Topical glucocorticoid application causing iatrogenic Cushing's syndrome followed by secondary adrenal insufficiency in infants: two case reports

BACKGROUND

Iatrogenic Cushing's syndrome induced by oral and parenteral glucocorticoid administration is a well-known complication. Immediate withdrawal from exogenous steroids can lead to life-threatening adrenal insufficiency. However, Cushing's syndrome caused by topical treatment with glucocorticoids, such as dexamethasone eye drops or dermal application, is rarely recognized. Young infants in particular are at high risk of suffering from iatrogenic Cushing's syndrome when treated with highly potent topical glucocorticoids.

CASE PRESENTATION

We present a 6-month-old Syrian boy with cushingoid face after dermal clobetasol cream treatment and a 2-year-old Iranian girl with severe growth retardation after application of dexamethasone eye drops. Both families have a migration background and language barriers. In both cases no endogenous cortisol secretion was initially detected in serum and in 24-hour collected urine. After dose reduction of glucocorticoids, severity of symptoms was reversible and serum cortisol was detectable.

DISCUSSION AND CONCLUSION

Young infants are at high risk of developing Cushing's syndrome from topically applied highly potent glucocorticoids. Precise recommendations of treatment dosage, duration, and frequency must be given to the parents, and if necessary, with the help of an interpreter. Monitoring of height and weight as well as regular pediatric follow-ups should be scheduled. Physicians should be aware of potential adrenal insufficiency following withdrawal from long-term topical glucocorticoid treatment, and hydrocortisone treatment should be considered.

The Action of Reproductive Fluids and Contained Steroids, Prostaglandins, and Zn2+ on CatSper Ca2+ Channels in Human Sperm

The sperm-specific Ca²⁺ channel CatSper registers chemical cues that assist human sperm to fertilize the egg. Prime examples are progesterone and prostaglandin E₁ that activate CatSper without involving classical nuclear and G protein-coupled receptors, respectively. Here, we study the action of seminal and follicular fluid as well of the contained individual prostaglandins and steroids on the intracellular Ca²⁺ concentration of sperm from donors and CATSPER2-deficient patients that lack functional CatSper channels. We show that any of the reproductive steroids and prostaglandins evokes a rapid Ca²⁺ increase that invariably rests on Ca²⁺ influx via CatSper. The hormones compete for the same steroid- and prostaglandin-binding site to activate the channel, respectively. Analysis of the hormones’ structure–activity relationship highlights their unique pharmacology in sperm and the chemical features determining their effective properties. Finally, we show that Zn²⁺ suppresses the action of steroids and prostaglandins on CatSper, which might prevent premature prostaglandin activation of CatSper in the ejaculate, aiding sperm to escape from the ejaculate into the female genital tract. Altogether, our findings reinforce that human CatSper serves as a promiscuous chemosensor that enables sperm to probe the varying hormonal microenvironment prevailing at different stages during their journey across the female genital tract.

Type 1 diabetes and epilepsy in childhood and adolescence: Do glutamic acid decarboxylase autoantibodies play a role? Data from the German/Austrian/Swiss/Luxembourgian DPV Registry

AIMS

We aimed to analyze the relationship between epilepsy and glutamic acid decarboxylase autoantibodies (GADA) in patients with type 1 diabetes mellitus (T1DM) and the impact of GADA on demographic, clinical, and metabolic data in T1DM patients with epilepsy.

METHODS

We searched for patients with T1DM ≤20 years and GADA measurements, and within this group for patients with epilepsy. We formed groups: T1DM + Epilepsy + GADA positive; T1DM + Epilepsy + GADA negative; T1DM + GADA positive; T1DM + GADA negative. We used logistic regression to analyze the relationship between epilepsy and GADA with odds ratio adjusted for sex, duration of diabetes (DOD), and age at diabetes onset (ADO). We used logistic regression with odds ratio adjusted for DOD and ADO onset using epilepsy as a dependent variable and GADA, HbA1c, ketoacidosis, severe hypoglycemia (SH), sex, celiac disease, and autoimmune thyroiditis as independent variables. We conducted regression analyses adjusted for sex, DOD, and ADO to analyze differences in clinical/metabolic parameters between the groups.

