A2 gene found on chromosome 6p. The disorder is transmitted as an autosomal recessive pattern and specific mutations may be correlated to enzymatic compromise of varying degrees, leading to the clinical manifestation of 21-hydroxylase deficiency (21-OHD) CAH.

Serum 17alpha-hydroxyprogesterone concentrations during the reproductive cycle in healthy dogs and dogs with hyperadrenocorticism

OBJECTIVE

To determine concentrations of 17alpha-hydroxyprogesterone (17OHP) in serum of healthy bitches during various stages of the reproductive cycle and in bitches with hyperadrenocorticism and to compare the dynamics of 17OHP with those of progesterone.

DESIGN

Prospective evaluation study.

ANIMALS

15 healthy sexually intact bitches and 28 spayed bitches with hyperadrenocorticism.

PROCEDURES

11 healthy bitches were evaluated during estrus, nonpregnant diestrus, and anestrus (group 1); 4 other healthy bitches were evaluated during pregnancy and after ovariohysterectomy (group 2). Cycle stages were determined via physical examination, vaginal cytologic evaluation, and serum progesterone concentration. Bitches with hyperadrenocorticism were evaluated once at the time of diagnosis (group 3). Serum hormone concentrations were determined with immunoassays.

RESULTS

In group 1, the serum 17OHP concentration was significantly higher in diestrus (median, 1.8 ng/mL) than in estrus (median, 1.1 ng/mL) and anestrus (median, 0.2 ng/mL) and higher in estrus than in anestrus. Changes in serum progesterone concentrations accounted for 22% (estrus) or 23% (diestrus) of the variation in serum 17OHP concentrations. In group 2, 17OHP and progesterone concentrations were significantly higher during pregnancy than after ovariohysterectomy. The serum 17OHP concentration in group 3 was significantly lower (median, 0.2 ng/mL) than in group 1 in estrus and diestrus and in group 2 during pregnancy (median, 0.7 ng/mL) but was not different from 17OHP concentrations in anestrus or after ovariohysterectomy (median, 0.2 ng/mL).

CONCLUSIONS AND CLINICAL RELEVANCE

Serum 17OHP concentrations in healthy bitches increased during estrus, diestrus, and pregnancy and at those times were higher than in spayed bitches with hyperadrenocorticism.

Congenital adrenal hyperplasia

Cogenital adrenal hyperplasia (CAH) is a family of genetic disorders from a deleterious mutation in a gene encoding adrenal steroidogenic enzyme essential for cortisol biosynthesis. Recent molecular advances have provided the genetic basis for the phenotypic variability in CAH, a means for accurately genotyping family members of CAH patients including prenatal prediction of the genotype in fetuses at risk of the disorder, and have helped to better define the hormonal criteria for the varying spectrum of CAH disorders. Biochemical advances have simultaneously aided the diagnosis and therapeutic monitoring of CAH patients. Prenatal maternal dexamethasone therapy for fetal CAH prevents or minimizes virilizing sequelae in the majority of prenatally treated affected females, but was associated with significant maternal side effects. Newborn screening for CAH has contributed to the prevention of morbidity of delayed diagnosis of CAH in more than two third of affected neonates. Current treatment methods, however, may not be optimal for achieving normal genetic height and appropriate weight in CAH patients, and more effective approaches to CAH therapy remain to be explored.

Value of selective screening for congenital adrenal hyperplasia in Hungary

Measurement of the 17-hydroxyprogesterone concentration in blood spots was used to identify cases of congenital adrenal hyperplasia among patients with inappropriate virilisation, or salt wasting, or both. Between 1978 and 1986 61 were identified among 707 patients (278 neonates, 204 infants, and 225 children). The incidence of classic congenital adrenal hyperplasia was calculated for a seven year prospective trial period using the blood spot 17-hydroxyprogesterone method in selective screening. There were 38 salt losers and 14 simple virilisers in 968,303 live births, an incidence of congenital adrenal hyperplasia of 1:18,000 in the Hungarian population. Selective screening led to earlier diagnosis of congenital adrenal hyperplasia and a pronounced decrease in mortality. A central laboratory to measure the blood spot 17-hydroxyprogesterone concentrations is valuable for the investigation of patients at risk for congenital adrenal hyperplasia in countries where blood steroid assays are not readily available.

