An in vivo functional assay to characterize human STAT5B genetic variants during zebrafish development.

Growth hormone (GH) binding to GH receptor activates janus kinase 2 (JAK2)-signal transducer and activator of transcription 5b (STAT5b) pathway, which stimulates transcription of insulin-like growth factor-1 (IGF1), insulin-like growth factor binding protein 3 (IGFBP3) and insulin-like growth factor acid-labile subunit (IGFALS). Although STAT5B deficiency was established as an autosomal recessive disorder, heterozygous dominant-negative STAT5B variants have been reported in patients with less severe growth deficit and milder immune dysfunction. We developed an in vivo functional assay in zebrafish to characterize the pathogenicity of three human STAT5B variants (p.Ala630Pro, p.Gln474Arg and p.Lys632Asn). Overexpression of human wild-type (WT) STAT5B mRNA and its variants led to a significant reduction of body length together with developmental malformations in zebrafish embryos. Overexpression of p.Ala630Pro, p.Gln474Arg or p.Lys632Asn led to an increased number of embryos with pericardial edema, cyclopia and bent spine compared with WT STAT5B. Although co-injection of WT and p.Gln474Arg and WT and p.Lys632Asn STAT5B mRNA in zebrafish embryos partially or fully rescues the length and the developmental malformations in zebrafish embryos, co-injection of WT and p.Ala630Pro STAT5B mRNA leads to a greater number of embryos with developmental malformations and a reduction in body length of these embryos. These results suggest that these variants could interfere with endogenous stat5.1 signaling through different mechanisms. In situ hybridization of zebrafish embryos overexpressing p.Gln474Arg and p.Lys632Asn STAT5B mRNA shows a reduction in igf1 expression. In conclusion, our study reveals the pathogenicity of the STAT5B variants studied.

Diagnosing and treating anterior pituitary hormone deficiency in pediatric patients.

Hypopituitarism, or the failure to secrete hormones produced by the anterior pituitary (adenohypophysis) and/or to release hormones from the posterior pituitary (neurohypophysis), can be congenital or acquired. When more than one pituitary hormone axis is impaired, the condition is known as combined pituitary hormone deficiency (CPHD). The deficiency may be primarily due to a hypothalamic or to a pituitary disorder, or concomitantly both, and has a negative impact on target organ function. This review focuses on the pathophysiology, diagnosis and management of anterior pituitary hormone deficiency in the pediatric age. Congenital hypopituitarism is generally due to genetic disorders and requires early medical attention. Exposure to toxicants or intrauterine infections should also be considered as potential etiologies. The molecular mechanisms underlying the fetal development of the hypothalamus and the pituitary are well characterized, and variants in the genes involved therein may explain the pathophysiology of congenital hypopituitarism: mutations in the genes expressed in the earliest stages are usually associated with syndromic forms whereas variants in genes involved in later stages of pituitary development result in non-syndromic forms with more specific hormone deficiencies. Tumors or lesions of the (peri)sellar region, cranial radiation therapy, traumatic brain injury and, more rarely, other inflammatory or infectious lesions represent the etiologies of acquired hypopituitarism. Hormone replacement is the general strategy, with critical periods of postnatal life requiring specific attention.

Assessment of testicular function in boys and adolescents.

OBJECTIVE: The hypothalamic-pituitary-testicular axis is characterised by the existence of major functional changes from its establishment in fetal life until the end of puberty. The assessment of serum testosterone and gonadotrophins and semen analysis, typically used in the adult male, is not applicable during most of infancy and childhood. On the other hand, the disorders of gonadal axis have different clinical consequences depending on the developmental stage at which the dysfunction is established. This review addresses the approaches to evaluate the hypothalamic-pituitary-testicular axis in the newborn, during childhood and at pubertal age. DESIGN: We focused on the hormonal laboratory and genetic studies as well as on the clinical signs and imaging studies that guide the aetiological diagnosis and the functional status of the gonads. RESULTS: Serum gonadotrophin and testosterone determination is useful in the first 3-6 months after birth and at pubertal age, whereas AMH and inhibin B are useful biomarkers of testis function from birth until the end of puberty. Clinical and imaging signs are helpful to appraise testicular hormone actions during fetal and postnatal life. CONCLUSIONS: The interpretation of results derived from the assessment of hypothalamic-pituitary-testicular in paediatric patients requires a comprehensive knowledge of the developmental physiology of the axis to understand its pathophysiology and reach an accurate diagnosis of its disorders.

