Characteristics of a nationwide cohort of patients presenting with isolated hypogonadotropic hypogonadism (IHH)

"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.

Variety of genetic defects in GnRH and hypothalamic-pituitary signaling and development in normosmic patients with IHH

Introduction

Normosmic isolated hypogonadotropic hypogonadism (nIHH) is a clinically and genetically heterogeneous disorder. Deleterious variants in over 50 genes have been implicated in the etiology of IHH, which also indicates a possible role of digenicity and oligogenicity. Both classes of genes controlling GnRH neuron migration/development and hypothalamic/pituitary signaling and development are strongly implicated in nIHH pathogenesis. The study aimed to investigate the genetic background of nIHH and further expand the genotype-phenotype correlation.

Methods

A total of 67 patients with nIHH were enrolled in the study. NGS technology and a 38-gene panel were applied.

Results

Causative defects regarded as at least one pathogenic/likely pathogenic (P/LP) variant were found in 23 patients (34%). For another 30 individuals, variants of unknown significance (VUS) or benign (B) were evidenced (45%). The most frequently mutated genes presenting P/LP alterations were GNRHR (n = 5), TACR3 (n = 3), and CHD7, FGFR1, NSMF, BMP4, and NROB1 (n = 2 each). Monogenic variants with solid clinical significance (P/LP) were observed in 15% of subjects, whereas oligogenic defects were detected in 19% of patients. Regarding recurrence, 17 novel pathogenic variants affecting 10 genes were identified for 17 patients. The most recurrent pathogenic change was GNRHR:p.Arg139His, detected in four unrelated subjects. Another interesting observation is that P/LP defects were found more often in genes related to hypothalamic-pituitary pathways than those related to GnRH.

Conclusions

The growing importance of the neuroendocrine pathway and related genes is drawing increasing attention to nIHH. However, the underestimated potential of VUS variants in IHH etiology, particularly those presenting recurrence, should be further elucidated.

Position statement on the diagnosis and management of congenital pituitary deficiency in adults: The French National Diagnosis and Treatment Protocol (NDTP)

Pituitary deficiency, or hypopituitarism, is a rare chronic disease. It is defined by insufficient synthesis of one or more pituitary hormones (growth hormone, TSH, ACTH, LH-FSH, prolactin), whether or not associated with arginine vasopressin deficiency (formerly known as diabetes insipidus). In adult patients, it is usually acquired (notably during childhood), but can also be congenital, due to abnormal pituitary development. The present study focuses on congenital pituitary deficiency in adults, from diagnosis to follow-up, including special situations such as pregnancy or the elderly. The clinical presentation is highly variable, ranging from isolated deficit to multiple deficits, which may be part of a syndromic form or not. Diagnosis is based on a combination of clinical, biological (assessment of all hormonal axes), radiological (brain and hypothalamic-pituitary MRI) and genetic factors. Treatment consists in hormonal replacement therapy, adapted according to the period of life and the deficits, which may be progressive. Comorbidities, risk of complications and acute decompensation, and the impact on fertility and quality of life all require adaptative multidisciplinary care and long-term monitoring.

Diagnosis and treatment of hypogonadism in men seeking to preserve fertility - what are the options?

Male hypogonadism is a clinical syndrome that results in low testosterone levels and frequently leads to infertility. The syndrome occurs due to disruption at one or more levels of the hypothalamic-pituitary-gonadal axis. Testosterone replacement therapy (TRT) is the most common treatment utilised for male hypogonadism. However, long-acting forms of TRT leads to infertility and so is inappropriate for patients wishing to conceive. For patients who wish to remain fertile, nasal TRT, clomiphene citrate, exogenous gonadotropins, gonadotropin releasing hormone and aromatase inhibitors have been used as alternative treatment options with different degrees of success. A review of the literature was performed to identify the safety and efficacy of alternative treatment options. Gonadotropin releasing hormone can successfully induce spermatogenesis but is impractical to administer. Likewise, aromatase inhibitors have limited use due to inducing osteopenia. Nasal TRT may be a good treatment option for these patients, but its efficacy has so far only been demonstrated in small sample sizes. However, clomiphene citrate and exogenous gonadotropins are safe, offer good symptom control and can successfully induce fertility in hypogonadism patients.

Classes and predictors of reversal in male patients with congenital hypogonadotropic hypogonadism: a cross-sectional study of six international referral centres

BACKGROUND

Although some male patients with congenital hypogonadotropic hypogonadism (CHH) undergo spontaneous reversal following treatment, predictors of reversal remain elusive. We aimed to assemble the largest cohort of male patients with CHH reversal to date and identify distinct classes of reversal.

METHODS

This multicentre cross-sectional study was conducted in six international CHH referral centres in Brazil, Finland, France, Italy, the UK, and the USA. Adult men with CHH (ie, absent or incomplete spontaneous puberty by age 18 years, low serum testosterone concentrations, and no identifiable cause of hypothalamic-pituitary-gonadal [HPG] axis dysfunction) were eligible for inclusion. CHH reversal was defined as spontaneous recovery of HPG axis function off treatment. Centres provided common data elements on patient phenotype, clinical assessment, and genetics using a structured, harmonised data collection form developed by COST Action BM1105. Latent class mixture modelling (LCMM) was applied to establish whether at least two distinct classes of reversal could be identified and differentially predicted, and results were compared with a cohort of patients without CHH reversal to identify potential predictors of reversal. The primary outcome was the presence of at least two distinct classes of reversal.

FINDINGS

A total of 87 male patients with CHH reversal and 108 without CHH reversal were included in the analyses. LCMM identified two distinct reversal classes (75 [86%] in class 1 and 12 [14%] in class 2) on the basis of mean testicular volume, micropenis, and serum follicle-stimulating hormone (FSH) concentration. Classification probabilities were robust (0·998 for class 1 and 0·838 for class 2) and modelling uncertainty was low (entropy 0·90). Compared with class 1, patients in class 2 had significantly larger testicular volume (p<0·0001), no micropenis, and higher serum FSH concentrations (p=0·041), consistent with the Pasqualini syndrome (fertile eunuch) subtype of CHH. Patients without CHH reversal were more likely to have anosmia (p=0·016), cryptorchidism (p=0·0012), complete absence of puberty (testicular volume <4 cm³; p=0·0016), and two or more rare genetic variants (ie, oligogenicity; p=0·0001). Among patients who underwent genetic testing, no patients (of 75) with CHH reversal had a rare pathogenic ANOS1 variant compared with ten (11%) of 95 patients without CHH reversal. Individuals with CHH reversal had a significantly higher rate of rare variants in GNRHR than did those without reversal (nine [12%] of 75 vs three [3%] of 95; p=0·025).

INTERPRETATION

Applying LCMM to a large cohort of male patients with CHH reversal uncovered two distinct classes of reversal. Genetic investigation combined with careful clinical phenotyping could help surveillance of reversal after withdrawing treatment, representing the first tailored management approach for male patients with this rare endocrine disorder.

FUNDING

National Institutes of Health National Center for Advancing Translational Sciences; Ministry of Health, Rome, Italy; Ministry of University, Rome, Italy; National Institutes of Health Eunice Kennedy Shriver National Institute of Child Health and Human Development; and the Josiah Macy Jr Foundation.

TRANSLATION

For the Italian translation of the abstract see Supplementary Materials section.

Outcomes and experiences of adults with congenital hypogonadism can inform improvements in the management of delayed puberty

Patients with congenital hypogonadism will encounter many health care professionals during their lives managing their health needs; from antenatal and infantile periods, through childhood and adolescence, into adult life and then old age. The pubertal transition from childhood to adult life raises particular challenges for diagnosis, therapy and psychological support, and patients encounter many pitfalls. Many patients with congenital hypogonadism and delayed or absent puberty are only diagnosed and treated after long diagnostic journeys, and their management across different centres and countries is not well standardised. Here we reconsider the management of pubertal delay, whilst addressing problematic diagnostic issues and highlighting the limitations of historic pubertal induction protocols - from the perspective of both an adult and a paediatric endocrinologist, dealing in our everyday work with the long-term adverse consequences to our hypogonadal patients of an incorrect and/or late diagnosis and treatment in childhood.

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.

Clinical Manifestations, Genetic Variants and Therapeutic Evaluation in Sporadic Chinese Patients with Idiopathic Hypogonadotropic Hypogonadism

Purpose

Genetic factors account for a large proportion of idiopathic hypogonadotropic hypogonadism (IHH) etiologies, although not necessarily a complete genetic basis. This study aimed to characterize the clinical presentations, genetic variants, and therapeutic outcomes of patients with sporadic IHH, which may be helpful for genetic counseling and treatment decisions.