RESULTS

Epilepsy was not more frequent in GADA-positive patients (GPP). Logistic regression including all patients with GADA measurements showed that hypoglycemia with coma (HC) correlated with epilepsy when compared to no SH. We found no differences in clinical and metabolic data between GPP and GADA-negative patients (GNP) with epilepsy. SH occurred more often in GPP with epilepsy in comparison to GPP without epilepsy. GNP with epilepsy had a higher rate of HC than GPP without epilepsy.

CONCLUSION

We found no relationship between epilepsy and GADA. A relationship between T1DM and epilepsy might be explainable by SH.

Clinical but Not Histological Outcomes in Males With 45,X/46,XY Mosaicism Vary Depending on Reason for Diagnosis

CONTEXT

Larger studies on outcomes in males with 45,X/46,XY mosaicism are rare.

OBJECTIVE

To compare health outcomes in males with 45,X/46,XY diagnosed as a result of either genital abnormalities at birth or nongenital reasons later in life.

DESIGN

A retrospective, multicenter study.

SETTING

Sixteen tertiary centers.

PATIENTS OR OTHER PARTICIPANTS

Sixty-three males older than 13 years with 45,X/46,XY mosaicism.

MAIN OUTCOME MEASURES

Health outcomes, such as genital phenotype, gonadal function, growth, comorbidities, fertility, and gonadal histology, including risk of neoplasia.

RESULTS

Thirty-five patients were in the genital group and 28 in the nongenital. Eighty percent of all patients experienced spontaneous pubertal onset, significantly more in the nongenital group (P = 0.023). Patients were significantly shorter in the genital group with median adult heights of 156.7 cm and 164.5 cm, respectively (P = 0.016). Twenty-seven percent of patients received recombinant human GH. Forty-four patients had gonadal histology evaluated. Germ cells were detected in 42%. Neoplasia in situ was found in five patients. Twenty-five percent had focal spermatogenesis, and another 25.0% had arrested spermatogenesis. Fourteen out of 17 (82%) with semen analyses were azoospermic; three had motile sperm.

CONCLUSION

Patients diagnosed as a result of genital abnormalities have poorer health outcomes than those diagnosed as a result of nongenital reasons. Most patients, however, have relatively good endocrine gonadal function, but most are also short statured. Patients have a risk of gonadal neoplasia, and most are azoospermic, but almost one-half of patients has germ cells present histologically and up to one-quarter has focal spermatogenesis, providing hope for fertility treatment options.

A Specific CNOT1 Mutation Results in a Novel Syndrome of Pancreatic Agenesis and Holoprosencephaly through Impaired Pancreatic and Neurological Development

We report a recurrent CNOT1 de novo missense mutation, GenBank: NM_016284.4; c.1603C>T (p.Arg535Cys), resulting in a syndrome of pancreatic agenesis and abnormal forebrain development in three individuals and a similar phenotype in mice. CNOT1 is a transcriptional repressor that has been suggested as being critical for maintaining embryonic stem cells in a pluripotent state. These findings suggest that CNOT1 plays a critical role in pancreatic and neurological development and describe a novel genetic syndrome of pancreatic agenesis and holoprosencephaly.

Area Deprivation and Regional Disparities in Treatment and Outcome Quality of 29,284 Pediatric Patients With Type 1 Diabetes in Germany: A Cross-sectional Multicenter DPV Analysis

OBJECTIVE

This study analyzed whether area deprivation is associated with disparities in health care of pediatric type 1 diabetes in Germany.

