46,XY DSD due to impaired androgen production

AAV-mediated gene therapy restores natural fertility and improves physical function in the Lhcgr-deficient mouse model of Leydig cell failure

Leydig cell failure (LCF) caused by gene mutations leads to testosterone deficiency, infertility and reduced physical function. Adeno-associated virus serotype 8 (AAV8)-mediated gene therapy shows potential in treating LCF in the Lhcgr-deficient (Lhcgr-/-) mouse model. However, the gene-treated mice still cannot naturally sire offspring, indicating the modestly restored testosterone and spermatogenesis in AAV8-treated mice remain insufficient to support natural fertility. Recognizing this, we propose that enhancing gene delivery could yield superior results. Here, we screened a panel of AAV serotypes through in vivo transduction of mouse testes and identified AAVDJ as an impressively potent vector for testicular cells. Intratesticular injection of AAVDJ achieved markedly efficient transduction of Leydig cell progenitors, marking a considerable advance over conventional AAV8 vectors. AAVDJ-Lhcgr gene therapy was well tolerated and resulted in significant recovery of testosterone production, substantial improvement in sexual development, and remarkable restoration of spermatogenesis in Lhcgr-/- mice. Notably, this therapy restored fertility in Lhcgr-/- mice through natural mating, enabling the birth of second-generation. Additionally, this treatment led to remarkable improvements in adipose, muscle, and bone function in Lhcgr-/- mice. Collectively, our findings underscore AAVDJ-mediated gene therapy as a promising strategy for LCF and suggest its broader potential in addressing various reproductive disorders.

Elevated plasma miR-210 expression is associated with atypical genitalia in patients with 46,XY differences in sex development

BACKGROUND

Differences of sex development (DSD) is a term used for conditions in which the chromosomal, gonadal or phenotypical sex is atypical. 46,XY DSD patients frequently present undervirilized external genitalia. The expression of different miRNAs in many organs of the male genital system has been reported, and these miRNAs have been associated with testicular function and its disorders, but no description has been related to DSD conditions. This study aimed to evaluate the plasma expression of miR-210 in 46,XY DSD patients who presented atypical genitalia at birth.

METHODS

Eighteen 46,XY DSD patients who presented atypical genitalia (undescended testis and/or hypospadias, bifid scrotum or micropenis) at birth and 36 male control individuals were selected. Plasma levels of miR-210 and reference miR-23a were measured using RT-qPCR and the data were analysed by the 2^-ΔCt method.

RESULTS

MiR-210 plasma levels were significantly higher in 46,XY DSD patients with atypical genitalia than in male control subjects (p = 0.0024). A positive association between miR-210 levels and the presence of cryptorchidism and hypospadias (p = 0.0146 and p = 0.0223) was found in these patients. Significantly higher levels of miR-210 were observed in patients with 46,XY DSD and cryptorchidism than in control subjects (p = 0.0118). These results are in agreement with previous literature reports, in which increased levels of miR-210 expression were observed in human testicular tissue from adult males with undescended testes in comparison with samples of descended testes.

CONCLUSION

Our study showed a positive association between the presence of atypical genitalia and plasma levels of miR-210 expression in the group of patients with 46,XY DSD of unknown aetiology studied. These findings contribute to reveal a new perspective on the role of miRNAs in the development of male external genitalia and the broad spectrum of phenotypes presented by patients with 46,XY DSD.

AAV-mediated gene therapy produces fertile offspring in the Lhcgr-deficient mouse model of Leydig cell failure

Leydig cell failure (LCF) caused by gene mutation results in testosterone deficiency and infertility. Serum testosterone levels can be recovered via testosterone replacement; however, established therapies have shown limited success in restoring fertility. Here, we use a luteinizing hormone/choriogonadotrophin receptor (Lhcgr)-deficient mouse model of LCF to investigate the feasibility of gene therapy for restoring testosterone production and fertility. We screen several adeno-associated virus (AAV) serotypes and identify AAV8 as an efficient vector to drive exogenous Lhcgr expression in progenitor Leydig cells through interstitial injection. We observe considerable testosterone recovery and Leydig cell maturation after AAV8-Lhcgr treatment in pubertal Lhcgr^-/- mice. Of note, this gene therapy partially recovers sexual development, substantially restores spermatogenesis, and effectively produces fertile offspring. Furthermore, these favorable effects can be reproduced in adult Lhcgr^-/- mice. Our proof-of-concept experiments in the mouse model demonstrate that AAV-mediated gene therapy may represent a promising therapeutic approach for patients with LCF.