Patients and Methods

Eleven Chinese patients with IHH were retrospectively analyzed. Rare genetic variants were evaluated using whole-exome sequencing and bioinformatics analysis and were further classified according to the ACMG-AMP guidelines. The therapeutic responses of patients were further evaluated.

Results

Six heterozygous variants of SOX10, WDR11, PROKR2, CHD7 and FGF17 were detected in five Kallmann syndrome (KS) patients, whereas two heterozygous variants of CHD7 and PROKR2 were detected in two normosmic IHH (nIHH) patients. Among these variants, a novel likely pathogenic variant in the SOX10 (c.429-1G>C) was considered to cause the KS phenotype in patient 02, and two potential variants of uncertain significance (VUS) in CHD7 (c.3344G>A and c.7391A>G) possibly contributed to the KS phenotype in patient 05 and the nIHH phenotype in patient 07, which need to be confirmed by further evidence. Additionally, long-term testosterone or estradiol replacement treatment effectively improved the development of sexual characteristics in patients with IHH.

Conclusion

Next-generation sequencing is a powerful tool for identifying the molecular etiology and early diagnosis of IHH. Efficient therapeutic outcomes strongly indicate a need for timely treatment.

The complications of male hypogonadism: is it just a matter of low testosterone?

The history of diagnosing hypogonadism and hypotestosteronemia shows us the many steps that were necessary to achieve our current knowledge and the ability to improve these patients' well-being. Moreover, so far, criteria for diagnosing hypotestosteronemia varies according to the underlying condition, and according to the consensus or guideline adopted. Furthermore, besides the many signs and symptoms, there are several complications associated with low testosterone levels such as osteoporosis, metabolic alterations, as well as cardiovascular disorders. However, data are often conflicting regarding the severity, timing or even the real clinical relevance of these complications, although these studies often lack essential information such as gonadotropin levels or the underlying cause of hypogonadism. The present review focus on the complications of male hypogonadism according to the cause of testosterone deficiency, highlighting the lack of information found in many studies investigating its effects. We thereby stress the necessity to always perform a complete evaluation of the type of hypogonadism (including at least gonadotropins and secondary causes) when investigating the effects of low testosterone levels.

Defective jagged-1 signaling affects GnRH development and contributes to congenital hypogonadotropic hypogonadism

In vertebrate species, fertility is controlled by gonadotropin-releasing hormone (GnRH) neurons. GnRH cells arise outside the central nervous system, in the developing olfactory pit, and migrate along olfactory/vomeronasal/terminal nerve axons into the forebrain during embryonic development. Congenital hypogonadotropic hypogonadism (CHH) and Kallmann syndrome are rare genetic disorders characterized by infertility, and they are associated with defects in GnRH neuron migration and/or altered GnRH secretion and signaling. Here, we documented the expression of the jagged-1/Notch signaling pathway in GnRH neurons and along the GnRH neuron migratory route both in zebrafish embryos and in human fetuses. Genetic knockdown of the zebrafish ortholog of JAG1 (jag1b) resulted in altered GnRH migration and olfactory axonal projections to the olfactory bulbs. Next-generation sequencing was performed in 467 CHH unrelated probands, leading to the identification of heterozygous rare variants in JAG1. Functional in vitro validation of JAG1 mutants revealed that 7 out of the 9 studied variants exhibited reduced protein levels and altered subcellular localization. Together our data provide compelling evidence that Jag1/Notch signaling plays a prominent role in the development of GnRH neurons, and we propose that JAG1 insufficiency may contribute to the pathogenesis of CHH in humans.

Genetic architecture of self-limited delayed puberty and congenital hypogonadotropic hypogonadism

Distinguishing between self limited delayed puberty (SLDP) and congenital hypogonadotropic hypogonadism (CHH) may be tricky as they share clinical and biochemical characteristics. and appear to lie within the same clinical spectrum. However, one is classically transient (SDLP) while the second is typically a lifetime condition (CHH). The natural history and long-term outcomes of these two conditions differ significantly and thus command distinctive approaches and management. Because the first presentation of SDLP and CHH is very similar (delayed puberty with low LH and FSH and low sex hormones), the scientific community is scrambling to identify diagnostic tests that can allow a correct differential diagnosis among these two conditions, without having to rely on the presence or absence of phenotypic red flags for CHH that clinicians anyway seem to find hard to process. Despite the heterogeneity of genetic defects so far reported in DP, genetic analysis through next-generation sequencing technology (NGS) had the potential to contribute to the differential diagnostic process between SLDP and CHH. In this review we will provide an up-to-date overview of the genetic architecture of these two conditions and debate the benefits and the bias of performing genetic analysis seeking to effectively differentiate between these two conditions.

Isolated anterior pituitary dysfunction in adulthood

Hypopituitarism is defined as a complete or partial deficiency in one or more pituitary hormones. Anterior hypopituitarism includes secondary adrenal insufficiency, central hypothyroidism, hypogonadotropic hypogonadism, growth hormone deficiency and prolactin deficiency. Patients with hypopituitarism suffer from an increased disability and sick days, resulting in lower health status, higher cost of care and an increased mortality. In particular during adulthood, isolated pituitary deficits are not an uncommon finding; their clinical picture is represented by vague symptoms and unclear signs, which can be difficult to properly diagnose. This often becomes a challenge for the physician. Aim of this narrative review is to analyse, for each anterior pituitary deficit, the main related etiologies, the characteristic signs and symptoms, how to properly diagnose them (suggesting an easy and reproducible step-based approach), and eventually the treatment. In adulthood, the vast majority of isolated pituitary deficits are due to pituitary tumours, head trauma, pituitary surgery and brain radiotherapy. Immune-related dysfunctions represent a growing cause of isolated pituitary deficiencies, above all secondary to use of oncological drugs such as immune checkpoint inhibitors. The diagnosis of isolated pituitary deficiencies should be based on baseline hormonal assessments and/or dynamic tests. Establishing a proper diagnosis can be quite challenging: in fact, even if the diagnostic methods are becoming increasingly refined, a considerable proportion of isolated pituitary deficits still remains without a certain cause. While isolated ACTH and TSH deficiencies always require a prompt replacement treatment, gonadal replacement therapy requires a benefit-risk evaluation based on the presence of comorbidities, age and gender of the patient; finally, the need of growth hormone replacement therapies is still a matter of debate. On the other side, prolactin replacement therapy is still not available. In conclusion, our purpose is to offer a broad evaluation from causes to therapies of isolated anterior pituitary deficits in adulthood. This review will also include the evaluation of uncommon symptoms and main etiologies, the elements of suspicion of a genetic cause and protocols for diagnosis, follow-up and treatment.

New and Consolidated Therapeutic Options for Pubertal Induction in Hypogonadism: In-depth Review of the Literature

Delayed puberty (DP) defines a retardation of onset/progression of sexual maturation beyond the expected age from either a lack/delay of the hypothalamo-pituitary-gonadal axis activation or a gonadal failure. DP usually gives rise to concern and uncertainty in patients and their families, potentially affecting their immediate psychosocial well-being and also creating longer term psychosexual sequelae. The most frequent form of DP in younger teenagers is self-limiting and may not need any intervention. Conversely, DP from hypogonadism requires prompt and specific treatment that we summarize in this review. Hormone therapy primarily targets genital maturation, development of secondary sexual characteristics, and the achievement of target height in line with genetic potential, but other key standards of care include body composition and bone mass. Finally, pubertal induction should promote psychosexual development and mitigate both short- and long-term impairments comprising low self-esteem, social withdrawal, depression, and psychosexual difficulties. Different therapeutic options for pubertal induction have been described for both males and females, but we lack the necessary larger randomized trials to define the best approaches for both sexes. We provide an in-depth and updated literature review regarding therapeutic options for inducing puberty in males and females, particularly focusing on recent therapeutic refinements that better encompass the heterogeneity of this population, and underlining key differences in therapeutic timing and goals. We also highlight persistent shortcomings in clinical practice, wherein strategies directed at "the child with delayed puberty of uncertain etiology" risk being misapplied to older adolescents likely to have permanent hypogonadism.