RESEARCH DESIGN AND METHODS

We selected patients <20 years of age with type 1 diabetes and German residence documented in the "diabetes patient follow-up" (Diabetes-Patienten-Verlaufsdokumentation [DPV]) registry for 2015/2016. Area deprivation was assessed by quintiles of the German Index of Multiple Deprivation (GIMD 2010) at the district level and was assigned to patients. To investigate associations between GIMD 2010 and indicators of diabetes care, we used multivariable regression models (linear, logistic, and Poisson) adjusting for sex, age, migration background, diabetes duration, and German federal state.

RESULTS

We analyzed data from 29,284 patients. From the least to the most deprived quintile, use of continuous glucose monitoring systems (CGMS) decreased from 6.3 to 3.4% and use of long-acting insulin analogs from 80.8 to 64.3%, whereas use of rapid-acting insulin analogs increased from 74.7 to 79.0%; average HbA_1c increased from 7.84 to 8.07% (62 to 65 mmol/mol), and the prevalence of overweight from 11.8 to 15.5%, but the rate of severe hypoglycemia decreased from 12.1 to 6.9 events/100 patient-years. Associations with other parameters showed a more complex pattern (use of continuous subcutaneous insulin infusion [CSII]) or were not significant.

CONCLUSIONS

Area deprivation was associated not only with key outcomes in pediatric type 1 diabetes but also with treatment modalities. Our results show, in particular, that the access to CGMS and CSII could be improved in the most deprived regions in Germany.

GENETICS IN ENDOCRINOLOGY: Approaches to molecular genetic diagnosis in the management of differences/disorders of sex development (DSD): position paper of EU COST Action BM 1303 ‘DSDnet’

The differential diagnosis of differences or disorders of sex development (DSD) belongs to the most complex fields in medicine. It requires a multidisciplinary team conducting a synoptic and complementary approach consisting of thorough clinical, hormonal and genetic workups. This position paper of EU COST (European Cooperation in Science and Technology) Action BM1303 ‘DSDnet’ was written by leading experts in the field and focuses on current best practice in genetic diagnosis in DSD patients. Ascertainment of the karyotpye defines one of the three major diagnostic DSD subclasses and is therefore the mandatory initial step. Subsequently, further analyses comprise molecular studies of monogenic DSD causes or analysis of copy number variations (CNV) or both. Panels of candidate genes provide rapid and reliable results. Whole exome and genome sequencing (WES and WGS) represent valuable methodological developments that are currently in the transition from basic science to clinical routine service in the field of DSD. However, in addition to covering known DSD candidate genes, WES and WGS help to identify novel genetic causes for DSD. Diagnostic interpretation must be performed with utmost caution and needs careful scientific validation in each DSD case.

Global Application of the Assessment of Communication Skills of Paediatric Endocrinology Fellows in the Management of Differences in Sex Development Using the ESPE E-Learning.Org Portal

BACKGROUND

Information sharing in chronic conditions such as disorders of/differences in sex development (DSD) is essential for a comprehensive understanding by parents and patients. We report on a qualitative analysis of communication skills of fellows undergoing training in paediatric endocrinology. Guidelines are created for the assessment of communication between health professionals and individuals with DSD and their parents.

METHODS

Paediatric endocrinology fellows worldwide were invited to study two interactive online cases (www.espe-elearning.org) and to describe a best practice communication with (i) the parents of a newborn with congenital adrenal hyperplasia and (ii) a young woman with 46,XY gonadal dysgenesis. The replies were analysed regarding completeness, quality, and evidence of empathy. Guidelines for structured assessment of responses were developed by 22 senior paediatric endocrinologists worldwide who assessed 10 selected replies. Consensus of assessors was established and the evaluation guidelines were created.

RESULTS

The replies of the fellows showed considerable variation in completeness, quality of wording, and evidence of empathy. Many relevant aspects of competent clinical communication were not mentioned; 15% (case 1) and 17% (case 2) of the replies were considered poor/insufficient. There was also marked variation between 17 senior experts in the application of the guidelines to assess communication skills. The guidelines were then adjusted to a 3-level assessment with empathy as a separate key item to better reflect the qualitative differences in the replies and for simplicity of use by evaluators.