Growth, puberty and testicular function in boys born small for gestational age with a nonspecific disorder of sex development.

OBJECTIVE: Being born small for gestational age (SGA) is frequently associated with unexplained disorders of sex development (nonspecific DSD) in boys. Little is known about their future growth, puberty and testicular function. Our objective is to determine the long-term endocrine outcome of boys born SGA who have a nonspecific DSD. DESIGN: Boys with a nonspecific DSD born SGA and appropriate for GA (AGA) were retrieved through the International Disorders of Sex Development registry and retrospective data collected, based on a spreadsheet containing 102 items. PATIENTS AND MEASUREMENTS: In total, 179 boys were included, of which 115 were born SGA and 64 were born AGA. Their growth and pubertal development were compared. Serum LH, FSH, testosterone, AMH and inhibin B levels in infancy and puberty were analysed to assess testicular function. RESULTS: At 2 years of age, 30% of SGA boys had incomplete or absent catch-up growth. Boys born SGA also had higher LH during minipuberty and lower testosterone in stimulation tests (p = 0.037 and 0.040, respectively), as compared to boys born AGA. No differences were observed in timing or course of puberty or end-pubertal hormone levels. CONCLUSIONS: Almost one out of three SGA boys with a nonspecific DSD experiences insufficient catch-up growth. In addition, our data suggest dysfunction of infantile Leydig cells or altered regulation of the hypothalamic-pituitary-gonadal axis in SGA boys during childhood. Sex steroid production during puberty seems unaffected.

A mutation inactivating the distal SF1 binding site on the human anti-Müllerian hormone promoter causes persistent Müllerian duct syndrome.

The persistent Müllerian duct syndrome (PMDS) is a 46,XY disorder of sexual development characterized by the persistence of Müllerian duct derivatives, uterus and tubes, in otherwise normally masculinized males. The condition, transmitted as a recessive autosomal trait, is usually due to mutations in either the anti-Müllerian hormone (AMH) gene or its main receptor. Many variants of these genes have been described, all targeting the coding sequences. We report the first case of PMDS due to a regulatory mutation. The AMH promoter contains two binding sites for steroidogenic factor 1 (SF1), one at -102 and the other at -228. Our patient carries a single base deletion at -225, significantly decreasing its capacity for binding SF1, as measured by the electrophoresis mobility shift assay. Furthermore, by linking the AMH promoter to the luciferase gene, we show that the transactivation capacity of the promoter is significantly decreased by the mutation, in contrast to the disruption of the -102 binding site. To explain the difference in impact we hypothesize that SF1 could partially overcome the lack of binding to the -102 binding site by interacting with a GATA4 molecule linked to a nearby response element. We show that disruption of both the -102 SF1 and the -84 GATA response elements significantly decreases the transactivation capacity of the promoter. In conclusion, we suggest that the distance between mutated SF1 sites and potentially rescuing GATA binding motifs might play a role in the development of PMDS.

CYP26B1 declines postnatally in Sertoli cells independently of androgen action in the mouse testis.

Meiosis begins at puberty and relies on several factors, including androgens and retinoic acid in the mouse testis. CYP26B1 degrades retinoic acid in the testis during prenatal development preventing meiosis initiation. Given the concurrence of meiotic entry and completion of Sertoli cell maturation in response to androgens at puberty in the mouse, we proposed that CYP26B1 is downregulated by androgens in the Sertoli cell during this period. By immunohistochemistry, we showed that CYP26B1 declines in Sertoli cells after birth. However, luciferase reporter assays and quantitative reverse transcription-polymerase chain reaction performed in the prepubertal mouse Sertoli cell line SMAT1 revealed no changes in Cyp26b1 expression in response to androgen treatment. Furthermore, studies carried out using primary Sertoli cells of 10-day-old mice showed no changes in either Cyp26b1 or CYP26B1 expression in response to androgen treatment. In summary, the hereby reported decline in CYP26B1 expression in Sertoli cells towards pubertal onset does not appear to be caused by a direct inhibitory effect of androgens on Sertoli cells in the mouse.