Development of a direct [125I]radioimmunoassay for serum levels of 17-hydroxyprogesterone

We describe a direct, rapid, sensitive and highly specific radioimmunoassay for determining serum levels of 17-hydroxyprogesterone. It is based on the use of highly specific sheep antiserum, 125I-labelled tracer, dextran-coated charcoal to separate the antibody bound and free fractions, and sodium salicylate to eliminate interference from endogenous binding proteins in serum. Intra- and interassay coefficients of variation are less than 8% and recovery is satisfactory. Sensitivity is 3.5 fmol per assay tube (0.14 nmol/l). Results correlate closely with those of an established technique using 3H-labelled steroid after initial solvent extraction and column chromatography of samples (y = 1.02x - 0.16; r = 0.998). The values found for serum from normal adult subjects ranged from 1.0 to 12.1 nmol/l while those from treated and untreated patients with congenital adrenal hyperplasia due to 21-hydroxylase deficiency were 1.4-18.4 and 27.3-650 nmol/l, respectively.

Comparison of separation techniques in radioimmunoassays for 17-hydroxyprogesterone

Separation techniques have been studied in the development of a direct radioimmunoassay to determine levels of 17-hydroxyprogesterone in serum. The same highly specific sheep antiserum was used throughout, together with the same amount of 125I-labelled 17-hydroxyprogesterone to which was added sodium salicylate to eliminate interference by endogenous binding proteins in serum samples. In one approach, dextran-coated charcoal was employed to adsorb the free fraction and, in another, the antibodies were covalently coupled to magnetisable particles. The antiserum was also adsorbed to assay tubes either directly or indirectly through second (double) antibodies. Analytical recovery and specificity were similar irrespective of the separation technique as was the correlation with results obtained by a reference assay. Levels of 17-hydroxyprogesterone in sera from normal adults and from treated and untreated patients with congenital adrenal hyperplasia due to 21-hydroxylase deficiency were also similar. However, the assay employing dextran-coated charcoal for separation showed the best precision and resulted in the greatest sensitivity, while the use of antibodies adsorbed indirectly to assay tubes was superior in terms of practicability.

Development of a direct fluoroimmunoassay for serum levels of 17-hydroxyprogesterone

A direct, rapid and highly specific fluoroimmunoassay for determining serum levels of 17-hydroxyprogesterone has been developed. It is based on the use of a sheep antiserum covalently coupled to magnetisable particles and fluorescein-labelled steroid. Sodium salicylate is employed to eliminate interference from endogenous binding proteins in serum. The sensitivity of 0.5 nmol/L is adequate for clinical purposes. Analytical recovery, linearity and precision are satisfactory and the results obtained correlate closely with those of an established radioimmuno-assay using 3H-labelled steroid and the same antiserum after initial sample extraction and chromatography. The values found for serum from normal adult subjects ranged from 1.0 to 12.6 nmol/L while those from treated and untreated patients with congenital adrenal hyperplasia due to 21-hydroxylase deficiency were 1.5 to 19.0 and 28.0 to 655 nmol/L, respectively.

Prenatal diagnosis of congenital adrenal hyperplasia: reliability of amniotic fluid steroid analysis

The concentration of 170H-progesterone was measured in amniotic fluid samples collected from 55 mothers who had previously had a child with congenital adrenal hyperplasia due to 21-hydroxylase deficiency. In eight pregnancies the levels of 170H-progesterone were raised; the parents elected to terminate in four and examinations of the fetus confirmed the diagnosis of congenital adrenal hyperplasia. In each case, the affected sib was a salt loser. The remaining four affected pregnancies proceeded to term and each infant had salt losing 21-hydroxylase deficiency. All 47 infants predicted to be unaffected were normal at birth. However, an increased plasma concentration of 170H-progesterone was documented in a male non-salt loser at three months of age. Prenatal diagnosis of congenital adrenal hyperplasia by amniotic fluid steroid analysis is reliable only for the salt losing variant of 21-hydroxylase deficiency. Of the affected sibs in this study, 20% died during infancy in a salt losing crisis. This simple and rapid prenatal test is sufficiently reliable to predict the group of infants most at risk in early infancy.

