GENETICS IN ENDOCRINOLOGY: Genetic counseling for congenital hypogonadotropic hypogonadism and Kallmann syndrome: new challenges in the era of oligogenism and next-generation sequencing

Evaluating co-created patient-facing materials to increase understanding of genetic test results

Patients often have difficulty understanding genetic test reports. Technical language and jargon can impede comprehension and limit patients using results to act on findings. One potential way to improve patient understanding of genetic test reports is to provide patient-facing materials. This study aimed to examine understandability and actionability of co-created patient-facing materials for genetic test results in a research context. We combined interprofessional perspectives and patient engagement to co-create patient-facing materials for patients undergoing research genetic testing for congenital hypogonadotropic hypogonadism (Kallmann syndrome). The iterative development process was guided by principles of health literacy and human-centered design (i.e., design thinking). Readability was assessed using eight validated algorithms. Patients and parents evaluated materials using a web-based survey. The gold standard Patient Education Materials Assessment Tool for print materials (PEMAT-P) was employed to measure understandability (content, style, use of numbers, organization, design, use of visual aids) and actionability. PEMAT-P scores >80% were considered high quality. Results were analyzed descriptively and correlations performed to identify relationships between education/health literacy and PEMAT-P ratings. A consensus score of eight algorithms indicated the materials were an 8^th -9th grade reading level. Our findings are consistent with the U.S. Department of Health and Human Services 'average difficulty' classification (i.e., 7th-9th grade). In total, 61 patients/parents evaluated the materials. 'Visual Aids' received the lowest mean PEMAT-P rating (89%). All other parameters scored 90%-97%. PEMAT-P scores did not differ according to educational attainment (less than college vs. college or more, p = 0.28). Participants with adequate health literacy were more likely to approve of the 'organization' of information (p < 0.05). Respondents with low health literacy had more favorable views of 'visual aids' (p < 0.01). Involving patients in a co-creation process can produce high-quality patient-facing materials that are easier to understand.

Homozygous p.R31H GNRH1 mutation and normosmic congenital hypogonadotropic hypogonadism in a patient and self-limited delayed puberty in his relatives

Objectives Congenital hypogonadotropic hypogonadism (CHH) is a rare condition resulting from GnRH deficiency. Gonadotropin Releasing Hormone 1 (GNRH1) homozygous mutations are an extremely rare cause of normosmic CHH (nCHH). Most heterozygous individuals are asymptomatic, with the notable exception of individuals heterozygous for a p.R31C GNRH1 mutation. Case presentation The patient is an index case from a consanguineous family, presenting with severe CHH and his parents presenting with late puberty and normal fertility. The index case is homozygous for a p.R31H GNRH1 variant, both parents being heterozygous. The analysis of a panel of genes implicated in CHH does not show any other clinically relevant variant in any other gene tested. Conclusions GNRH1 mutations are a rare cause of nCHH. Five different mutations have been reported so far in homozygous individuals. Most are frameshift in nature but the one reported here causes an amino acid change in the Gonadotropin-releasing hormone (GnRH) decapeptide. Both independently reported patients with the p.R31H mutation are from Turkish origin. The question of the possible role of this mutation in the late puberty of the heterozygous parents needs further documentation. An analogy is made with the heterozygous individuals carrying the p.R31C and displaying partial CHH. No nonreproductive disorder is noted.

Congenital pituitary hypoplasia model demonstrates hypothalamic OTX2 regulation of pituitary progenitor cells

Pituitary develops from oral ectoderm in contact with adjacent ventral hypothalamus. Impairment in this process results in congenital pituitary hypoplasia (CPH); however, there have been no human disease models for CPH thus far, prohibiting the elucidation of the underlying mechanisms. In this study, we established a disease model of CPH using patient-derived induced pluripotent stem cells (iPSCs) and 3D organoid technique, in which oral ectoderm and hypothalamus develop simultaneously. Interestingly, patient iPSCs with a heterozygous mutation in the orthodenticle homeobox 2 (OTX2) gene showed increased apoptosis in the pituitary progenitor cells, and the differentiation into pituitary hormone-producing cells was severely impaired. As an underlying mechanism, OTX2 in hypothalamus, not in oral ectoderm, was essential for progenitor cell maintenance by regulating LHX3 expression in oral ectoderm via FGF10 expression in the hypothalamus. Convincingly, the phenotype was reversed by the correction of the mutation, and the haploinsufficiency of OTX2 in control iPSCs revealed a similar phenotype, demonstrating that this mutation was responsible. Thus, we established an iPSC-based congenital pituitary disease model, which recapitulated interaction between hypothalamus and oral ectoderm and demonstrated the essential role of hypothalamic OTX2.

Rare variant of the epigenetic regulator SMCHD1 in a patient with pituitary hormone deficiency

Isolated hypogonadotropic hypogonadism (IHH), combined pituitary hormone deficiency (CPHD), and septo-optic dysplasia (SOD) constitute a disease spectrum whose etiology remains largely unknown. This study aimed to clarify whether mutations in SMCHD1, an epigenetic regulator gene, might underlie this disease spectrum. SMCHD1 is a causative gene for Bosma arhinia microphthalmia syndrome characterized by arhinia, microphthalmia and IHH. We performed mutation screening of SMCHD1 in patients with etiology-unknown IHH (n = 31) or CPHD (n = 43, 19 of whom also satisfied the SOD diagnostic criteria). Rare variants were subjected to in silico analyses and classified according to the American College of Medical Genetics and Genomics guidelines. Consequently, a rare likely pathogenic variant, p.Asp398Asn, was identified in one patient. The patient with p.Asp398Asn exhibited CPHD, optic nerve hypoplasia, and a thin retinal nerve fiber layer, and therefore satisfied the criteria of SOD. This patient showed a relatively low DNA methylation level of the 52 SMCHD1-target CpG sites at the D4Z4 locus. Exome sequencing for the patient excluded additional variants in other IHH/CPHD-causative genes. In vitro assays suggested functional impairment of the p.Asp398Asn variant. These results provide the first indication that SMCHD1 mutations represent a rare genetic cause of the HH-related disease spectrum.

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.

Nectin-like molecule 2, a necessary sexual maturation regulator, participates in congenital hypogonadotropic hypogonadism

BACKGROUND

Congenital hypogonadotropic hypogonadism (CHH) is a rare genetically heterogeneous disorder. We aimed to determine the prevalence and pathogenesis of NECL2 (Nectin-like molecule 2) variants in a cohort of female patients with CHH.

METHODS

We sequenced and determined the prevalence of NECL2 variants in 68 female patients with CHH and 243 healthy controls collected from an academic medical center. Further cellular and animal studies were performed to verify the pathogenicity of the mutations. Necl2 knockout female mice were generated, and their puberty development was observed.