Cohort profile: pathways to care among people with disorders of sex development (DSD)

PURPOSE

The 'DSD Pathways' study was initiated to assess health status and patterns of care among people enrolled in large integrated healthcare systems and diagnosed with conditions comprising the broad category of disorders (differences) of sex development (DSD). The objectives of this communication are to describe methods of cohort ascertainment for two specific DSD conditions-classic congenital adrenal hyperplasia with 46,XX karyotype (46,XX CAH) and complete androgen insensitivity syndrome (CAIS).

PARTICIPANTS

Using electronic health records we developed an algorithm that combined diagnostic codes, clinical notes, laboratory data and pharmacy records to assign each cohort candidate a 'strength-of-evidence' score supporting the diagnosis of interest. A sample of cohort candidates underwent a review of the full medical record to determine the score cutoffs for final cohort validation.

FINDINGS TO DATE

Among 5404 classic 46,XX CAH cohort candidates the strength-of-evidence scores ranged between 0 and 10. Based on sample validation, the eligibility cut-off for full review was set at the strength-of-evidence score of ≥7 among children under the age of 8 years and ≥8 among older cohort candidates. The final validation of all cohort candidates who met the cut-off criteria identified 115 persons with classic 46,XX CAH. The strength-of-evidence scores among 648 CAIS cohort candidates ranged from 2 to 10. There were no confirmed CAIS cases among cohort candidates with scores <6. The in-depth medical record review for candidates with scores ≥6 identified 61 confirmed cases of CAIS.

FUTURE PLANS

As the first cohort of this type, the DSD Pathways study is well-positioned to fill existing knowledge gaps related to management and outcomes in this heterogeneous population. Analyses will examine diagnostic and referral patterns, adherence to care recommendations and physical and mental health morbidities examined through comparisons of DSD and reference populations and analyses of health status across DSD categories.

A rare cause of primary amenorrhea: LHCGR gene mutations

INTRODUCTION

The luteinizing hormone/choriogonadotropin receptor (LHCGR) plays a critical role in sexual differentiation and reproductive functions in men and women. Inactivating mutations in this gene lead to Leydig cell hypoplasia (LCH), and cause disorders of sex development (DSD) in patients with 46,XY. In this study, it was aimed to discuss the clinical, laboratory and molecular genetic analysis results of nine patients with 46,XY karyotype who had mutations in the LHCGR gene.

MATERIALS AND METHODS

The ages, complaints, anthropometric measurements and hormonal results (follicle stimulating hormone (FSH), luteinizing hormone (LH), testosterone) of the patients at the time of admission were recorded retrospectively from their medical records. The mutations in the LHCGR gene were investigated using the Sanger sequencing method.

FINDINGS

In this study, LHCGR gene mutations were detected in a total of nine patients as a result of the analysis of the index patients presenting with primary amenorrhea from four different families and the examination of the families. In the first three families with no consanguinity between, the same mutation was detected in seven patients in total (Homozygous c.161 + 4A > G). A different mutation was detected in the fourth family (Homozygous p.A483D c.1448C > A).

CONCLUSION

In this study, nine patients with karyotype 46,XY, most of whom presented with the complaint of delayed puberty/primary amenorrhea, were diagnosed with LCH. Especially in patients, in whom the elevation of LH is pronounced and there is no testosterone synthesis, LCH should be considered.

Testosterone therapy in children and adolescents: to whom, how, when?

Male production of testosterone is crucial for the development of a wide range of functions. External and internal genitalia formation, secondary sexual characteristics, spermatogenesis, growth velocity, bone mass density, psychosocial maturation, and metabolic and cardiovascular profiles are closely dependent on testosterone exposure. Disorders in androgen production can present during all life-stages, including childhood and adolescence, and testosterone therapy (TT) is in many cases the only treatment that can correct the underlying deficit. TT is controversial in the pediatric population as hypoandrogenism is difficult to classify and diagnose in these age groups, and standardized protocols of treatment and monitorization are still lacking. In pediatric patients, hypogonadism can be central, primary, or a combination of both. Testosterone preparations are typically designed for adults' TT, and providers need to be aware of the advantages and disadvantages of these formulations, especially cognizant of supratherapeutic dosing. Monitoring of testosterone levels in boys on TT should be tailored to the individual patient and based on the anticipated duration of therapy. Although clinical consensus is lacking, an approximation of the current challenges and common practices in pediatric hypoandrogenism could help elucidate the broad spectrum of pathologies that lie behind this single hormone deficiency with wide-ranging implications.