Radioimmunoassay of blood-spot 17 alpha-hydroxyprogesterone in the management of congenital adrenal hyperplasia

A robust assay for routine measurement of blood-spot 17 alpha-hydroxyprogesterone (17-OHP) concentrations has been developed using a magnetizable, solid-phase antiserum and an 125I-radioligand. The working range of this assay (13.5-500 nmol/L) is well suited for the initial diagnosis of congenital adrenal hyperplasia (CAH) and for monitoring replacement therapy in CAH patients. Data derived from multiple blood-spot samples, collected on two consecutive days, provide 17-OHP profiles. These profiles have been used to construct a chart allowing a rapid visual assessment of the efficacy of replacement therapy in CAH patients. Measurement of 17-OHP in the blood-spots of overtreated patients and accurate determination of normal range values in healthy infants relied on development of a sensitive assay (range 1.7-34 nmol/L). In the blood-spots of normal male (n = 50) and female (n = 50) infants collected 5-7 days after birth, 17-OHP concentrations were 7.62 +/- 2.55 nmol/L and 7.32 +/- 2.87 nmol/L respectively. Retrospective measurement of this steroid in samples from known CAH patients (n = 4), which had values ranging from 224 to 2145 nmol/L, support a role for measurement of blood-spot 17-OHP in high-risk screening programmes.

Response to ACTH in the newborn

Adrenocortical function was studied in 52 newborn infants who had been divided into three groups: preterm well, preterm ill, and term ill. Basal plasma 17-hydroxyprogesterone concentrations were significantly increased in both groups of preterm infants. There was no significant difference in basal plasma cortisol concentrations, although they were highest in preterm ill infants. All infants responded to adrenocorticotrophic hormone (ACTH) stimulation (36 micrograms/kg intramuscularly) with a two to three fold increase in the concentration of both steroids. The peak plasma 17-hydroxyprogesterone response was significantly higher in preterm ill infants. A subgroup of five infants, who were highly stressed but had undetectable basal plasma cortisol concentrations, also showed an appropriate response to ACTH. The results provide useful reference data to assess adrenal function in the infant of a mother given glucocorticoids during pregnancy. There is also a change from the pattern of fetal adrenal steroidogenesis soon after birth, which may be affected by exogenous ACTH stimulation. Roughly 10% of stressed newborns failed to synthesise cortisol basally; temporary glucocorticoid replacement for such infants may be appropriate.

Clinical aspects of congenital adrenal hyperplasia: early diagnosis and prognosis

The neonatal presentation of congenital adrenal hyperplasia is either virilization of females or salt loss in both sexes. Early diagnosis is based on the rapid measurement of plasma 17 alpha-hydroxyprogesterone. Milder forms of congenital adrenal hyperplasia can present later in life with abnormalities of somatic or sexual development. The majority of cases of congenital adrenal hyperplasia are clinically diagnosable in the first 2-3 weeks of life: the need for screening for the remaining missed cases and the late onset types remains to be established.

Possible abnormalities of steroid secretion in children with Smith-Lemli-Opitz syndrome and their parents

In early infancy, two unrelated children with Smith-Lemli-Opitz syndrome were found to have elevated levels of androgen sulfates. When the steroid conjugates in the serum of normal infants were hydrolyzed and chromatographed on Sephadex LH-20, 4 androgen containing peaks (I, II, III, IV) were found. In the serum from these two infants with Smith-Lemli-Opitz syndrome, Peaks I and III were increased, but Peaks II and IV were absent. The parents of the two children, and of three additional unrelated children with Smith-Lemli-Opitz syndrome, had exaggerated 17-hydroxyprogesterone responses to an intravenous bolus of ACTH. These findings suggest that a defect in steroid metabolism may be linked to the Smith-Lemli-Opitz syndrome.

A rapid assay for 17 alpha OH-progesterone in plasma, saliva and amniotic fluid using a magnetisable solid-phase antiserum

A radioimmunoassay suitable for measurement of 17 alpha OH-progesterone concentrations in small aliquots of plasma (20 microL), amniotic fluid (20 microL) and saliva (200 microL) is described. The assay features an antiserum raised against a 17 alpha OH-progesterone-3-(O-carboxymethyl)oxime/BSA conjugate coupled to a magnetisable, solid-phase support; the homologous radioligand is a 125I-iodohistamine conjugate. This combination of a gamma-emitting ligand and a magnetic-separation procedure has the advantage of reducing assay time and cost; it also allows processing of plasma and saliva samples in the same assay batch. The method has satisfactory sensitivity, precision and accuracy. Data derived from clinical studies of patients with congenital adrenal hyperplasia indicate the usefulness of this assay in routine practice.