RESULTS

A novel NECL2 variant (c.1052_1060del, p.Thr351_Thr353del) was detected in 4 of 68 (5.9%) patients with CHH. Its prevalence was significantly higher in CHH patients than in healthy controls (0%). At the cellular level, the necl2 variant leads to a decrease in gonadotropin-releasing hormone. In animal models, we found that the Necl2 protein was expressed in the hypothalamus, especially in the ventromedial hypothalamic nucleus of mice. Necl2 knockout female mice showed delayed puberty and an irregular estrous cycle, consistent with CHH patient phenotypes.

CONCLUSIONS

Our findings predict that NECL2 may be a new candidate gene for CHH and that the NECL2 protein plays a critical role in the progression of puberty development.

Functional Characteristics of Novel FGFR1 Mutations in Patients with Isolated Gonadotropin-Releasing Hormone Deficiency

BACKGROUND

Isolated gonadotropin-releasing hormone (GnRH) deficiency (IGD) has a wide phenotypic spectrum including Kallmann syndrome (KS) and normosmic idiopathic hypogonadotropic hypogonadism (nIHH). FGFR1 mutations have been identified in 3-10% of patients with KS or nIHH. This study was performed to investigate clinical phenotypes and functional characteristics of FGFR1 mutations in patients with IGD.

METHODS

This study included 8 patients (from 7 families) with FGFR1 mutations identified by targeted gene panel sequencing or whole exome sequencing (WES). The impact of the identified mutations on FGFR1 function was assessed using in vitro studies.

RESULTS

Seven heterozygous mutations in FGFR1 were identified in 8 patients from 7 independent families. The patients exhibited a wide spectrum of pubertal development, including anosmia in a prepubertal boy (n=1), delayed puberty (n=2), nIHH (n=3), and KS (n=2). Four of the mutations were classified as likely pathogenic, and the other three were variants of uncertain significance. FGF8-FGFR1 signaling activities for the novel FGFR1 variants (p.Y339H, p.S681I, and p.N185Kfs*16) were reduced by in vitro functional assay, indicating loss-of-function mutations.

CONCLUSIONS

This study identified seven rare sequence variants in FGFR1 in patients with KS and nIHH. Probands with an FGFR1 mutations displayed a wide phenotypic spectrum ranging from KS to anosmia. A prepubertal male with anosmia should be followed up to assess pubertal development because they can manifest hypogonadotropic hypogonadism after puberty. These results expand the phenotypic spectrum of FGFR1 mutations and suggest a broader biologic role of FGFR1 in reproduction.

Prevalence and associated phenotypes of DUSP6, IL17RD and SPRY4 variants in a large Chinese cohort with isolated hypogonadotropic hypogonadism

BACKGROUND

FGF8-FGFR1 signalling is involved in multiple biological processes, while impairment of this signalling is one of the main reasons for isolated hypogonadotropic hypogonadism (IHH). Recently, several negative modulators of FGF8-FGFR1 signalling were also found to be involved in IHH, including DUSP6, IL17RD, SPRY2 and SPRY4. The aim of this study was to investigate the genotypic and phenotypic spectra of these genes in a large cohort of Chinese patients with IHH.

METHODS

A total of 196 patients with IHH were enrolled in this study. Whole-exome sequencing was performed to identify variants, which was verified by PCR and Sanger sequencing.

RESULTS

Four heterozygous DUSP6 variants (p.S157I, p.R83Q, p.P188L and p.N355I) were found in six patients. Cryptorchidism, dental agenesis, syndactyly and blue colour blindness were commonly observed in patients with DUSP6 mutations. Six heterozygous IL17RD variants (p.P191L, p.G35V, p.S671L, p.A221T, p.I329M and p.I329V) were found in seven patients. Segregation analysis indicated that 100% (5/5) of probands inherited the IL17RD variants from their unaffected parents, and oligogenicity was found in 4/7 patients. One rare SPRY4 variant (p.T68S) was found in a female patient with Kallmann syndrome who also carried a PLXNA1 mutation.

CONCLUSION

Our study greatly enriched the genotypic and phenotypic spectra of DUSP6, IL17RD and SPRY4 in IHH. Mutations in DUSP6 alone seem sufficient to cause IHH in an autosomal dominant manner, whereas IL17RD or SPRY4 mutations may cause IHH phenotypes in synergy with variants in other IHH-associated genes.

Psychosexual effects resulting from delayed, incomplete, or absent puberty

Puberty is a remarkable period of postnatal development culminating in reproductive capacity. Biological changes of puberty are accompanied by social and emotional changes including psychosexual development. Developmental changes of adolescence are influenced by numerous biological, psychological and social influences. Work to date has identified associations between disrupted puberty (i.e. delayed, incomplete or absent) and psychosexual development. This brief review summarizes our current understanding of the psychosexual effects of delayed puberty and congenital hypogonadotropic hypogonadism (Kallmann syndrome). The importance of psychosocial support and transitional care is highlighted and future directions are discussed.

Metabolomic alterations associated with Kallmann syndrome

Background

This study was conducted to identify potential seminal plasma metabolic markers associated with disease activity in Kallmann syndrome (KS).

Methods

We collected medical records and seminal plasma samples from 17 KS patients and 20 age-matched healthy controls (HC) and performed metabolomics analysis using the UPLC-QTOF-MS method.

Results

Partial least squares discriminant analysis (PLS-DA) showed that the metabolomics profile of KS patients was clearly separated from HC. Statistical analysis of the data indicates that there are differential metabolites between KS patients and HC. The main metabolic pathways focus on linoleic acid (LA) metabolism, Glycerophospholipid metabolism.

Conclusions

The seminal plasma metabolomics profile of KS patients has changed. Glycerophospholipids and LA are promising biomarkers for KS diagnosis.

Molecular genetic diagnostics of hypogonadotropic hypogonadism: from panel design towards result interpretation in clinical practice

Congenital hypogonadotropic hypogonadism (CHH) is a clinically and genetically heterogeneous congenital disease. Symptoms cover a wide spectrum from mild forms to complex phenotypes due to gonadotropin-releasing hormone (GnRH) deficiency. To date, more than 40 genes have been identified as pathogenic cause of CHH. These genes could be grouped into two major categories: genes controlling development and GnRH neuron migration and genes being responsible for neuroendocrine regulation and GnRH neuron function. High-throughput, next-generation sequencing (NGS) allows to analyze numerous gene sequences at the same time. Nowadays, whole exome or whole genome datasets could be investigated in clinical genetic diagnostics due to their favorable cost-benefit. The increasing genetic data generated by NGS reveal novel candidate genes and gene variants with unknown significance (VUSs). To provide clinically valuable genetic results, complex clinical and bioinformatics work are needed. The multifaceted genetics of CHH, the variable mode of inheritance, the incomplete penetrance, variable expressivity and oligogenic characteristics further complicate the interpretation of the genetic variants detected. The objective of this work, apart from reviewing the currently known genes associated with CHH, was to summarize the advantages and disadvantages of the NGS-based platforms and through the authors' own practice to guide through the whole workflow starting from gene panel design, performance analysis and result interpretation. Based on our results, a genetic diagnosis was clearly identified in 21% of cases tested (8/38).