Biallelic PROKR2 variants and congenital hypogonadotropic hypogonadism: a case report and a literature review

Congenital hypogonadotropic hypogonadism (CHH) is a rare disorder that causes gonadotropin-releasing hormone (GnRH) deficiency and sexual immaturity. CHH may accompany an abnormal sense of smell (Kallmann syndrome, KS) or no such manifestation (normosmic-CHH). This unusual combination of manifestations is explained by the fact that GnRH neurons originate in the olfactory placode and migrate to the forebrain during embryogenesis. We describe the case of a 31-year-old man with normosmic-CHH, who also had obesity, type 2 diabetes and intellectual disability. He was noticed to have sexual immaturity (small testes with no pubic hair) at age 20 years, when diabetic ketoacidosis developed. Basal and GnRH-stimulated levels of LH (1.0→12.0 IU/L) and FSH (1.9→6.1 IU/L) were detectable but low. The results of the T&T olfactometer and the Alinamin test were definitely normal, with an anatomically normal olfactory system on MRI. Sequencing of 22 CHH-related genes was performed, and compound heterozygous PROKR2 variants were identified: one was a previously known loss-of-function variant (p.Trp178Ser) and the other was a nonsense variant (p.Trp212*). Through a literature review, we found 22 patients (including our patient) with CHH due to biallelic PROKR2 variants, which led us to recognize that most of the patients (86%) were diagnosed with KS. Clinical observations in this study indicate that, even though they have CHH, biallelic PROKR2 variant carriers may have a normal olfactory system as well as presumably normal migration of GnRH neurons. This suggests that the PROK2-PROKR2 pathway affects the function of GnRH neurons after their migration.

Reproductive Phenotypes in Men With Acquired or Congenital Hypogonadotropic Hypogonadism: A Comparative Study

CONTEXT

In men with congenital hypogonadotropic hypogonadism (CHH), gonadotropin deficiency and testicular impairment exist since fetal development and persist throughout life. In a few reported cases of acquired HH (AHH), HH onset occurs mainly post pubertally.

OBJECTIVE

This work aimed to compare the natural history and reproductive status in large series of CHH and lesional AHH evaluated in a single expert academic center.

METHODS

We included 172 controls, 668 male HH patients (CHH: n = 201 [age 16.9 ± 9.0 years], lesional AHH: n = 467 [age 45.6 ± 18.4 years]) caused by hypothalamic and/or pituitary tumors (mainly adenomas and craniopharyngiomas) or infiltrative/traumatic diseases.

RESULTS

At diagnosis, CHH were significantly younger, with 52.9% diagnosed before age 18 years, compared to only 9.6% of AHH patients. Cryptorchidism (21.9% vs 0.3%) and micropenis were more prevalent in CHH than AHH patients. Low testicular volume (TV) was present in 97% of patients with CHH (mean TV: 3.4 ± 2.7 mL) but in only 30% of those with AHH (mean TV: 20.8 ± 5.0 mL). Whereas no men with persistent CHH had spontaneous fertility, 70.4% of AHH men fathered at least one child without medical therapy. Total testosterone was lower both in CHH and AHH patients than in controls. Compared to controls, circulating gonadotropins and testicular peptides (insulin-like factor-3 and inhibin B) were decreased both in CHH and AHH, but were significantly higher in patients with AHH.

CONCLUSION

In AHH patients, the HH has later onset and is less severe than in CHH and the phenotype can overlap with that of individuals with normal laboratory values. Our data suggest that age at diagnosis is a predictor of the reproductive phenotype in AHH.

Pubertal induction and transition to adult sex hormone replacement in patients with congenital pituitary or gonadal reproductive hormone deficiency: an Endo-ERN clinical practice guideline

An Endo-European Reference Network guideline initiative was launched including 16 clinicians experienced in endocrinology, pediatric and adult and 2 patient representatives. The guideline was endorsed by the European Society for Pediatric Endocrinology, the European Society for Endocrinology and the European Academy of Andrology. The aim was to create practice guidelines for clinical assessment and puberty induction in individuals with congenital pituitary or gonadal hormone deficiency. A systematic literature search was conducted, and the evidence was graded according to the Grading of Recommendations, Assessment, Development and Evaluation system. If the evidence was insufficient or lacking, then the conclusions were based on expert opinion. The guideline includes recommendations for puberty induction with oestrogen or testosterone. Publications on the induction of puberty with follicle-stimulation hormone and human chorionic gonadotrophin in hypogonadotropic hypogonadism are reviewed. Specific issues in individuals with Klinefelter syndrome or androgen insensitivity syndrome are considered. The expert panel recommends that pubertal induction or sex hormone replacement to sustain puberty should be cared for by a multidisciplinary team. Children with a known condition should be followed from the age of 8 years for girls and 9 years for boys. Puberty induction should be individualised but considered at 11 years in girls and 12 years in boys. Psychological aspects of puberty and fertility issues are especially important to address in individuals with sex development disorders or congenital pituitary deficiencies. The transition of these young adults highlights the importance of a multidisciplinary approach, to discuss both medical issues and social and psychological issues that arise in the context of these chronic conditions.

Regulation of the Hypothalamic-Pituitary-Testicular Axis: Pathophysiology of Hypogonadism

Male hypogonadism is a clinical syndrome characterized by the diminished functional activity of the testis resulting in low levels of testosterone and/or spermatozoa. Defects at one or more levels of the hypothalamic-pituitary-testicular (HPT) axis can result in either primary or secondary hypogonadism. The changes that occur in the HPT axis from fetal to adult life are fundamental to understanding the pathophysiology of hypogonadism. In this article, we summarize the maturation and neuroendocrine regulation of the HPT axis and discuss the major congenital and acquired causes of male hypogonadism both at the (1) hypothalamic-pituitary (secondary hypogonadism) and (2) testicular (primary hypogonadism) levels.

Genetic and phenotypic differences between sexes in congenital hypogonadotropic hypogonadism (CHH): Large cohort analysis from a single tertiary centre

BACKGROUND

Congenital hypogonadotropic hypogonadism (CHH) is a condition with a strong genetic background, caused by a deficient production, secretion, or action of gonadotropin-releasing hormone (GnRH). Published data on CHH cohorts indicate a male predominance, although this is not supported by our current understandings.

AIMS

In order to unravel the possible causes or contributors to such epidemiological sex difference, the aim of our study is to investigate differences in genetic background and clinical presentation between males and females in a large cohort of CHH patients.

MATERIALS AND METHODS

We enrolled 338 CHH patients with absent or arrested pubertal development, referred to our Center from 01/2016. Data collection included clinical assessment at diagnosis and genetic analysis performed by next generation sequencing (NGS), employing a custom panel of 28 candidate genes.

RESULTS

Among 338 patients 94 were female (F) and 244 male (M), with a ratio of 1:2.6. We found that 36.09% (122/338) of patients harbored potentially pathogenic rare genetic variants (RVs) with no significant differences between sexes; on the other hand, a significantly higher frequency of oligogenicity was observed in females (F 9,57% 9/94 vs M 3,69% 9/244, P = 0.034). The prevalence of non-reproductive phenotypic features was significantly higher (P = 0.01) in males (53/228, 23.2%) than in females (10/93, 10.8%): in particular, kidney abnormalities affected only male patients and midline defects had a significantly higher prevalence in males (P = 0.010). Finally, BMI SDS was -0.04 ± 1.09 in females and 0.69 ± 1.51 in males, with a statistically significant difference between groups (P = <0.001).

CONCLUSION

Our data confirm the male predominance in CHH and identify some differences with regard to the clinical presentation between males and females that could indicate a variable expression of genetic rare variants and a dimorphic modulation of phenotype according to metabolic/behavioral factors, which will need to be substantiated and investigated by further studies.

FSH and bone: Comparison between males with central versus primary hypogonadism

OBJECTIVE

Experimental studies proposed a direct effect of follicle-stimulating hormone (FSH) on the skeletal metabolism, but results of human studies mainly conducted in females are controversial. The present study aims to investigate the possible role of FSH excess in male bone health, by comparing for the first time primary and central hypogonadism.

DESIGN AND METHODS

119 men were enrolled in this cross-sectional observational study at the time of the first diagnosis of hypogonadism. All participants had spontaneous pubertal development. Regarding patients with hypergonadotropic hypogonadism (Hyper-H), Klinefelter syndrome (KS) patients were distinguished from the other forms (non-KS-Hyper-H) based on the onset of FSH elevation. Bone mineral density (BMD) at both lumbar spine (LS) and femoral neck (FN), as well as the prevalence of morphometric vertebral fractures (VFx), were assessed.

RESULTS

Across the whole cohort, higher LS and FN BMD were associated with older age at diagnosis and higher body mass index (BMI), respectively. After adjusting for potential confounders (age at diagnosis, BMI, smoking habits, degree of hypogonadism defined by calculated free testosterone, and 25OH vitamin D levels), non-KS-Hyper-H patients showed significantly lower LS BMD and tended to show lower FN BMD values, as compared to those with hypogonadotropic hypogonadism (Hypo-H). In KS men, LS BMD was significantly lower than in those with non-KS-Hyper-H. No significant differences in the prevalence of VFx were found between the groups.