CONCLUSIONS

E-learning can play an important role in assessing communication skills. A practical tool is provided to assess how information is shared with patients with DSD and their families and should be refined by all stakeholders, notably interdisciplinary health professionals and patient representatives.

Steroid hormone analysis in diagnosis and treatment of DSD: position paper of EU COST Action BM 1303 'DSDnet'

Disorders or differences in sex development (DSD) comprise a heterogeneous group of conditions with an atypical sex development. For optimal diagnosis, highly specialised laboratory analyses are required across European countries. Working group 3 of EU COST (European Cooperation in Science and Technology) Action BM 1303 'DSDnet' 'Harmonisation of Laboratory Assessment' has developed recommendations on laboratory assessment for DSD regarding the use of technologies and analytes to be investigated. This position paper on steroid hormone analysis in diagnosis and treatment of DSD was compiled by a group of specialists in DSD and/or hormonal analysis, either from participating European countries or international partner countries. The topics discussed comprised analytical methods (immunoassay/mass spectrometry-based methods), matrices (urine/serum/saliva) and harmonisation of laboratory tests. The following positions were agreed upon: support of the appropriate use of immunoassay- and mass spectrometry-based methods for diagnosis and monitoring of DSD. Serum/plasma and urine are established matrices for analysis. Laboratories performing analyses for DSD need to operate within a quality framework and actively engage in harmonisation processes so that results and their interpretation are the same irrespective of the laboratory they are performed in. Participation in activities of peer comparison such as sample exchange or when available subscribing to a relevant external quality assurance program should be achieved. The ultimate aim of the guidelines is the implementation of clinical standards for diagnosis and appropriate treatment of DSD to achieve the best outcome for patients, no matter where patients are investigated or managed.

The Long-Term Outcome of Boys With Partial Androgen Insensitivity Syndrome and a Mutation in the Androgen Receptor Gene

BACKGROUND

In boys with suspected partial androgen insensitivity syndrome (PAIS), systematic evidence that supports the long-term prognostic value of identifying a mutation in the androgen receptor gene (AR) is lacking.

OBJECTIVE

To assess the clinical characteristics and long-term outcomes in young men with suspected PAIS in relation to the results of AR analysis.

METHODS

Through the International Disorders of Sex Development Registry, clinical information was gathered on young men suspected of having PAIS (n = 52) who presented before the age of 16 years and had genetic analysis of AR.

RESULTS

The median ages at presentation and at the time of the study were 1 month (range, 1 day to 16 years) and 22 years (range, 16 to 52 years), respectively. Of the cohort, 29 men (56%) had 20 different AR mutations reported. At diagnosis, the median external masculinization scores were 7 and 6 in cases with and without AR mutation, respectively (P = .9), and median current external masculinization scores were 9 and 10, respectively (P = .28). Thirty-five men (67%) required at least one surgical procedure, and those with a mutation were more likely to require multiple surgeries for hypospadias (P = .004). All cases with an AR mutation had gynecomastia, compared to 9% of those without an AR mutation. Of the six men who had a mastectomy, five (83%) had an AR mutation.

CONCLUSIONS

Boys with genetically confirmed PAIS are likely to have a poorer clinical outcome than those with XY DSD, with normal T synthesis, and without an identifiable AR mutation. Routine genetic analysis of AR to confirm PAIS informs long-term prognosis and management.

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.

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.