Late Diagnosis of Partial Androgen Insensitivity Syndrome in a Peruvian Child

Disorders of sexual differentiation are congenital pathologies characterized by atypical development of genetic, gonadal, or phenotypic sex. These are caused by the alteration of any primordial phases of sexual development and may be evident at birth or in the later stage of life. Here, we present the case of a nine-year-old Peruvian school patient who has female gender assigned at birth, has no contributory antecedents and was found to have clitoromegaly and hypospadia on physical examination. In the blood tests, anti-Müllerian hormone and testosterone were found, and 46 XY karyotype and sex-determining region Y (SRY) genes were present. On abdominal ultrasound, testicles were found in the inguinal canals. The human chorionic gonadotropin (HCG) stimulation test was conducted, which allowed us to rule out defects in testosterone biosynthesis and enzyme defects in dihydrotestosterone production; the main suspected diagnosis was partial androgen insensitivity syndrome (PAIS). A multidisciplinary medical meeting was held, accepting the patient’s desire to opt for the male gender, after acceptance by the parents. Thus, the patient underwent bilateral orchidopexy and genitoplasty. He is currently receiving therapy with testosterone, with an adequate response to the treatment and the molecular study confirmed the androgen-receptor gene mutation. In conclusion, we highlight the importance of a timely multidisciplinary diagnosis and management of disorders of sexual differentiation to avoid premature gender assignment and major social and family repercussions that it implies.

Cholesterol Contributes to Male Sex Differentiation Through Its Developmental Role in Androgen Synthesis and Hedgehog Signaling

Two specialized functions of cholesterol during fetal development include serving as a precursor to androgen synthesis and supporting hedgehog (HH) signaling activity. Androgens are produced by the testes to facilitate masculinization of the fetus. Recent evidence shows that intricate interactions between the HH and androgen signaling pathways are required for optimal male sex differentiation and defects of either can cause birth anomalies indicative of 46,XY male variations of sex development (VSD). Further, perturbations in cholesterol synthesis can cause developmental defects, including VSD, that phenocopy those caused by disrupted androgen or HH signaling, highlighting the functional role of cholesterol in promoting male sex differentiation. In this review, we focus on the role of cholesterol in systemic androgen and local HH signaling events during fetal masculinization and their collective contributions to pediatric VSD.

Androgen Treatment in Adolescent Males With Hypogonadism

During adolescence, androgens are responsible for the development of secondary sexual characteristics, pubertal growth, and the anabolic effects on bone and muscle mass. Testosterone is the most abundant testicular androgen, but some effects are mediated by its conversion to the more potent androgen dihydrotestosterone (DHT) or to estradiol. Androgen deficiency, requiring replacement therapy, may occur due to a primary testicular failure or secondary to a hypothalamic–pituitary disorder. A very frequent condition characterized by a late activation of the gonadal axis that may also need androgen treatment is constitutional delay of puberty. Of the several testosterone or DHT formulations commercially available, very few are employed, and none is marketed for its use in adolescents. The most frequently used androgen therapy is based on the intramuscular administration of testosterone enanthate or cypionate every 3 to 4 weeks, with initially low doses. These are progressively increased during several months or years, in order to mimic the physiology of puberty, until adult doses are attained. Scarce experience exists with oral or transdermal formulations. Preparations containing DHT, which are not widely available, are preferred in specific conditions. Oxandrolone, a non-aromatizable drug with higher anabolic than androgenic effects, has been used in adolescents with preserved testosterone production, like Klinefelter syndrome, with positive effects on cardiometabolic health and visual, motor, and psychosocial functions. The usual protocols applied for androgen therapy in boys and adolescents are discussed.

