Basal follicle-stimulating hormone and peak gonadotropin levels after gonadotropin-releasing hormone infusion show high diagnostic accuracy in boys with suspicion of hypogonadotropic hypogonadism

"Management of andrological disorders from childhood and adolescence to transition age: guidelines from the Italian Society of Andrology and Sexual Medicine (SIAMS) in collaboration with the Italian Society for Pediatric Endocrinology and Diabetology (SIEDP)-Part-1"

PURPOSE

Andrological pathologies in the adulthood are often the results of conditions that originate during childhood and adolescence and sometimes even during gestation and neonatal period. Unfortunately, the reports in the literature concerning pediatric andrological diseases are scares and mainly concerning single issues. Furthermore, no shared position statement are so far available.

METHODS

The Italian Society of Andrology and Sexual Medicine (SIAMS) commissioned an expert task force involving the Italian Society of Pediatric Endocrinology and Diabetology (SIEDP) to provide an updated guideline on the diagnosis and management of andrological disorders from childhood and adolescence to transition age. Derived recommendations were based on the grading of recommendations, assessment, development, and evaluation (GRADE) system.

RESULTS

A literature search of articles in English for the term "varicoceles", "gynecomastia", "fertility preservation", "macroorchidism", "precocious puberty" and "pubertal delay" has been performed. Three major aspects for each considered disorder were assessed including diagnosis, clinical management, and treatment. Recommendations and suggestions have been provided for each of the mentioned andrological disorders.

CONCLUSIONS

These are the first guidelines based on a multidisciplinary approach that involves important societies related to the field of andrological medicine from pediatric to transition and adult ages. This fruitful discussion allowed for a general agreement on several recommendations and suggestions to be reached, which can support all stakeholders in improving andrological and general health of the transitional age.

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.

X-linked congenital adrenal hypoplasia: Report of long clinical follow-up and description of a new complex variant in the NR0B1 gene

Adrenal hypoplasia congenita, attributed to NR0B1 pathogenic variants, accounts for more than 50% of the incidence of primary adrenal insufficiency in children. Although more than 250 different deleterious variations have been described, no genotype-phenotype correlation has been defined to date. We report a case of an adopted boy who reported the onset of an adrenal crisis at 2 weeks of age, requiring replacement therapy with mineralocorticoids and glucocorticoids for 4 months. For 3 years, he did well without treatment. At almost 4 years of age, the disorder was restarted. A long follow-up showed the evolution of hypogonadotropic hypogonadism. Molecular studies on NR0B1 revealed a novel and deleterious deletion-insertion-inversion-deletion complex rearrangement sorted in the 5'-3' direction, which is described as follows: (1) deletion of the intergenic region (between TASL and NR0B1 genes) and 5' region, (2) insertion of a sequence containing 37 bp at the junction of the intergenic region of the TASL gene and a part of exon 1 of the NR0B1 gene, (3) inversion of a part of exon 1, (4) deletion of the final portion of exon 1 and exon 2 and beginning of the 3'UTR region, (5) maintenance of part of the intergenic sequence (between genes MAGEB1 and NR0B1, telomeric sense), (6) large posterior deletion, in the same sense. The path to molecular diagnosis was challenging and involved several molecular biology techniques. Evaluating the breakpoints in our patient, we assumed that it was a nonrecurrent rearrangement that had not yet been described. It may involve a repair mechanism known as nonhomologous end-joining (NHEJ), which joins two ends of DNA in an imprecise manner, generating an "information scar," represented herein by the 37 bp insertion. In addition, the local Xp21 chromosome architecture with sequences capable of modifying the DNA structure could impact the formation of complex rearrangements.

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.

Role of Inhibin B, AMH, GnRHa Test and HCG Stimulation Test to Distinguish Isolated Hypogonadotropic Hypogonadism (IHH) from Constitutional Delay in Growth and Puberty (CDGP)

Introduction

This study aimed to distinguish isolated hypogonadotropic hypogonadism (IHH) from constitutional delay in growth and puberty (CDGP) by various hormonal tests in both sexes.

Methods

Boys with testicular volume (TV) <4 ml (14-18 years) and girls with breast B1 stage (13-18 years) were enrolled in this study. A detailed history, clinical examination and hormonal analysis including basal luteinising hormone (LH), follicle-stimulating hormone (FSH), inhibin B, anti-Mullerian hormone (AMH), testosterone (boys), oestradiol (girls), triptorelin stimulation test and 3-day human chorionic gonadotropin (HCG) stimulation test (boys) were performed. All patients were followed for 1.5 years or till 18 years of age. Receiver operating characteristic (ROC) curve analysis was performed to determine the optimal cut-offs with sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for various hormones to distinguish IHH from CDGP.