Mutation analysis of FOXF2 in patients with disorders of sex development (DSD) in combination with cleft palate

In contrast to disorders of sexual differentiation caused by lack of androgen production or inhibited androgen action, defects affecting development of the bipotent genital anlagen have rarely been investigated in humans. We have previously documented that the transcription factor FOXF2 is highly expressed in human foreskin. Moreover, Foxf2 knockout mice present with cleft palate in combination with hypoplasia of the genital tubercle. We hypothesized that humans with disorders of sex development (DSD) in combination with cleft palate could have mutations in the FOXF2 gene. Eighteen children with DSD and cleft palate were identified in the Lübeck DSD database (about 1,500 entries). Genomic DNA sequence analysis of the FOXF2 gene was performed and compared with 10 normal female and 10 normal male controls, respectively. Two heterozygous DNA sequence variations were solely present in one single patient each but in none of the 20 normal controls: a duplication of GCC (c.97GCC[9]+[10]) resulting in an extra alanine within exon 1 and a 25*G>A substitution in the 3'-untranslated region. Two patients carried a c.262G>A sequence variation predicting for an Ala88Thr exchange which was also detected in 2 normal controls. Two silent mutations, c.1272C>T (Ser424Ser) and c.1284T>C (Tyr428Tyr), respectively, occurred in the coding region of exon 2, again in both patients and normal controls. In conclusion, the majority of the detected sequence alterations were polymorphisms without obvious functional relevance. However, it cannot be excluded that the 2 unique DNA sequence alterations could have affected FOXF2 on the mRNA or protein level thus contributing to the observed disturbances in genital and palate development.

Prevailing therapeutic regimes and predictive factors for prandial insulin substitution in 26 687 children and adolescents with Type 1 diabetes in Germany and Austria

AIMS

To analyse current therapeutic strategies for prandial insulin substitution in a large number of children and adolescents with Type 1 diabetes in Germany and Austria, along with changes in therapeutic habits and outcome.

METHODS

We classified the data of 26 687 patients, treated from 1995 to 2005 in 152 paediatric clinics, using a database established for quality control and scientific surveys in paediatric diabetology (DPV).

RESULTS

Seventy-three per cent of all patients (mean age 13.6 years., mean duration of diabetes 5.4 years.) were treated with > or = 4 daily injections (intensified conventional treatment; ICT), 14% with continuous subcutaneous insulin infusion (CSII), 13% with 1-3 injections per day (conventional treatment). Frequency of daily injections increased with age, duration of diabetes and insulin dose. The insulin dose at breakfast was higher than for the evening meal or lunch, from diagnosis onwards. Individuals using insulin analogues received up to 11% higher insulin doses per day compared with patients treated with human insulin. The time of day, age, duration of diabetes, female gender, insulin analogues and ICT all had a significant influence on prandial insulin doses. Although the number of patients treated with ICT or CSII increased over the period of observation, mean glycated haemoglobin (HbA(1c)) was approximately 8.0% each year, and decreased by only 0.01%.

CONCLUSIONS

Eighty-seven per cent of patients were treated with ICT or CSII. However, while this percentage increased over the observation period, mean HbA(1c) was almost constant. Longer duration of diabetes, increasing age, female gender, insulin analogues and ICT were associated with higher prandial insulin doses.

Molecular features and clinical phenotypes in androgen insensitivity syndrome in the absence and presence of androgen receptor gene mutations

Androgen insensitivity syndrome (AIS) is characterized by deficient or absent virilization in 46,XY individuals despite normal or even elevated androgen levels. AIS is usually caused by mutations in the androgen receptor (AR) gene. We aimed at contrasting clinical, biochemical, and molecular genetic characteristics of three patients (P1-P3) with clinically evident partial (P1) and complete (P2, P3) AIS with and without AR gene mutations. AR expression was studied in cultured genital skin fibroblasts (GSF) by Western immunoblotting, ligand binding analyses, Northern blotting, semiquantitative reverse transcription-polymerase chain reaction (RT-PCR), and RT-PCR spanning exons 1-8. AR gene DNA sequence was analyzed by single-strand conformation analysis (SSCA), and DNA sequencing. GSF revealed reduced (P1) or absent (P2, P3) ligand binding. Northern blots showed either slightly reduced hybridization of the 10.5-kb AR transcript (P3) or no hybridization (P1, P2), as confirmed by semiquantitative RT-PCR. RT-PCR spanning exons 1-8 detected single AR mRNA bands in P1-P3 excluding splicing errors. Western analyses showed either low (P1) or no (P2, P3) AR protein. While SSCA initially did not reveal any molecular abnormality, sequencing showed a novel CAG (Gln) to TAG (stop) mutation at codon 59 (P3) and a previously described 2-bp deletion at codon 472, leading to a frameshift and premature stop in codon 499 (P2). Intriguingly, P1 showed an unaltered DNA sequence of the coding region of the AR gene including all intron-exon boundaries. In conclusion, patients with clinically evident complete AIS are likely to harbor an AR gene mutation, demanding that the two polymorphic regions must always be included in molecular analyses of the AR gene. Moreover, our data support the concept that in a subset of AIS patients, particularly those with partial AIS, molecular alterations outside the coding region of the AR gene must be presumed.