A novel variant in LCHGR gene in 3 siblings with type 1 Leydig cell hypoplasia

INTRODUCTION

Leydig cell hypoplasia (LCH) is an autosomal recessive disease that causes 46, XY sex development disorder. The patients with LCH are usually in the female phenotype and are presented with the complaints of no breast development and primary amenorrhea. In this article, the cases of three siblings who presented with primary amenorrhea and who had LCH were presented.

CASE

A 16-year-old patient with female phenotype is presented with primary amenorrhea. Breast development was at Tanner stage 1, the external genitalia were completely in female phenotype. The karyotype was determined as 46, XY. The hormonal analyses revealed that the testosterone synthesis was insufficient despite the high level of luteinizing hormone (LH). Cortisol, ACTH, 17-Hydroxyprogesterone, and AMH levels were normal. LCH diagnosis was considered in the patient with elevated LH and no testosterone synthesis. A new mutation of homozygous c.161 + 4A > G was detected in LHCGR gene. The same mutation was detected in the patient's two siblings with female phenotype and 46, XY karyotype.

CONCLUSION

In patients presenting with primary amenorrhea and karyotype 46, XY, there is no testosterone synthesis and if there is LH elevation, LCH should be considered. We found a novel variant in the LHCGR gene in three siblings with karyotype 46, XY and female phenotype.

Biomarcadores de hipogonadismo masculino en la infancia y la adolescencia

El eje hipotálamo-hipófiso-testicular es activo en la vida fetal y durante los primeros meses de la vida posnatal: la hipófisis secreta hormona luteinizante (LH) y folículo-estimulante (FSH), mientras que el testículo produce testosterona y factor insulino-símil 3 (INSL3) en las células de Leydig y hormona anti-Mülleriana (AMH) e inhibina B en las células de Sertoli. En la infancia, los niveles séricos de gonadotrofinas, testosterona y factor INSL3 disminuyen a valores prácticamente indetectables, pero los de AMH e inhibina B permanecen altos. En la pubertad, se reactivan las gonadotrofinas y la producción de testosterona e INSL3, aumenta la inhibina y disminuye la AMH, como signo de maduración de la célula de Sertoli. Sobre la base del conocimiento de la fisiología del desarrollo del eje, es posible utilizar clínicamente estos biomarcadores para interpretar la fisiopatología y diagnosticar las diferentes formas de hipogonadismo que pueden presentarse en la infancia y la adolescencia.

Biomarkers of male hypogonadism in childhood and adolescence

Objectives

The objective of this review was to characterize the use of biomarkers of male hypogonadism in childhood and adolescence.

Contents

The hypothalamic-pituitary-gonadal (HPG) axis is active during fetal life and over the first months of postnatal life. The pituitary gland secretes follicle stimulating hormone (FSH) and luteinizing hormone (LH), whereas the testes induce Leydig cells to produce testosterone and insulin-like factor 3 (INSL), and drive Sertoli cells to secrete anti-Müllerian hormone (AMH) and inhibin B. During childhood, serum levels of gonadotropins, testosterone and insulin-like 3 (INSL3) decline to undetectable levels, whereas levels of AMH and inhibin B remain high. During puberty, the production of gonadotropins, testosterone, and INSL3 is reactivated, inhibin B increases, and AMH decreases as a sign of Sertoli cell maturation.

Summary and outlook

Based on our knowledge of the developmental physiology of the HPG axis, these biomarkers can be used in clinical practice to interpret the physiopathology of hypogonadism. Additionally, these markers can have diagnostic value in different forms of hypogonadism that may appear during childhood and adolescence.

Male Hypogonadism and Disorders of Sex Development

Disorders of Sex Development (DSD) are congenital anomalies in which there is a discordance between chromosomal, genetic, gonadal, and/or internal/external genital sex. In XY individuals, the process of fetal sex differentiation can be disrupted at the stage of gonadal differentiation, resulting in gonadal dysgenesis, a form of early fetal-onset primary hypogonadism characterized by insufficient androgen and anti-Müllerian hormone (AMH) production, which leads to the development of ambiguous or female genitalia. The process of sex differentiation can also be disrupted at the stage of genital differentiation, due to isolated defects in androgen or AMH secretion, but not both. These are forms of fetal-onset hypogonadism with dissociated gonadal dysfunction. In this review, we present a perspective on impaired testicular endocrine function, i.e., fetal-onset male hypogonadism, resulting in incomplete virilization at birth.

What Does AMH Tell Us in Pediatric Disorders of Sex Development?