Results

Of 34 children (male: 22 and female: 12), CDGP and IHH were diagnosed in 21 and 13 children, respectively. 4 hours post-triptorelin LH had the highest sensitivity (100%) and specificity (100%) for identifying IHH in both sexes. Basal inhibin B had good sensitivity (male: 85.7% and female: 83.8%) and specificity (male: 93.3% and female: 100%) for diagnosing IHH. 24 hours post-triptorelin testosterone (<34.5 ng/dl), day 4 post-HCG testosterone (<99.7 ng/dl) and 24 hours post-triptorelin oestradiol (<31.63 pg/ml) had reasonable sensitivity and specificity for identifying IHH. Basal LH, FSH and AMH were poor discriminators for IHH in both sexes.

Conclusion

The best indicator was post-triptorelin 4-hour LH followed by inhibin B, which had a reasonable diagnostic utility to distinguish IHH from CDGP in both boys and girls.

Idiopathic hypogonadotropic hypogonadism caused by compound heterozygosity for two novel mutations in the GNRH1 gene: a case report

BACKGROUND

Idiopathic hypogonadotropic hypogonadism (IHH) is a rare congenital or acquired genetic disorder caused by gonadotropin-releasing hormone (GnRH) deficiency. IHH patients are divided into two major groups, hyposmic or anosmic IHH (Kallmann syndrome) and normosmic IHH (nIHH), according to whether their sense of smell is intact. Here we report a case of novel compound heterozygous mutations in the GNRH1 gene in a 15-year-old male with nIHH.

CASE PRESENTATION

The patient presented typical clinical symptoms of delayed testicular development, with testosterone < 3.5 mmol/L and reduced gonadotropin (follicle-stimulating hormone, luteinizing hormone) levels. Two heterozygous variants of the GNRH1 gene were detected, nonsense variant 1: c.85G > T:p.G29* and variant 2: c.1A > G:p.M1V, which disrupted the start codon.

CONCLUSIONS

Two GNRH1 mutations responsible for nIHH are identified in this study. Our findings extend the mutational spectrum of GNRH1 by revealing novel causative mutations of nIHH.

Endocrine Disorders in Children with Brain Tumors: At Diagnosis, after Surgery, Radiotherapy and Chemotherapy

INTRODUCTION

Brain tumors are the second most frequent type of all pediatric malignancies. Depending on their localization, patients with brain tumors may present neurological or ophthalmological symptoms, but also weight anomalies and endocrine disorders ranging from growth hormone deficiency, anomalies of puberty, diabetes insipidus to panhypopituitarism. Immediately at diagnosis, all patients with brain tumors require a complete assessment of the hypothalamic-pituitary function in order to address eventual endocrine disorders. Moreover, children and adolescents undergoing brain surgery must receive peri- and postoperative hydrocortisone stress therapy. Post-operative disorders of water homeostasis are frequent, ranging from transient diabetes insipidus, as well as syndrome of inappropriate antidiuretic hormone secretion to persistent diabetes insipidus. Late endocrine disorders may result from surgery near or within the hypothalamic-pituitary region. Pituitary deficits are frequent after radiotherapy, especially growth hormone deficiency. Thyroid nodules or secondary thyroid cancers may arise years after radiotherapy. Gonadal dysfunction is frequent after chemotherapy especially with alkylating agents.

CONCLUSION

Early detection and treatment of specific endocrine disorders at diagnosis, perioperatively, and during long-term follow-up result in improved general and metabolic health and quality of life.

Considerations when treating male pubertal delay pharmacologically

INTRODUCTION

Delayed puberty, defined as the appearance of pubertal signs after the age of 14 years in males, usually affects psychosocial well-being. Patients and their parents show concern about genital development and stature. The condition is transient in most of the patients; nonetheless, the opportunity should not be missed to diagnose an underlying illness.

AREAS COVERED

The aetiologies of pubertal delay in males and their specific pharmacological therapies are discussed in this review.

EXPERT OPINION

High-quality evidence addressing the best pharmacological therapy approach for each aetiology of delayed puberty in males is scarce, and most of the current practice is based on small case series or unpublished experience. Male teenagers seeking attention for pubertal delay most probably benefit from medical treatment to avoid psychosocial distress. While watchful waiting is appropriate in 12- to 14-year-old boys when constitutional delay of growth and puberty (CGDP) is suspected, hormone replacement should not be delayed beyond the age of 14 years in order to avoid impairing height potential and peak bone mass. When primary or central hypogonadism is diagnosed, hormone replacement should be proposed by the age of 12 years provided that a functional central hypogonadism has been ruled out. Testosterone replacement regimens have been used for decades and are fairly standardised. Aromatase inhibitors have arisen as an interesting alternative for boy with CDGP and short stature. Gonadotrophin therapy seems more physiological in patients with central hypogonadism, but its relative efficacy and most adequate timing still need to be established.

