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Pubertal timing is a highly heritable trait in the general population. Recently, a large-scale exome-wide association study has implicated rare variants in six genes (KDM4C, MC3R, MKRN3, PDE10A, TACR3, and ZNF483) as genetic determinants of pubertal timing within the general population. Two of the genes (TACR3, MKRN3) are already implicated in extreme disorders of pubertal timing. This observation suggests that there may be a pervasive "genetic risk continuum" wherein genes that govern pubertal timing in the general population, by extension, may also be causal for rare Mendelian disorders of pubertal timing. Hence, we hypothesized that the four novel genes linked to pubertal timing in the population will also contribute to idiopathic hypogonadotropic hypogonadism (IHH), a genetic disorder characterized by absent puberty. Exome sequencing data from 1322 unrelated IHH probands were reviewed for rare sequence variants (RSVs) (minor allele frequency bins: <1%; <0.1%; <0.01%) in the six genes linked to puberty in the general population. A gene-based rare variant association testing (RVAT) was performed between the IHH cohort and a reference public genomic sequences repository-the Genome Aggregation Database (gnomAD). As expected, RVAT analysis showed that RSVs in TACR3, a known IHH gene, were significantly enriched in the IHH cohort compared to gnomAD cohort across all three MAF bins. However, RVAT analysis of the remaining five genes failed to show any RSV enrichment in the IHH cohort across all MAF bins. Our findings argue strongly against a pervasive genetic risk continuum between pubertal timing in the general population and extreme pubertal phenotypes. The biologic basis of such distinct genetic architectures' merits further evaluation., (© 2024 British Society for Neuroendocrinology.)

Precision medicine requires precise genetic variant interpretation, yet many disease-associated genes have unresolved variants of unknown significance (VUS). We analyzed variants in a well-studied gene, FGFR1, a common cause of Idiopathic Hypogonadotropic Hypogonadism (IHH) and examined whether regional genetic enrichment of missense variants could improve variant classification. FGFR1 rare sequence variants (RSVs) were examined in a large cohort to (i) define regional genetic enrichment, (ii) determine pathogenicity based on the American College of Medical Genetics/Association for Molecular Pathology (ACMG/AMP) variant classification framework, and (iii) characterize the phenotype of FGFR1 variant carriers by variant classification. A total of 143 FGFR1 RSVs were identified in 175 IHH probands (n = 95 missense, n = 48 protein-truncating variants). FGFR1 missense RSVs showed regional enrichment across biologically well-defined domains: D1, D2, D3, and TK domains and linker regions (D2-D3, TM-TK). Using these defined regions of enrichment to augment the ACMG/AMP classification reclassifies 37% (20/54) of FGFR1 missense VUS as pathogenic or likely pathogenic (PLP). Non-proband carriers of FGFR1 missense VUS variants that were reclassified as PLP were more likely to express IHH or IHH-associated phenotypes [anosmia or delayed puberty] than non-proband carriers of FGFR1 missense variants that remained as VUS (76.9% vs 34.7%, p = 0.035). Using the largest cohort of FGFR1 variant carriers, we show that integration of regional genetic enrichment as moderate evidence for pathogenicity improves the classification of VUS and that reclassified variants correlated with phenotypic expressivity. The addition of regional genetic enrichment to the ACMG/AMP guidelines may improve clinical variant interpretation., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Idiopathic hypogonadotropic hypogonadism (IHH) is characterized by the absence of pubertal development and subsequent impaired fertility often due to gonadotropin-releasing hormone (GnRH) deficits. Exome sequencing of two independent cohorts of IHH patients identified 12 rare missense variants in POU6F2 in 15 patients. POU6F2 encodes two distinct isoforms. In the adult mouse, expression of both isoform1 and isoform2 was detected in the brain, pituitary, and gonads. However, only isoform1 was detected in mouse primary GnRH cells and three immortalized GnRH cell lines, two mouse and one human. To date, the function of isoform2 has been verified as a transcription factor, while the function of isoform1 has been unknown. In the present report, bioinformatics and cell assays on a human-derived GnRH cell line reveal a novel function for isoform1, demonstrating it can act as a transcriptional regulator, decreasing GNRH1 expression. In addition, the impact of the two most prevalent POU6F2 variants, identified in five IHH patients, that were located at/or close to the DNA-binding domain was examined. Notably, one of these mutations prevented the repression of GnRH transcripts by isoform1. Normally, GnRH transcription increases as GnRH cells mature as they near migrate into the brain. Augmentation earlier during development can disrupt normal GnRH cell migration, consistent with some POU6F2 variants contributing to the IHH pathogenesis., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Cho, Gurbuz, Stamou, Kotan, Farmer, Can, Tompkins, Mammadova, Altincik, Gokce, Catli, Bugrul, Bartlett, Turan, Balasubramanian, Yuksel, Seminara, Wray and Topaloglu.)