Disorders of sex development (DSD) are conditions where genetic, gonadal, and/or internal/external genital sexes are discordant. In many cases, serum testosterone determination is insufficient for the differential diagnosis. Anti-Müllerian hormone (AMH), a glycoprotein hormone produced in large amounts by immature testicular Sertoli cells, may be an extremely helpful parameter. In undervirilized 46,XY DSD, AMH is low in gonadal dysgenesis while it is normal or high in androgen insensitivity and androgen synthesis defects. Virilization of a 46,XX newborn indicates androgen action during fetal development, either from testicular tissue or from the adrenals or placenta. Recognizing congenital adrenal hyperplasia is usually quite easy, but other conditions may be more difficult to identify. In 46,XX newborns, serum AMH measurement can easily detect the existence of testicular tissue, leading to the diagnosis of ovotesticular DSD. In sex chromosomal DSD, where the gonads are more or less dysgenetic, AMH levels are indicative of the amount of functioning testicular tissue. Finally, in boys with a persistent Müllerian duct syndrome, undetectable or very low serum AMH suggests a mutation of the AMH gene, whereas normal AMH levels orient toward a mutation of the AMH receptor.

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.

Management of 46,XY Differences/Disorders of Sex Development (DSD) Throughout Life

Differences/disorders of sex development (DSD) are a heterogeneous group of congenital conditions that result in discordance between an individual's sex chromosomes, gonads, and/or anatomic sex. Advances in the clinical care of patients and families affected by 46,XY DSD have been achieved since publication of the original Consensus meeting in 2006. The aims of this paper are to review what is known about morbidity and mortality, diagnostic tools and timing, sex of rearing, endocrine and surgical treatment, fertility and sexual function, and quality of life in people with 46,XY DSD. The role for interdisciplinary health care teams, importance of establishing a molecular diagnosis, and need for research collaborations using patient registries to better understand long-term outcomes of specific medical and surgical interventions are acknowledged and accepted. Topics that require further study include prevalence and incidence, understanding morbidity and mortality as these relate to specific etiologies underlying 46,XY DSD, appropriate and optimal options for genitoplasty, long-term quality of life, sexual function, involvement with intimate partners, and optimizing fertility potential.

Update on the genetics of differences of sex development (DSD)

Human gonadal development is regulated by the temporospatial expression of many different genes with critical dosage effects. Subsequent sex steroid hormone production requires several consecutive enzymatic steps and functional hormone receptors. Disruption of this complex process can result in atypical sex development and lead to conditions referred to as differences (disorders) of sex development (DSD). With the advent of massively parallel sequencing technologies, in silico protein modeling and innovative tools for the generation of animal models, new genes and pathways have been implicated in the pathogenesis of these conditions. Here, we provide an overview of the currently known DSD genes and mechanisms involved in the process of gonadal and phenotypical sex development and highlight phenotypic findings that may trigger further diagnostic investigations.

A perivascular niche for multipotent progenitors in the fetal testis

Androgens responsible for male sexual differentiation in utero are produced by Leydig cells in the fetal testicular interstitium. Leydig cells rarely proliferate and, hence, rely on constant differentiation of interstitial progenitors to increase their number during fetal development. The cellular origins of fetal Leydig progenitors and how they are maintained remain largely unknown. Here we show that Notch-active, Nestin-positive perivascular cells in the fetal testis are a multipotent progenitor population, giving rise to Leydig cells, pericytes, and smooth muscle cells. When vasculature is disrupted, perivascular progenitor cells fail to be maintained and excessive Leydig cell differentiation occurs, demonstrating that blood vessels are a critical component of the niche that maintains interstitial progenitor cells. Additionally, our data strongly supports a model in which fetal Leydig cell differentiation occurs by at least two different means, with each having unique progenitor origins and distinct requirements for Notch signaling to maintain the progenitor population.

Leydig cells are steroidogenic cells in the testes and produce the androgens required for male development and spermatogenesis. Here the authors show that a multipotent progenitor population producing Leydig cells, pericytes and smooth muscle cells is maintained in a perivascular niche within the mouse fetal testis.