CONCLUSIONS

These findings suggest a potential negative effect of FSH excess on the male bone mass, especially at spine. The duration of high FSH levels may also contribute to these findings.

Current concepts surrounding neonatal hormone therapy for boys with congenital hypogonadotropic hypogonadism

INTRODUCTION

Congenital hypogonadotropic hypogonadism (CHH) is a genetic disorder of reproduction and development, characterized by deficient gonadotropin-releasing hormone (GnRH) secretion or action, affecting 1-in-4,000-15,000 males. Micropenis and undescended testes are cardinal features of antenatal GnRH deficiency and could indicate absent minipuberty in the first postnatal months. In this review, we outline the pathophysiology and clinical consequences of absent minipuberty and its implications for optimal approaches to the endocrine management of affected boys.

AREAS COVERED

Deficient GnRH activity during fetal development and neonatal-infancy phase of minipuberty accounts for the diminished mass of Sertoli cells and seminiferous tubules among CHH males, enduring impairment of reproductive function even during gonadotropin replacement in adult life. In overcoming this obstacle, several clinical studies of neonatal gonadotropin replacement have consistently shown positive results in inducing testicular development and correcting cryptorchidism.

EXPERT OPINION

A high index of clinical suspicion, combined with hormonal testing undertaken in the postnatal period of 1-4 months, can reliably confirm or refute the diagnosis of CHH. Timely identification of CHH in affected male infants (having characteristic "red flag' developmental anomalies) opens up the possibility for gonadotropin replacement as a targeted therapy to restore the normal hormonal milieu of minipuberty. Further work is necessary in formulating optimal gonadotropin treatment regimens to be more widely adopted in clinical practice.

TUBB3 Arg262His causes a recognizable syndrome including CFEOM3, facial palsy, joint contractures, and early-onset peripheral neuropathy

Microtubules are formed from heterodimers of alpha- and beta-tubulin, each of which has multiple isoforms encoded by separate genes. Pathogenic missense variants in multiple different tubulin isoforms cause brain malformations. Missense mutations in TUBB3, which encodes the neuron-specific beta-tubulin isotype, can cause congenital fibrosis of the extraocular muscles type 3 (CFEOM3) and/or malformations of cortical development, with distinct genotype-phenotype correlations. Here, we report fourteen individuals from thirteen unrelated families, each of whom harbors the identical NM_006086.4 (TUBB3):c.785G>A (p.Arg262His) variant resulting in a phenotype we refer to as the TUBB3 R262H syndrome. The affected individuals present at birth with ptosis, ophthalmoplegia, exotropia, facial weakness, facial dysmorphisms, and, in most cases, distal congenital joint contractures, and subsequently develop intellectual disabilities, gait disorders with proximal joint contractures, Kallmann syndrome (hypogonadotropic hypogonadism and anosmia), and a progressive peripheral neuropathy during the first decade of life. Subsets may also have vocal cord paralysis, auditory dysfunction, cyclic vomiting, and/or tachycardia at rest. All fourteen subjects share a recognizable set of brain malformations, including hypoplasia of the corpus callosum and anterior commissure, basal ganglia malformations, absent olfactory bulbs and sulci, and subtle cerebellar malformations. While similar, individuals with the TUBB3 R262H syndrome can be distinguished from individuals with the TUBB3 E410K syndrome by the presence of congenital and acquired joint contractures, an earlier onset peripheral neuropathy, impaired gait, and basal ganglia malformations.

Age at diagnosis in patients with chronic congenital endocrine conditions: a regional cohort study from a reference center for rare diseases

Background

For chronic congenital endocrine conditions, age at diagnosis is a key issue with implications for optimal management and psychological concerns. These conditions are associated with an increase in the risk of comorbid conditions, particularly as  it concerns growth, pubertal development and fertility potential. Clinical presentation and severity depend on the disorder and the patient’s age, but diagnosis is often late.

Objective

To evaluate age at diagnosis for the most frequent congenital endocrine diseases affecting growth and/or development.

Patients and Methods

This observational cohort study included all patients (n = 4379) with well-defined chronic congenital endocrine diseases—non-acquired isolated growth hormone deficiency (IGHD), isolated congenital hypogonadotropic hypogonadism (ICHH), ectopic neurohypophysis (NH), Turner syndrome (TS), McCune-Albright syndrome (MAS), complete androgen insensitivity syndrome (CAIS) and gonadal dysgenesis (GD)—included in the database of a single multisite reference center for rare endocrine growth and developmental disorders, over a period of 14 years. Patients with congenital hypothyroidism and adrenal hyperplasia were excluded as they are generally identified during neonatal screening.

Results

Median age at diagnosis depended on the disease: first year of life for GD, before the age of five years for ectopic NH and MAS, 8–10 years for IGHD, TS (11% diagnosed antenatally) and CAIS and 17.4 years for ICHH. One third of the patients were diagnosed before the age of five years. Diagnosis occurred in adulthood in 22% of cases for CAIS, 11.6% for TS, 8.8% for GD, 0.8% for ectopic NH, and 0.4% for IGHD. A male predominance (2/3) was observed for IGHD, ectopic NH, ICHH and GD.

Conclusion

The early recognition of growth/developmental failure during childhood is essential, to reduce time-to-diagnosis and improve outcomes.

Predictors of reproductive and non-reproductive outcomes of gonadotropin mediated pubertal induction in male patients with congenital hypogonadotropic hypogonadism (CHH)

PURPOSE

To investigate predictors of testicular response and non-reproductive outcomes (height, body proportions) after gonadotropin-induced puberty in congenital hypogonadotropic hypogonadism (CHH).

DESIGN

A retrospective analysis of the puberty induction in CHH male patients, undergoing an off-label administration of combined gonadotropin (FSH and hCG).

METHODS

Clinical and hormonal evaluations before and during gonadotropin stimulation in 19 CHH patients genotyped by Targeted Next Generation Sequencing for CHH genes; 16 patients underwent also semen analysis after gonadotropins.

RESULTS

A lesser increase in testicular volume after 24 months of induction was significantly associated with: (I) cryptorchidism; (II) a positive genetic background; (III) a complete form of CHH. We found no significant correlation with the cumulative dose of hCG administered in 24 months. We found no association with the results of semen analyses, probably due to the low numerosity. Measures of body disproportion (eunuchoid habitus and difference between adult and target height: deltaSDSth), were significantly related to the: (I) age at the beginning of puberty induction; (II) duration of growth during the induction; (III) initial bone age. The duration of growth during induction was associated with previous testosterone priming and to partial forms of CHH.

CONCLUSIONS

This study shows that a strong genetic background and cryptorchidism, as indicators of a complete GnRH deficiency since intrauterine life, are negative predictors of testicular response to gonadotropin stimulation in CHH. Body disproportion is associated with a delay in treatment and duration of growth during the induction, which is apparently inversely related to previous androgenization.

Cell adhesion molecule L1 like plays a role in the pathogenesis of idiopathic hypogonadotropic hypogonadism

PURPOSE

The pathogenesis of idiopathic hypogonadotropic hypogonadism (IHH) is genetically complex. The aims of this study were to investigate the genetic profile and clinical manifestation of IHH in a Chinese pedigree and to discover new IHH-associated genes.

METHODS

The first step was to follow up the clinical phenotype and therapeutic outcomes of the pedigree in university hospital. The second step was that mutation screening was performed in this pedigree and 100 healthy controls. The third step was to further verify the pathogenicity of the discovered rare sequencing variant (RSV) by functional experiments. Whole exome sequencing, Sanger sequencing, testicular volume (TV), semen analysis, assessment of cell migration and necroptosis were performed.

RESULTS

One heterozygous RSV (p.G517E) in CHL1 was identified in two male IHH patients and their mother in the pedigree, but not in healthy controls. All the three individuals exhibited olfactory impairment. hCG/hMG treatment significantly improved TV, serum testosterone and/or semen parameters of the two male patients. Functional analysis indicated that CHL1 significantly regulated GnRH neuronal cell line (GN11 cells) migration and necroptosis, with alteration of ERK1/2 activation, calcium loading, and transcription of RIPK3 and MLKL. However, the above processes were negatively influenced by the CHL1 RSV.

CONCLUSIONS

Our study reports the genetic relevance of CHL1 in IHH, and characterizes the phenotypic and therapeutic profiles in patients carrying the CHL1 RSV. CHL1 may act as a new IHH-associated gene, and should be taken into consideration in future investigations for this field.