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.

Correlations Among Genotype and Outcome in Chinese Male Patients With Congenital Hypogonadotropic Hypogonadism Under HCG Treatment

BACKGROUND

Congenital hypogonadotropic hypogonadism (CHH) is a genetically heterogeneous disorder characterized by absent or incomplete puberty and infertility, and heterogeneous responses are often observed during treatment.

AIM

To investigate the role of CHH-associated variants in patients with CHH with poor responses to human chorionic gonadotropin (hCG).

METHODS

This retrospective study investigated 110 Chinese male patients with CHH undergoing genetic analysis and hCG treatment. CHH-associated rare sequence variants (RSVs) were identified by using a tailored next-generation sequencing panel and were interpreted in accordance with the American College of Medical Genetics and Genomics criteria. Clinical characteristics were recorded, and Kyoto Encyclopedia of Genes and Genomes analysis was conducted to assess pathways enriched in protein networks implicated in poor responses.

OUTCOMES

The outcomes include testicular volume, serum hormonal profiles, parameters of semen analysis, pathogenicity classification, and pathway enrichment.

RESULTS

Among the 110 patients, 94.55% achieved normal serum testosterone and 54.55% achieved seminal spermatozoa appearance (SSA). PLXNB1, ROBO3, LHB, NRP2, CHD7, and PLXNA1 RSVs were identified in patients who had an abnormal serum testosterone level during treatment. In spermatogenesis, the number of CHH-associated RSVs was not significantly strongly associated with delayed SSA. After pathogenicity classification, pathogenic/likely pathogenic (P/LP) RSVs were identified in 30% (33/110) of patients. Patients with P/LP RSVs showed delayed SSA compared with noncarriers, and P/LP PROKR2 RSVs showed the strongest association (48, 95% CI: 34.1-61.9 months, P = .043). Enriched pathways implicated in delayed SSA included neuroactive ligand-receptor interaction; Rap1, MAPK, PI3K-Akt signaling; and regulation of actin cytoskeleton.

CLINICAL IMPLICATIONS

Male patients with CHH harboring P/LP PROKR2 RSVs should be aware of a high probability of poor responses to hCG; If these patients desire fertility, it might be better to recommend hCG/human menopausal gonadotropin, hCG/recombinant follicle-stimulating hormone, or pulsatile GnRH administration before treatments start or as early as possible.

STRENGTHS & LIMITATIONS

Strengths are the standardized regimen and extensive follow-up (median time of 40 months). However, included patients in the study voluntarily chose hCG treatment because of the burden of drug cost and/or little fertility desire. Therefore, human menopausal gonadotropin or follicle-stimulating hormone was not added to this cohort. Our observed correlations should be further verified in patients with CHH undergoing other treatments.

CONCLUSION

Among all P/LP RSVs, P/LP PROKR2 RSVs might correlate with poor responses in CHH under hCG treatment; our study supports the pathogenicity assessment of American College of Medical Genetics and Genomics criteria in genetic counseling, to improve management of patients with CHH. Chen Y, Sun T, Niu Y, et al. Correlations AmongGenotype and Outcome in Chinese Male Patients WithCongenital Hypogonadotropic Hypogonadism Under HCG Treatment. J Sex Med 2020;17:645-657.

Oligogenic Origin of Differences of Sex Development in Humans

Sex development is a very complex biological event that requires the concerted collaboration of a large network of genes in a spatial and temporal correct fashion. In the past, much has been learned about human sex development from monogenic disorders/differences of sex development (DSD), but the broad spectrum of phenotypes in numerous DSD individuals remains a conundrum. Currently, the genetic cause of less than 50% of DSD individuals has been solved and oligogenic disease has been proposed. In recent years, multiple genetic hits have been found in individuals with DSD thanks to high throughput sequencing. Our group has been searching for additional genetic hits explaining the phenotypic variability over the past years in two cohorts of patients: 46,XY DSD patients carriers of NR5A1 variants and 46,XY DSD and 46,XX DSD with MAMLD1 variants. In both cohorts, our results suggest that the broad phenotypes may be explained by oligogenic origin, in which multiple hits may contribute to a DSD phenotype, unique to each individual. A search for an underlying network of the identified genes also revealed that a considerable number of these genes showed interactions, suggesting that genetic variations in these genes may affect sex development in concert.

Functional analysis of SEMA3A variants identified in Chinese patients with isolated hypogonadotropic hypogonadism

Isolated hypogonadotropic hypogonadism (IHH) is a rare disorder characterized by impaired sexual development and infertility, caused by the deficiency of hypothalamic gonadotropin-releasing hormone neurons. IHH is named Kallmann's syndrome (KS) or normosmic IHH (nIHH) when associated with a defective or normal sense of smell. Variants in SEMA3A have been recently identified in patients with KS. In this study, we screened SEMA3A variants in a cohort of Chinese patients with IHH by whole exome sequencing. Three novel heterozygous SEMA3A variants (R197Q, R617Q and V458I) were identified in two nIHH and one KS patients, respectively. Functional studies indicated that R197Q and R617Q variants were ineffective in activating the phosphorylation of FAK (focal adhesion kinase) in GN11 cells, despite normal production and secretion in HEK293T cells. The V458I SEMA3A had defect in secretion as it was not detected in the conditioned medium from HEK293T cells. Compared with wild type SEMA3A protein, all three SEMA3A mutant proteins were ineffective in inducing the migration of GN11 cells. Our study further showed the contribution of SEMA3A loss-of-function variants to the pathogenesis of IHH.

Expanding the mutational spectrum of monogenic hypogonadotropic hypogonadism: novel mutations in ANOS1 and FGFR1 genes

BACKGROUND

Congenital hypogonadotropic hypogonadism (CHH) is a rare disease, triggered by defective GnRH secretion, that is usually diagnosed in late adolescence or early adulthood due to the lack of spontaneous pubertal development. To date more than 30 genes have been associated with CHH pathogenesis with X-linked recessive, autosomal dominant, autosomal recessive and oligogenic modes of inheritance. Defective sense of smell is present in about 50-60% of CHH patients and called Kallmann syndrome (KS), in contrast to patients with normal sense of smell referred to as normosmic CHH. ANOS1 and FGFR1 genes are all well established in the pathogenesis of CHH and have been extensively studied in many reported cohorts. Due to rarity and heterogenicity of the condition the mutational spectrum, even in classical CHH genes, have yet to be fully characterized.

