Explore the vast range of titles available.

Congenital hypogonadotropic hypogonadism (CHH) is a rare endocrine disorder that results in reproductive hormone deficiency and reduced potential for fertility in adult life. Discoveries of the genetic aetiology of CHH have advanced dramatically in the past 30 years, with currently over 40 genes recognised to cause or contribute to the development of this condition. The genetic complexity of CHH is further increased by the observation of di- and oligogenic, as well as classic monogenic, inheritance and incomplete penetrance. Very recently in the UK, a panel of 14 genes has been curated for the genetic diagnosis of CHH within the NHS Genomic Medicine Service programme. The aim of this review is to appraise the advantages and potential pitfalls of the use of a CHH panel in clinical endocrine diagnostics, and to consider the future avenues for developing this panel including the potential of whole exome or whole genome sequencing data analysis in this condition.

This review presents a comprehensive discussion of the clinical condition of delayed puberty, a common presentation to the pediatric endocrinologist, which may present both diagnostic and prognostic challenges. Our understanding of the genetic control of pubertal timing has advanced thanks to active investigation in this field over the last two decades, but it remains in large part a fascinating and mysterious conundrum. The phenotype of delayed puberty is associated with adult health risks and common etiologies, and there is evidence for polygenic control of pubertal timing in the general population, sex-specificity, and epigenetic modulation. Moreover, much has been learned from comprehension of monogenic and digenic etiologies of pubertal delay and associated disorders and, in recent years, knowledge of oligogenic inheritance in conditions of GnRH deficiency. Recently there have been several novel discoveries in the field of self-limited delayed puberty, encompassing exciting developments linking this condition to both GnRH neuronal biology and metabolism and body mass. These data together highlight the fascinating heterogeneity of disorders underlying this phenotype and point to areas of future research where impactful developments can be made.

Early or late pubertal onset affects up to 5% of adolescents and is associated with adverse health and psychosocial outcomes. Self‐limited delayed puberty (DP) segregates predominantly in an autosomal dominant pattern, but the underlying genetic background is unknown. Using exome and candidate gene sequencing, we have identified rare mutations in IGSF10 in 6 unrelated families, which resulted in intracellular retention with failure in the secretion of mutant proteins. IGSF10 mRNA was strongly expressed in embryonic nasal mesenchyme, during gonadotropin‐releasing hormone (GnRH) neuronal migration to the hypothalamus. IGSF10 knockdown caused a reduced migration of immature GnRH neurons in vitro , and perturbed migration and extension of GnRH neurons in a gnrh3:EGFP zebrafish model. Additionally, loss‐of‐function mutations in IGSF10 were identified in hypothalamic amenorrhea patients. Our evidence strongly suggests that mutations in IGSF10 cause DP in humans, and points to a common genetic basis for conditions of functional hypogonadotropic hypogonadism (HH). While dysregulation of GnRH neuronal migration is known to cause permanent HH, this is the first time that this has been demonstrated as a causal mechanism in DP. ‡ Synopsis Self‐limited delayed puberty (DP) has strong familial inheritance, but the underlying genetic determinants are unknown. IGSF10 deficiency is found to affect embryonic GnRH neuronal migration and results in DP in humans. Pathogenic mutations in IGSF10 are found in patients with self‐limited delayed puberty. IGSF10 is a gene of previously unclear function with no known human mutations. IGSF10 is expressed within the nasal mesenchyme during fetal development, in a pattern similar to known chemokines that direct migrational GnRH neurons to the hypothalamus. Knockdown of IGSF10 led to a reduced migration of GnRH neurons in vitro and in a transgenic zebrafish model. IGSF10 loss‐of‐function mutations were also identified in patients with hypothalamic amenorrhea, suggesting an overlapping genetic and mechanistic basis between different types of functional hypogonadotropic hypogonadism, including DP and hypothalamic amenorrhea. Graphical Abstract Self‐limited delayed puberty (DP) has strong familial inheritance, but the underlying genetic determinants are unknown. IGSF10 deficiency is found to affect embryonic GnRH neuronal migration and results in DP in humans.