Delayed Puberty Due to a WDR11 Truncation at Its N-Terminal Domain Leading to a Mild Form of Ciliopathy Presenting With Dissociated Central Hypogonadism: Case Report

Pubertal delay in males is frequently due to constitutional delay of growth and puberty, but pathologic hypogonadism should be considered. After general illnesses and primary testicular failure are ruled out, the main differential diagnosis is central (or hypogonadotropic) hypogonadism, resulting from a defective function of the gonadotropin-releasing hormone (GnRH)/gonadotropin axis. Ciliopathies arising from defects in non-motile cilia are responsible for developmental disorders affecting the sense organs and the reproductive system. WDR11-mediated signaling in non-motile cilia is critical for fetal development of GnRH neurons. Only missense variants of WDR11 have been reported to date in patients with central hypogonadism, suggesting that nonsense variants could lead to more complex phenotypes. We report the case of a male patient presenting with delayed puberty due to Kallmann syndrome (central hypogonadism associated with hyposmia) in whom the next-generation sequencing analysis identified a novel heterozygous base duplication, leading to a frameshift and a stop codon in the N-terminal region of WDR11. The variant was predicted to undergo nonsense-mediated decay and classified as probably pathogenic following the American College of Medical Genetics and Genomics (ACMG) criteria. This is the first report of a variant in the WDR11 N-terminal region predicted to lead to complete expression loss that, contrary to expectations, led to a mild form of ciliopathy resulting in isolated Kallmann syndrome.

Accuracy of various tests alone and in combination to differentiate IHH from CDGP

CONTEXT

Constitutional delay in growth and puberty (CDGP) is a normal physiological variant of delayed puberty in both sexes and is the most common cause of delayed puberty. Idiopathic hypogonadotropic hypogonadism (IHH) is due to deficiency in or insensitivity to gonadotropin-releasing hormone (GnRH) with normal structure and function of the anterior pituitary after exclusion of secondary causes of hypogonadotropic hypogonadism. To differentiate CDGP from IHH is crucial because it not only helps in decision making in management but also lessen anxiety of the parents.

AIM

In this study we aimed to find out the accuracy of hormonal tests used individually as well as in various combinations to distinguish cases of IHH from CDGP.

METHODS

A cohort of 34 boys with delayed puberty were recruited in this study. Detailed history, clinical examination, hormonal analysis including basal serum testosterone, inhibin-B, LH, FSH as well as GnRH analogue stimulated gonadotrophins and testosterone along with hCG stimulated testosterone was done. At 6 monthly follow-up, detailed clinical examination was repeated and the cohort was followed until 2 years.

RESULTS

Out of the 29 boys taken for final analysis, CDGP was diagnosed in 23 boys and IHH in 6 boys. Basal LH, basal inhibin-B, 3 hours post leuprolide LH and 72 hours post hCG testosterone were significantly higher in CDGP than IHH. However, no statistically significant difference was observed between basal FSH, basal testosterone and 3 hours post leuprolide FSH between these two groups. When basal LH (cut-off <0.565 IU/L) and basal inhibin-B (cut-off <105 pg/ml) were taken together the sensitivity and specificity were increased to 100% as was for the combination of basal LH (cutoff <0.565 IU/L) and 3 hours post leuprolide LH (cutoff <6.16 IU/L) for diagnosis of IHH. Both combinations have PPV of 100% and NPV of 100%. A combination of 3 hours post leuprolide LH with 72 hours post hCG testosterone also has good sensitivity (100%), specificity (96%), PPV (90%) and NPV (100%).

CONCLUSION

Differentiating IHH from CDGP is a challenging task due to considerable overlap in their clinical as well as hormonal profiles. Therefore we suggest that a combination of basal LH and basal inhibin-B may be considered as a useful screening tool to differentiate IHH from CDGP rather than the cumbersome and invasive stimulation tests.

Recent advancement in the treatment of boys and adolescents with hypogonadism

Clinical manifestations and the need for treatment varies according to age in males with hypogonadism. Early foetal-onset hypogonadism results in disorders of sex development (DSD) presenting with undervirilised genitalia whereas hypogonadism established later in foetal life presents with micropenis, cryptorchidism and/or micro-orchidism. After the period of neonatal activation of the gonadal axis has waned, the diagnosis of hypogonadism is challenging because androgen deficiency is not apparent until the age of puberty. Then, the differential diagnosis between constitutional delay of puberty and central hypogonadism may be difficult. During infancy and childhood, treatment is usually sought because of micropenis and/or cryptorchidism, whereas lack of pubertal development and relative short stature are the main complaints in teenagers. Testosterone therapy has been the standard, although off-label, in the vast majority of cases. However, more recently alternative therapies have been tested: aromatase inhibitors to induce the hypothalamic-pituitary-testicular axis in boys with constitutional delay of puberty and replacement with GnRH or gonadotrophins in those with central hypogonadism. Furthermore, follicle-stimulating hormone (FSH) priming prior to hCG or luteinizing hormone (LH) treatment seems effective to induce an enhanced testicular enlargement. Although the rationale for gonadotrophin or GnRH treatment is based on mimicking normal physiology, long-term results are still needed to assess their impact on adult fertility.

