Idiopathic Hypogonadotropic Hypogonadism Research Articles

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.

TCF12 haploinsufficiency causes autosomal dominant Kallmann syndrome and reveals network-level interactions between causal loci.

Dysfunction of the gonadotropin-releasing hormone (GnRH) axis causes a range of reproductive phenotypes resulting from defects in the specification, migration and/or function of GnRH neurons. To identify additional molecular components of this system, we initiated a systematic genetic interrogation of families with isolated GnRH deficiency (IGD). Here, we report 13 families (12 autosomal dominant and one autosomal recessive) with an anosmic form of IGD (Kallmann syndrome) with loss-of-function mutations in TCF12, a locus also known to cause syndromic and non-syndromic craniosynostosis. We show that loss of tcf12 in zebrafish larvae perturbs GnRH neuronal patterning with concomitant attenuation of the orthologous expression of tcf3a/b, encoding a binding partner of TCF12, and stub1, a gene that is both mutated in other syndromic forms of IGD and maps to a TCF12 affinity network. Finally, we report that restored STUB1 mRNA rescues loss of tcf12 in vivo. Our data extend the mutational landscape of IGD, highlight the genetic links between craniofacial patterning and GnRH dysfunction and begin to assemble the functional network that regulates the development of the GnRH axis.

Distinguishing between hidden testes and anorchia: the role of endocrine evaluation in infancy and childhood

Non-palpable testes remain a diagnostic challenge, often involving exploratory laparoscopy. We evaluated the diagnostic value of a wide range of reproductive hormones in order to distinguish between bilateral cryptorchidism and bilateral anorchia. In this retrospective study, we identified and included 36 boys with non-palpable testes (20 with cryptorchidism, 3 with congenital hypogonadotropic hypogonadism (CHH), and 13 with anorchia) at first examination during childhood. Information on karyotype, phenotype, surgical results from laparoscopy, and biochemistry was retrieved from patient files. We compared serum concentrations of AMH, inhibin B, FSH, LH, testosterone, estradiol, and hCG stimulation testing in cryptorchid and anorchid boys to serum concentrations in a large, age-matched control group. Receiver-operating characteristic curves were used to determine the cut-off values of each reproductive hormone as a predictor of the presence of functional testicular tissue. Concentrations of AMH in 0-1 year olds: ≥155 pmol/L and >1-15 year olds: ≥19 pmol/L, inhibin B (≥22 pg/mL and ≥4 pg/mL), FSH (≤28.9 IU/L and ≤20.3 IU/L) and hCG-induced testosterone (>1-15 year olds: ≥2 nmol/L) were significantly sensitive and specific markers in predicting the presence of functional testicular tissue in boys with non-palpable testes. In infancy, anorchid infants had significantly elevated gonadotropin levels, while CHH had low levels. Our findings suggest that laparoscopy may not be necessary in all boys with non-palpable testes if reproductive hormones unequivocally confirm the presence of functional testicular tissue. However, proving the absence may still be a diagnostic challenge.

WDR11 Mutations as A Potential Player of Idiopathic Hypogonadotropic Hypogonadism

The hypothalamic-pituitary-gonadal axis plays animportant role in the development and progression of the reproductive system through puberty and adolescence...

SEMA3A and IGSF10 Are Novel Contributors to Combined Pituitary Hormone Deficiency (CPHD).