Isolated hypogonadotropic hypogonadism (IHH) is a rare disease with hypogonadism and infertility caused by the defects in embryonic migration of hypothalamic gonadotropin-releasing hormone (GnRH) neurons, hypothalamic GnRH secretion or GnRH signal transduction. PROKR2 gene, encoding a G-protein coupled receptor PROKR2, is one of the most frequently mutated genes identified in IHH patients. However, the functional consequences of several PROKR2 mutants remain elusive. In this study, we systematically analyzed the Gαq, Gαs and ERK1/2 signaling of 23 IHH-associated PROKR2 mutations which are yet to be functionally characterized. We demonstrate that blockage of Gαq, instead of MAPK/ERK pathway, inhibited PROK2-induced migration of PROKR2-expressing cells, implying that PROKR2-related IHH results primarily due to Gαq signaling pathway disruption. Combined with previous reports, we categorized a total of 63 IHH-associated PROKR2 mutations into four distinct groups according Gαq pathway functionality: (i) neutral (N, >80% activity); (ii) low pathogenicity (L, 50-80% activity); (iii) medium pathogenicity (M, 20-50% activity) and (iv) high pathogenicity (H, <20% activity). We further compared the cell-based functional results with in silico mutational prediction programs. Our results indicated that while Sorting Intolerant from Tolerant predictions were accurate for transmembrane region mutations, mutations localized in the intracellular and extracellular domains were accurately predicted by the Combined Annotation Dependent Depletion prediction tool. Our results thus provide a functional database that can be used to guide diagnosis and appropriate genetic counseling in IHH patients with PROKR2 mutations., (© The Author(s) 2023. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Context: Isolated hypogonadotropic hypogonadism (IHH) is phenotypically and genetically heterogeneous., Objective: This work aimed to determine the correlation between genotypic severity with pubertal and neuroendocrine phenotypes in IHH men., Methods: A retrospective study was conducted (1980-2020) examining olfaction (Kallmann syndrome [KS] vs normosmic IHH [nHH]), baseline testicular volume (absent vs partial puberty), neuroendocrine profiling (pulsatile vs apulsatile luteinizing hormone [LH] secretion), and genetic variants in 62 IHH-associated genes through exome sequencing (ES)., Results: In total, 242 men (KS: n = 131 [54%], nHH: n = 111 [46%]) were included. Men with absent puberty had significantly lower gonadotropin levels (P < .001) and were more likely to have undetectable LH (P < .001). Logistic regression showed partial puberty as a statistically significant predictor of pulsatile LH secretion (R2 = 0.71, P < .001, OR: 10.8; 95% CI, 3.6-38.6). Serum LH of 2.10 IU/L had a 95% true positive rate for predicting LH pulsatility. Genetic analyses in 204 of 242 IHH men with ES data available revealed 36 of 204 (18%) men carried protein-truncating variants (PTVs) in 12 IHH genes. Men with absent puberty and apulsatile LH were enriched for oligogenic PTVs (P < .001), with variants in ANOS1 being the predominant PTV in this genotype-phenotype association. Men with absent puberty were enriched for ANOS1 PTVs compared to partial puberty counterparts (P = .002). PTVs in other IHH genes imparted more variable reproductive phenotypic severity., Conclusion: Partial puberty and LH greater than or equal to 2.10 IU/L are proxies for pulsatile LH secretion. ANOS1 PTVs confer severe reproductive phenotypes. Variable phenotypic severity in the face of severe genetic variants in other IHH genes point to significant neuroendocrine plasticity of the HPG axis in IHH men., (© The Author(s) 2022. Published by Oxford University Press on behalf of the Endocrine Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Pathogenic SRY-box transcription factor 2 (SOX2) variants typically cause severe ocular defects within a SOX2 disorder spectrum that includes hypogonadotropic hypogonadism. We examined exome-sequencing data from a large, well-phenotyped cohort of patients with idiopathic hypogonadotropic hypogonadism (IHH) for pathogenic SOX2 variants to investigate the underlying pathogenic SOX2 spectrum and its associated phenotypes. We identified 8 IHH individuals harboring heterozygous pathogenic SOX2 variants with variable ocular phenotypes. These variant proteins were tested in vitro to determine whether a causal relationship between IHH and SOX2 exists. We found that Sox2 was highly expressed in the hypothalamus of adult mice and colocalized with kisspeptin 1 (KISS1) expression in the anteroventral periventricular nucleus of adult female mice. In vitro, shRNA suppression of mouse SOX2 protein in Kiss-expressing cell lines increased the levels of human kisspeptin luciferase (hKiss-luc) transcription, while SOX2 overexpression repressed hKiss-luc transcription. Further, 4 of the identified SOX2 variants prevented this SOX2-mediated repression of hKiss-luc. Together, these data suggest that pathogenic SOX2 variants contribute to both anosmic and normosmic forms of IHH, attesting to hypothalamic defects in the SOX2 disorder spectrum. Our study describes potentially novel mechanisms contributing to SOX2-related disease and highlights the necessity of SOX2 screening in IHH genetic evaluation irrespective of associated ocular defects.