Transactivation Properties of Wild-Type and Mutant Androgen Receptors in Transiently Transfected Primary Human Fibroblasts

BACKGROUND

Stromal cells play key roles during androgen-mediated male sexual differentiation. Our objective was to establish a transient transfection method for primary human fibroblasts enabling functional characterization of wild-type (wt) and mutant androgen receptor (AR) plasmid constructs, corresponding to partial and complete androgen insensitivity syndrome (PAIS/CAIS).

METHODS

An AR-negative fibroblast strain (ARD842) was established from the gonads of a CAIS patient. Wt-AR or either mutants L712F (PAIS), R774C or V866M (CAIS) were transfected using a polyamine-based procedure. Alternatively, two AR-positive male foreskin fibroblast strains were investigated. Androgen-induced activation of two co-transfected reporter plasmids ((ARE)(2)TATA-, MMTV-luciferase) was measured.

RESULTS

All three fibroblast strains showed a ligand-dependent rise of luciferase activity after transfection of wt-AR. Mutant plasmids were assessed in AR-negative ARD842 cells. While L712F showed high partial activity, R774C and V866M were nearly inactive. The intrinsic AR of normal foreskin fibroblasts revealed no measurable ligand-inducible reporter gene activity.

CONCLUSIONS

Polyamine-based transfection of AR plasmids into cultured fibroblasts provides a promising tool for analysis of AR transactivation, thereby considering a stromal cellular background. This is supported by the mutant ARs which showed the expected levels of impaired transactivation with respect to the corresponding AIS phenotypes. The role of the intrinsic AR in normal male human foreskin fibroblasts needs further exploration.

Novel insertion frameshift mutation of the LH receptor gene: problematic clinical distinction of Leydig cell hypoplasia from enzyme defects primarily affecting testosterone biosynthesis

Leydig cell hypoplasia (LCH) is a rare autosomal recessive condition that interferes with normal development of male external genitalia in 46,XY individuals and is caused by inactivating mutations of the LH receptor gene. The clinical and biochemical diagnostic parameters of LCH are not always specific and may therefore show significant overlap with other causes of insufficient testicular steroid biosynthesis. We have studied a 46,XY newborn with completely female external genitalia and palpable testes. Due to an increased basal serum ratio of androstenedione/testosterone, 17 beta-hydroxysteroid dehydrogenase type 3 (17 beta-HSD 3) deficiency was initially suspected. DNA analysis of the corresponding HSD17B3 gene, however, showed no abnormalities in the entire coding region. In contrast, direct sequencing of the LH receptor gene revealed a novel homozygous single nucleotide insertion in exon 11 (codon A589fs) producing a frame shift in the open reading frame predicting for premature termination of translation 17 amino acids downstream. From the genetic perspective, this mutation represents the first frame shift mutation in the LH receptor gene ever reported to date. From the clinical standpoint, LCH should always be considered in the differential diagnosis as steroid profiles may not be informative. Therefore, molecular genetic analysis should be warranted for androgen biosynthesis defects in all cases.

