LC-MS/MS based determination of basal- and ACTH-stimulated plasma concentrations of 11 steroid hormones: implications for detecting heterozygote CYP21A2 mutation carriers

OBJECTIVE

Heterozygosity in 21-hydroxylase deficiency (21OHD) has been associated with hyperandrogenemic symptoms in children and adults. Moreover, the carrier status is mandatory for genetic counseling. We aimed at defining a hormonal parameter for carrier detection by mass spectrometry.

DESIGN

Eleven basal and ACTH-stimulated steroid hormones of heterozygous carriers of CYP21A2 mutations and control individuals were compared.

METHOD

Hormones were determined in plasma samples by liquid chromatography tandem mass spectrometry (LC-MS/MS) in 58 carriers (35 males, 23 females, age range 6-78 years) and 44 random controls (25 males, 19 females, age range 8-58 years).

RESULTS

Heterozygotes could be identified best applying the 17-hydroxyprogesterone+21-deoxycortisol/cortisol×1000 ((17OHP+21S)/F×1000) equation 30  min after ACTH injection. An optimal cut-off value of 8.4 provided 89% sensitivity and specificity. Considering this data and a published frequency of heterozygotes of 1/50 to 1/61, the positive predictive value (PPV) of this cut-off is 12%. Of note, the negative predictive value (NPV) excluding heterozygosity in a given patient is 99.8%.

CONCLUSION

Considering only marginal biochemical effects anticipated from heterozygosity, the stimulated ((17OHP+21S)/F×1000) identifies and excludes heterozygotes remarkably well. Nevertheless, LC-MS/MS cannot replace genetic testing, since sensitivity and specificity did not reach 100%. However, due to the considerably high NPV of the optimal cut-off and to a specificity of even 100% applying a cut-off higher than 14.7, hormonal assessment of heterozygosity can be of significant aid in conditions with limited access to genetic testing, as in some health care systems. The ((17OHP+21S)/F×1000) equation can guide diagnostic considerations in the differential diagnosis of hyperandrogenism.

Rare missense P450c17 (CYP17A1) mutation in exon 1 as a cause of 46,XY disorder of sexual development: implications of breast tissue 'unresponsiveness' despite adequate estradiol substitution

17-Alpha-hydroxylase/17,20-lyase deficiency (17OHD) is a rare autosomal recessive disorder resulting from mutations in the CYP17A1 gene, leading to impaired adrenal and gonadal steroidogenesis. We report for the first time a patient with a missense mutation at codon 96 (R96Q) of the CYP17A1 gene causing a 46,XY disorder of sexual development (DSD) that additionally showed lack of breast development despite highly dosed estradiol replacement treatment. This phenomenon could be attributed to irreversible breast tissue alterations following high serum progesterone levels.

Aldosterone synthase deficiency type II with hypospadias

Aldosterone synthase deficiency (ASD) type II was diagnosed in a 3 week old boy with severe dehydration. Elevated plasma renin activity, low-normal aldosterone, increased levels for 18-OH corticosterone (18-OHB) and 18-OH-deoxycorticosterone were measured. Sequencing revealed a homozygous mutation for c554C > T in exon 3 (p.T185I) (CYP11B2). Hypospadias has so far not been reported in ASD.

Principles and clinical applications of liquid chromatography - tandem mass spectrometry for the determination of adrenal and gonadal steroid hormones

Liquid-chromatography - tandem mass spectrometry (LC-MS/MS) is becoming the method of choice for clinical steroid analysis. In most instances, it has the advantage of higher sensitivity, better reproducibility and greater specificity than commercial immunoassay techniques. The method requires only minimal sample preparation and a small sample volume. Furthermore, it has the potential to analyze multiple steroids simultaneously. Modern instruments guarantee high throughput, allowing an affordable price for the individual assay. All this makes LC-MS/MS an attractive method for use in a clinical setting. Reliable reference ranges for the detected analytes are the pre-requisite for their clinical use. If these are available, LC-MS/MS can find application in congenital disorders of steroid metabolism, such as congenital adrenal hyperplasia, disorders of sex development and disorders of salt homeostasis, as well as in acquired disorders of steroid metabolism, such as primary aldosteronism, Cushing's disease, Addison's disease, and hyperandrogenemia, as well as in psychiatric disease states such as depression or anxiety disorders. The principles of LC-MS/MS for steroid measurement, the pros and cons of LC-MS/MS compared with conventional immunoassays and the possible applications in clinical routine, with a special focus on pediatric endocrinology needs, are discussed here.