Background: The mutation frequencies of pituitary transcription factors genes in patients with combined pituitary hormone deficiencies (CPHD) vary substantially between populations. However, apart from PROP1 the mutation rate of other genes is low and for almost half of the patients with CPHD the routine sequencing of known genes is unsuccessful in the identification of genetic causes.Methods: A cohort of 66 sporadic and nine familial CPHD cases (80 patients in total) were subjected to initial testing of the genes PROP1, POU1F1, LHX3, LHX4, and HESX1 using a targeted gene panel and MLPA. In patients who tested negative, a whole exome sequencing approach was employed.Results: In nine of the familial cases and 32 of the sporadic patients mutations in the PROP1 gene were found (the common pathogenic variants included c.301_302delAG and c.150delA). Mutations were also found in genes so far not related directly to CPHD. A unique homozygous and clinically relevant variant was identified in the SEMA3A gene, which may contribute to neural development and his phenotypic spectrum including short stature and isolated hypogonadotropic hypogonadism (IHH). Another pathogenic variant p.A1672T was found in the IGSF10 gene reported to be responsible for delayed puberty and neuronal migration during embryogenesis. Several suspected novel but predicted benign variants were also identified for the CHD7, WDR11 and FGF17 genes.Conclusion: Although PROP1 defects account for a majority of CPHD patients, identification of rare, less frequent variants constitutes a big challenge. Multiple genetic factors responsible for CPHD are still awaiting discovery and therefore the usage of efficient genomic tools (i.e., whole exome sequencing) will further broaden our knowledge regarding pituitary development and function.

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

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. 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. 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. 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.

Pubertal timing predicts adult psychosexuality: Evidence from typically developing adults and adults with isolated GnRH deficiency

Evidence suggests that psychosexuality in humans is modulated by both organizational effects of prenatal and peripubertal sex steroid hormones, and by activational effects of circulating hormones in adulthood. Experimental work in male rodents indicates that sensitivity to androgen-driven organization of sexual motivation decreases across the pubertal window, such that earlier puberty leads to greater sex-typicality. We test this hypothesis in typically developing men (n = 231) and women (n = 648), and in men (n = 72) and women (n = 32) with isolated GnRH deficiency (IGD), in whom the precise timing of peripubertal hormone exposure can be ascertained via the age at which hormone replacement therapy (HRT) was initiated. Psychosexuality was measured with the Sexual Desire Inventory-2 (SDI-2) and Sociosexual Orientation Inventory-Revised (SOI-R). In both sexes, earlier recalled absolute pubertal timing predicted higher psychosexuality in adulthood, although the magnitude of these associations varied with psychosexuality type and group (i.e., typically developing and IGD). Results were robust when controlling for circulating steroid hormones in typically developing participants. Age of initiation of HRT in men with IGD negatively predicted SOI-R. We discuss the clinical implications of our findings for conditions in which pubertal timing is medically altered.

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

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. 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. 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. 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.

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.

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.

Integrative analysis of genomic and epigenetic regulation of endometrial cancer.

Endometrial carcinomas (EC) are characterized by high DNA copy numbers and DNA methylation aberrations. In this study, we sought to comprehensively explore the effect of these two factors on development and progression of EC by analyzing integrated genomic and epigenetic analysis to. We found high DNA copy number and DNA methylation abnormalities in EC, with 6308 copy-number variation genes (CNV-G) and 4376 methylation genes (MET-G). We used these CNV-G and MET-G to subcategorize the samples for prognostic analysis, and identified three molecular subtypes (iC1, iC2, iC3). Moreover, the subtypes exhibited different tumor immune microenvironment characteristics. A further analysis of their molecular characteristics revealed three potential prognostic markers (KIAA1324, nonexpresser of pathogenesis-related genes1 (NPR1) and idiopathic hypogonadotropic hypogonadism (IHH)). Notably, all three markers showed distinct CNV, DNA methylation, and gene expression profiles. Analysis of mutations among the three subtypes revealed that iC2 had fewer mutations than the other subtypes. Conversely, iC2 showed significantly higher CNV levels than other subtypes. This comprehensive analysis of genomic and epigenetic profiles identified three prognostic markers, therefore, provides new insights into the multi-layered pathology of EC. These can be utilized for accurate treatment of EC patients.

Identification of two novel mutations in three Chinese families with Kallmann syndrome using whole exome sequencing.