METHODS

To address this issue we screened for ANOS1 and FGFR1 variants in a cohort of 47 unrelated CHH subjects using targeted panel sequencing. All potentially pathogenic variants have been validated with Sanger sequencing.

RESULTS

Sequencing revealed two ANOS1 and four FGFR1 mutations in six subjects, of which five are novel and one had been previously reported in CHH. Novel variants include a single base pair deletion c.313delT in exon 3 of ANOS1, three missense variants of FGFR1 predicted to result in the single amino acid substitutions c.331C > T (p.R111C), c.1964 T > C (p.L655P) and c.2167G > A (p.E723K) and a 15 bp deletion c.374_388delTGCCCGCAGACTCCG in exon 4 of FGFR1. Based on ACMG-AMP criteria reported variants were assigned to class 5, pathogenic or class 4, likely pathogenic. Protein structural predictions, the rarity of novel variants and amino acid conservation in case of missense substitutions all provide strong evidence that these mutations are highly likely to be deleterious.

CONCLUSIONS

Despite the fact that ANOS1 and FGFR1 are classical CHH genes and were thoroughly explored in several CHH cohorts we identified new, yet undescribed variants within their sequence. Our results support the genetic complexity of the disorder. The knowledge of the full genetic spectrum of CHH is increasingly important in order to be able to deliver the best personalised medical care to our patients.

Genetic Evaluation of Patients With Delayed Puberty and Congenital Hypogonadotropic Hypogonadism: Is it Worthy of Consideration?

Delayed puberty is a common reason of pediatric endocrinological consultation. It is often a self-limited (or constitutional) condition with a strong familial basis. The type of inheritance is variable but most commonly autosomal dominant. Despite this strong genetic determinant, mutations in genes implicated in the regulation of hypothalamic-pituitary-gonadal axis have rarely been identified in cases of self-limited delayed puberty and often in relatives of patients with congenital hypogonadotropic hypogonadism (i.e., FGFR1 and GNRHR genes). However, recently, next-generation sequencing analysis has led to the discovery of new genes (i.e., IGSF10, HS6ST1, FTO, and EAP1) that are implicated in determining isolated self-limited delayed puberty in some families. Despite the heterogeneity of genetic defects resulting in delayed puberty, genetic testing may become a useful diagnostic tool for the correct classification and management of patients with delayed puberty. This article will discuss the benefits and the limitations of genetic testing execution in cases of delayed puberty.

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.

Clinical Characteristics and Spermatogenesis in Patients with Congenital Hypogonadotropic Hypogonadism Caused by FGFR1 Mutations

OBJECTIVE

The aim of this study was to investigate the clinical characteristics of patients diagnosed with congenital hypogonadotropic hypogonadism (CHH) caused by FGFR1 (fibroblast growth factor receptor 1) gene mutations and to evaluate the effect of gonadotropin or pulsatile gonadotropin-releasing hormone (GnRH) therapy on spermatogenesis.

METHODS

A retrospective study was conducted on CHH patients admitted to Peking Union Medical College Hospital from January 2012 to March 2020. Clinical features and laboratory results were recorded. Testicular volume and sperm count responding to gonadotropin and pulsatile GnRH therapy were compared between the FGFR1 mutation group and the mutation-negative group.

RESULTS

(1) FGFR1 mutation group included 14 patients who received sperm-induction therapy, and the mutation-negative group enrolled 25 CHH patients. (2) The incidence of cryptorchidism was 50.0% (7/14) and 12.0% (3/25) in the FGFR1 group and the mutation-negative group, respectively (p=0.019). The baseline testicular volume of the FGFR1 mutation group was smaller than that of the mutation-negative group, 1.6 (0.5-2.0) mL vs. 2 (1.75-4) mL (p=0.033). The baseline luteinizing hormone (LH), Follicle-stimulating hormone (FSH), and testosterone levels were similar between the two groups. (3) Using the Kaplan-Meier and log-rank tests for the analysis of spermatogenesis, it was found that there was no significant difference in the first sperm appearance between the FGFR1 mutation group and the mutation-negative group (χ ² = 1.974, p=0.160). The median time of spermatogenesis in the FGFR1 mutation group was longer than that in the mutation-negative group, 16 months vs. 10 months, respectively. The cumulative spermatogenesis success rate at 12 months in the FGFR1 mutation group (35.71%) was lower than that in the mutation-negative group (68.75%) (p=0.047). The sperm concentration in the mutation-negative group was more easily achieved for different thresholds compared with that in the FGFR1 mutation group, but no significant difference was observed (p > 0.05) between the two groups. The last follow-up examination showed that the testicular volume was 7.00 (4.75-12.00) mL and 10.56 ± 4.82 mL (p=0.098), the ejaculate volume of sperm was 2.20 (1.40-2.26) mL and 3.06 ± 1.42 mL (p=0.175), and the sperm concentration was 7.19 (1.00-9.91) million/mL and 18.80 (4.58-53.62) million/mL (p=0.038) in the FGFR1 mutation and mutation-negative groups, respectively, while the sperm motility (A%, A + B%, and A + B + C%) was similar for the two groups (p=0.839, 0.909, and 0.759, respectively). The testosterone level during treatment was 366.02 ± 167.03 ng/dL and 362.27 ± 212.86 ng/dL in the FGFR1 mutation and mutation-negative groups, respectively (p=0.956).

CONCLUSION

Patients with FGFR1 mutations have a higher prevalence of cryptorchidism and smaller testicular volume. Although patients with FGFR1 mutations have a similar rate of success for spermatogenesis compared to that of the mutation-negative patients, a longer treatment period was required and a lower sperm concentration was achieved.

Parallel Multi-Gene Panel Testing for Diagnosis of Idiopathic Hypogonadotropic Hypogonadism/Kallmann Syndrome

Kallmann syndrome (KS)/Idiopathic hypogonadotropic hypogonadism (IHH) is characterized by hypogonadotropic hypogonadism and anosmia or hyposmia due to the abnormal migration of olfactory and gonadotropin releasing hormone producing neurons. Multiple genes have been implicated in KS/IHH. Sequential testing of these genes utilising Sanger sequencing is time consuming and not cost effective. The introduction of parallel multigene panel sequencing of small gene panels for the identification of causative gene variants has been shown to be a robust tool in the clinical setting. Utilizing multiplex PCR for the four gene KS/IHH panel followed by NGS, we describe herewith two cases of hypogonadotropic hypogonadism with a Prokineticin receptor 2 (PROKR2) gene and KAL1 gene mutation. The subject with a PROKR2 mutation had a normal perception of smell and normal olfactory bulbs on imaging. The subject with a KAL1 gene mutation had anosmia and a hypoplastic olfactory bulb.