Gonadotropin-releasing hormone (GnRH) deficiency (GD) is a disorder characterized by absent or delayed puberty, with largely unknown genetic causes. The purpose of this study was to obtain and exploit gene expression profiles of GnRH neurons during development to unveil novel biological mechanisms and genetic determinants underlying GD. Here, we combined bioinformatic analyses of immortalized and primary embryonic GnRH neuron transcriptomes with exome sequencing from GD patients to identify candidate genes implicated in the pathogenesis of GD. Among differentially expressed and filtered transcripts, we found loss-of-function (LoF) variants of the autism-linked neuroligin 3 (NLGN3) gene in two unrelated patients co-presenting with GD and neurodevelopmental traits. We demonstrated that NLGN3 is upregulated in maturing GnRH neurons and that NLGN3 wild-type, but not mutant, protein promotes neuritogenesis when overexpressed in developing GnRH cells. Our data represent proof of principle that this complementary approach can identify new candidate GD genes and demonstrate that LoF NLGN3 variants can contribute to GD. This novel genotype–phenotype correlation implies common genetic mechanisms underlying neurodevelopmental disorders, such as GD and autistic spectrum disorder.

Developmental abnormalities of the gonadotropin-releasing hormone (GnRH) neuronal network result in a range of conditions from idiopathic hypogonadotropic hypogonadism to self-limited delayed puberty. We aimed to discover important underlying regulators of self-limited delayed puberty through interrogation of GnRH pathways. Whole exome sequencing (WES) data consisting of 193 individuals, from 100 families with self-limited delayed puberty, was analysed using a virtual panel of genes related to GnRH development and function (n = 12). Five rare predicted deleterious variants in Coiled-Coil Domain Containing 141 (CCDC141) were identified in 21 individuals from 6 families (6% of the tested cohort). Homology modeling predicted all five variants to be deleterious. CCDC141 mutant proteins showed atypical subcellular localization associated with abnormal distribution of acetylated tubulin, and expression of mutants resulted in a significantly delayed cell migration, demonstrated in transfected HEK293 cells. These data identify mutations in CCDC141 as a frequent finding in patients with self-limited delayed puberty. The mis-localization of acetylated tubulin and reduced cell migration seen with mutant CCDC141 suggests a role of the CCDC141-microtubule axis in GnRH neuronal migration, with heterozygous defects potentially impacting the timing of puberty.

Self-limited delayed puberty (DP) segregates in an autosomal-dominant pattern, but the genetic basis is largely unknown. Although DP is sometimes seen in relatives of patients with hypogonadotropic hypogonadism (HH), mutations in genes known to cause HH that segregate with the trait of familial self-limited DP have not yet been identified. To assess the contribution of mutations in genes known to cause HH to the phenotype of self-limited DP. We performed whole-exome sequencing in 67 probands and 93 relatives from a large cohort of familial self-limited DP, validated the pathogenicity of the identified gene variant in vitro, and examined the tissue expression and functional requirement of the mouse homolog in vivo. A potentially pathogenic gene variant segregating with DP was identified in 1 of 28 known HH genes examined. This pathogenic variant occurred in HS6ST1 in one pedigree and segregated with the trait in the six affected members with heterozygous transmission (P = 3.01 × 10-5). Biochemical analysis showed that this mutation reduced sulfotransferase activity in vitro. Hs6st1 mRNA was expressed in peripubertal wild-type mouse hypothalamus. GnRH neuron counts were similar in Hs6st1+/- and Hs6st1+/+ mice, but vaginal opening was delayed in Hs6st1+/- mice despite normal postnatal growth. We have linked a deleterious mutation in HS6ST1 to familial self-limited DP and show that heterozygous Hs6st1 loss causes DP in mice. In this study, the observed overlap in potentially pathogenic mutations contributing to the phenotypes of self-limited DP and HH was limited to this one gene.