Expression of acid-labile subunit (ALS) in developing and adult zebrafish and its role in dorso-ventral patterning during development.

Mammalian acid-labile subunit (ALS) is a serum protein that binds binary complexes between Insulin-like growth factors (IGFs) and Insulin-like growth factor-binding proteins (IGFBPs) extending their half-life and keeping them in the vasculature. Human ALS deficiency (ACLSD), due to homozygous or compound heterozygous mutations in IGFALS, leads to moderate short stature with reduced levels of IGF-I and IGFBP-3. There is only one corresponding zebrafish ortholog gene and it has not yet been studied. In this study we elucidate the role of igfals during zebrafish development. In zebrafish embryos igfals mRNA is expressed throughout development, mainly in the brain and subsequently also in the gut and swimbladder. To determine its role during development, we knocked down igfals gene product using morpholinos (MOs). Igfals morphant embryos displayed dorsalization in different degrees of severity, including a shortened trunk and loss of tail. Furthermore, co-injection of human IGFALS (hIGFALS) mRNA was able to rescue the MO-induced phenotype. Finally, overexpression of either hIGFALS or zebrafish igfals (zigfals) mRNA leads to ventralization of embryos including a reduced head and enlarged tail. These findings suggest that als plays an important role in dorso-ventral patterning during zebrafish development.

Safety of standardised treatments for haematologic malignancies as regards to testicular endocrine function in children and teenagers.

STUDY QUESTION: Does standardised treatments used in children and adolescents with haematologic malignancies, including acute lymphoblastic (ALL) or myeloid leukaemia (AML) and non-Hodgkin lymphoma (NHL), affect endocrine function of the developing testes? SUMMARY ANSWER: Therapy of haematologic malignancies do not provoke an overt damage of Sertoli and Leydig cell populations, as revealed by normal levels of anti-Müllerian hormone (AMH) and testosterone, but a mild primary testicular dysfunction may be observed, compensated by moderate gonadotropin elevation, during pubertal development. WHAT IS KNOWN ALREADY: Evidence exists on the deleterious effect that chemotherapy and radiotherapy have on germ cells, and some attention has been given to the effects on Leydig and Sertoli cells of the adult gonads, but information is virtually non-existent on the effects of oncologic treatment on testicular somatic cell components during childhood and adolescence. STUDY DESIGN, SIZE, DURATION: A retrospective, analytical, observational study included 97 boys with haematological malignancies followed at two tertiary paediatric public hospitals in Buenos Aires, Argentina, between 2002 and 2015. PARTICIPANTS/MATERIALS, SETTING, METHODS: Clinical records of males aged 1-18 years, referred with the diagnoses of ALL, AML or NHL for the assessment of gonadal function, were eligible. We assessed serum levels of AMH and FSH as biomarkers of Sertoli cell endocrine function and testosterone and LH as biomarkers of Leydig cell function. MAIN RESULTS AND THE ROLE OF CHANCE: All hormone levels were normal in the large majority of patients until early pubertal development. From Tanner stage G3 onwards, while serum AMH and testosterone kept within the normal ranges, gonadotropins reached mildly to moderately elevated values in up to 35.9% of the cases, indicating a compensated Sertoli and/or Leydig cell dysfunction, which generally did not require hormone replacement therapy. LIMITATIONS, REASONS FOR CAUTION: Serum inhibin B determination and semen analysis were not available for most patients; therefore, we could not conclude on potential fertility impairment or identify whether primary Sertoli cell dysfunction resulted in secondary depleted spermatogenesis or whether primary germ cell damage impacted Sertoli cell function. WIDER IMPLICATIONS OF THE FINDINGS: The regimens used in the treatment of boys and adolescents with ALL, AML or NHL in the past two decades seem relatively safe for endocrine testicular function; nonetheless, a mild primary testicular endocrine dysfunction may be observed, usually compensated by slightly elevated gonadotropin secretion by the pituitary in adolescents, and not requiring hormone replacement therapy. No clinically relevant risk factor, such as severity of the disease or treatment protocol, could be identified in association with the compensated endocrine dysfunction. STUDY FUNDING/COMPETING INTEREST(S): This work was partially funded by grants PIP 11220130100687 of Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) and PICT 2016-0993 of Fondo para la Investigación Científica y Tecnológica (FONCYT), Argentina. R.A.R., R.P.G. and P.B. have received honoraria from CONICET (Argentina) for technology services using the AMH ELISA. L.A.A. is part-time employee of CSL Behring Argentina. The other authors have no conflicts of interest to disclose.