Androgen receptor mutations are associated with altered epigenomic programming as evidenced by HOXA5 methylation

Male external genital differentiation is accompanied by implementation of a long-term, male-specific gene expression pattern indicating androgen programming in cultured genital fibroblasts. We hypothesized the existence of an epigenetic background contributing to this phenomenon. DNA methylation levels in 2 normal scrotal fibroblast strains from 46,XY males compared to 2 labia majora fibroblast strains from 46,XY females with complete androgen insensitivity syndrome (AIS) due to androgen receptor (AR) mutations were analyzed by Illumina GoldenGate methylation arrays®. Results were validated with pyrosequencing in labia majora fibroblast strains from fifteen 46,XY patients and compared to nine normal male scrotal fibroblast strains. HOXA5 showed a significantly higher methylation level in complete AIS. This finding was confirmed by bisulfite pyrosequencing of 14 CpG positions within the HOXA5 promoter in the same strains. Extension of the 2 groups revealed a constant low HOXA5 methylation pattern in the controls in contrast to a highly variable methylation pattern in the AIS patients. HOXA5 represents a candidate gene of androgen-mediated promoter methylation. The constantly low HOXA5 DNA methylation level of normal male scrotal fibroblast strains and the frequently high methylation levels in labia majora fibroblast strains in AIS indicate for the first time that androgen programming in sexual differentiation is not restricted to global gene transcription but also occurs at the epigenetic level.

No correlation between androgen receptor CAG and GGN repeat length and the degree of genital virilization in females with 21-hydroxylase deficiency

CONTEXT

In 21-hydroxylase (CYP21A2) deficiency (21OHD), the level of in vitro enzymatic function allows for classification of mutation groups (null, A, B, C) and prediction of disease severity. However, genital virilization in affected females correlates only weakly with CYP21A2 mutation groups, suggesting the influence of genetic modifiers.

OBJECTIVE

The objective of the study was to investigate the influence of the polymorphic CAG and GGn repeats of the androgen receptor (AR) gene on the degree of genital virilization in 21OHD females.

DESIGN AND PATIENTS

Design of the study was the determination of CYP21A2 genotype, degree of genital virilization (Prader stage), and X-weighted biallelic mean of AR CAG and GGn repeat length in 205 females with 21OHD.

OUTCOME MEASUREMENTS

Correlation of AR CAG and GGn repeat lengths with Prader stages using nested stepwise logistic regression analysis was measured.

RESULTS

CYP21A2 mutation groups null and A showed significantly higher levels of genital virilization than groups B and C (P < 0.01). However, Prader stages varied considerably within mutation groups: null, Prader I-V (median IV); A, Prader I-V (median IV); B, Prader I-V (median III); C, 0-III (median I). Mean GGn repeat length of patients was not significantly associated with Prader stages, classified as low (0-I), intermediate (II-III), or severe (IV-V) (odds ratio per repeat: 0.98, 95% confidence interval 0.71-1.35). In contrast, patients with Prader 0-I showed a trend toward longer CAG repeats without reaching statistical significance (P = 0.07, odds ratio per repeat: 0.82, 95% confidence interval 0.65-1.02).

CONCLUSION

Neither CAG nor GGn repeat lengths are statistically significant modifiers of genital virilization in females with 21OHD.

A novel ultrapressure liquid chromatography tandem mass spectrometry method for the simultaneous determination of androstenedione, testosterone, and dihydrotestosterone in pediatric blood samples: age- and sex-specific reference data

CONTEXT

Current immunoassays for analysis of plasma androgens in children have several limitations due to antibody-specific variations of data and normal ranges. Mass spectrometry-based methods are available for individual steroids but need complex sample preparation and report only fragmentary reference data for the pediatric population.

OBJECTIVE

Our objective was to develop a state of the art sensitive and specific tandem mass spectrometry method for high-throughput simultaneous determination of plasma concentrations of androstenedione (A), testosterone (T), and dihydrotestosterone (DHT) and to report age-, sex-, and pubertal stage-specific reference levels for these steroids in children aged 0-18 yr.

SUBJECTS AND METHODS

Plasma (100 microl) was mixed with internal standard and extracted by solid-phase extraction. Androgens were measured by ultrapressure liquid chromatography tandem mass spectrometry. Samples of 138 boys and 131 girls with neither signs of endocrine nor systemic disease were considered for the generation of reference data. The following age groups were used: less than 1 wk, 2 wk to 2 months, 3-5 months, 6-11 months, 1-3 yr, 4-6 yr, 7-9 yr, 10-12 yr, 13-15 yr, and over 16 yr.