Whole Exome Sequencing Revealed a Novel Nonsense Variant in the GNRHR Gene Causing Normosmic Hypogonadotropic Hypogonadism in a Pakistani Family

BACKGROUND

Congenital hypogonadotropic hypogonadism (CHH) is a heterogeneous disorder characterized by delayed or loss of puberty and infertility due to functional deficiency in the hypothalamic gonadotropin-releasing hormone (GnRH). CHH can be classified into 2 subtypes on the basis of olfaction: Kallmann syndrome and normosmic CHH (nCHH). The spectrum of genetic variants causing CHH is continually expanding. Here, we recruited a consanguineous Pakistani family having 2 male and 2 female infertile patients diagnosed with idiopathic nCHH.

AIMS

The aim of this study was to investigate the genetic cause of nCHH in the family.

METHODS

Clinical and physical analyses were performed for the patients. Genetic analysis was carried out using whole exome and Sanger sequencing.

RESULTS

Clinical and physical investigations confirmed low levels of gonadotropins and failure of secondary sexual development in the patients. Genetic analysis identified a novel nonsense mutation (chr4: g.68619942G>A, c.112C>T, p.Arg38*) in the gonadotropin-releasing hormone receptor gene (GNRHR) recessively co-segregating with nCHH in this family. All the patients are homozygous and their parents are heterozygous carriers, while normal siblings are heterozygous carriers or wild-type for this mutation, indicating that the identified mutation is pathogenic for nCHH in the family.

CONCLUSION

We report the first homozygous nonsense mutation in the GNRHR gene (chr4: g. 68619942G>A, c.112C>T, p. Arg38*) that is associated with familial nCHH. Hence, our study displayed a good correlation of the genotype and phenotype of nCHH patients.

Live birth in male de novo Kallmann syndrome after cross-generational genetic sequencing

PURPOSE

To present the first case proposing the use of preimplantation genetic testing for monogeneic disorders for Kallmann syndrome, providing comprehensive care in the genomic era of precision medicine.

METHODS

Gonadotropin therapy was used for spermatogenesis, followed by in vitro fertilization by intracytoplasmic sperm injection and embryo transfer. Cross-generational targeted next-generation sequencing was then done for genes known to cause Kallmann syndrome.

RESULTS

A heterozygous mutation at codon 102 of the FGFR1 gene was found in the patient, but the father was found to have the same mutation yet is unaffected by Kallmann syndrome. Since no causative mutation was found, a de novo or sporadic mutation was suspected as the cause of Kallmann syndrome in this case.

CONCLUSIONS

Comprehensive care must be available for male Kallmann syndrome patients, as treatment should not stop at spermatogenesis, but continue with genetic counseling due to possible inheritance.

Hypogonadotrophic hypogonadism, delayed puberty and risk for neurodevelopmental disorders

Hypogonadotrophic hypogonadism (HH) is a rare disorder that manifests absent puberty and infertility. Genetic syndromes with hypogonadism, such as Klinefelter syndrome, are associated with an increased risk of neurodevelopmental disorders (NDDs). However, it is not clear whether patients with HH or transient delayed puberty in general, have an increased risk of NDDs. We performed a register-based study on a national cohort of 264 patients with HH and 7447 patients diagnosed with delayed puberty that was matched with 2640 and 74 470 controls, respectively. The outcome was defined as having any of the following NDD diagnoses: (i) autism spectrum disorder (ASD); (ii) attention deficit hyperactivity disorder (ADHD); or (iii) intellectual disability (ID). Additional sensitivity analyses were performed to control for different parental and birth variables, as well as diagnosed malformation syndromes and chromosomal anomalies (ie, Down's and Turner syndromes). Patients with HH had increased risk for being diagnosed with ASD (odds ratio [OR] = 5.7; 95% confidence interval [CI] = 2.6-12.6), ADHD (OR = 3.0; 95% CI = 1.8-5.1) and ID (OR = 18.0; 95% CI = 8.9-36.3) compared to controls. Patients with delayed puberty also had a significantly increased risk of being diagnosed with an NDD. These associations remained significant after adjustments. This is the first study to demonstrate a significant association between HH, delayed puberty and NDDs in a population-based cohort. Clinicians should be aware of the overlap between these disorders. Further studies should explore the mechanisms behind these associations.

Similarities and differences in the reproductive phenotypes of women with congenital hypogonadotrophic hypogonadism caused by GNRHR mutations and women with polycystic ovary syndrome

STUDY QUESTION

Does the phenotype of women with normosmic congenital hypogonadotrophic hypogonadism (nCHH) and pituitary resistance to GnRH caused by biallelic mutations in the GnRH receptor (GNRHR) (nCHH/bi-GNRHR) differ from that of women with polycystic ovary syndrome (PCOS)?

SUMMARY ANSWER

Women with nCHH/bi-GNRHR have variable pubertal development but nearly all have primary amenorrhea and an exaggerated LH response to GnRH stimulation, similar to that seen in women with PCOS.

WHAT IS KNOWN ALREADY

Women with nCHH/bi-GNRHR are very rare and their phenotype at diagnosis is not always adequately documented. The results of gonadotrophin stimulation by acute GnRH challenge test and ovarian features have not been directly compared between these patients and women with PCOS.

STUDY DESIGN, SIZE, DURATION

We describe the phenotypic spectrum at nCHH/bi-GNRHR diagnosis in a series of 12 women. Their reproductive characteristics and acute responses to GnRH were compared to those of 70 women with PCOS.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Patients and controls (healthy female volunteers aged over 18 years) were enrolled in a single French referral centre. Evaluation included clinical and hormonal studies, pelvic ultrasonography and GnRH challenge test. We also functionally characterized two missense GNRHR mutations found in two new consanguineous families.