Kallmann syndrome (KS) is a rare developmental disorder that manifests as congenital hypogonadotropic hypogonadism with anosmia. More than 19 genes have been found to be associated with KS. However, approximately 70% of the causes of KS remain unclear. Here, we studied seven KS patients, from three families, who had delayed puberty and olfactory bulb dysplasia. However, the families of these patients showed a range of other unique clinical features, including hearing loss, anosmia (to varying degrees) and unilateral renal agenesis. We performed whole exome sequencing and copy number variation (CNV) sequencing on samples acquired from these patients. We identified two novel mutations (c.844delC in ANOS1, c.475C>T in SOX10) and a novel trigenic pattern, PROKR2/CHD7/FEZF1 (c.337T>C in PROKR2, c.748C>G in FEZF1, c.8773G>A in CHD7). The c.844delC mutation in the ANOS1 gene was predicted to generate a truncated form of the anosmin-1 protein. SIFT and PolyPhen-2 predicted that the c.475C>T mutation in SOX10 had a damaging effect. The PROKR2 mutation (c.337T>C) was previously reported as harmful. No pathogenic copy number alterations were detected. Our study expands the genotypic and phenotypic spectrum of KS, a disease that shows considerable clinical and genetic heterogeneity. The application of whole exome sequencing could facilitate our understanding of the pathogenesis of KS.

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

BackgroundFGF8-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...

SUN-036 Evaluation of Gender Experience Among Individuals with Isolated GnRH Deficiency Compared to Controls

Background: Sex hormones play a role in gender identity development. For example, 46,XY individuals with complete androgen insensitivity typically have a female gender identity. Isolated GnRH deficiency (IGD) leads to hypogonadism due to decreased GnRH-induced gonadotropin production. It is unknown if decreased sex hormone exposure leads to differences in gender identity among individuals with IGD compared with the general population. Our objective was to determine if the gender identity in subjects with IGD differs from controls.Methods: We distributed a validated questionnaire; the Gender Identity/Gender Dysphoria Questionnaire for Adults and Adolescents (GIDYQ-AA) (1), to IGD participants who previously enrolled in a phenotyping study. Subjects also provided their age, sex assigned at birth (SAAB), gender and information about their condition and treatment. Group survey scores are expressed as mean ± SD. IGD subject scores were compared with control data (Student’s t-test) obtained from a validation study for the GIDYQ-AA (2).Results: Out of 79 subjects who were contacted, 8 males (M) assigned at birth and 7 females (F) assigned at birth chose to participate and one person actively declined. Average age was 30 y for F and 28 y for M. At the time of the study, all subjects were on hormone supplementation except for one F. A score of 5 indicates a gender identity congruent with SAAB. Among F, mean scaled IGD score was 4.73 ± 0.29 vs. controls (4.8 ± 0.28, n=57; not significant (ns)), and for M it was 4.62 ± 0.52 vs. controls (4.82 ± 0.24, n=37; ns). One female identified as “non-gendered”, one male identified as “intersex/DSD” (14% of respondents), one female did not respond and gender was congruent with SAAB in the remainder. The lowest mean score for an individual question for the IGD F group was in response to whether they felt satisfied being a woman and for the IGD M group, it was in response to whether they felt they were a real man.Conclusions: Men and women with IGD did not show a significant difference in their gender identity compared with controls, and gender was found to be congruent with SAAB for the majority. However, the individual question responses and the self-described gender in this small cohort may suggest that there are differences in how some individuals with IGD experience their gender development. We speculate that this may be related to how they perceive the differences in physical development that they experienced related to their condition. Larger studies in participants with IGD and other disorders that alter sex hormone production/effect are necessary to further understand the relationship between decreased sex hormone exposure during critical developmental periods and gender identity development.