Mechanisms of Central Hypogonadism

Reproductive function depends upon an operational hypothalamo–pituitary–gonadal (HPG) axis. Due to its role in determining survival versus reproductive strategies, the HPG axis is vulnerable to a diverse plethora of signals that ultimately manifest with Central Hypogonadism (CH) in all its many guises. Acquired CH can result from any pituitary or hypothalamic lesion, including its treatment (such as surgical resection and/or radiotherapy). The HPG axis is particularly sensitive to the suppressive effects of hyperprolactinaemia that can occur for many reasons, including prolactinomas, and as a side effect of certain drug therapies. Physiologically, prolactin (combined with the suppressive effects of autonomic neural signals from suckling) plays a key role in suppressing the gonadal axis and establishing temporary CH during lactation. Leptin is a further key endocrine regulator of the HPG axis. During starvation, hypoleptinaemia (from diminished fat stores) results in activation of hypothalamic agouti-related peptide neurons that have a dual purpose to enhance appetite (important for survival) and concomitantly suppresses GnRH neurons via effects on neural kisspeptin release. Obesity is associated with hyperleptinaemia and leptin resistance that may also suppress the HPG axis. The suppressibility of the HPG axis also leaves it vulnerable to the effects of external signals that include morphine, anabolic-androgenic steroids, physical trauma and stress, all of which are relatively common causes of CH. Finally, the HPG axis is susceptible to congenital malformations, with reports of mutations within >50 genes that manifest with congenital CH, including Kallmann Syndrome associated with hyposmia or anosmia (reduction or loss of the sense of smell due to the closely associated migration of GnRH with olfactory neurons during embryogenesis). Analogous to the HPG axis itself, patients with CH are often vulnerable, and their clinical management requires both sensitivity and empathy.

Gonadotropin treatment for male partial congenital hypogonadotropic hypogonadism in Chinese patients

Partial congenital hypogonadotropic hypogonadism (PCHH) is caused by an insufficiency in, but not a complete lack of, gonadotropin secretion. This leads to reduced testosterone production, mild testicular enlargement, and partial pubertal development. No studies have shown the productivity of spermatogenesis in patients with PCHH. We compared the outcomes of gonadotropin-induced spermatogenesis between patients with PCHH and those with complete congenital hypogonadotropic hypogonadism (CCHH). This retrospective study included 587 patients with CHH who were treated in Peking Union Medical College Hospital (Beijing, China) from January 2008 to September 2016. A total of 465 cases were excluded from data analysis for testosterone or gonadotropin-releasing hormone treatment, cryptorchidism, poor compliance, or incomplete medical data. We defined male patients with PCHH as those with a testicular volume of ≥4 ml and patients with a testicular volume of <4 ml as CCHH. A total of 122 compliant, noncryptorchid patients with PCHH or CCHH received combined human chorionic gonadotropin and human menopausal gonadotropin and were monitored for 24 months. Testicular size, serum luteinizing hormone levels, follicle-stimulating hormone levels, serum total testosterone levels, and sperm count were recorded at each visit. After gonadotropin therapy, patients with PCHH had a higher spermatogenesis rate (92.3%) than did patients with CCHH (74.7%). During 24-month combined gonadotropin treatment, the PCHH group took significantly less time to begin producing sperm compared with the CCHH group (median time: 11.7 vs 17.8 months, P < 0.05). In conclusion, after combined gonadotropin treatment, patients with PCHH have a higher spermatogenesis success rate and sperm concentrations and require shorter treatment periods for sperm production.

Reduced Quality of Life and Sexual Satisfaction in Isolated Hypogonadotropic Hypogonadism

(1) Background: Isolated hypogonadotropic hypogonadism (IHH) is a genetic condition characterized by impaired puberty and fertility. IHH can significantly impact patient health-related quality of life (HRQoL), sexual satisfaction (SS) and mood. (2) Methods: Participants included 132 IHH subjects (89 men and 43 women) and 132 sex- and age-matched controls. HRQoL, depressive symptoms, erectile dysfunction (ED), and SS were assessed in an online survey using the Zung Self-Rating Depression Scale (SDS), 15D instrument of HRQoL (15D), Sexual Satisfaction Questionnaire (SSQ), and 5-item International Index of Erectile Function (IIEF-5). (3) Results: QoL and SS were significantly lower in the IHH group vs. controls. There was a high rate of ED (53.2% vs. 33%, p = 0.008) and depressive symptoms (45.00 ± 17.00 vs. 32.00 ± 12.00, p < 0.001) in patients vs. controls. The age of patients at IHH diagnosis inversely correlated with their overall 15D scores. An alarming non-compliance rate was seen (51.6%). No differences were found between scores of patients receiving hormone replacement therapy (HRT) and untreated subjects in any of the scales. (4) Conclusions: The HRQoL, SS, ED, and depression levels observed in IHH patients, despite HRT, are alarming. Late IHH diagnosis may have a particularly negative impact on HRQoL. More attention should be devoted to HRT adherence and various HRQoL aspects of IHH patients.

Defects in GnRH Neuron Migration/Development and Hypothalamic-Pituitary Signaling Impact Clinical Variability of Kallmann Syndrome

Kallmann syndrome (KS) is a combination of isolated hypogonadotropic hypogonadism (IHH) with olfactory dysfunction, representing a heterogeneous disorder with a broad phenotypic spectrum. The genetic background of KS has not yet been fully established. This study was conducted on 46 Polish KS subjects (41 males, 5 females; average age: 29 years old). The studied KS patients were screened for defects in a 38-gene panel with next-generation sequencing (NGS) technology. The analysis revealed 27 pathogenic and likely pathogenic (P/LP) variants, and 21 variants of uncertain significance (VUS). The P/LP variants were detected in 20 patients (43.5%). The prevalence of oligogenic P/LP defects in selected genes among KS patients was 26% (12/46), whereas the co-occurrence of other variants was detected in 43% (20 probands). The examined KS patients showed substantial genotypic and phenotypic variability. A marked difference in non-reproductive phenotypes, involving defects in genes responsible for GnRH neuron development/migration and genes contributing to pituitary development and signaling, was observed. A comprehensive gene panel for IHH testing enabled the detection of clinically relevant variants in the majority of KS patients, which makes targeted NGS an effective molecular tool. The significance of oligogenicity and the high incidence of alterations in selected genes should be further elucidated.

Cardiovascular risk and testosterone - from subclinical atherosclerosis to lipoprotein function to heart failure

The cardiovascular (CV) benefit and safety of treating low testosterone conditions is a matter of debate. Although testosterone deficiency has been linked to a rise in major adverse CV events, most of the studies on testosterone replacement therapy were not designed to assess CV risk and thus excluded men with advanced heart failure or recent history of myocardial infarction or stroke. Besides considering observational, interventional and prospective studies, this review article evaluates the impact of testosterone on atherosclerosis process, including lipoprotein functionality, progression of carotid intima media thickness, inflammation, coagulation and thromboembolism, quantification of plaque volume and vascular calcification. Until adequately powered studies evaluating testosterone effects in hypogonadal men at increased CV risk are available (TRAVERSE trial), clinicians should ponder the use of testosterone in men with atherosclerotic cardiovascular disease and discuss benefit and harms with the patients.

Recent advances in understanding and managing Kallmann syndrome

Many of the recent advances in our understanding of human reproductive biology and its genetic basis have arisen directly via the genetic investigation of patients with Kallmann syndrome and their families. The disease is characterised by the association of an isolated defect in the secretion (or, less commonly, action) of gonadotropin-releasing hormone (GnRH) and consequent infertility, with anosmia and potentially other associated non-reproductive features. GnRH-producing neurons are located in the hypothalamic brain region after a peculiar migration during embryonic life. To date, different genes affecting GnRH neuron development/migration have so far been implicated in Kallmann syndrome, but our knowledge of the genetic basis of the syndrome remains incomplete. From a clinical point of view, the disease has suffered from a lack of definitive diagnosis and treatment, and although progress has been made in terms of timely diagnosis and evidence-based treatment of patients, implementation remains inconsistent. These aspects will be discussed in this review, which examines new strategies for arriving at more evidence-based and patient-centred medical practice in Kallmann syndrome.

Central hypogonadism in Klinefelter syndrome: report of two cases and review of the literature

PURPOSE

Klinefelter syndrome (KS) is characterized by late adolescence/young adulthood onset of primary hypogonadism. Hypogonadotropic hypogonadism (HH), when congenital, is usually associated with absent/incomplete puberty and low/normal gonadotropins. We report the clinical and genetic features of two subjects with KS and an unexpected HH hormone profile.