RESULTS

Lower quantification limit was 2.9 ng/dl (0.1 nmol/liter) for A, T, and DHT. No relevant interference with other steroids was detected. Reference data for A, T, and DHT are reported as functions of age, sex, pubertal maturation, and testicular volume.

CONCLUSION

Simplicity, velocity, sensitivity, specificity, and the availability of pediatric reference data allow application of our new method in clinical routine as well as in research settings.

Extreme hyponatremia in an infant with congenital adrenal hypoplasia due to a novel NR0B1 (DAX-1) mutation

BACKGROUND

Extreme hyponatremia (<105 mmol/l) has rarely been reported in infants. It is potentially life-threatening and requires intensive care treatment.

PATIENT

We report on a male infant with absence of weight gain from birth to day 33 of life despite adequate nutrition. On admission serum sodium and potassium were 104 and 5.9 mmol/L respectively. The infant's physical status revealed dehydration, but normal activity with no apparent neurological, circulatory or respiratory impairment.

MAIN RESULTS

Global adrenocortical insufficiency was diagnosed and treated with hormonal substitution in addition to intravenous application of fluid, glucose and electrolytes. The rise of serum sodium was carefully monitored and adjusted to a target rate of 0.5 mmol/L/h. X-linked adrenal hypoplasia congenita (X-AHC) was confirmed by the identification of a novel nonsense NR0B1 (DAX-1) mutation (W236X).

CONCLUSIONS

X-AHC in infants may present as failure to thrive despite adequate nutrition. Extreme hyponatremia may be associated with little symptoms if developing slowly. Rehydration and slow correction of serum sodium with solutions containing less sodium than normal saline is essential.

Calcinosis cutis bei hereditärer Albright-Osteodystrophie

Albright hereditary osteodystrophy (AHO) is characterized by a symptom complex including short stature, brachymetacarpia, obesity, round facies, cutaneous osteomas, and mental retardation. AHO is caused by mutations in the GNAS-gene localized on chromosome 20 encoding for Gsalpha protein, a signal transducer of endocrine pathways. Therefore, AHO is often associated with endocrinopathy such as pseudohypoparathyroidism or hypothyroidism. A nine-month-old boy presented with typical features of this syndrome. The diagnosis was confirmed by biochemical and molecular analyses. An unusual feature was calcinosis cutis at such an early age, which led to extensive differential diagnostic procedures.

Initially elevated TSH and congenital central hypothyroidism due to a homozygous mutation of the TSH beta subunit gene: case report and review of the literature

Congenital central hypothyroidism (CCH) is a rare disease which can be caused by mutations in the gene for the thyrotropin (TSH) beta subunit ( TSHB). The diagnosis is usually delayed because the TSH serum levels in these patients are not elevated leading to a negative result in the neonatal TSH screening. Herein, we report a 2-year-old girl with CCH due to a mutation in the TSHB gene, in whom the unusual finding of an initially elevated TSH level complicated the diagnostic workup. The proposita, who had a supposedly normal TSH screening result, is a German girl of non-consanguineous parents. At 5 weeks of age, her thyroid function tests showed peripheral hypothyroidism with a moderately increased TSH (23.8 microIU/ml) so that thyroid hormone substitution was initiated. At the age of 2 years, the administration of TRH failed to increase the TSH serum concentrations, which prompted TSH measurements with two different assay systems. Variable TSH levels ranging from not detectable low to elevated were found so that central hypothyroidism due to a mutation in the TSHB gene was suspected. This was confirmed by molecular analysis of the TSHB gene, which identified a homozygous deletion (delta 313 T) in the coding sequence. This mutation has been found in the German population before and may be a founder mutation. We conclude that depending on the assay system variable TSH serum levels in individuals with mutations in the TSHB gene may complicate the diagnostic workup.

Absence of exercise-induced leptin suppression associated with insufficient epinephrine reserve in patients with classic congenital adrenal hyperplasia due to 21-hydroxylase deficiency

OBJECTIVE

Patients with congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency suffer from glucocorticoid and mineralocorticoid deficiency. They have insufficient epinephrine reserves and increased basal leptin levels and are often insulin resistant. In healthy subjects, an inhibitory effect of acute catecholamine elevation on the leptin plasma concentrations has been reported. However, it is not yet known how leptin levels respond to exercise in CAH patients.