MAIN RESULTS AND THE ROLE OF CHANCE

Breast development was highly variable at nCHH/bi-GNRHR diagnosis, but only one patient had undeveloped breasts. Primary amenorrhea was present in all but two cases. In untreated nCHH/bi-GNRHR patients, uterine height (UH) correlated (P = 0.01) with the circulating estradiol level and was shorter than in 23 nulliparous post-pubertal age-matched controls (P < 0.0001) and than in 15 teenagers with PCOS under 20-years-old (P < 0.0001) in which PCOS was revealed by primary amenorrhea or primary-secondary amenorrhea. Unexpectedly, the stimulated LH peak response in nCHH/bi-GNRHR patients was variable, and often normal or exaggerated. Interestingly, the LH peak response was similar to that seen in the PCOS patients, but the latter women had significantly larger mean ovarian volume (P < 0.001) and uterine length (P < 0.001) and higher mean estradiol (P < 0.001), anti-Müllerian hormone (AMH) (P = 0.02) and inhibin-B (P < 0.001) levels. In the two new consaguineous families, the affected nCHH/bi-GNRHR women carried the T269M or Y290F GNRHR missense mutation in the homozygous state. In vitro analysis of GnRHR showed complete or partial loss-of-function of the T269M and Y290F mutants compared to their wildtype counterpart.

LIMITATIONS, REASONS FOR CAUTION

The number of nCHH/bi-GNRHR patients reported here is small. As this disorder is very rare, an international study would be necessary to recruit a larger cohort and consolidate the phenotypic spectrum observed here.

WIDER IMPLICATIONS OF THE FINDINGS

In teenagers and young women with primary amenorrhea, significant breast and uterine development does not rule out CHH caused by biallelic GNRHR mutations. In rare patients with PCOS presenting with primary amenorrhea and a mild phenotype, the similar exaggerated pituitary LH responses to GnRH in PCOS and nCHH/bi-GNRHR patients could lead to diagnostic errors. This challenge test should therefore not be recommended. As indicated by consensus and guidelines, careful analysis of clinical presentation and measurements of testosterone circulating levels remain the basis of PCOS diagnosis. Also, analysis of ovarian volume, UH and of inhibin-B, AMH, estradiol and androgen circulating levels could help to distinguish between mild PCOS and nCHH/bi-GNRHR.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by the French National Research Agency (ANR) grant ANR-09-GENO-017 KALGENOPATH, France; and by the Italian Ministry of Education, University and Research (MIUR) grant PRIN 2012227FLF_004, Italy. The authors declare no conflict of interest.

Functional Hypogonadotropic Hypogonadism in Men: Underlying Neuroendocrine Mechanisms and Natural History

CONTEXT

After completion of puberty a subset of men experience functional hypogonadotropic hypogonadism (FHH) secondary to excessive exercise or weight loss. This phenomenon is akin to hypothalamic amenorrhea (HA) in women, yet little is known about FHH in men.

OBJECTIVE

To investigate the neuroendocrine mechanisms, genetics, and natural history underlying FHH.

DESIGN

Retrospective study in an academic medical center.

PARTICIPANTS

Healthy postpubertal men presenting with symptoms of hypogonadism in the setting of excessive exercise (>10 hours/week) or weight loss (>10% of body weight). Healthy age-matched men served as controls.

INTERVENTIONS

Clinical assessment, biochemical and neuroendocrine profiling, body composition, semen analysis, and genetic evaluation of genes known to cause isolated GnRH deficiency.

MAIN OUTCOME MEASURES

Reproductive hormone levels, endogenous GnRH-induced LH pulse patterns, and rare genetic variants.

RESULTS

Ten men with FHH were compared with 18 age-matched controls. Patients had significantly lower body mass index, testosterone, LH, and mean LH pulse amplitudes yet normal LH pulse frequency, serum FSH, and sperm counts. Some patients exhibited nocturnal, sleep-entrained LH pulses characteristic of early puberty, and one FHH subject showed a completely apulsatile LH secretion. After decreased exercise and weight gain, five men with men had normalized serum testosterone levels, and symptoms resolved. Rare missense variants in NSMF (n = 1) and CHD7 (n = 1) were identified in two men with FHH.

CONCLUSIONS

FHH is a rare, reversible form of male GnRH deficiency. LH pulse patterns in male FHH are similar to those observed in women with HA. This study expands the spectrum of GnRH deficiency disorders in men.

Nasal Placode Development, GnRH Neuronal Migration and Kallmann Syndrome

The development of Gonadotropin releasing hormone-1 (GnRH) neurons is important for a functional reproduction system in vertebrates. Disruption of GnRH results in hypogonadism and if accompanied by anosmia is termed Kallmann Syndrome (KS). From their origin in the nasal placode, GnRH neurons migrate along the olfactory-derived vomeronasal axons to the nasal forebrain junction and then turn caudally into the developing forebrain. Although research on the origin of GnRH neurons, their migration and genes associated with KS has identified multiple factors that influence development of this system, several aspects still remain unclear. This review discusses development of the olfactory system, factors that regulate GnRH neuron formation and development of the olfactory system, migration of the GnRH neurons from the nose into the brain, and mutations in humans with KS that result from disruption of normal GnRH/olfactory systems development.

Constitutional delay of puberty versus congenital hypogonadotropic hypogonadism: Genetics, management and updates

Delayed puberty (DP) affects approximately 2% of adolescents. In the vast majority of patients in both sexes, it is due to constitutional delay of growth and puberty (CDGP), a self-limited condition in which puberty starts later than usual but progresses normally. However, some CDGP patients may benefit from medical intervention with low-dose sex steroids or peroral aromatase inhibitor letrozole (only for boys). Other causes of DP include permanent hypogonadotropic hypogonadism, functional hypogonadotropic hypogonadism (due to chronic diseases and conditions), and gonadal failure. In this review we discuss these themes along with the latest achievements in the field of puberty research, and include a brief synopsis on the differential diagnosis and management of patients with CDGP and congenital hypogonadotropic hypogonadism.

Nonstop mutation in the Kisspeptin 1 receptor (KISS1R) gene causes normosmic congenital hypogonadotropic hypogonadism

PURPOSE

Congenital hypogonadotropic hypogonadism (CHH) is a rare genetic disorder mostly characterized by gonadotropins release and/or action deficiencies. Both isolated (idiopathic hypogonadotropic hypogonadism) and syndromic (Kallmann) forms are identified depending on the olfactory ability. Clinical and genetic heterogeneities of CHH have been widely explored, thus improving our understanding of the disease's pathophysiology. This work aims to (1) provide a detailed clinical and hormonal description of normosmic CHH patients and (2) identify the mutation linked to the studied phenotype.

PARTICIPANTS AND METHODS

We investigated three affected patients with normosmic CHH, belonging to a consanguineous Tunisian family. Patients underwent an insulin-induced hypoglycemia test. We performed whole exome sequencing to identify the causal mutation.

RESULTS

At first diagnosis, a total gonadotropic deficiency was identified in all patients. The insulin-induced hypoglycemia test has also revealed a reduced cortisol secretion and complete growth hormone deficiency. At 20.8 years, one female exhibited a spontaneous recovery of the hypothalamic-pituitary-adrenal axis function, unlike her affected siblings who still depend on corticosteroid replacement therapy. Herein, we identified a novel homozygous nonstop mutation (c.1195T>C) in KISS1R gene in all affected subjects. This mutation led to the substitution of the physiologic stop codon by an arginine (p.X399R).