Genetics of congenital central hypogonadism

The diagnostic suspicion of congenital central hypogonadism is based on clinical signs. Biochemical confirmation is challenging, especially after the postnatal activation stage of the hypothalamic-pituitary-testicular axis. Sertoli cell markers, like AMH and inhibin B, have become useful tools for the diagnosis of male central hypogonadism during childhood. Different mechanisms can participate in the aetiopathogenesis of central hypogonadism, leading to a deficiency in the production of gonadotrophins. Advances in genetic studies, mainly next generation sequencing techniques, have allowed the discovery of a large number of genes related to central hypogonadism. However, a causal variant is found in approximately half of the patients. Central hypogonadism has been classically described as a pathology with variable expressivity and incomplete penetrance. Currently, these characteristics are known to be partially explained by the presence of oligogenicity, that is the participation of variants in more than one gene in the aetiology of central hypogonadism in the same patient.

Diagnosis of Male Central Hypogonadism During Childhood

The diagnosis of male central (or hypogonadotropic) hypogonadism, typically based on low luteinizing hormone (LH) and testosterone levels, is challenging during childhood since both hormones are physiologically low from the sixth month until the onset of puberty. Conversely, follicle-stimulating hormone (FSH) and anti-Müllerian hormone (AMH), which show higher circulating levels during infancy and childhood, are not used as biomarkers for the condition. We report the case of a 7-year-old boy with a history of bilateral cryptorchidism who showed repeatedly low FSH and AMH serum levels during prepuberty. Unfortunately, the diagnosis could not be ascertained until he presented with delayed puberty at the age of 14 years. A gonadotropin-releasing hormone (GnRH) test showed impaired LH and FSH response. By then, his growth and bone mineralization were partially impaired. Gene panel sequencing identified a variant in exon 15 of FGFR1, affecting the tyrosine kinase domain of the receptor, involved in GnRH neuron migration and olfactory bulb morphogenesis. Testosterone replacement was started, which resulted in the development of secondary sexual characteristics and partial improvement of bone mineral density. This case illustrates the difficulty in making the diagnosis of central hypogonadism in boys during childhood based on classical criteria, and how serum FSH and AMH assessment may be helpful if it is suspected before the age of puberty, and confirm it using next-generation sequencing. The possibility of making an early diagnosis of central hypogonadism may be useful for a timely start of hormone replacement therapy, and to avoid delays that could affect growth and bone health as well as psychosocial adjustment.

Serum inhibin B for differentiating between congenital hypogonadotropic hypogonadism and constitutional delay of growth and puberty: a systematic review and meta-analysis

PURPOSE

The distinction between congenital hypogonadotropic hypogonadism (CHH) and constitutional delay of growth and puberty (CDGP) in patients with delayed puberty is difficult to distinguish, but important for timely treatment. The aim of this study is to perform a systematic review and meta-analysis to determine the diagnostic performance of serum inhibin B (INHB) levels for differentiating CHH and CDGP.

METHODS

PubMed, EMBASE, and Cochrane Library databases were systematically searched from the date of database inception to November 10, 2019 for studies examining the use of serum INHB to discriminate between CHH and CDGP. Pooled odds ratios (OR), sensitivity, specificity, and 95% confidence intervals (CI) were calculated. The Quality Assessment of Diagnostic Studies-2 (QUADAS-2) was used to assess the quality of the included studies. Sub-analyses were performed including that based on testicular volume (TV) and study design.

RESULTS

Seven studies, comprising of 349 patients (96 CHH and 253 CDGP), were included in the meta-analysis. For differentiating between CHH and CDGP, INHB level exhibited good diagnostic accuracy with a pooled sensitivity of 92% (95% confidence interval [CI]: 0.86-0.96, I² = 0.4%, p = 0.4343), specificity of 92% (95% CI: 0.88-0.94, I² = 68.1%, p = 0.0009), and pooled area under the receiver operating characteristic curve (AUC) of 0.9619. The cut-off values of INHB for boys were 56, 66, 80, 96, 94.7, 111, and 113 pg/ml (assay method standardized to Gen II ELISA). Sub-analyses showed that testicular volume and study design could be a source of statistically significant heterogeneity in specificity. In boys with a testicular volume of ≤3 ml, INHB performed well with a sensitivity of 92%, specificity of 98%, and AUC of 0.9956.

CONCLUSION

INHB exhibits excellent diagnostic efficiency in distinguishing CHH from CDGP, especially in boys with severe puberty deficiency (TV ≤ 3 ml).