METHODS

We performed a cycle ergometer test in six CAH patients to measure the response of plasma leptin, glucose and the catecholamines, epinephrine (E) and norepinephrine (N), as well as their respective metabolites, metanephrine (M) and normetanephrine (NM), to intense exercise.

RESULTS

Baseline leptin concentrations in CAH patients were not different from those of controls. Leptin levels decreased significantly with exercise in healthy controls, whereas they remained unchanged in CAH patients. In contrast to controls, CAH patients showed no rise of plasma glucose. Basal and stimulated E and M levels were significantly lower in CAH patients compared to controls. Baseline and stimulated N and NM levels were comparable, showing a significant rise after exercise. Peak systolic blood pressure and peak heart rate in both groups were comparable.

CONCLUSION

CAH patients do not manifest exercise-induced leptin suppression. The most probable reason for this is their severely impaired epinephrine stress response. In addition, epinephrine deficiency is leading to secondary changes in various catecholamine dependent metabolic pathways, e. g., energy balance. Although obvious clinical sequelae are so far unknown, the catecholamine-deficient state and the resulting hyperleptinemia might contribute to the severity of the disease in CAH.

Three novel point mutations of the CYP21 gene detected in classical forms of congenital adrenal hyperplasia due to 21-hydroxylase deficiency

Congenital adrenal hyperplasia (CAH) [OMIM 201 910] is a group of autosomal recessive disorders most commonly due to 21-hydroxylase deficiency and presenting with a wide range of clinical manifestations. A limited number of inactivating pseudogene-derived mutations account for the majority of 21-hydroxylase gene ( CYP21) mutations, additional rare mutations can be found in single families and small populations. We found three novel CYP21 mutations in CAH patients suffering from the classical form of the disease, of which one is a frameshift mutation (1353-1354insA) leading to a premature termination codon (K277K, Q228A...E294X), one results in a premature stop codon (2551C>T, R444X), and one is a missense mutation (2609T>C; P463L). The frameshift and premature stop mutations can be predicted to result in a CYP21 protein without any residual enzyme activity. To determine the functional consequences of the P463L mutation, the IN VITRO enzyme activity was studied in COS-7 cells and revealed a reduced 21-hydroxylase activity of 2.6+/-0.8 (SD)% for the conversion of 17-hydroxyprogesterone (17OHP) to 11-deoxycortisol and of 3.0+/-0.5 % for the conversion of progesterone to 11-deoxycorticosterone (DOC). We conclude that functional analyses of unknown mutations provide information on the disease severity and should be always performed when novel CYP21 mutations are detected. Knowledge of the residual 21-hydroxylase function improves both genetic counselling and individual clinical management in CAH patients.

Serum cortisol and cortisone levels in newborns with congenital adrenal hyperplasia before the start of therapy

Sodium loss in infants with salt wasting (SW) congenital adrenal hyperplasia (CAH) does usually not occur within the first week of life. We hypothesized that sufficient mineralocorticoid activity might by temporarily maintained by still appropriate concentrations of cortisol. Plasma samples were obtained from 15 infants with SW-CAH before the onset of sodium loss, 17 patients with simple virilizing (SV)-CAH and 28 healthy infants under 14 days of age. Plasma aldosterone concentrations were significantly lower in SW-CAH infants than in SV-CAH patients and in healthy neonates. Plasma cortisol levels and cortisol/cortisone (F/E) ratios in SW-CAH patients were almost the same as in the SV-CAH and control group. While declining plasma aldosterone levels precede the onset of SW in CAH patients, plasma cortisol concentrations are kept normal in SW-CAH infants, temporarily maintaining sufficient mineralocorticoid activity.

Congenital adrenal hyperplasia - how to improve the transition from adolescence to adult life

Congenital adrenal hyperplasia (CAH) is caused by a defect in the biosynthesis of cortisol that results in maximal activity of the hypothalamic-pituitary adrenal axis with hyperplasia of the adrenals and hyperandrogenism due to the accumulation of androgen precursors. In the salt-wasting subtype of the disorder, which accounts for appr. 75 % of patients with classical CAH, patients are unable to synthesise sufficient amounts of aldosterone and are prone to life-threatening salt-losing crises, whereas the simple virilising form is predominantly characterized by clitoris hypertrophy and posterior labial fusion. In addition, a non-classical variant can be discerned which in most cases is diagnosed at the time of puberty or early adolescence when hirsutism and menstrual irregularities may occur. The vast majority of CAH patients have 21-hydroxylase deficiency (90 - 95 %). Less common forms, such as 11beta-hydroxylase deficiency, will not be discussed in this review. Unfortunately, a considerable number of CAH patients is lost to regular and competent follow-up once they move out of paediatric care. This is most probably the result of insufficient co-operation between paediatric and adult endocrinologists at the time of transition from adolescence to adulthood. Furthermore, there is a lack of clinical guidance regarding psychosexual development in these patients. In this overview we will focus on special aspects of CAH treatment in adolescence and adulthood, and report on our 10-year experience with a transfer system for endocrine patients from paediatric to internal medical care, known as the "Kieler Modell". For practical purposes, we here provide charts for follow-up of CAH patients that can be adapted for use in any endocrine outpatient clinic.