MON-273 Retrospective Analysis of Gonadotropin-Mediated Pubertal Induction in Male Patients with Congenital Hypogonadotropic Hypogonadism (CHH)

CHH is a rare disease characterized by a failure to enter (complete forms) or to complete (partial forms) pubertal development. It has a strong genetic background and it needs a treatment to allow the puberty to complete. In male this goal could be achieved either by the classic testosterone replacement therapy or by the exogenous gonadotropins (Gn) administration which allows both the endogenous testosterone production and the testicular development. So far, only few studies have explored this latter therapeutic approach in inducing the CHH pubertal development and no internationally recognized protocols are available. Aim of this retrospective analysis is to (i) investigate clinical and biochemical predictors of testicular response to Gn-induced puberty in CHH; (ii) study the non-reproductive outcomes of this treatment (height, body proportions) and their determinants. A total of 19 CHH male patients, undergoing two years of Gn-mediated (FSH and hCG) puberty induction started between the ages of 14 and 23 years, were retrospectively evaluated. For each patient clinical history, physical examination, hormonal evaluation, and genetic analysis using Targeted Next Generation Sequencing for CHH genes was performed; 8 patients accepted to perform a semen analysis (SA) at the end of their treatment.Mann Whitney test and multiple regression analysis showed testicular volume after 24 months of Gn-mediated pubertal induction, to be significantly associated with: (i) the presence of cryptorchidism; (ii) the presence of a completely definable genetic cause for the disease; (iii) the presence of a complete CHH form. No significant association was found with the cumulative dose of hCG administered in 24 months. The statistical analyses regarding SA could not find the same associations. Multiple regression analyses investigating the eunuchoid habitus and a measure of the difference of subject’s final height from his target (deltaSDSth), showed a significant association with: (i) age at the beginning of the induction; (ii) the duration of growth during induction; (iii) and (for deltaSDSth) bone age before the induction. Duration of growth during induction resulted to be associated with previous testosterone priming and with partial CHH.In summary, our study confirms cryptorchidism and complete genetic forms of CHH as negative predictors of testicular response probably because they usually affect early phases of life with a complete GnRH deficiency. We also found that the eunuchoid habitus and deltaSDSth are associated not only with delayed treatment, but also with the duration of stature growth during the induction, apparently related to earlier androgenization.

SUN-253 PROKR2 Neurons of the Amygdalohippocampal Area in Reproductive Function

Kallmann Syndrome (KS) is characterized by infertility and anosmia due to deficiency in gonadotropin releasing hormone (GnRH) neuronal migration and olfactory bulb dysgenesis. Genetic studies have revealed that KS is caused by loss-of-function mutations in several genes including the prokineticin receptor 2 (PROKR2) gene (Abreu et al., 2008, Hardelin & Dode 2008). Mice with global deletion of Prokr2 replicate the phenotype of KS patients (Ng et al., 2005, Matsumoto et al., 2006). Whereas the role of PROKR2 during development is defined, little is known about PROKR2 neurons in adult reproduction. PROKR2 mRNA are highly expressed in reproductive control sites of the adult mouse brain (Cheng et al., 2006). Previous studies in our lab found PROKR2 mRNA and Prokr2-Cre GFP+ cells highly expressed in the amygdalohippocampal area (AHi, also called posterior nucleus of the amygdala) in a sexually-dimorphic pattern. Male mice have higher PROKR2 expression in the AHi compared to female mice (Mohsen et al., 2017). The amygdala is an important site of socio-sexual inputs and reproductive neuroendocrine responses in rodents and primates, including humans. We hypothesize Prokr2-Cre neurons in the AHi have a role in both male and female reproductive function. Using genetic tracing techniques, we mapped AHi Prokr2-Cre neuronal projections in both male and female mice and found dense innervation to reproductive control sites such as the medial preoptic area and the ventral premammillary nucleus in a sexually dimorphic pattern. A soiled bedding exposure test in sexually experienced male mice showed that an estimated 45% of cFos + cells in the AHi express Prokr2-Cre GFP. Dense sex steroid receptors expression was observed in AHi Prokr2-Cre GFP neurons of both male and female mice. Our preliminary data suggests AHi Prokr2-Cre neurons have a reproductive function in male and potentially also in female mice. Future studies will focus on selective activation and inhibition of these neurons using chemogenetic technology to determine putative inputs to brain sites that control the hypothalamo-pituitary-gonadal axis. We expect our studies will contribute to the understanding of the role of PROKR2 neurons in adult reproduction and reproductive deficits associated with PROKR2 mutations.