Hypoglycemia and jaundice in newborns with pituitary stalk interruption syndrome

Pituitary stalk interruption syndrome (PSIS) is a rare disease associated with either isolated growth hormone deficiency (GHD) or combined pituitary hormone deficiency (CPHD). In older children and adults, most patients experience short stature or hypogonadism. Neonatal PSIS is extremely rare and is difficult to recognize due to absence of dwarfism. However, when this condition occurs in newborns, it is often life-threatening. Here, we collected patients with neonatal PSIS to clarify its characteristics to improve its early diagnosis.The patients included in this study were treated at the pediatric endocrine department of Shandong Provincial Hospital from January 2017 to July 2020. We obtained the clinical characteristics, endocrine hormone levels, pituitary magnetic resonance imaging (MRI) and further genetic data for all the patients. Hormone therapy was first given at the time of diagnosis, and the patients received regular follow-up.Three neonatal patients were identified in our clinic. The characteristics of these patients included hypoglycemia and jaundice, as well as CPHD, which included features such as micropenis and hypothyroidism. Genetic etiology was still hard to discover. All the patients responded well to alternative therapy, and the longest follow-up period was 3 years. Regular replacement ensures good prognosis.Sustained hypoglycemia and jaundice in newborns, indicate the presentation of PSIS. Early recognition is of great importance to avoid a life-threatening crisis.

GnRH stimulation testing and serum inhibin B in males: insufficient specificity for discriminating between congenital hypogonadotropic hypogonadism from constitutional delay of growth and puberty

STUDY QUESTION

Are GnRH tests and serum inhibin B levels sufficiently discriminating to distinguish transient constitutional delay of growth and puberty (CDGP) from congenital hypogonadotropic hypogonadism (CHH) that affects reproductive health for life?

SUMMARY ANSWER

Both parameters lack the specificity to discriminate CDGP from CHH.

WHAT IS KNOWN ALREADY

GnRH tests and inhibin B levels have been proposed to differentiate CDGP from CHH. However, their diagnostic accuracies have been hampered by the small numbers of CHH included and enrichment of CHH patients with more severe forms.

STUDY DESIGN, SIZE, DURATION

The aim of this study was to assess the diagnostic performance of GnRH tests and inhibin B measurements in a large cohort of CHH male patients with the whole reproductive spectrum. From 2008 to 2018, 232 males were assessed: 127 with CHH, 74 with CDGP and 31 healthy controls.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The participants were enrolled in two French academic referral centres. The following measurements were taken: testicular volume (TV), serum testosterone, inhibin B, LH and FSH, both at baseline and following the GnRH test.

MAIN RESULTS AND THE ROLE OF CHANCE

Among CHH patients, the LH response to the GnRH test was very variable and correlated with TV. Among CDGP patients, the LH peak was also variable and 47% of CHH patients had peak LH levels overlapping with the CDGP group. However, no patients with CDGP had an LH peak below 4.0 IU/l, while 53% CHH patients had LH peak below this threshold. Among CHH patients, inhibin B levels were also variable and correlated with TV and peak LH. Inhibin B was significantly lower in CHH patients than in CDGP patients but 50% of CHH values overlapped with CDGP values. Interestingly, all patients with CDGP had inhibin B levels above 35 pg/ml but 50% of CHH patients also had levels above this threshold.

LIMITATIONS, REASONS FOR CAUTION

As CHH is very rare, an international study would be necessary to recruit a larger CHH cohort and consolidate the conclusion reached here.

WIDER IMPLICATIONS OF THE FINDINGS

Peak LH and basal inhibin B levels are variable in both CHH and CDGP with significant overlap. Both parameters lack specificity and sensitivity to efficiently discriminate CHH from CDGP. This reflects the varying degree of gonadotropin deficiency inherent to CHH. These two diagnostic procedures may misdiagnose partial forms of isolated (non-syndromic) CHH, allowing them to be erroneously considered as CDGP.

STUDY FUNDING/COMPETING INTEREST(S)

This study was funded by Agence Française de Lutte contre le Dopage: Grant Hypoproteo AFLD-10 (to J.Y.); Agence Nationale de la Recherche (ANR): Grant ANR-09-GENO-017-01 (to J.Y.); European Cooperation in Science and Technology, COST Action BM1105; Programme Hospitalier de Recherche Clinique (PHRC), French Ministry of Health: PHRC-2009 HYPO-PROTEO (to J.Y.); and Programme Hospitalier de Recherche Clinique (PHRC) “Variété”, French Ministry of Health, N° P081216/IDRCB 2009-A00892-55 (to P.C.). There are no competing interests.

TRIAL REGISTRATION NUMBER

N/A

A Tool to Explore Discrete-Time Data: The Time Series Response Analyser

The analysis of time series data is common in nutrition and metabolism research for quantifying the physiological responses to various stimuli. The reduction of many data from a time series into a summary statistic(s) can help quantify and communicate the overall response in a more straightforward way and in line with a specific hypothesis. Nevertheless, many summary statistics have been selected by various researchers, and some approaches are still complex. The time-intensive nature of such calculations can be a burden for especially large data sets and may, therefore, introduce computational errors, which are difficult to recognize and correct. In this short commentary, the authors introduce a newly developed tool that automates many of the processes commonly used by researchers for discrete time series analysis, with particular emphasis on how the tool may be implemented within nutrition and exercise science research.