CONCLUSIONS

Our study highlights the importance of the KISS1R signaling, in gonadotropin-releasing hormone neurons, in the control of reproductive function. Additionally, our data suggests a complex central and peripheral metabolic control of puberty, through the hypothalamic KISS1R signaling. We suggest a mutual link between the hypothalamic-pituitary-gonadal, -adrenal, and -somatotropic axes.

Screening for mutations in selected miRNA genes in hypogonadotropic hypogonadism patients

In approximately half of congenital hypogonadotropic hypogonadism (cHH) patients, the genetic cause remains unidentified. Since the lack of certain miRNAs in animal models has led to cHH, we sequenced human miRNAs predicted to regulate cHH-related genes (MIR7-3, MIR141, MIR429 and MIR200A-C) in 24 cHH patients with Sanger sequencing. A heterozygous variant in MIR200A (rs202051309; general population frequency of 0.02) was found in one patient. Our results suggest that mutations in the studied miRNAs are unlikely causes of cHH. However, the complex interplay between miRNAs and their target genes in these diseases requires further investigations.

Clinical Management of Congenital Hypogonadotropic Hypogonadism

The initiation and maintenance of reproductive capacity in humans is dependent on pulsatile secretion of the hypothalamic hormone GnRH. Congenital hypogonadotropic hypogonadism (CHH) is a rare disorder that results from the failure of the normal episodic GnRH secretion, leading to delayed puberty and infertility. CHH can be associated with an absent sense of smell, also termed Kallmann syndrome, or with other anomalies. CHH is characterized by rich genetic heterogeneity, with mutations in >30 genes identified to date acting either alone or in combination. CHH can be challenging to diagnose, particularly in early adolescence where the clinical picture mirrors that of constitutional delay of growth and puberty. Timely diagnosis and treatment will induce puberty, leading to improved sexual, bone, metabolic, and psychological health. In most cases, patients require lifelong treatment, yet a notable portion of male patients (∼10% to 20%) exhibit a spontaneous recovery of their reproductive function. Finally, fertility can be induced with pulsatile GnRH treatment or gonadotropin regimens in most patients. In summary, this review is a comprehensive synthesis of the current literature available regarding the diagnosis, patient management, and genetic foundations of CHH relative to normal reproductive development.

Variant analysis of the chromodomain helicase DNA-binding protein 7 in pediatric disorders of sex development

IMPORTANCE

This study investigated the role of the chromodomain helicase DNA-binding protein 7 (CHD7) in disorders of sex development (DSD).

OBJECTIVE

We aimed to present the potential pathogenicity of CHD7 variants in pediatric patients with DSD.

METHODS

Choosing cases with CHD7 variants from DSD patients in Beijing Children's Hospital to assess for the study. Prediction software tools were used to predict variant pathogenicity in these subjects.

RESULTS

Among the 113 DSD patients, 22 cases had CHD7 variants. Twenty-four different CHD7 variants were identified in the 22 DSD patients. Prediction software combined with ClinVar database information and their clinical manifestations revealed that, of the 18 patients with 46, XY DSD, two had CHARGE syndrome and two had Kallmann syndrome. Seven of the variants were highly categorized as "likely to be pathogenic" and seven as "suspected to be pathogenic". Of the four patients with 46, XX DSD, three had ovotesticular DSD (c.305A>G, c.2788G>A, and c.3098G>A) and one had testicular DSD (c.2831G>A).

INTERPRETATION

A high frequency of CHD7 variants was found in the DSD patients, especially those with 46, XY DSD. Thus, the detection of a pathogenic CHD7 variant could suggest a diagnosis of hypogonadotropic hypogonadism for 46, XY DSD patients, but pre-pubescent patients should be reassessed in adolescence to confirm this diagnosis. This study also suggests that DNA sequencing could help to identify pre-pubescent DSD patients. Further data are required to determine the connection between CHD7 variants and sex-reversal in patients with 46, XX DSD, and the accumulation of these data is essential and necessary for DSD research.

Congenital Hypogonadotrophic Hypogonadism: Minipuberty and the Case for Neonatal Diagnosis

Congenital hypogonadotrophic hypogonadism (CHH) is a rare but important etiology of pubertal failure and infertility, resulting from impaired gonadotrophin-releasing hormone secretion or action. Despite the availability of effective hormonal therapies, the majority of men with CHH experience unsatisfactory outcomes, including chronic psychosocial and reproductive sequelae. Early detection and timely interventions are crucial to address the gaps in medical care and improve the outlook for these patients. In this paper, we review the clinical implications of missing minipuberty in CHH and therapeutic strategies that can modify the course of disease, as well as explore a targeted approach to identifying affected male infants by integrating clinical and biochemical data in the early postnatal months.

Psychological Aspects of Congenital Hypogonadotropic Hypogonadism

Congenital hypogonadotropic hypogonadism/Kallmann syndrome (CHH/KS) is a rare, treatable form of infertility. Like other rare disease patients, individuals with CHH/KS frequently experience feelings of isolation, shame, and alienation. Unlike many rare diseases, CHH/KS is not life threatening and effective treatments are available. Nevertheless, it remains a profoundly life-altering condition with psychosocial distress on a par with untreatable or life-limiting disease. Patients with CHH/KS frequently express lasting adverse psychological, emotional, social, and psychosexual effects resulting from disrupted puberty. They also frequently experience a "diagnostic odyssey," characterized by distressing and convoluted medical referral pathways, lack-of-information, misinformation, and sometimes-incorrect diagnoses. Unnecessary delays in diagnosis and treatment-initiation can significantly contribute to poor body image and self-esteem. Such experiences can erode confidence and trust in medical professionals as well as undermine long-term adherence to treatment-with negative sequelae on health and wellbeing. This review provides a summary of the psychological aspects of CHH/KS and outlines an approach to comprehensive care that spans medical management as well as appropriate attention, care and referrals to peer-to-peer support and mental health services to ameliorate the psychological aspects of CHH/KS.

Managing congenital hypogonadotrophic hypogonadism: a contemporary approach directed at optimizing fertility and long-term outcomes in males

Hormonal induction of spermatogenesis offers men with azoospermia due to hypogonadotrophic hypogonadism (HH) the promising prospect of fertility restoration. However, an important exception is the subset of individuals affected by congenital hypogonadotrophic hypogonadism (CHH), also known as Kallmann syndrome if associated with anosmia, who often display dismal responses to fertility induction, despite prolonged therapy. This primarily stems from the loss of minipuberty, which is a crucial phase of testicular maturation in early life that has a far-reaching impact on eventual spermatogenic capacity. Further exacerbating the compromised reproductive health is the failure to initiate timely pubertal induction in many CHH patients, resulting in suboptimal genital and psychosexual development. In this paper, the clinical implications and management of male HH across the lifespan is comprehensively reviewed, with a special focus on novel strategies that have the potential to modify disease severity and maximize fertility potential in CHH by addressing the inadequacies of conventional approaches.