Androgen insensitivity syndrome: a review

Androgenic insensitivity syndrome is the most common cause of disorders of sexual differentiation in 46,XY individuals. It results from alterations in the androgen receptor gene, leading to a frame of hormonal resistance, which may present clinically under 3 phenotypes: complete (CAIS), partial (PAIS) or mild (MAIS). The androgen receptor gene has 8 exons and 3 domains, and allelic variants in this gene occur in all domains and exons, regardless of phenotype, providing a poor genotype - phenotype correlation in this syndrome. Typically, laboratory diagnosis is made through elevated levels of LH and testosterone, with little or no virilization. Treatment depends on the phenotype and social sex of the individual. Open issues in the management of androgen insensitivity syndromes includes decisions on sex assignment, timing of gonadectomy, fertility, physcological outcomes and genetic counseling.

Hormone therapy and patient satisfaction with treatment, in a large cohort of diverse disorders of sex development

OBJECTIVES

To describe and investigate the hormone treatments in individuals with different forms of disorders of sex development (DSD) and the patients' own views on their treatment.

DESIGN

Multicentre cross-sectional clinical evaluation, dsd-LIFE in 6 European countries from February 2014 to September 2015.

PARTICIPANTS

A total of 1040 adolescents and adults (≥16 years) with different DSD conditions.

MAIN OUTCOMES MEASURES

Hormone replacement, information received and patient satisfaction.

RESULTS

Included were women with Turner syndrome (301), 46,XX GD (n = 20), and women with 45,X/46XY (n = 24). Individuals with Klinefelter syndrome (n = 218), 46,XX males (n = 6), individuals with different forms of 46,XY DSD (n = 243): 46,XY DSD conditions (n = 222), men with 45,X/46XY (n = 21) 46,XX CAH, (n = 226). Oestrogen ± progestin was used by 306 (81%) individuals, 72 (19%) received ethinylestradiol and 198 had testosterone treatment. The overall adherence was good, with 10% of women with oestrogen and 5% of those on testosterone had stopped the medication despite 20% reporting dissatisfaction with the treatment, mostly because of psychological side effects. Glucocorticoid replacement in patients with CAH was very seldom stopped. More than 75% were satisfied with the information about the treatment, but the satisfaction with information about treatment options and side effects was lower.

CONCLUSIONS

More than 50% in the total cohort had hormone replacement. Although adherence was generally good, this study shows that hormone replacement therapy may be improved. This may be achieved by better individualization of the treatment and by providing specific information to patients regarding both long-term and short-term hormonal effects and side effects.

Fertility Issues in Disorders of Sex Development

Fertility potential should be considered by the multidisciplinary team when addressing gender assignment, surgical management, and patient and family counselling of individuals with disorders of sex development. In 46,XY individuals, defects of gonadal differentiation or androgen or anti-Müllerian hormone synthesis or action result in incomplete or absent masculinization. In severe forms, raised as females, motherhood is possible with oocyte donation if Müllerian ducts have developed. In milder forms, raised as males, azoospermia or oligospermia are frequently found, however paternity has been reported. Most 46,XX patients with normal ovarian organogenesis are raised as females, and fertility might be possible after treatment.

Disorders of sexual development

Disorders of sexual development (DSDs) are a group of disorders in which there is discordance between anatomic or hormonal sex and sex chromosome complement. These disorders present with ambiguity in the newborn period and require prompt evaluation to determine the underlying cause for treatment and appropriate sex assignment of the infant. Neonatologists should confer with a multidisciplinary team for the diagnostic evaluation and management of patients with DSDs. This article provides a review of normal sexual development, algorithms used for evaluating infants with ambiguous genitalia, and conditions that can present with ambiguous genitalia in the newborn period.

46,XY disorder of sexual development resulting from a novel monoallelic mutation (p.Ser31Phe) in the steroid 5α-reductase type-2 (SRD5A2) gene

Inactivating mutations of the 5α-steroid reductase type-2 (SRD5A2) gene result in a broad spectrum of masculinization defects, ranging from a male phenotype with hypospadias to a female phenotype with Wolffian structures. Molecular studies of the SRD5A2 revealed a new heterozygous gene variant within the coding region that results in phenotypic expression. A c.92C>T transition changing serine to phenylalanine at codon 31 of exon 1 (p.Ser31Phe) was identified in a patient with 46,XY disorder of sexual development who displayed glandular hypospadias with micropenis and bilateral cryptorchidism. The restoration of the p.Ser31Phe mutation by site-directed mutagenesis and transient expression assays using cultured HEK-293 cells showed that this novel substitution does not abolish but does deregulate the catalytic efficiency of the enzyme. Thus, the maximum velocity (V_max) value was higher for the mutant enzyme (22.5 ± 6.9 nmol DHT mg protein⁻¹ h⁻¹) than for the wild-type enzyme (9.8 ± 2.0 nmol DHT mg protein⁻¹ h⁻¹). Increased in vitro activity of the p.Ser31Phe mutant suggested an activating effect. This case provides evidence that heterozygous missense mutations in SRD5A2 may induce the abnormal development of male external genitalia.