Plasma 17-hydroxyprogesterone concentrations in ill newborn infants

Plasma 17-hydroxyprogesterone concentrations were determined in 47 preterm and term infants who were ill from a variety of causes. The results were compared with those in 53 healthy term infants. Mean plasma 17-hydroxyprogesterone values were appreciably higher in ill term and healthy preterm infants compared with healthy term infants, but the highest values were found in ill preterm infants. None of the infants had adrenal disease but some very ill infants had plasma 17-hydroxyprogesterone values approaching those seen in untreated infants with congenital adrenal hyperplasia. Interpretation of the results of plasma steroid measurements in newborn infants must take account of gestational age and the presence of stress related illness.

Increased urinary excretion of total 16 alpha-hydroxypregnenolone in newborn infants with congenital adrenal hyperplasia due to 21-hydroxylase deficiency

Urinary excretion of total 16 alpha-hydroxypregnenolone (16 alpha-OH-P'O), pregnanetriol (PT), and 11-oxopregnanetriol (11-O-PT) were determined by capillary gas chromatography in 32 healthy neonates and three newborn infants with congenital adrenal hyperplasia (CAH) during the first 4 weeks of life. In the 2nd and 3rd week of life, only the 16 alpha-OH-P'O excretion was pathognomonically elevated in infants with 21-hydroxylase deficiency. The values amounted to 1023, 1611 (age 1--2 weeks), and 2955 micrograms/day (3 weeks of life) compared to much lower levels in healthy peers (2nd week: mean 243, range 0--520 micrograms/day; 3rd week; mean 515, range 66--1541 micrograms/day).

Neonatal screening for 21-hydroxylase deficiency: a microfilter paper method for 17-alpha-hydroxyprogesterone assay

A micromethod for measuring 17 alpha-hydroxyprogesterone in blood collected on filter paper has been developed. Our method is rapid, easy and has the specificity, accuracy and precision of the radioimmunoassay in whole blood. The method has been applied for screening patients with congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency. Fifty samples collected on filter paper were assayed by our method, using 125I as tracer, and results were compared with those obtained for the same samples using a tritium tracer. The agreement between the two methods was particularly good in the area ranging from 15 to 100 pg/disc. In one neonate the diagnosis of CAH was made utilizing the microfilter paper method. Our method is a promising screening test for CAH. An indication of the advantages or disadvantages of this type of screening will become available when an adequate number of infants has been examined.

"Dot-17 alpha-hydroxyprogesterone" radioimmunoassay for identification of congenital adrenal hyperplasia in young infants

Using a simplified radioimmunoassay method for the determination of 17-hydroxyprogesterone (17-OHP) concentration in blood dried on filter paper seven untreated cases of congenital adrenal hyperplasia were identified among newborns and infants at risk for congenital adrenal hyperplasia (CAH) having ambiguous genitalia and/or failure to thrive with electrolyte disturbances. In three additional cases the diagnosis of congenital adrenal hyperplasia was confirmed by high 'dot-17-OHP' values even after glucocorticoid therapy had been started. Capillary blood samples taken in a local hospital on a filter paper routinely used for the screening of phenylketonuria can be sent by mail into a central laboratory for performing the analysis. Assays of 'dot-17-OHP' are clearly of diagnostic value in the C21-hydroxylase form of CAH and permit a rapid diagnosis of this condition in the newborn period.

7 alpha- and 7 beta-carboxymethyl-derivatives of 17-hydroxyprogesterone and 11-deoxycortisol. Synthesis and immunogenic properties

7 alpha- and 7 beta-carboxymethyl-derivatives of 17-hydroxyprogesterone and 11-deoxycortisol have been synthesized. After coupling to bovine serum albumin, they were used to elicit antibodies in rabbits. No major difference in the steroid specificity of the antisera was observed when either 7 alpha- or 7 beta-epimers were used for immunization. In both cases, highly specific antisera were obtained which may possibly be used to assay human plasma 17-hydroxyprogesterone and 11-deoxycortisol without chromatographic purification.

Plasma 17OH-progesterone concentrations in newborn infants

Plasma concentrations of 17OH-progesterone were determined in 60 normal newborn infants aged between 3 and 36 hours. Mean levels decreased rapidly during this time after removal of the placental contribution of this steroid. A further 70 normal infants, studied between ages 2 and 7 days, showed a mean plasma 17OH-progesterone concentration of 3.5 nmol/1 (1.2 ng/ml). By comparison, plasma concentrations in untreated infants with congenital adrenal hyperplasia were markedly raised. At 36 hours of age, there was an obvious difference between plasma levels of this steroid in normal and affected infants. Determination of plasma 17OH-progesterone concentrations are valuable in the evaluation of disorders of sexual differentiation and electrolyte balance in newborn infants, provided due care is given to the timing of sample collections.