Molecular Characterization of XX Maleness.

Androgens and anti-Müllerian hormone (AMH), secreted by the foetal testis, are responsible for the development of male reproductive organs and the regression of female anlagen. Virilization of the reproductive tract in association with the absence of Müllerian derivatives in the XX foetus implies the existence of testicular tissue, which can occur in the presence or absence of SRY. Recent advancement in the knowledge of the opposing gene cascades driving to the differentiation of the gonadal ridge into testes or ovaries during early foetal development has provided insight into the molecular explanation of XX maleness.

Androgens downregulate anti-Müllerian hormone promoter activity in the Sertoli cell through the androgen receptor and intact steroidogenic factor 1 sites.

Testicular anti-Müllerian hormone (AMH) production is inhibited by androgens around pubertal onset, as observed under normal physiological conditions and in patients with precocious puberty. In agreement, AMH downregulation is absent in patients with androgen insensitivity. The molecular mechanisms underlying the negative regulation of AMH by androgens remain unknown. Our aim was to elucidate the mechanisms through which androgens downregulate AMH expression in the testis. A direct negative effect of androgens on the transcriptional activity of the AMH promoter was found using luciferase reporter assays in the mouse prepubertal Sertoli cell line SMAT1. A strong inhibition of AMH promoter activity was seen in the presence of both testosterone and DHT and of the androgen receptor. By site-directed mutagenesis and chromatin immunoprecipitation assays, we showed that androgen-mediated inhibition involved the binding sites for steroidogenic factor 1 (SF1) present in the proximal promoter of the AMH gene. In this study, we describe for the first time the mechanism behind AMH inhibition by androgens, as seen in physiological and pathological conditions in males. Inhibition of AMH promoter activity by androgens could be due to protein-protein interactions between the ligand-bound androgen receptor and SF1 or by blockage of SF1 binding to its sites on the AMH promoter.

Characterization of four Latin American families confirms previous findings and reveals novel features of acid-labile subunit deficiency.

OBJECTIVE: Acid-labile subunit deficiency (ACLSD), caused by inactivating mutations in both IGFALS gene alleles, is characterized by marked reduction in IGF-I and IGFBP-3 levels associated with mild growth retardation. The aim of this study was to expand the known phenotype and genetic characteristics of ACLSD by reporting data from four index cases and their families. DESIGN: Auxological data, biochemical and genetic studies were performed in four children diagnosed with ACLSD and all available relatives. METHODS: Serum levels of IGF-I, IGFBP-3, acid-labile subunit (ALS), and in vitro ternary complex formation (ivTCF) were determined. After sequencing the IGFALS gene, pathogenicity of novel identified variants was evaluated by in vitro expression in transfected Chinese hamster ovarian (CHO) cells. ALS protein was detected in patients' sera and CHO cells conditioned media and lysates by Western immunoblot (WIB). RESULTS: Four index cases and four relatives were diagnosed with ACLSD. The following variants were found: p.Glu35Glyfs*17, p.Glu35Lysfs*87, p.Leu213Phe, p.Asn276Ser, p.Leu409Phe, p.Ala475Val and p.Ser490Trp. ACLSD patients presented low IGF-I and low or undetectable levels of IGFBP-3 and ALS. Seven out of 8 patients did not form ivTCF. CONCLUSIONS: This study confirms previous findings in ACLSD, such as the low IGF-I and a more severe reduction in IGFBP-3 levels, and a gene dosage effect observed in heterozygous carriers (HC). In addition, father-to-son transmission (father compound heterozygous and mother HC), preservation of male fertility, and marginal ALS expression with potential involvement in preserved responsiveness to rhGH treatment, are all novel aspects, not previously reported in this condition.