Spreading the clinical window for diagnosing fetal-onset hypogonadism in boys

In early fetal development, the testis secretes - independent of pituitary gonadotropins - androgens and anti-Müllerian hormone (AMH) that are essential for male sex differentiation. In the second half of fetal life, the hypothalamic-pituitary axis gains control of testicular hormone secretion. Follicle-stimulating hormone (FSH) controls Sertoli cell proliferation, responsible for testis volume increase and AMH and inhibin B secretion, whereas luteinizing hormone (LH) regulates Leydig cell androgen and INSL3 secretion, involved in the growth and trophism of male external genitalia and in testis descent. This differential regulation of testicular function between early and late fetal periods underlies the distinct clinical presentations of fetal-onset hypogonadism in the newborn male: primary hypogonadism results in ambiguous or female genitalia when early fetal-onset, whereas it becomes clinically undistinguishable from central hypogonadism when established later in fetal life. The assessment of the hypothalamic-pituitary-gonadal axis in male has classically relied on the measurement of gonadotropin and testosterone levels in serum. These hormone levels normally decline 3-6 months after birth, thus constraining the clinical evaluation window for diagnosing male hypogonadism. The advent of new markers of gonadal function has spread this clinical window beyond the first 6 months of life. In this review, we discuss the advantages and limitations of old and new markers used for the functional assessment of the hypothalamic-pituitary-testicular axis in boys suspected of fetal-onset hypogonadism.

The prepubertal testis: biomarkers and functions

PURPOSE OF REVIEW

Biomarkers of prepubertal testicular function have become widely available only in recent years. The aim of this review is to update the knowledge on key biomarkers used to assess hypogonadism in boys.

RECENT FINDINGS

Sertoli cells are the most representative cells of the prepubertal testis. Anti-Müllerian hormone and inhibin B are essential biomarkers of Sertoli cell function. Also, INSL3 arises as an additional marker of Leydig cell dysfunction.

SUMMARY

The widespread use of these biomarkers has enhanced our knowledge on the pathophysiology and diagnosis of prepubertal male hypogonadism. Beyond their well known germ-cell toxicity, oncologic treatments may also affect Sertoli cell function. Pathophysiology is not the same in all aneuploidies leading to infertility: while hypogonadism is not evident until mid-puberty in Klinefelter syndrome, it is established in early infancy in Down syndrome. In Noonan syndrome, the occurrence of primary hypogonadism depends on the existence of cryptorchidism, and Prader-Willi syndrome may present with either primary or combined forms of hypogonadism. Prepubertal testicular markers have also provided insights into the effects of environmental disruptors on gonadal function from early life, and helped dissipate concerns about testicular function in boys born preterm or small for gestational age or conceived by assisted reproductive technique procedures.

Review and management of 46,XY disorders of sex development

Disorders of sex development (DSD) among 46,XY individuals are rare and challenging conditions. Abnormalities of karyotype, gonadal formation, androgen synthesis, and androgen action are responsible for the multiple disorders that result in undervirilization during development. Phenotypic appearance and timing of presentation are quite variable. The focus of treatment has shifted from early gender assignment and corrective surgery to careful diagnosis, proper education of patients and their families, and individualized treatment by a multi-disciplinary team. The modern management of these patients is difficult and controversial. Conflicting data on long-term outcomes of these individuals have been reported in the literature. The various etiologies of 46,XY DSD, current approaches to diagnosis and treatment, and reported long-term results are reviewed.