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.

Plasma kisspeptin levels in boys with hypogonadotropic delayed puberty

BACKGROUND

In hypogonadotropic forms of delayed puberty (DP), hypophyseal follicle-stimulating (FSH) and luteinizing (LH) hormones, normally released with GnRH stimulation, are detected low. Since kisspeptin (KP) is a strong stimulant of GnRH neurons, it is considered to have a role in DP etiology. It may be hypothesized that abnormal plasma levels of KP are indicative of DP. The study aimed at evaluation and comparison of plasma KP levels in boys of pre-pubertal age, with normal puberty and diagnosed primary hypogonadotropic forms of DP.

METHODS

The study comprised 22 boys with verified hypogonadotropic DP (age 14-17 years), 25 boys with normal puberty (age 14-17 years), and 28 pre-pubertal boys (age 6-9 years). Triprorelin stimulation test was performed in DP patients. Plasma KP values were compared between three groups.

RESULTS

Statistically significant difference was found for the overall distribution of the plasma KP values across different groups (Kruskal-Wallis H=21.95, P<0.001). The highest values were found in the DP group (median: 45.0 pg/mL). Median values in the pre-pubertal boys and in the normal pubertal adolescents were equal to 13.8 pg/mL. No statistically significant difference was found for plasma KP levels in the DP boys who had either positive or negative response to Triptorelin stimulation test. Plasma KP level exceeding 16.9 pg/mL was a reliable predictor of hypoganadotropic DP (sensitivity 72.7%, specificity 92.0%).

CONCLUSIONS

Plasma KP levels are elevated in hypogonadotropic DP cases and may serve as a useful diagnostic tool in evaluating boys with DP.

Paediatric and adult-onset male hypogonadism

The hypothalamic-pituitary-gonadal axis is of relevance in many processes related to the development, maturation and ageing of the male. Through this axis, a cascade of coordinated activities is carried out leading to sustained testicular endocrine function, with gonadal testosterone production, as well as exocrine function, with spermatogenesis. Conditions impairing the hypothalamic-pituitary-gonadal axis during paediatric or pubertal life may result in delayed puberty. Late-onset hypogonadism is a clinical condition in the ageing male combining low concentrations of circulating testosterone and specific symptoms associated with impaired hormone production. Testosterone therapy for congenital forms of hypogonadism must be lifelong, whereas testosterone treatment of late-onset hypogonadism remains a matter of debate because of unclear indications for replacement, uncertain efficacy and potential risks. This Primer focuses on a reappraisal of the physiological role of testosterone, with emphasis on the critical interpretation of the hypogonadal conditions throughout the lifespan of the male individual, with the exception of hypogonadal states resulting from congenital disorders of sex development.

Male Central Hypogonadism in Paediatrics - the Relevance of Follicle-stimulating Hormone and Sertoli Cell Markers

The definition of male hypogonadism, used in adult endocrinology, is not fully applicable to paediatrics. A clear understanding of the developmental physiology of the hypothalamic-pituitary-testicular axis is essential for the comprehension of the pathogenesis of hypogonadal states in boys and for the establishment of adequate definitions and classifications in paediatric ages. This is particularly true for central hypogonadism, usually called hypogonadotropic in adults. Because childhood is a period characterised by a physiological state of low gonadotropin and testosterone production, these markers of hypogonadism, typically used in adult endocrinology, are uninformative in the child. This review is focused on the physiological importance of prepubertal Sertoli cell markers - anti-Müllerian hormone (AMH) and inhibin B - and of the intratesticular actions of follicle-stimulating hormone (FSH) and testosterone during early infancy and the first stages of pubertal development. We discuss the role of FSH in regulating the proliferation of Sertoli cells - the main determinant of prepubertal testicular volume - and the secretion of AMH and inhibin B. We also address how intratesticular testosterone concentrations have different effects on the seminiferous tubule function in early infancy and during pubertal development.

Congenital hypogonadotropic hypogonadism, functional hypogonadotropism or constitutional delay of growth and puberty? An analysis of a large patient series from a single tertiary center

STUDY QUESTION

What diagnoses underlie delayed puberty (DP) and predict its outcome?

SUMMARY ANSWER

A multitude of different diagnoses underlie DP, and in boys a history of cryptorchidism, small testicular size and slow growth velocity (GV) predict its clinical course.

WHAT IS KNOWN ALREADY

DP is caused by a variety of underlying etiologies. Hormonal markers can be used in the differential diagnosis of DP but none of them have shown complete diagnostic accuracy.