When hormone defects cannot explain it: malformative disorders of sex development.

The birth of a baby with malformations of the genitalia urges medical action. Even in cases where the condition is not life-threatening, the identification of the external genitalia as male or female is emotionally essential for the family, and genital malformations represent one of the most stressful situations around a newborn. The female or male configuration of the genitalia normally evolves during fetal life according to the genetic, gonadal, and hormonal sex. Disorders of sex development occur when male hormone (androgens and anti-Müllerian hormone) secretion or action is insufficient in the 46,XY fetus or when there is an androgen excess in the 46,XX fetus. However, sex hormone defects during fetal development cannot explain all congenital malformations of the reproductive tract. This review is focused on those congenital conditions in which gonadal function and sex hormone target organ sensitivity are normal and, therefore, not responsible for the genital malformation. Furthermore, because the reproductive and urinary systems share many common pathways in embryo-fetal development, conditions associating urogenital malformations are discussed.

Testicular function during adolescence in boys with type 1 diabetes mellitus (T1D): absence of hypogonadism and differences in endocrine profile at the beginning and end of puberty.

AIM: Conflicting results regarding testicular function in adults with type 1 diabetes (T1D) have been reported, but little is known about Leydig and Sertoli cell function during puberty in boys treated with multiple daily insulin doses. Our aim was to assess testicular function in boys with T1D. METHODS: Pubertal boys with T1D (n = 71) and healthy control boys (Control group; n = 104) who were 10-18 years were studied. Both groups were matched by pubertal stage, age, and BMI. Total testosterone (TT), calculated free testosterone (cfT), SHBG, inhibin B, AMH, and gonadotropin levels were determined. RESULTS: At the beginning of puberty, the T1D group had higher levels of SHBG (p = 0.003) and similar androgen levels than the Control group. At the end of puberty, higher TT, and cfT were observed in T1D compared to the Control group (p < 0.01 and p < 0.001, respectively). Gonadotropins and AMH were similar in both groups. Regression analysis showed that T1D was a significant factor, even after adjusting for Tanner stage and BMI-SDS, affecting TT, cFT, and SHBG levels. BMI-SDS was a significant factor affecting TT and SHBG levels. Higher HbA1c had a negative effect on total testosterone and cFT and a positive effect on SHBG levels in T1D boys. CONCLUSION: Adolescents with T1D do not exhibit hypogonadism, as shown by normal gonadotropin, testosterone, inhibin B, and AMH levels. However, in T1D boys, HbA1c and BMI-SDS had a negative association with testosterone levels. Elevated testosterone levels are observed during late puberty, which were not present earlier.

Anti-Müllerian hormone, testicular descent and cryptorchidism.

Anti-Müllerian hormone (AMH) is a Sertoli cell-secreted glycoprotein involved in male fetal sex differentiation: it provokes the regression of Müllerian ducts, which otherwise give rise to the Fallopian tubes, the uterus and the upper part of the vagina. In the first trimester of fetal life, AMH is expressed independently of gonadotropins, whereas from the second trimester onwards AMH testicular production is stimulated by FSH and oestrogens; at puberty, AMH expression is inhibited by androgens. AMH has also been suggested to participate in testicular descent during fetal life, but its role remains unclear. Serum AMH is a well-recognized biomarker of testicular function from birth to the first stages of puberty. Especially in boys with nonpalpable gonads, serum AMH is the most useful marker of the existence of testicular tissue. In boys with cryptorchidism, serum AMH levels reflect the mass of functional Sertoli cells: they are lower in patients with bilateral than in those with unilateral cryptorchidism. Interestingly, serum AMH increases after testis relocation to the scrotum, suggesting that the ectopic position result in testicular dysfunction, which may be at least partially reversible. In boys with cryptorchidism associated with micropenis, low AMH and FSH are indicative of central hypogonadism, and serum AMH is a good marker of effective FSH treatment. In patients with cryptorchidism in the context of disorders of sex development, low serum AMH is suggestive of gonadal dysgenesis, whereas normal or high AMH is found in patients with isolated androgen synthesis defects or with androgen insensitivity. In syndromic disorders, assessment of serum AMH has shown that Sertoli cell function is preserved in boys with Klinefelter syndrome until mid-puberty, while it is affected in patients with Noonan, Prader-Willi or Down syndromes.