17-Hydroxyprogesterone in normal children and congenital adrenal hyperplasia. Measurement in serum by radioimmunoassay after thin-layer chromatography

Serum 17alpha-hydroxyprogesterone (17 OH-P) was measured by a specific radioimmunoassay technique combined with thin-layer chromatography. Normal values for children are less than 1.1 microgram/1 (less than 3.3 nmol/l)--corresponding to values found in the literature. In congenital adrenal hyperplasia (CAH) values up to several hundred microgram/l are found. The values rise after ACTH stimulation and are suppressed by decadrone or cortisone treatment. The rise in 17 ketosteroids and pregnanetriol in untreated CAH is relatively smaller (15--25 fold). This clinical sensitivity of 17 OH-P is thus valuable for the diagnosis of CAH (21 hydroxylase deficiency). Furthermore it is easier to take a blood sample than to collect urine for 24 hours. The usefulness in therapeutic monitoring is being studied.

A method for identification and follow-up of patients with a steroid-21-hydroxylase deficiency

A method is described for the determination of 17 alpha-hydroxyprogesterone from blood samples obtained by heel prick and dried on filter paper. Discs (10 mm diameter) were cut from the filter paper and extracted in the assay tubes with 1 ml of a methanol/diethyl ether/ethyl acetate (50 :45 :5, v/v) solvent mixture. Antibody, tritium-labelled tracer and dextran-coated charcoal were added to assay tubes using a multichannel dispenser. The approach used permits one technician to analyze two series, each of 60 duplicate samples, within one working day. Thus the method is applicable for the centralized screening of suspected cases, while emergency samples may be analyzed at the same time within 4 h. Comparisons with a highly specific but more elaborate technique for the determination of blood 17 alpha-hydroxyprogesterone showed a correlation coefficient of 0.99, and the regression equation for the present method (y) against the established method (x) was y = 1.07x + 2.72. The calculated upper reference limit (mean +/- S.D.) for 17 alpha-hydroxyprogesterone in healthy infants from two days to eight years of age of 7.5 ng/ml of serum.

Effect of cortisol treatment on hormonal relationships in congenital adrenal hyperplasia

The temporal relationship between administration of cortisol and serum 17alpha-hydroxyprogesterone was investigated in five patients aged 9-19 years with congenital adrenal hyperplasia due to 21-hydroxylase deficiency. There was marked variability in the 17alpha-hydroxyprogesterone response (determined hourly for 24 h) of individual patients to administration of cortisol. Mean concentration was less than 0.030 micronmol/l in one patient but 0.519 micronmol/l in another. Levels were higher in all patients while off treatment, and were greatest in those with salt-losing adrenal hyperplasia. Growth hormone secretion was not suppressed by treatment with cortisol. Withdrawal of cortisol for 3 days resulted in a significant decrease in the mean serum FSH/LH ratio and a rise in serum testosterone in all subjects. Episodic release of gonadotrophins persisted in the adolescent patients.

Congenital adrenal hyperplasia caused by defect in steroid 21-hydroxylase. Establishment of definitive urinary steroid excretion pattern during first weeks of life

The steroid excretion of two female infants with congenital adrenal hyperplasia due to 21-hydroxylase deficiency has been studied during the first weeks of life. The techniques used were gas chromatography on an open-tubular column and combined gas chromatography-mass spectrometry using selected ion recording. During the first days of life 3beta-hydroxy-5-ene steroids predominate and the levels found were considerably greater than those found in normal infants. Selected ion recording mass spectrometry permitted detection of pregnanetriol and 11-oxo-pregnanetriol several days before these steroids could be determined with accuracy by conventional gas chromatography. Pregnanetriol and 11-oxo-pregnanetriol were first detected on the third day of life. The results of this investigation demonstrate that 21-hydroxylase deficiency may be indicated during the first week of life by an increased 3beta-hydroxy-5-ene steroid excretion, but the definitive excretion pattern required for firm diagnosis may not develop for several days. The amounts of the definitive steroids excreted may not be sufficient to be detected by the more usual methods for several weeks.