METHODS

Magnetic resonance imaging (MRI) of hypothalamus-pituitary region and next generation sequencing (NGS) of congenital HH-associated genes were obtained. A narrative review of the literature was conducted.

RESULTS

Patients were diagnosed with Klinefelter syndrome following karyotype analysis. Nevertheless, they showed unusual features: both had incomplete puberty, low gonadotropins and testosterone levels, and the first one was anosmic. Sellar lesions were excluded by MRI, and NGS was negative in both subjects. Our data add to those of the only 14 similar cases reported so far. Unexplained HH rarely occurs in KS and is variably associated with anosmia, other pituitary hormones deficiencies and heterogeneous karyotypes. However, most cases show an early, pre-pubertal onset of hypogonadism. If the causes behind this gonadotropins defect are largely unknown, hereby we provide the first review of the literature on this topic and propose some pathogenetic hypotheses, including the coexistence of KS and congenital HH as suggested by overlapping clinical features in some of these patients.

CONCLUSION

HH is an exceptional occurrence in Klinefelter syndrome and is associated with heterogeneous phenotypes and, probably, aetiologies. Moreover, KS could underlie HH nonresponsive to gonadotropins. An exhaustive diagnostic workup and a tailored clinical management are advisable in these rare forms.

ENDO-ERN expert opinion on the differential diagnosis of pubertal delay

The differential diagnoses of pubertal delay include hypergonadotropic hypogonadism and congenital hypogonadotropic hypogonadism (CHH), as well as constitutional delay of growth and puberty (CDGP). Distinguishing between CDGP and CHH may be challenging, and the scientific community has been struggling to develop diagnostic tests that allow an accurate differential diagnosis. Indeed, an adequate and timely management is critical in order to enable optimal clinical and psychosocial outcomes of the different forms of pubertal delays. In this review, we provide an updated insight on the differential diagnoses of pubertal delay, including the available tests, their meanings and accuracy, as well as some clues to effectively orientate towards either constitutional pubertal delay or pathologic CHH and hypergonadotropic hypogonadism.

Insights into non-classic and emerging causes of hypopituitarism

Hypopituitarism is defined as one or more partial or complete pituitary hormone deficiencies, which are related to the anterior and/or posterior gland and can have an onset in childhood or adulthood. The most common aetiology is a sellar or suprasellar lesion, often an adenoma, which causes hypopituitarism due to tumour mass effects, or the effects of surgery and/or radiation therapy. However, other clinical conditions, such as traumatic brain injury, and autoimmune and inflammatory diseases, can result in hypopituitarism, and there are also genetic causes of hypopituitarism. Furthermore, the use of immune checkpoint inhibitors to treat cancer is increasing the risk of hypopituitarism, with a pattern of hormone defects that is different from the classic patterns and depends on mechanisms that are specific for each drug. Moreover, autoantibody production against the pituitary and hypothalamus has been demonstrated in studies investigating the development or worsening of some cases of hypopituitarism. Finally, evidence suggests that posterior pituitary damage can affect oxytocin secretion. The aim of this Review is to summarize current knowledge on non-classic and emerging causes of hypopituitarism, so as to help clinicians improve early identification, avoid life-threatening events and improve the clinical care and quality of life of patients at risk of hypopituitarism.

Kisspeptin-54 Accurately Identifies Hypothalamic Gonadotropin-Releasing Hormone Neuronal Dysfunction in Men with Congenital Hypogonadotropic Hypogonadism

BACKGROUND

Hypogonadotropic hypogonadism (HH) is hypogonadism due to either hypothalamic or pituitary dysfunction. While gonadotropin-releasing hormone (GnRH) can directly test pituitary function, no specific test of hypothalamic function exists. Kisspeptin-54 (KP54) is a neuropeptide that directly stimulates hypothalamic GnRH release and thus could be used to specifically interrogate hypothalamic function. Congenital HH (CHH) is typically due to variants in genes that control hypothalamic GnRH neuronal migration or function. Thus, we investigated whether KP54 could accurately identify hypothalamic dysfunction in men with CHH.

METHODS

Men with CHH (n = 21) and healthy eugonadal men (n = 21) received an intravenous bolus of either GnRH (100 μg) or KP54 (6.4 nmol/kg), on 2 occasions, and were monitored for 6 h after administration of each neuropeptide.

RESULTS

Maximal luteinizing hormone (LH) rise after KP54 was significantly greater in healthy men (12.5 iU/L) than in men with CHH (0.4 iU/L; p < 0.0001). KP54 more accurately differentiated CHH men from healthy men than GnRH (area under receiver operating characteristic curve KP54: 1.0, 95% CI 1.0-1.0; GnRH: 0.88, 95% CI 0.76-0.99). Indeed, all CHH men had an LH rise <2.0 iU/L following KP54, whereas all healthy men had an LH rise >4.0 iU/L. Anosmic men with CHH (i.e., Kallmann syndrome) had even lower LH rises after KP54 than did normosmic men with CHH (p = 0.017). Likewise, men identified to have pathogenic/likely pathogenic variants in CHH genes had even lower LH rises after KP54 than other men with CHH (p = 0.035).

CONCLUSION

KP54 fully discriminated men with CHH from healthy men. Thus, KP54 could be used to specifically interrogate hypothalamic GnRH neuronal function in patients with CHH.

Treatment of Men with Central Hypogonadism: Alternatives for Testosterone Replacement Therapy

Central hypogonadism is a clinical condition, characterized by sexual symptoms and low serum testosterone levels, due to an impaired function of the hypothalamus or pituitary gland. Testosterone replacement therapy (TRT) is the standard treatment for hypogonadism, but it has some disadvantages. TRT is not a good option in men wishing to preserve fertility, nor in men with (a high risk of) prostate cancer, polycythemia, thrombophilia and severe cardiovascular disease. In this review, we discuss alternative treatments for central hypogonadism. If reversible causes are present, non-pharmacological interventions can be therapeutic. Gonadotropins are a good alternative to TRT when fertility is desired in the near future though they require frequent injections. Clomiphene citrate and tamoxifen seem to be a safe alternative for the treatment of functional central hypogonadism in men, as several studies reported a significant increase in testosterone levels with these drugs. However, their use is off-label and data supporting the efficacy of clomiphene citrate and tamoxifen on hypogonadal symptoms are insufficient. For this reason, clomiphene citrate and tamoxifen should not be used in routine clinical practice to treat sexual symptoms in men with central hypogonadism.

Barocrinology: The Endocrinology of Obesity from Bench to Bedside

Obesity has reached pandemic proportions. Hormonal and metabolic imbalances are the key factors that lead to obesity. South Asian populations have a unique phenotype, peculiar dietary practices, and a high prevalence of consanguinity. Moreover, many lower middle-income countries lack appropriate resources, super-specialists, and affordability to manage this complex disorder. Of late, there has been a substantial increase in both obesity and diabesity in India. Thus, many more patients are being managed by different types of bariatric procedures today than ever before. These patients have many types of endocrine and metabolic disturbances before and after bariatric surgery. Therefore, these patients should be managed by experts who have knowledge of both bariatric surgery and endocrinology. The authors propose “Barocrinology”, a novel terminology in medical literature, to comprehensively describe the field of obesity medicine highlighting the role of knowing endocrine physiology for understating its evolution, insights into its complications and appreciating the changes in the hormonal milieu following weight loss therapies including bariatric surgery. Barocrinology, coined as a portmanteau of “baro” (weight) and endocrinology, focuses upon the endocrine and metabolic domains of weight physiology and pathology. This review summarizes the key pointers of bariatric management from an endocrine perspective.

Novel Microdeletion in the X Chromosome Leads to Kallmann Syndrome, Ichthyosis, Obesity, and Strabismus

Background

A large deletion in Xp22.3 can result in contiguous gene syndromes, including X-linked ichthyosis (XLI) and Kallmann syndrome (KS), presenting with short stature, chondrodysplasia punctata, intellectual disability, and strabismus. XLI and KS are caused by the deletion of STS and ANOS1, respectively.

Method

Two KS patients with XLI were screened to identify possible pathogenic mutations using whole exome sequencing. The clinical characteristics, molecular genetics, treatment outcomes, and genotype–phenotype association for each patient were analyzed.

Results

We identified a novel 3,923 kb deletion within the Xp22.31 region (chrX: 5810838–9733877) containing STS, ANOS1, GPR143, NLGN4X, VCX-A, PUDP, and PNPLA4 in patient 1, who presented with KS, XLI, obesity, hyperlipidemia, and strabismus. We identified a novel 5,807 kb deletion within the Xp22.31-p22.33 regions (chrX: 2700083–8507807) containing STS, ANOS1, and other 24 genes in patient 2, who presented with KS, XLI, obesity, and strabismus. No developmental delay, abnormal speech development, or autistic behavior were noticed in either patient.