Abstract Context The melanocortin 3 receptor (MC3R) has recently emerged as a critical regulator of pubertal timing, linear growth, and the acquisition of lean mass in humans and mice. In population-based studies, heterozygous carriers of deleterious variants in MC3R report a later onset of puberty than noncarriers. However, the frequency of such variants in patients who present with clinical disorders of pubertal development is currently unknown. Objective This work aimed to determine whether deleterious MC3R variants are more frequently found in patients clinically presenting with constitutional delay of growth and puberty (CDGP) or normosmic idiopathic hypogonadotropic hypogonadism (nIHH). Methods We examined the sequence of MC3R in 362 adolescents with a clinical diagnosis of CDGP and 657 patients with nIHH, experimentally characterized the signaling properties of all nonsynonymous variants found and compared their frequency to that in 5774 controls from a population-based cohort. Additionally, we established the relative frequency of predicted deleterious variants in individuals with self-reported delayed vs normally timed menarche/voice-breaking in the UK Biobank cohort. Results MC3R loss-of-function variants were infrequent but overrepresented in patients with CDGP (8/362 [2.2%]; OR = 4.17; P = .001). There was no strong evidence of overrepresentation in patients with nIHH (4/657 [0.6%]; OR = 1.15; P = .779). In 246 328 women from the UK Biobank, predicted deleterious variants were more frequently found in those self-reporting delayed (aged ≥16 years) vs normal age at menarche (OR = 1.66; P = 3.90E-07). Conclusion We have found evidence that functionally damaging variants in MC3R are overrepresented in individuals with CDGP but are not a common cause of this phenotype.

Abstract Context Self-limited delayed puberty (DP) is often associated with a delay in physical maturation, but although highly heritable the causal genetic factors remain elusive. Genome-wide association studies of the timing of puberty have identified multiple loci for age at menarche in females and voice break in males, particularly in pathways controlling energy balance. Objective/Main Outcome Measures We sought to assess the contribution of rare variants in such genes to the phenotype of familial DP. Design/Patients We performed whole-exome sequencing in 67 pedigrees (125 individuals with DP and 35 unaffected controls) from our unique cohort of familial self-limited DP. Using a whole-exome sequencing filtering pipeline one candidate gene [fat mass and obesity–associated gene (FTO)] was identified. In silico, in vitro, and mouse model studies were performed to investigate the pathogenicity of FTO variants and timing of puberty in FTO+/− mice. Results We identified potentially pathogenic, rare variants in genes in linkage disequilibrium with genome-wide association studies of age at menarche loci in 283 genes. Of these, five genes were implicated in the control of body mass. After filtering for segregation with trait, one candidate, FTO, was retained. Two FTO variants, found in 14 affected individuals from three families, were also associated with leanness in these patients with DP. One variant (p.Leu44Val) demonstrated altered demethylation activity of the mutant protein in vitro. Fto+/− mice displayed a significantly delayed timing of pubertal onset (P < 0.05). Conclusions Mutations in genes implicated in body mass and timing of puberty in the general population may contribute to the pathogenesis of self-limited DP. We assessed the contribution of rare variants in genes important in the timing of puberty and body mass regulation in the general population to the phenotype of familial delayed puberty.

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.