Contributions of common genetic variants to constitutional delay of puberty and idiopathic hypogonadotropic hypogonadism.

CONTEXT: Constitutional delay of puberty (CDP) is highly heritable, but the genetic basis for CDP is largely unknown. Idiopathic hypogonadotropic hypogonadism (IHH) can be caused by rare genetic variants, but in about half of cases, no rare-variant cause is found. OBJECTIVE: To determine whether common genetic variants that influence pubertal timing contribute to CDP and IHH. DESIGN: Case-control study. PARTICIPANTS: 80 individuals with CDP; 301 with normosmic IHH, and 348 with Kallmann syndrome; control genotyping data from unrelated studies. MAIN OUTCOME MEASURES: Polygenic scores (PGS) based on genome-wide association studies for timing of male pubertal hallmarks and age at menarche (AAM). RESULTS: The CDP cohort had higher PGS for male pubertal hallmarks and for AAM compared to controls (for male hallmarks, Cohen's d = 0.85, p = 1 × 10-16; for AAM, d = 0.67, p = 1 × 10-10). The normosmic IHH cohort also had higher PGS for male hallmarks compared to controls, but the difference was smaller (male hallmarks d = 0.20, p = 0.003; AAM d = 0.10, p = 0.055). No differences were seen for the KS cohort compared to controls (male hallmarks d = 0.04, p = 0.45; AAM d = -0.03, p = 0.86). CONCLUSIONS: Common genetic variants that influence pubertal timing in the general population contribute strongly to the genetics of CDP, weakly to normosmic IHH, and potentially not at all to KS. These findings demonstrate that the common-variant genetics of CDP and normosmic IHH are largely but not entirely distinct.

Case report: Novel SIN3A loss-of-function variant as causative for hypogonadotropic hypogonadism in Witteveen-Kolk syndrome.

Pubertal delay can be due to hypogonadotropic hypogonadism (HH), which may occur in association with anosmia or hyposmia and is known as Kallmann syndrome (OMIM #308700). Recently, hypogonadotropic hypogonadism has been suggested to overlap with Witteveen-Kolk syndrome (WITKOS, OMIM #613406) associated with 15q24 microdeletions encompassing SIN3A. Whether hypogonadotropic hypogonadism is due to haploinsufficiency of SIN3A or any of the other eight genes present in 15q24 is not known. We report the case of a female patient with delayed puberty associated with intellectual disability, behavior problems, dysmorphic facial features, and short stature, at the age of 14 years. Clinical, laboratory, and imaging assessments confirmed the diagnosis of Kallmann syndrome. Whole-exome sequencing identified a novel heterozygous frameshift variant, NM_001145358.2:c.3045_3046dup, NP_001138830.1:p.(Ile1016Argfs*6) in SIN3A, classified as pathogenic according to the American College of Medical Genetics and Genomics (ACMG/AMP) criteria. Reverse phenotyping led to the clinical diagnosis of WITKOS. No other variant was found in the 96 genes potentially related to hypogonadotropic hypogonadism. The analysis of the other contiguous seven genes to SIN3A in 15q24 did not reveal any clinically relevant variant. In conclusion, these findings point to SIN3A as the gene in 15q24 related to the reproductive phenotype in patients with overlapping WITKOS and Kallmann syndrome.

Accelerated early pubertal progression, ovarian morphology, and ovarian function in prospectively followed low birth weight (LBW) girls.