SUN-032 Digenic Inheritance of PCSK1 and CHD7 Mutations in PAX4 Homozygous Diabetic Male with Normosmic Hypogonadotropic Hypogonadism

Background: Normosmic congenital hypogonadotropic hypogonadism denotes Kallmann syndrome not associated with anosmia or hyposmia. Over the past few years, the availability of next-generation sequencing has started to unravel the complex molecular basis of congenital hypogonadotrophic hypogonadism including digenic or oligogenic pathogenecity in addition to classic monogenic causality (1). Clinical Case: A 22-year-old male patient was referred to the endocrine clinic in 2018 with recent -onset hyperglycemia. His weight was 82.2 kg with a height of 180 cm (BMI of 25.3 kg/m2). Physical examination revealed small testes, micropenis, and no axillary and pubic terminal hair. His smell sense was intact. His hormonal test reveals low testosterone (0.10 ng/mL) and low free testosterone (0.65 pg/mL) levels with inappropriately low gonadotrophins levels. Secretion of LH and FSH increased 2-fold after GnRH stimulation. His bone age was 13-years 6-months old, and brain magnetic resonance imaging showed the presence of olfactory bulbs, and unremarkable findings except for small size of the pituitary gland. There were no signs associated with CHARGE syndrome (coloboma ocular, heart defects, atresia or stenosis of the choanae, retardation of growth and/or development, genitourinary anomalies, and ear abnormalities). Biochemical investigation demonstrated high serum glucose level and high HbA1c (13.8%). To identify variants to cause the phenotype of the proband, we adopted trio-based whole exome sequencing (WES) and candidate gene approach. Candidate genes was listed from the orphanet (https://www.orpha.net). WES of the proband revealed the presence of heterozygote missense mutations of the CHD7 gene (c.6107C>T, p.Pro2036Leu, rs369543203) and PCSK1 gene (c.239G>A, p.Arg80Gln, rs1799904). The missense variants were predicted to have a damaging effect on the encoded protein, by SIFT and PolyPhen-2 analyses. Genetic analyses of his family revealed that his father had the same heterozygote missense mutations of the CHD7 gene, but wild type of PCSK1. Proband’s mother had the same heterozygote missense mutations of PCSK1, but wild type of CHD7. Furthermore, the proband had homozygote missense mutation of PAX4 (c.575G>A, p.Arg192His, rs2233580) known as maturity-onset diabetes of the young (MODY) 9 gene. Both parents have the same but heterozygous mutation of PAX4 p.Arg192His, and pre-diabetic range of hyperglycemia. Conclusion: This is the first case demonstrating digenic inheritance of mutations in PCSK1 and CHD7 as a potential cause of normosmic hypogonadotrophic hypogonadism, interestingly in PAX4 homozygous diabetic male. Reference: (1) Maione L, et al. Genetic counseling for congenital hypogonadotropic hypogonadism and Kallmann syndrome: new challenges in the era of oligogenism and next-generation sequencing. Eur J Endocrinol. 2018;178(3):R55-R80.