Male hypogonadism: an extended classification based on a developmental, endocrine physiology-based approach

Normal testicular physiology results from the integrated function of the tubular and interstitial compartments. Serum markers of interstitial tissue function are testosterone and insulin-like factor 3 (INSL3), whereas tubular function can be assessed by sperm count, morphology and motility, and serum anti-Müllerian hormone (AMH) and inhibin B. The classical definition of male hypogonadism refers to testicular failure associated with androgen deficiency, without considering potential deficiencies in germ and Sertoli cells. Furthermore, the classical definition does not consider the fact that low basal serum testosterone cannot be equated to hypogonadism in childhood, because Leydig cells are normally quiescent. A broader clinical definition of hypogonadism that could be applied to male patients in different periods of life requires a comprehensive consideration of the physiology of the hypothalamic-pituitary-testicular axis and its disturbances along development. Here we propose an extended classification of male hypogonadism based on the pathophysiology of the hypothalamic-pituitary-testicular axis in different periods of life. The clinical and biochemical features of male hypogonadism vary according to the following: (i) the level of the hypothalamic-pituitary-testicular axis primarily affected: central, primary or combined; (ii) the testicular cell population initially impaired: whole testis dysfunction or dissociated testicular dysfunction, and: (iii) the period of life when the gonadal function begins to fail: foetal-onset or postnatal-onset. The evaluation of basal testicular function in infancy and childhood relies mainly on the assessment of Sertoli cell markers (AMH and inhibin B). Hypergonadotropism should not be considered a sine qua non condition for the diagnosis of primary hypogonadism in childhood. Finally, the lack of elevation of gonadotropins in adolescents or adults with primary gonadal failure is indicative of a combined hypogonadism involving the gonads and the hypothalamic-pituitary axis.

Gender Development in 46,XY DSD: Influences of Chromosomes, Hormones, and Interactions with Parents and Healthcare Professionals

Variables that impact gender development in humans are difficult to evaluate. This difficulty exists because it is not usually possible to tease apart biological influences on gender from social variables. People with disorders of sex development, or DSD, provide important opportunities to study gender within individuals for whom biologic components of sex can be discordant with social components of gender. While most studies of gender development in people with 46,XY DSD have historically emphasized the importance of genes and hormones on gender identity and gender role, more recent evidence for a significant role for socialization exists and is considered here. For example, the influence of parents' perceptions of, and reactions to, DSD are considered. Additionally, the impact of treatments for DSD such as receiving gonadal surgeries or genitoplasty to reduce genital ambiguity on the psychological development of people with 46,XY DSD is presented. Finally, the role of multi-disciplinary care including access to peer support for advancing medical, surgical and psychosexual outcomes of children and adults with 46,XY DSD, regardless of sex of rearing, is discussed.

RWDD1 interacts with the ligand binding domain of the androgen receptor and acts as a coactivator of androgen-dependent transactivation

During embryogenesis, the development of the male genital is dependent on androgens. Their actions are mediated by the androgen receptor (AR), which functions as a transcription factor. To identify AR coregulators that support AR action during the critical time window of androgen-dependent development in the genital tubercle of male mice, we performed yeast two-hybrid screenings with cDNA libraries of genital tubercles from male mouse embryos using human AR as bait. RWD domain containing 1 (RWDD1) was identified as an AR-interacting protein from three independent libraries of the embryonic days E15, E16 and E17. The interaction between the AR and RWDD1 was confirmed in vitro and in vivo and the ligand binding domain of the AR was shown to be sufficient to mediate the interaction. RWDD1 enhanced AR-dependent transactivation in reporter assays with promoters of different complexity and in different cell lines. These results suggest that RWDD1 functions as a coactivator of androgen-dependent transcription.

Ethical and legal aspects of management for disorders of sex development

Intense controversy surrounds the management of disorders of sex development, particularly in relation to the validity of parental consent for genital surgery and the removal of gonadal tissue carried out during infancy or childhood. Past practices have been heavily criticised on ethical grounds by patient advocacy organisations, who have demanded a moratorium on these kinds of operations unless authorised by a court. Some doctors and hospital administrators have been influenced by the controversy and have referred cases to the Family Court of Australia, where a series of judgements have now established legal precedents that apply across Australia, restricting the circumstances in which parents can give consent for surgery. An alternative approach is to use a hospital-based Clinical Ethics Response Group and, if necessary, Clinical Ethics Committee, which has lay and legal representatives as well as health professionals, as a semi-independent committee of review. Finding a solution that protects the human rights and best interests of children is an ongoing challenge.