AIM: To compare pubertal development in age-matched healthy girls born with low birth weight (LBW) or appropriate birth weight for gestational age (AGA). SUBJECTS AND METHODS: Girls with breast in Tanner stage II and normal body mass index were followed for 3 years with a complete physical exam, bone age, pelvic ultrasound, and measurement of gonadal hormones using a leuprolide test. RESULTS: Forty-one girls (AGA 25/LBW 16) were followed up for 3 years. By 3 years, they had similar bone age, adjusted height, and body composition. In LBW girls, breast Tanner stage advanced faster during the first 2 years of follow-up, which was associated with higher serum androgens. Hirsutism score, ovarian volume, and number of follicles between AGA and LBW were not different nor was age of menarche. By the third year, basal and poststimulated levels of gonadotropins and androgens anti-Müllerian hormone and inhibin B were similar in both groups and did not show differences related to birth weight or degree of catch-up growth. CONCLUSION: LBW recruits showed a slightly faster breast development but no differences in androgen excess signs, internal genitalia, and gonadal hormonal patterns.

Steroid receptors in the testis: implications in the physiology of prenatal and postnatal development and translation to clinical application.

The testes are the main source of sex steroids in the male, especially androgens and to a lesser extent estrogens. In target cells, steroid hormones typically signal after binding to intracellular receptors, which act as transcription factors. Androgens and estrogens have ubiquitous functions in peripheral organs, but also have paracrine actions within the gonads where they are far more concentrated. The levels of steroid production by the testes vary throughout fetal and postnatal development: they are high in intrauterine life and in the first months after birth, then they decline and are almost undetectable in childhood and increase again during puberty to attain adult levels. The expression of the androgen and estrogen receptors also depict specific ontogenies in the various testicular cell types. The combination of intratesticular steroid concentration with the pattern of expression of the steroid hormone receptors defines androgen and estrogen action on Sertoli, germ and Leydig cells. Here, we review the ontogeny of expression of the androgen and estrogen receptors in the testis, its impact on testicular physiology during prenatal and postnatal development, as well as its implication on the pathophysiology of different disorders affecting gonadal function throughout life.

Challenges in managing disorders of sex development associated with adrenal dysfunction.

INTRODUCTION: Disorders of Sex Development (DSD) associated with adrenal dysfunction occur due to different defects in the proteins involved in gonadal and adrenal steroidogenesis. AREAS COVERED: The deficiencies in 21-hydroxylase and 11ß-hydroxylase lead to DSD in 46,XX patients, defects in StAR, P450scc, 17α-hydroxylase and 17,20-lyase lead to 46,XY DSD, and 3ß-HSD2 and POR deficiencies cause both 46,XX and 46,XY DSD. Challenges in diagnosis arise from the low prevalence and the variability in serum steroid profiles. Replacement therapy with hydrocortisone and fludrocortisone helps to minimize life-threatening adrenal crises; however, availability is still an unresolved problem in many countries. Adverse health outcomes, due to the disease or its treatment, are common and include adult short stature, hypertension, osteoporosis, obesity, cardiometabolic risk, and reproductive health issues. Potential biomarkers to improve monitoring and novel treatment options that have been developed with the primary aim to decrease adrenal androgen production are promising tools to help improve the health and quality of life of these patients. EXPERT OPINION: Steroid profiling by mass spectrometry and next-generation sequencing technologies represent useful tools for establishing an etiologic diagnosis and drive personalized management. Nonetheless, access to health care still remains an issue requiring urgent solutions in many resource-limited settings.

Up-to-Date Clinical and Biochemical Workup of the Child and the Adolescent with a Suspected Disorder of Sex Development.

BACKGROUND: The suspicion of a disorder of sex development (DSD) often arises at birth, when the newborn presents with ambiguous genitalia, or even during prenatal ultrasound assessments. Less frequently, the aspect of the external genitalia is typically female or male, and the diagnosis of DSD may be delayed until a karyotype is performed for another health issue, or until pubertal age when a girl presents with absence of thelarche and/or menarche or a boy consults for gynaecomastia and/or small testes. SUMMARY: In this review, we provide a practical, updated approach to clinical and hormonal laboratory workup of the newborn, the child, and the adolescent with a suspected DSD. We focus on how to specifically address the diagnostic approach according to the age and presentation. KEY MESSAGE: We particularly highlight the importance of a detailed anatomic description of the external and internal genitalia, adequate imaging studies or surgical exploration, the assessment of reproductive hormone levels - especially testosterone, anti-Müllerian hormone, 17-hydroxyprogesterone, and gonadotropins - and karyotyping.