Chromatographic system for the simultaneous measurement of plasma 18-hydroxy-11-deoxycorticosterone and 18-hydroxycorticosterone by radioimmunoassay: reference data for neonates and infants and its application in aldosterone-synthase deficiency

A new chromatographic system for the steroid precursor separation and a sensitive radioimmunoassay system for the subsequent measurement of 18-hydroxy-11-deoxycorticosterone and 18-hydroxycorticosterone has been developed. 18-Hydroxy-11-deoxycorticosterone and 18-hydroxycorticosterone were extracted with methylene chloride and separated from cross-reacting steroids by Sephadex LH-20 column chromatography. Anti-18-hydroxy-11-deoxycorticosterone and anti-18-hydroxycorticosterone antibodies raised in rabbits were used. The lower detection limit of the assay is 0.03 nmol/l and 0.128 nmol/l for 18-hydroxy-11-deoxycorticosterone and 18-hydroxycorticosterone, respectively. Normal values for this assay in 128 healthy neonates and infants aged 0-5 months were established as a basis for the early hormonal diagnosis of aldosterone synthase deficiency types I and II. Its application for the diagnosis of aldosterone synthase deficiency is demonstrated in two patients with homozygous mutation/deletion in the encoding CYP11B2 gene.

Automated chromatographic system for the simultaneous measurement of plasma pregnenolone and 17-hydroxypregnenolone by radioimmunoassay

A new, simple, rapid and highly practicable automated chromatographic system for the separation, and a sensitive radioimmunoassay system for the subsequent measurement of pregnenolone and 17-hydroxypregnenolone has been developed. Pregnenolone and 17-hydroxypregnenolone were extracted with methylene chloride and separated from cross-reacting steroids by mechanised Sephadex-LH20 multi-column chromatography. Anti-pregnenolone and anti-17-hydroxypregnenolone were obtained by immunising rabbits with pregnenolone-20-oxime-BSA and 17-hydroxypregnenolone-20-oxime-BSA. The lower detection limit of the assay is 0.15 and 0.28 nmol/l for pregnenolone and 17-hydroxypregnenolone, respectively. Normal values for this assay in young male adults, in adult females, and in prepubertal boys and girls were established as a basis for the functional diagnosis of androgen excess syndromes/steroidogenesis defects.

Longitudinal imaging reveals pituitary enlargement preceding hypoplasia in two brothers with combined pituitary hormone deficiency attributable to PROP1 mutation

Mutations of the PROP-1 gene cause combined pituitary hormone deficiency. Progressive ACTH/cortisol insufficiency is found in a few patients. Congenital hypoplasia of the anterior pituitary gland is the most common magnetic resonance imaging finding in patients with PROP-1 mutations. We present two brothers with compound heterozygosity for the two mutations 150delA and 301-302delAG of the PROP-1 gene. Both showed combined pituitary hormone deficiency of GH, TSH, PRL, and gonadotropins, as is typical for PROP-1 deficiency. We observed a developing insufficiency of ACTH and cortisol secretory capacity in both patients. Computed tomography revealed an enlarged pituitary in the older brother at 3.5 yr of age. Repeated magnetic resonance imaging after 12 yr showed a constant hypoplasia of the anterior pituitary lobe. Similarly, magnetic resonance imaging of the younger brother showed a constant enlargement of the anterior pituitary gland until 10 yr. At the age of 11 yr, the anterior pituitary was hypoplastic. The reason for pituitary enlargement in early childhood with subsequent decrease in pituitary size is not known. We speculate that altered expression of early transcription factors could be involved. Because both patients have the same PROP-1 mutations and an identical pattern of combined pituitary hormone deficiency, we suggest that early pituitary enlargement may be the typical course in such patients in whom pituitary surgery is not indicated.