Conclusion

We identified two novel microdeletions in the X chromosome leading to KS and XLI. These findings contribute to the understanding of the molecular mechanisms that drive contiguous gene syndromes. Our research confirmed that the Kallmann-Ichthyosis phenotype is caused by microdeletions at the chromosome level.

Rates of hypogonadism forms in Klinefelter patients undergoing testicular sperm extraction: A multicenter cross-sectional study

INTRODUCTION AND OBJECTIVES

Adult patients with Klinefelter syndrome (KS) may present with testicular volume loss and a decrease in circulating testosterone (T) levels. However, the actual rate of hypogonadism in adult KS men is unknown. We aimed to (a) assess the prevalence of different forms of hypogonadism in a cohort of KS patients with non-obstructive azoospermia (NOA); and (b) investigate potential preoperative predictor of positive sperm retrieval (SR) at surgery in the same cohort of men.

METHODS

Complete data from 103 KS men with NOA who underwent testicular sperm extraction (TESE) between 2008 and 2019 at five centers were analyzed. Comorbidities were scored with the Charlson Comorbidity Index (CCI). Patients were categorized into four groups of hypogonadism as follows: eugonadism [normal total T (tT) (≥3.03 ng/mL) and normal luteinizing hormone (LH) (≤9.4 mUI/mL)], secondary hypogonadism [low tT (≤3.03 ng/mL) and low/normal LH (≤9.4 mUI/mL)], primary hypogonadism [low tT (≤3.03 ng/mL) and elevated LH (≥9.4 mUI/mL)], and compensated hypogonadism [normal tT (≥3.03 ng/mL) and elevated LH (≥9.4 mUI/mL)]. Descriptive statistics tested the association between clinical characteristics and laboratory values among the four groups.

RESULTS

Median (IQR) patients age was 32 (24, 37) years. Baseline follicle-stimulating hormone and tT levels were 29.5 (19.9, 40.9) mUI/mL and 3.8 (2.5, 11.0) ng/mL, respectively. Eugonadism, primary hypogonadism, and compensated hypogonadism were found in 16 (15.6%), 34 (33.0%), and 53 (51.4%) men, respectively. No patients had secondary hypogonadism. Positive SR rate at TESE was 21.4% (22 patients); of 22, 15 (68.2%) patients underwent assisted reproductive technology and five (22.7%) ended in live birth children. Patients' age, BMI, CCI, FSH levels, and positive SR rates were comparable among hypogonadism groups. No preoperative parameters were associated with positive SR at logistic regressions analysis.

CONCLUSIONS

Findings from this cross-sectional study showed that 15.6% of adult KS men have normal tT values at presentation in the real-life setting. Most KS patients presented with either compensated or primary hypogonadism. Sperm retrieval rates were not associated with different forms of hypogonadism.

LGR4 deficiency results in delayed puberty through impaired Wnt/β-catenin signaling

The initiation of puberty is driven by an upsurge in hypothalamic gonadotropin-releasing hormone (GnRH) secretion. In turn, GnRH secretion upsurge depends on the development of a complex GnRH neuroendocrine network during embryonic life. Although delayed puberty (DP) affects up to 2% of the population, is highly heritable, and is associated with adverse health outcomes, the genes underlying DP remain largely unknown. We aimed to discover regulators by whole-exome sequencing of 160 individuals of 67 multigenerational families in our large, accurately phenotyped DP cohort. LGR4 was the only gene remaining after analysis that was significantly enriched for potentially pathogenic, rare variants in 6 probands. Expression analysis identified specific Lgr4 expression at the site of GnRH neuron development. LGR4 mutant proteins showed impaired Wnt/β-catenin signaling, owing to defective protein expression, trafficking, and degradation. Mice deficient in Lgr4 had significantly delayed onset of puberty and fewer GnRH neurons compared with WT, whereas lgr4 knockdown in zebrafish embryos prevented formation and migration of GnRH neurons. Further, genetic lineage tracing showed strong Lgr4-mediated Wnt/β-catenin signaling pathway activation during GnRH neuron development. In conclusion, our results show that LGR4 deficiency impairs Wnt/β-catenin signaling with observed defects in GnRH neuron development, resulting in a DP phenotype.

Defects of LGR4/Wnt-β-catenin activity compromise the development of the GnRH neuroendocrine network, resulting in delayed onset of puberty in humans and mice.

Pubertal delay: the challenge of a timely differential diagnosis between congenital hypogonadotropic hypogonadism and constitutional delay of growth and puberty

Distinguishing between constitutional delay of growth and puberty (CDGP) and congenital hypogonadotropic hypogonadism (CHH) may be challenging. CDGP and CHH appear to belong to the same clinical spectrum (with low sex hormones and low LH and FSH), although one is classically transient and known as a self-limited form of delayed puberty (CDGP) while the other is permanent (CHH). Thus, the clinical history and the outcomes of these two conditions require different approaches, and an adequate and timely management for the patients is mandatory. Since the initial presentation of CDGP and CHH is almost identical and given the similarities of CDGP and partial forms of CHH (i.e. patients with partial and early interrupted pubertal development) the scientific community has been struggling to find some diagnostic tests able to allow an accurate differential diagnosis between these two conditions in delayed puberty. In this review we provide an up to date insight on the tests available, their meanings and accuracy, as well as some clues to effectively differentiate between constitutional pubertal delay and pathologic CHH.

Knocking-down of the Prokineticin receptor 2 affects reveals its complex role in the regulation of the hypothalamus-pituitary-gonadal axis in the zebrafish model

Prokineticin receptors (PROKR1 and PROKR2) are G protein-coupled receptors which control human central and peripheral reproductive processes. Importantly, allelic variants of PROKR2 in humans are associated with altered migration of GnRH neurons, resulting in congenital hypogonadotropic hypogonadism (CHH), a heterogeneous disease characterized by delayed/absent puberty and/or infertility. Although this association is established in humans, murine models failed to fully recapitulate the reproductive and olfactory phenotypes observed in patients harboring PROKR2 mutations. Here, taking advantage of zebrafish model we investigated the role of prokr1b (ortholog of human PROKR2) during early stages of GnRH neuronal migration. Real-Time PCR and whole mount in situ hybridization assays indicate that prokr1b spatial-temporal expression is consistent with gnrh3. Moreover, knockdown and knockout of prokr1b altered the correct development of GnRH3 fibers, a phenotype that is rescued by injection of prokr1b mRNA. These results suggest that prokr1b regulates the development of the GnRH3 system in zebrafish. Analysis of gonads development and mating experiments indicate that prokr1b is not required for fertility in zebrafish, although its loss determine changes also at the testis level. Altogether, our results support the thesis of a divergent evolution in the control of vertebrate reproduction and provide a useful in vivo model for deciphering the mechanisms underlying the effect of PROKR2 allelic variants on CHH.

Genetische Diagnostik vor assistierter Reproduktion – Empfehlungen der neuen S2k-Leitlinie 2019

Genetische Ursachen sind für etwa 10–20 % der männlichen und 5–10 % der weiblichen In- oder Subfertilität verantwortlich. Bei Männern ist die andrologische Untersuchung Voraussetzung dafür, genetische Ursachen von Spermatogenesestörungen einordnen zu können. Außer Störungen der Geschlechtschromosomen können auch balancierte Chromosomenumbauten zu einer Fertilitätsminderung führen. Eine Azoospermiefaktoranalyse in Bezug auf Y‑chromosomale Mikrodeletionen ist bei Männern mit Azoospermie indiziert, da sie über den Erfolg einer assistierten Reproduktion entscheiden kann. Bei Verdacht auf obstruktive Azoospermie soll eine Analyse des CFTR-Gens zur Diagnostik einer zystischen Fibrose erfolgen. Bei endokrinen Auffälligkeiten sind genetische Ursachen des häufigeren hypergonadotropen Hypogonadismus von denen eines seltenen kongenitalen hypogonadotropen Hypogonadismus zu unterscheiden. Algorithmen zur genetischen Diagnostik sind in der aktuellen Leitlinie im internationalen Vergleich ausgeführt.