STUDY DESIGN, SIZE, DURATION

Medical records of 589 patients evaluated for DP in a single tertiary care center between 2004 and 2014 were retrospectively reviewed.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Clinical and biochemical data of 174 boys and 70 girls who fulfilled the criteria of DP were included in the analyses. We characterized the frequencies of underlying conditions and evaluated the predictive efficacy of selected clinical and hormonal markers.

MAIN RESULTS AND THE ROLE OF CHANCE

Thirty etiologies that underlie DP were identified. No markers of clinical value could be identified in the girls, whereas a history of cryptorchidism in the boys was associated with an increase in the risk of permanent hypogonadism (odds ratio 17.2 (95% CI; 3.4-85.4, P < 0.001)). The conditions that cause functional hypogonadotropic hypogonadism were more frequent in boys with a GV below 3 cm/yr than in those growing faster (19% vs 4%, P < 0.05). In this series, the most effective markers to discriminate the prepubertal boys with constitutional delay of growth and puberty (CDGP) from those with congenital hypogonadotropic hypogonadism (CHH) were testicular volume (cut-off 1.1 ml with a sensitivity of 100% and a specificity of 91%), GnRH-induced maximal LH (cut-off 4.3 IU/L; 100%, 75%) and basal inhibin B (INHB) level (cut-off 61 ng/L; 90%, 83%).

LIMITATIONS, REASONS FOR CAUTION

The main limitation of the study is the retrospective design.

WIDER IMPLICATIONS OF THE FINDINGS

Prior cryptorchidism and slow GV are two important clinical cues that may help clinicians to predict the clinical course of DP in boys, whereas markers of similar value could not be identified in girls. In prepubertal boys, testicular size appeared as effective as INHB and GnRH-induced LH levels in the differential diagnosis between CHH and CDGP.

STUDY FUNDING/COMPETING INTERESTS

This study was supported by the Academy of Finland (268356), Foundation for Pediatric Research (7495), Sigrid Juselius Foundation (2613) and the Finnish Medical Foundation (011115). The authors have no competing interests to report.

TRIAL REGISTRATION NUMBER

Not applicable.

Inhibin B plus LH vs GnRH agonist test for distinguishing constitutional delay of growth and puberty from isolated hypogonadotropic hypogonadism in boys

OBJECTIVE

The distinction between constitutional delay of growth and puberty (CDGP) and isolated hypogonadotropic hypogonadism (IHH) in males with delayed puberty is difficult but important for timely treatment. We assessed the accuracy of the GnRH agonist test (triptorelin 0·1 mg) in comparison with inhibin B alone or in combination with basal LH for the diagnosis of IHH.

PATIENTS AND MEASUREMENTS

Ninety-seven prepubertal males aged 13·7-17·5 year, with testicular volumes ≤4 ml, were examined every 6 months. CDGP was defined by a testicular volume ≥8 ml after 18 months, and IHH was defined by a testicular volume <5 ml after 24 months follow-up. Inhibin B concentrations were measured by ELISA, and LH concentrations were measured by CLIA.

RESULTS

At follow-up, the cohort comprised 52 boys with CDGP and nine with IHH. The other patients were lost for follow-up (n = 10), had not reached follow-up yet (n = 20) or did not reach a definite testicular volume (n = 6). Basal LH <0·3 IU/l, stimulated LH (4 h) <5·3 IU/l or inhibin B <111 pg/ml had 100% sensitivity for IHH. Only LH (4 h) <5·3 IU/l had a specificity of 100%, and the specificities of basal LH <0·3 IU/l (88%) or inhibin B <110 pg/ml (92%) were lower. The combination of LH <0·3 IU/l with inhibin B <111 pg/ml increased the specificity to 98·1%.

CONCLUSIONS

The LH response 4 h after GnRH agonist stimulation has an excellent accuracy for the diagnosis of IHH in prepubertal boys with delayed puberty. However, the measurement of inhibin B and basal LH in combination is a valid, reliable and less-invasive alternative test.

Biomarkers of chemotherapy-induced testicular damage

Increasing numbers of men are having or wanting children after chemotherapy treatment. This can be attributed to improvements in cancer therapies that increase survival. However, a side effect of most chemotherapy drugs is disruption of spermatogenesis and a drastic reduction in sperm count and quality. Although many men eventually recover reproductive function, as indicated by normal semen analyses, there is no clinical test that can assess sperm quality at a high level of sensitivity. Sperm fluorescent in situ hybridization (i.e., FISH) and several different tests for deoxyribonucleic acid (DNA) fragmentation have been used infrequently in clinical assessment. Animal models of chemotherapy-induced testicular damage are currently being used to identify potential molecular biomarkers that may be translatable to humans-these include sperm messenger RNAs, microRNAs, histone modifications, and DNA methylation patterns. Changes in these molecular measurements are quantitative and sensitive, potentially making them important clinical biomarkers of testicular function after chemotherapy treatment.

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.

Comparison of detection of normal puberty in boys by a hormonal sleep test and a gonadotropin-releasing hormone agonist test

CONTEXT

The magnitude of sleep-related gonadotropin rise required to activate pubertal gonadal function is not established.