Anabolic steroids, testosterone-precursors and virilizing androgens induce distinct activation profiles of androgen responsive promoter constructs

Different androgens, e.g. virilizing androgens such as testosterone and its precursors as well as synthetic anabolic steroids, respectively, induce diverse biological effects. The molecular basis for this variety in biological actions, however, is not well understood. We hypothesized that this variability of actions may be due to steroid-specific target gene expression profiles following androgen receptor (AR)-activation. Therefore, we investigated androgen receptor dependent transactivation of three structurally different androgen responsive promoter constructs ((ARE)(2)TATA-luc, MMTV-luc, GRE-OCT-luc) in co-transfected Chinese hamster ovary (CHO)-cells as an artificial model simulating different natural target genes. Three virilizing androgens (dihydrotestosterone, testosterone, methyltrienolone), three anabolic steroids (oxandrolone, stanozolol, nandrolone) and two testosterone-precursors of gonadal and adrenal origin (dehydroepiandrosterone, androstenedione) were used as ligands (0.001-100 nM). All steroids proved to be potent activators of the AR. Remarkably, anabolic steroids and testosterone-precursors showed characteristic promoter activation profiles distinct from virilizing androgens with significantly lower (ARE)(2)TATA-luc activation. Hierarchical clustering based on similarity of activation profiles lead to a dendrogram with two major branches: first virilizing androgens, and second anabolics/testosterone-precursors. We conclude that steroid-specific differences in gene transcription profiles due to androgen receptor activation could contribute to differences in biological actions of androgens.

A unique exonic splicing mutation in the human androgen receptor gene indicates a physiologic relevance of regular androgen receptor transcript variants

In a patient with partial androgen insensitivity syndrome (AIS), we identified a single inherited presumably silent nucleotide variation (AGC -> AGT) in exon 8 (codon 888) of the AR gene. However, in the patient's genital skin fibroblasts, a considerably shortened transcript of 5.5 kb (normal: 10.5 kb) was detected, which misses a part of exon 8 and a prominent portion of the 3'-untranslated region. The translation product includes eight missense amino acids from codon 886 onward followed by a premature stop codon. As shown by in vitro expression analysis, the mutant protein lacks any residual function. However, reverse transcribed PCRs and sequence data indicate the existence of two additional splicing variants of 6.4 kb and 7.8-kb length both in patient and normal control genital skin fibroblasts. These splicing variants comprise the complete coding region but a shortened 3'-untranslated region. Thus, a distinct alternative pre-messenger RNA-processing event leading to two additional transcripts occurs generally in genital skin fibroblasts. In addition, this process partially prevents aberrant splicing in the patient and produces a small fraction of normal, functionally intact AR-protein that could explain the partial masculinization in this patient. This first report of an exonic splicing mutation in the AR-gene indicates a physiologic relevance of the regular AR-messenger RNA variants with shortened 3'-untranslated regions and their functional translation products in human genital development.

Phenotypic diversity and testosterone-induced normalization of mutant L712F androgen receptor function in a kindred with androgen insensitivity

Molecular causes of phenotypic diversity in androgen insensitivity syndrome, occurring even in the same family, have rarely been identified. We report on a family with four affected individuals, three brothers (B1-3) and their uncle, displaying strikingly different external genitalia: B1, ambiguous; B2, severe micropenis; B3, slight micropenis; and uncle, micropenis and penoscrotal hypospadias. All had been assigned a male gender. We detected the same L712F mutation of the androgen receptor (AR) gene in each subject. Methyltrienolone binding on cultured genital skin fibroblasts of B2 suggested moderate impairment of the ligand-binding domain [maximal binding capacity, 38.2 fmol/mg protein (normal); Kd, 0.21 nmol/L; normal range, 0.03-0.13 nmol/L]. In trans-activation assays, the mutant 712F-AR showed considerable deficiency at low concentrations of testosterone (0.01-0.1 nmol/L) or dihydrotestosterone (0.01 nmol/L). Remarkably, this could be fully neutralized by testosterone concentrations greater than 1.0 nmol/L. Hence, the 712F-AR could switch its function from subnormal to normal within the physiological concentration range of testosterone. This was reflected by an excellent response to testosterone therapy in B1, B2, and the uncle. Taking into account the well documented individual and time-dependent variation in testosterone concentration in early fetal development, our observations clearly illustrate the potential impact of varying ligand concentrations for distinct cases of phenotypic variability in androgen insensitivity syndrome.