Are recombinant FSH (rFSH) and hCG effective therapies for promoting testicular growth and spermatogenesis in male adolescents and young adults with gonadotropin deficiency? Combined gonadotropin therapy is effective in inducing puberty and promoting spermatogenesis in male adolescents and young adults with gonadotropin deficiency and has the potential to improve adult outcomes relating to both fertility and quality of life. Deficiency of pituitary gonadotropins (LH and FSH) due to hypogonadotropic hypogonadism (HH) can result in poor testicular development, low testicular volumes, micropenis and cryptorchidism. Inadequate hormonal replacement can lead to long-term issues, including subfertility or infertility, and reduced quality of life. Exogenous testosterone for pubertal induction can elevate serum testosterone concentrations and induce virilization, but it does not promote testicular development nor induce spermatogenesis. Fertility and testes growth remain primary concerns for patients seeking treatment. We conducted a retrospective observational review of male adolescents and young adults with gonadotropin deficiency and seeking puberty replacement therapy at two large tertiary centre hospitals in London, UK, from 2010 to 2024. A total of 35 males, with diagnosis of congenital hypogonadotropic hypogonadism (CHH: n = 23; further subdivided into those with partial [pHH: n = 8] and those with complete gonadotropin deficiency [cHH: n = 15]), acquired HH (AHH: n = 4) or Kallmann syndrome (KS: n = 8), received combined gonadotropin therapy. We assessed testicular growth and semen quality post-treatment. The majority of patients were referred for pubertal delay, alone or in combination with cryptorchidism, micropenis or microorchidism. Out of 35 patients, 22 (63%) had previously received testosterone, and the median age at gonadotropin treatment initiation was 15.8 years (range: 11.8-22.7). Semen analysis was obtained in 18 out of 19 patients who had received gonadotropin therapy for a median treatment duration of 21.1 months (range: 4.5-66.9) for rFSH and 19.5 months (range: 8.3-61.1) for hCG. The median sperm count on semen analysis was 8.9 × 10 /ml (range: 0.0-54.9). Significant increases were noted in testicular volume (median change after therapy: 10.5 ml [95% CI 9.5-13.6],  < 0.0001), testosterone (median increase: 25.7 nmol/l [95% CI 19.8-31.5],  < 0.0001) and inhibin B levels (67.7 pg/ml [95% CI 18.4-86.7],  = 0.0008). The relatively low representation of patients with acquired HH in our study emphasizes the need to extrapolate the findings with caution in this specific subgroup of adolescent males with HH. The study is also an observational one, therefore meaning that some outcomes (such as change in inhibin B concentration) were not collected routinely and not reported for all patients. The observational nature of the study design also accounts for the differences in doses and duration observed in gonadotropin therapy. The treatment of adult male infertility is particularly difficult in severe forms of gonadotropin deficiency, where there has been no testicular stimulation during mini-puberty or puberty. Appropriate hormonal replacement in puberty with combined gonadotropins can induce testicular maturation and spermatogenesis, but data are limited and at present, there is no international consensus on best practice regimens in adolescent and young adult males. Our treatment protocol induced testicular growth and caused increases in serum testosterone and Sertoli cell biomarkers, and spermatogenesis in 15/18 of patients who had completed semen analysis. This indicates the potential to substantially improve the reproductive, physical, and psychological health of patients who have a significant and unmet need for adequate hormonal replacement during puberty. The study described here included patients with diverse forms of HH (congenital, acquired, complete, and partial HH), thereby providing encouraging results across a variety of subjects with impaired puberty facing increased odds of fertility problems in adulthood. Additionally, we observed similar sperm counts between those who received exogenous testosterone treatment prior to gonadotropin therapy and those who began directly on gonadotropins for pubertal induction. This last finding is aligned with previous data and may help to reassure paediatric endocrinologists with limited access to rFSH or hCG that the use of exogenous testosterone to induce androgen-dependent changes in patients seeking treatment for pubertal delay is unlikely to compromise spermatogenic potential, should gonadotropins become available at a later stage. S.C. was funded by an ESPE Early Career Scientific Development Grant. S.R.H. was funded by the Wellcome Trust (222049/Z/20/Z) and Barts Charity [MGU0552]. K.N.Y. was employed under the NIHR Specialist Foundation Programme. F.d.A. was funded by the student traineeship, University of Rome 'Tor Vergata', an Erasmus Grant and an ESPE Early Career Scientific Development Grant. E.C.A. was funded by an NIHR Academic Clinical Fellowship (ACF-2021-19-002). The views expressed in this publication are those of the author(s) and not necessarily those of the NIHR, NHS, or the UK Department of Health and Social Care. G.B. received an ESPE Mid-Career Research Fellowship to enable the development of the clinical treatment schedule. The authors have no conflicting interests. N/A.