SAT-LB5 Prevalence of Hypogonadism in Young Obese Males

Ageing, obesity, and chronic illness are major factors affecting serum testosterone (T) levels in men.The magnitude of the impact of ageing on serum T levels is well established, for obesity this is less clear. Severe obesity may lead to isolated hypogonadotropic hypogonadism (IHH). Several explanations have been offered to clarify the presence of reduced T levels in obese men. One relates to the technique that is generally employed to measure serum androgen levels, i.e. measurement of total testosterone (TT) instead of free testosterone (FT). TT represents the sum of FT and T bound to albumin and sex hormone binding globulin (SHBG). A profound reduction in SHBG level is commonly found in obese men, and this is a major factor causing a decrease in TT.Measurement of free testosterone levels may provide a more accurate assessment of androgen status than the (usually preferred) measurement of total testosterone in situations where SHBG levels are outside the reference range. However, reference ranges for free testosterone levels are not well established, especially in older men, and some have argued that the measurement of free testosterone levels merely reintroduces age in a covert form. This is a cross sectional study to estimate prevalence of hypogonadism in young obese males. In this study 147 young obese men participated, of which we confirmed low total testosterone (TT) levels in 35.37% of subjects with a p value of 0.06. Since only Total Testosterone was measured for categorizing subjects with or without hypogonadism, Free Testosterone measurement would be a better indicator for the diagnosis of hypogonadism as in cases where the total testosterone is borderline-low or when SHBG concentrations are abnormal. As such, the study is valuable in the context of the ongoing controversy as to whether testosterone treatment should be limited to men with classical hypogonadism, or be considered for appropriately selected men with functional hypogonadism as well. The principal findings are in general agreement with existing literature reporting correlation between levels of testosterone, body mass index and constitutional symptoms. However, this has never been shown before in context of Indian population. The present study was carried out at Armed Forces Medical College and Command Hospital, Pune between October 2017 to August 2019.We studied to see if there is association between testosterone levels and BMI. In our study we found no statistical association as the p value was 0.26 (>0.05)

MON-355 Charge Syndrome: Unusual Cause of Hypogonadism Leading to Osteoporosis

CHARGE syndrome is an unusual cause of hypogonadism; it is characterized by coloboma, heart defect, ateresia choanae, retarded growth and development, genital hypoplasia and ear anomalies. Two-thirds of affected patients have a mutation within the chromodomain helicase DNA-binding protein-7 gene, which is involved in embryonic development. The involvement of this gene in the pathogenesis of isolated idiopathic hypogonadotropic hypogonadism (HH) has been postulated. The reported incidence of this syndrome ranges from 0.1–0.2/10000 (1).A 24 year old female presented to our facility for further management of her HH and osteoporosis in the setting of her CHARGE syndrome. She was born full-term and diagnosed with this condition at the age of 6. Formal genetic testing as an adult demonstrated mutation within the CHD7 gene (chr 8:61,757,970). She had delayed puberty secondary to her hypogonadism; she was not treated with HRT as benefits were not considered significantly sufficient. She subsequently developed osteoporosis at the age of 20 which was treated at an outside facility with pamidronate IV Q4 months along with calcium and Vitamin D supplementation. Her initial Dual-energy X-ray absorptiometry (DXA) showed scoliosis in the lumbar spine [bone mass density (BMD): 0.514,osteoporosis by Z-score] with total hip showing BMD: 0.738,osteopenia by Z-score. Follow-up DXA after 3 years showed statistically significant improvement in bone mineralization of her L-spine [BMD: 0.595, +16%] and total hip [BMD: 0.777, +13.5%]. She presented to our facility in 2018 with labs showing normal calcium and 25-OH D; treatment with pamidronate was continued. She had a repeat DXA in 2019 which showed Z-scores of 0 in the left and right femoral necks. She was given the option of continued treatment for her osteoporosis versus monitoring and chose the latter with follow-up DXA.Hypogonadotropic hypogonadism is associated with delays in puberty or pubertal arrest. Luteinizing Hormone Releasing Hormone and HCG tests should be performed within the four months of life or at puberty in cases of hypogenitalism. GH deficiency should be investigated as a cause for growth retardation with GH stimulation levels. Hormone replacement is often required at puberty for females and is indicated for prevention of osteoporosis. Radiological testing with DXA scan should be included. Early proper endocrinological assessment and management is essential for adequate sexual development in these patients; this leads to improved overall quality of life along with prevention of serious morbidities, including bone demineralization (2).1. Blake K D, Prasad C. CHARGE syndrome. Orphanet Journal of Rare Diseases 2006, 1:34.2. Foppiani L, Maffe A. CHARGE syndrome as unusual cause of hypogonadism: endocrine and molecular evaluation. Andrologia (2010). 42: 326–330.

Prokineticin receptor 2 affects GnRH3 neuron ontogeny but not fertility in zebrafish

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.