Significance of mutations in the androgen receptor gene in males with idiopathic infertility

Abnormal human spermatogenesis is caused by a variety of genetic and acquired conditions. Because spermatogenesis is dependent on androgens, some males may have a minimal form of androgen insensitivity that does not inhibit virilization but impairs fertility. This has lead us to investigate the possibility of abnormalities in the androgen receptor (AR) gene in a large cohort of males suffering from infertility of unknown cause. We studied 180 males with variable impairment of spermatogenesis. In all patients, serum levels of testosterone and gonadotropins were analyzed to define an androgen sensitivity index (ASI). Single-strand conformation analysis and direct DNA sequencing of PCR-amplified blood leukocyte DNA were used to identify mutations within the whole coding region of the AR-gene. Endocrine and molecular investigations were compared with 53 normal males with proven fertility. In three infertile males, mutations in the AR were identified. Two unrelated males had the same variation within the first exon encoding for the transactivation domain of the receptor (Pro390Ser), whereas, in the third, a mutation in the hormone-binding region was characterized (Gln798Glu). All identified mutation carriers had a significantly elevated ASI. A proportion of males with idiopathic infertility carry relevant variations within the AR-gene. These males may be distinguished on the basis of hormone levels, calculating the ASI, although this index lacks specificity.

The molecular basis of male sexual differentiation

Male sexual differentiation is the result of complex mechanisms involving developmental genetics and endocrinology. Formation of the bipotential gonads and subsequently the testes is dependent on a series of sex chromosome-linked and autosomal genes. The testes secrete both peptide and steroid hormones essential for the formation of internal and external genitalia. Hormone action is mediated via specific receptors, functioning as transcription regulators. Disruption of these genetic events leads to sexual dimorphism involving external and internal genitalia, and may also interfere with the development of other organs.

Clinical and molecular spectrum of somatic mosaicism in androgen insensitivity syndrome

We recently found that postzygotic de novo mutations occur at the expected high rate of an X-linked recessive mutation in androgen insensitivity syndrome. The resulting somatic mosaicism can be an important molecular determinant of in vivo androgen action caused by expression of the wild-type androgen receptor (AR). However, the clinical relevance of this previously underestimated genetic condition in androgen insensitivity syndrome has not been investigated in detail as yet. Here, we present the clinical and molecular spectrum of somatic mosaicism considering all five patients with mosaic androgen insensitivity syndrome, whom we have identified since 1993: Patient 1 (predominantly female, clitoromegaly), 172 TTA(Leu)/TGA(Stop); patient 2 (ambiguous), 596 GCC(Ala)/ACC(Thr); patient 3 (ambiguous), 733 CAG(Gln)/ CAT(His); patient 4 (completely female), 774 CGC(Arg)/TGC (Cys); and patient 5 (ambiguous), 866 GTG(Val)/ATG(Met). Serum sex hormone binding globulin response to stanozolol, usually correlating well with in vivo AR function, was inconclusive for assessment of the phenotypes in all tested mosaic individuals. An unexpectedly strong virilization occurred in patients 1, 3, and 5 compared with phenotypes as published with corresponding inherited mutations and compared with the markedly impaired transactivation caused by the mutant ARs in cotransfection experiments. Only the prepubertal virilization of patients 2 and 4 matched appropriately with transactivation studies (patient 4) or the literature (patients 2 and 4). However, partial pubertal virilization in patient 4 caused by increasing serum androgens and subsequent activation of the wild-type AR could not be excluded. We conclude that somatic mosaicism is of particular clinical relevance in androgen insensitivity syndrome. The possibility of functionally relevant expression of the wild-type AR needs to be considered in all mosaic individuals, and treatment should be adjusted accordingly.