Pituitary Transcription Factor Mutations Leading to Hypopituitarism

Congenital pituitary hormone deficiency is a disabling condition. It is part of a spectrum of disorders including craniofacial midline developmental defects ranging from holoprosencephaly through septo-optic dysplasia to combined and isolated pituitary hormone deficiency. The first genes discovered in the human disease were based on mouse models of dwarfism due to mutations in transcription factor genes. High-throughput DNA sequencing technologies enabled clinicians and researchers to find novel genetic causes of hypopituitarism for the more than three quarters of patients without a known genetic diagnosis to date. Transcription factor (TF) genes are at the forefront of the functional analysis of novel variants of unknown significance due to the relative ease in in vitro testing in a research lab. Genetic testing in hypopituitarism is of high importance to the individual and their family to predict phenotype composition, disease progression and to avoid life-threatening complications such as secondary adrenal insufficiency.This chapter aims to highlight our current understanding about (1) the contribution of TF genes to pituitary development (2) the diversity of inheritance and phenotype features in combined and select isolated pituitary hormone deficiency and (3) provide an initial assessment on how to approach variants of unknown significance in human hypopituitarism. Our better understanding on how transcription factor gene variants lead to hypopituitarism is a meaningful step to plan advanced therapies to specific genetic changes in the future.

Genetics of ncHH: from a peculiar inheritance of a novel GNRHR mutation to a comprehensive review of the literature

BACKGROUND

Normosmic congenital hypogonadotropic hypogonadism (ncHH) is caused by the deficient production, secretion, or action of gonadotropin-releasing hormone (GnRH). Its typical clinical manifestation is delayed puberty and azoospermia. Homozygous and compound heterozygous mutations in the GNRHR gene (4q13.2) are the most frequent genetic causes of ncHH.

OBJECTIVES

(i) Characterization at the molecular level (genetic origin and functional effect) of a unique homozygous mutation (p.Gly99Glu) in a ncHH man; (ii) to provide a comprehensive catalog of GNRHR mutations with genotype-phenotype correlation and comparison of in vitro studies vs. in silico prediction tools.

MATERIAL AND METHODS

A ncHH man and his parents, in whom we performed the following: (i) Sanger sequencing, qPCR of the GNRHR gene; (ii) chromosome 4 SNP array; and (iii) competition binding assay and inositol phosphate signaling assay. PubMed and Human Genome Mutation Database (HGMD) search for GNRHR mutations. Bioinformatic analysis of 55 reported variants.

RESULTS

qPCR showed two GNRHR copies in the index case. SNP array revealed the inheritance of two homologous chromosomes 4 from the mother (maternal heterodisomy; hUPD) with two loss of heterozygosity regions, one of them containing the mutated gene (maternal isodisomy; iUPD). Functional studies for the p.Gly99Glu mutation demonstrated a right-shifted GnRH-stimulated signaling response. Bioinformatic tools show that commonly used in silico tools are poor predictors of the function of ncHH-associated GNRHR variants.

DISCUSSION

Functional analysis of the p.Gly99Glu mutation is consistent with severely decreased GnRH binding affinity (a severe partial loss-of-function mutation). Complete LOF variants are associated with severe and severe/moderate phenotype, whereas partial LOF variants show wide range of clinical manifestations.

CONCLUSION

This is the first ncHH patient carrying a novel causative missense mutation of GNRHR with proven 'severe pLOF' due to maternal hUPD/iUPD of chromosome 4. Our literature review shows that functional studies remain essential both for diagnostic and potential therapeutic purposes.

The Pulsatile Gonadorelin Pump Induces Earlier Spermatogenesis Than Cyclical Gonadotropin Therapy in Congenital Hypogonadotropic Hypogonadism Men

The objective of this study was to compare the effect of pulsatile gonadorelin pump (PGP) and cyclical gonadotropin (human chorionic gonadotropin [HCG]/human menopausal gonadotropin [HMG]) therapy (CGT) on spermatogenesis in congenital hypogonadotropic hypogonadism (CHH) men. Twenty-eight azoospermic CHH males were included in this nonrandomized study. Ten received PGP and 18 received CGT. The primary endpoint was the earliest time spermatogenesis occurred during 24 months of treatment. Spermatogenesis time was significant earlier in the PGP group than the CGT group (median of 6 and 14 months, respectively, χ² = 6.711, p = .01). Spermatogenesis occurred in 90% of the PGP group and 83.3% of the CGT group and showed statistically insignificant difference in the superiority analysis and the no-inferior test. Contributing factors significant for spermatogenesis were previous HCG/or testosterone treatment and the peak serum luteinizing hormone level of triptorelin stimulation test at baseline. Although testis volume and penile length increased significantly from baseline, the differences between the two therapies were not significant. There was a tendency for high serum testosterone level, associated with more facial acne and breast tenderness in the CGT group. Skin allergic erythema scleroma was a common side effect of the PGP. In summary, PGP resulted in earlier spermatogenesis and more desirable testosterone levels than CGT.

Fertility Issues in Pediatric Urology

Improved understanding of the pathogenesis and natural history of many urologic disorders, as well as advances in fertility preservation techniques, has increased the awareness of and options for management of fertility threats in pediatric patients. In children, fertility may be altered by oncologic conditions, by differences in sexual differentiation, by gonadotoxic drugs and other side effects of treatment for nonurologic disorders, and by urologic conditions, such as varicocele and cryptorchidism. Although fertility concerns are best addressed in a multidisciplinary setting, pediatric urologists should be aware of the underlying pathophysiology and management options to properly counsel and advocate for patients.

Recent advances in understanding inheritance of holoprosencephaly

Holoprosencephaly (HPE) is a complex genetic disorder of the developing forebrain characterized by high phenotypic and genetic heterogeneity. HPE was initially defined as an autosomal dominant disease, but recent research has shown that its mode of transmission is more complex. The past decade has witnessed rapid development of novel genetic technologies and significant progresses in clinical studies of HPE. In this review, we recapitulate genetic epidemiological studies of the largest European HPE cohort and summarize the novel genetic discoveries of HPE based on recently developed diagnostic methods. Our main purpose is to present different inheritance patterns that exist for HPE with a particular emphasis on oligogenic inheritance and its implications in genetic counseling.