OBJECTIVE

Our objective was to determine the normal relationship between sleep-related pubertal hormone levels and pituitary-testicular responsiveness to a GnRH agonist (GnRHag) test across the pubertal transition. DESIGN/SETTING AND PARTICIPANTS: We conducted a prospective study in a General Clinical Research Center with healthy 9- to 15-yr-old volunteer boys.

INTERVENTIONS

INTERVENTIONS included overnight blood sampling followed by leuprolide acetate injection (10 μg/kg).

PRIMARY OUTCOME VARIABLES

LH, FSH, and testosterone levels were evaluated.

RESULTS

LH levels during sleep and post-GnRHag rose steadily during the late prepubertal years. Sleep peak LH correlated highly with the LH response to GnRHag across groups (r = 0.913). A sleep peak LH level of at least 3.7 U/liter predicted pubertal testicular activation with 100% accuracy. LH of at least 14.8 and at least 19.0 U/liter 4 h after GnRHag, respectively, predicted puberty with 100% sensitivity/94% specificity and 100% specificity/94% sensitivity. Overweight pubertal boys had transiently prolonged responses to GnRHag. FSH rose during both waking and sleeping hours during the prepubertal years, and all pubertal boys had an FSH level of at least 0.9 U/liter awake and at least 1.2 U/liter asleep. Sleep LH was more closely related than FSH to testicular size.

CONCLUSIONS

These data suggest that a critical LH level during sleep (≥3.7 U/liter) heralds the onset of pubertal virilization and that this level is predictable by LH of at least 14.8-19 U/liter 4 h after GnRHag. These data also suggest that LH stimulation of testicular androgen production plays a role in stimulating testicular tubule growth once a critical level of FSH is achieved.

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.

Evaluation of GnRH analogue testing in diagnosis and management of children with pubertal disorders

CONTEXT

Gonadotrophin releasing hormone (GnRH) stimulation test is pivotal in the assessment of children with pubertal disorders. However, lack of availability and high cost often result in the test falling into disfavor. We routinely use the GnRH analogue stimulation test as an alternative at our center.

AIM

To present the data on children with endocrine disorders who underwent GnRH agonist stimulation test in pediatric endocrine clinic of a tertiary care referral hospital.

SETTING AND DESIGN

Pediatric endocrine clinic of a tertiary care referral hospital. Retrospective analysis of case records.

MATERIALS AND METHODS

The details pertaining to clinical and radiological parameters and hormonal tests were retrieved from case records of 15 children who underwent GnRH agonist stimulation test from May 2010 to April 2011.

RESULTS

Indications for testing with GnRH analogue were evaluation of delayed puberty, diagnosis of precocious puberty, assessment of hormonal suppression in treatment of precocious puberty and micropenis in two, nine, three and one cases, respectively. The results of the test and clinical and radiological parameters were in concordance. The test was also crucial in diagnosing the onset of central precocious puberty in two children with congenital adrenal hyperplasia.

CONCLUSION

GnRH agonist test is a convenient, safe test that can be performed on an out-patient basis and can help the clinicians in the correct diagnosis and appropriate treatment of various puberty-related disorders.

Approach to the male patient with congenital hypogonadotropic hypogonadism

The term "congenital hypogonadotropic hypogonadism" (CHH) refers to a group of disorders featuring complete or partial pubertal failure due to insufficient secretion of the pituitary gonadotropins LH and FSH. Many boys (or their parents) will seek medical consultation because of partial or absent virilization after 14 yr of age. Small testes are very frequent, but height is generally normal. Laboratory diagnosis of hypogonadotropic hypogonadism is relatively simple, with very low circulating total testosterone and low to low-normal gonadotropin and inhibin B levels. This hormone profile rules out a primary testicular disorder. Before diagnosing CHH, however, it is necessary to rule out a pituitary tumor or pituitary infiltration by imaging studies, juvenile hemochromatosis, and a systemic disorder that, by undermining nutritional status, could affect gonadotropin secretion and pubertal development. Anterior pituitary function must be thoroughly investigated to rule out a more complex endocrine disorder with multiple hormone deficiencies and thus to conclude that the hypogonadotropic hypogonadism is isolated. The most likely differential diagnosis before age 18 yr is constitutional delay of puberty. Apart from non-Kallmann syndromic forms, which are often diagnosed during childhood, the two main forms of CHH seen by endocrinologists are Kallmann syndrome, in which CHH is associated with impaired sense of smell, and isolated CHH with normal olfaction. Anosmia can be easily diagnosed by questioning the patient, whereas olfactometry is necessary to determine reliably whether olfaction is normal or partially defective. This step is important before embarking on a search for genetic mutations, which will also be useful for genetic counseling. The choice of a particular hormone replacement therapy protocol aimed at virilizing the patient will depend on age at diagnosis and local practices.