Genetics of congenital hypogonadotropic hypogonadism: peculiarities and phenotype of an oligogenic disease

A genetic basis of congenital isolated hypogonadotropic hypogonadism (CHH) can be defined in almost 50% of cases, albeit not necessarily the complete genetic basis. Next-generation sequencing (NGS) techniques have led to the discovery of a great number of loci, each of which has illuminated our understanding of human gonadotropin-releasing hormone (GnRH) neurons, either in respect of their embryonic development or their neuroendocrine regulation as the "pilot light" of human reproduction. However, because each new gene linked to CHH only seems to underpin another small percentage of total patient cases, we are still far from achieving a comprehensive understanding of the genetic basis of CHH. Patients have generally not benefited from advances in genetics in respect of novel therapies. In most cases, even genetic counselling is limited by issues of apparent variability in expressivity and penetrance that are likely underpinned by oligogenicity in respect of known and unknown genes. Robust genotype-phenotype relationships can generally only be established for individuals who are homozygous, hemizygous or compound heterozygotes for the same gene of variant alleles that are predicted to be deleterious. While certain genes are purely associated with normosmic CHH (nCHH) some purely with the anosmic form (Kallmann syndrome-KS), other genes can be associated with both nCHH and KS-sometimes even within the same kindred. Even though the anticipated genetic overlap between CHH and constitutional delay in growth and puberty (CDGP) has not materialised, previously unanticipated genetic relationships have emerged, comprising conditions of combined (or multiple) pituitary hormone deficiency (CPHD), hypothalamic amenorrhea (HA) and CHARGE syndrome. In this review, we report the current evidence in relation to phenotype and genetic peculiarities regarding 60 genes whose loss-of-function variants can disrupt the central regulation of reproduction at many levels: impairing GnRH neurons migration, differentiation or activation; disrupting neuroendocrine control of GnRH secretion; preventing GnRH neuron migration or function and/or gonadotropin secretion and action.

Identification of ROBO1/2 and SCEL as candidate genes in Kallmann syndrome with emerging bioinformatic analysis

Kallmann syndrome (KS) is a congenital hypogonadotropic hypogonadism that coincides with anosmia or hyposmia. Although this rare genetic disease has a very low incidence, it harbors a complicated genetic heterogeneity, which indicates X-linked, autosomal, and oligogenic inheritance of puberty, sexuality, reproductivity, and olfactory defects. There has been limited elucidation of molecular etiologies completed to date. Here, a chromosome reciprocal translocation (46, XX, t (3; 13) (p13; q22)) was identified in a 27-year-old Chinese female diagnosed with KS. Genome sequencing found an intronic breakpoint of SCEL in chromosome 13 and an intergenic breakpoint between ROBO1 and ROBO2 in chromosome 3. This translocation resulted in the reduced expression levels of these genes. An array-CGH test captured no abnormal genomic copy numbers of clinical significance. The basic features of all known KS-related genes were also reviewed and analyzed for their roles in KS onset with bioinformatic methods. Signal pathway and gene enrichment analysis of KS-related genes suggested that these genes have integrated functions in neuronal migration and differentiation. An interesting chromosome locational pattern of KS-related genes was also discovered. This study provided constructive clues for further investigations into the molecular etiology of KS.

GnRH Deficient Patients With Congenital Hypogonadotropic Hypogonadism: Novel Genetic Findings in ANOS1, RNF216, WDR11, FGFR1, CHD7, and POLR3A Genes in a Case Series and Review of the Literature

Background: Congenital hypogonadotropic hypogonadism (CHH) is a rare genetic disease caused by Gonadotropin-Releasing Hormone (GnRH) deficiency. So far a limited number of variants in several genes have been associated with the pathogenesis of the disease. In this original research and review manuscript the retrospective analysis of known variants in ANOS1 (KAL1), RNF216, WDR11, FGFR1, CHD7, and POLR3A genes is described, along with novel variants identified in patients with CHH by the present study. Methods: Seven GnRH deficient unrelated Cypriot patients underwent whole exome sequencing (WES) by Next Generation Sequencing (NGS). The identified novel variants were initially examined by in silico computational algorithms and structural analysis of their predicted pathogenicity at the protein level was confirmed. Results: In four non-related GnRH males, a novel X-linked pathogenic variant in ANOS1 gene, two novel autosomal dominant (AD) probably pathogenic variants in WDR11 and FGFR1 genes and one rare AD probably pathogenic variant in CHD7 gene were identified. A rare autosomal recessive (AR) variant in the SRA1 gene was identified in homozygosity in a female patient, whilst two other male patients were also, respectively, found to carry novel or previously reported rare pathogenic variants in more than one genes; FGFR1/POLR3A and SRA1/RNF216. Conclusion: This report embraces the description of novel and previously reported rare pathogenic variants in a series of genes known to be implicated in the biological development of CHH. Notably, patients with CHH can harbor pathogenic rare variants in more than one gene which raises the hypothesis of locus-locus interactions providing evidence for digenic inheritance. The identification of such aberrations by NGS can be very informative for the management and future planning of these patients.

Diagnosis and Treatment Before Assisted Reproductive Treatments. Guideline of the DGGG, OEGGG and SGGG (S2k Level, AWMF Register Number 015-085, February 2019) - Part 2, Hemostaseology, Andrology, Genetics and History of Malignant Disease

Introduction Supporting and counselling couples with fertility issues prior to starting ART is a multidisciplinary diagnostic and therapeutic challenge. The first German-language interdisciplinary S2k guideline on "Diagnosis and Therapy Before Assisted Reproductive Treatments (ART)" was published in February 2019. The guideline was developed in the context of the guidelines program of the German Society of Gynecology and Obstetrics (DGGG) in cooperation with the Swiss Society of Gynecology and Obstetrics (SGGG) and the Austrian Society of Gynecology and Obstetrics (OEGGG). Aim In one third of cases, the cause of involuntary childlessness remains unclear, even if the woman or man have numerous possible risk factors. Because the topic is still very much taboo, couples may be socially isolated and often only present quite late to a fertility center. There is no standard treatment concept for these patients at present, as there are currently no standard multidisciplinary procedures for the diagnostic workup and treatment of infertility. The aim of this guideline is to provide physicians with evidence-based recommendations for counselling, diagnosis and treatment. Methods This S2k guideline was developed on behalf of the Guidelines Commission of the DGGG by representative members from different professional medical organizations and societies using a structured consensus process. Recommendations This second part of the guideline describes the hematological workup for women as well as additional diagnostic procedures which can be used to investigate couples and which are carried out in cooperation with physicians working in other medical fields such as andrologists, geneticists and oncologists.

Addressing gaps in care of people with conditions affecting sex development and maturation

Differences of sex development are conditions with discrepancies between chromosomal, gonadal and phenotypic sex. In congenital hypogonadotropic hypogonadism, a lack of gonadotropin activity results primarily in the absence of pubertal development with prenatal sex development being (almost) unaffected in most patients. To expedite progress in the care of people affected by differences of sex development and congenital hypogonadotropic hypogonadism, the European Union has funded a number of scientific networks. Two Actions of the Cooperation of Science and Technology (COST) programmes - DSDnet (BM1303) and GnRH Network (BM1105) - provided the framework for ground-breaking research and allowed the development of position papers on diagnostic procedures and special laboratory analyses as well as clinical management. Both Actions developed educational programmes to increase expertise and promote interest in this area of science and medicine. In this Perspective article, we discuss the success of the COST Actions DSDnet and GnRH Network and the European Reference Network for Rare Endocrine Conditions (Endo-ERN), and provide recommendations for future research.

The relationship between the olfactory bulb and precocious puberty: from the nose to the pituitary

Background/objective The olfactory bulb (OB) and pubertal development have a close relationship as they share a common ontogenetic origin. The aim of this study was to analyze the potential relationship between precocious puberty (PP) in girls as a sign of early pubertal timing and their OB volume as an indicator of its functional activity. Design In the study group (n = 125), OB volume, pituitary height (PH), body mass index (BMI) and body surface (S) variables were retrospectively investigated in 49 girls included in the PP group and 76 healthy girls constituting the control group. Volumetric and length measurements were performed on a magnetic resonance imaging (MRI) scan by using manual segmentation of slices. Results The mean OB volume (73.41 ± 17.21 mm3) and PH (4.96 ± 1.01 mm) were significantly higher in the PP group (p = 0.001 and p = 0.001, respectively). The mean volume difference between the right and left bulbs (1.52 ± 1.87) was higher in the PP group (p = 0.03). The body surface (1.05 ± 0.16 m2) was larger in the PP group (p = 0.09). There was a high correlation between the OB volume and PH (r125 = 0.716). There was a moderate correlation between the body surface and OB volume (r125 = 654), and a weak correlation between the former (S) and the PH (r125 = 452). Conclusions This study showed that there is a strong correlation between increased OB volume and PH in cases with PP. It indicates that increased OB volume may be a strong clue that olfactory functions play a role in pubertal timing in humans, although it does not show definitive proof of a causal relationship.