Purpose: The study aimed to identify novel genes for idiopathic hypogonadotropic hypogonadism (IHH)., Methods: A cohort of 1387 probands with IHH underwent exome sequencing and de novo, familial, and cohort-wide investigations. Functional studies were performed on 2 p190 Rho GTPase-activating proteins (p190 RhoGAP), ARHGAP35 and ARHGAP5, which involved in vivo modeling in larval zebrafish and an in vitro p190A-GAP activity assay., Results: Rare protein-truncating variants (PTVs; n = 5) and missense variants in the RhoGAP domain (n = 7) in ARHGAP35 were identified in IHH cases (rare variant enrichment: PTV [unadjusted P = 3.1E-06] and missense [adjusted P = 4.9E-03] vs controls). Zebrafish modeling using gnrh3:egfp phenotype assessment showed that mutant larvae with deficient arhgap35a, the predominant ARHGAP35 paralog in the zebrafish brain, display decreased GnRH3-GFP+ neuronal area, a readout for IHH. In vitro GAP activity studies showed that 1 rare missense variant [ARHGAP35 p.(Arg1284Trp)] had decreased GAP activity. Rare PTVs (n = 2) also were discovered in ARHGAP5, a paralog of ARHGAP35; however, arhgap5 zebrafish mutants did not display significant GnRH3-GFP+ abnormalities., Conclusion: This study identified ARHGAP35 as a new autosomal dominant genetic driver for IHH and ARHGAP5 as a candidate gene for IHH. These observations suggest a novel role for the p190 RhoGAP proteins in GnRH neuronal development and integrity., Competing Interests: Conflict of Interest The authors declare no conflict of interest., (Copyright © 2022 American College of Medical Genetics and Genomics. All rights reserved.)

Objective: To study phenotype-genotype data of Asian-Indian Kallmann syndrome (KS) from our center and systematically review the studies analyzing multiple congenital hypogonadotropic hypogonadism (CHH) genes in KS cohorts using next-generation sequencing., Design, Patients, Measurement: Five hundred twenty-two KS probands (our center n = 78, published studies n = 444) were included in this systematic review. Molecular diagnosis was considered if the likely pathogenic/pathogenic variant in known CHH gene/s was reported in the appropriate allelic state. Varsome prediction tool (following American College of Medical Genetics standards) was used to analyze the variants., Result: For our center, the molecular diagnosis was seen in 20.5% of probands and was seen more often with severe than partial reproductive phenotype (28.3% vs. 4%, p = .0013). Our center data adds eight novel variants. The molecular diagnosis was seen in 31% as per the systematic review and analysis. It ranged from 16.6% to 72.2% at different centers. The affected genes were FGFR1 (9.8%), ANOS1 (7.5%), PROKR2 (6.1%), CHD7 (5.4%), oligogenic (2.1%), and others &lt;1% each (FGF8, SOX10, PROK2, SEMA3A, IL17RD, and GNRHR). FGFR1 and ANOS1 were the commonly affected genes globally, whereas PROKR2 was commonest in studies from China and CHD7 from Japan, South Korea and Poland., Conclusion(s): This systematic review highlights that the genetic yield is 31% in KS probands, with distinct regional variations. The association of severe reproductive phenotype with the higher genetic yield needs further validation., (© 2022 John Wiley & Sons Ltd.)

Congenital hypogonadotropic hypogonadism (HH) is a heterogeneous genetic disorder characterized by disrupted puberty and infertility. In most cases, HH is abiding yet 10-15% undergo reversal. Men with HH and absent and partial puberty (i.e., testicular volume <4mL and >4mL respectively) have been well-studied, but the rare fertile eunuch (FE) variant remains poorly characterized. This natural history study of 240 men with HH delineates the clinical presentation, neuroendocrine profile, rate of reversal and genetics of the FE variant. We compared three HH groups: FE (n=38), absent puberty (n=139), and partial puberty (n=63). The FE group had no history of micropenis and 2/38 (5%) had cryptorchidism ( p <0.0001 vs. other groups). The FE group exhibited higher rates of detectable gonadotropins, higher mean LH/FSH levels, and higher serum inhibin B levels (all p <0.0001). Neuroendocrine profiling showed pulsatile LH secretion in 30/38 (79%) of FE men ( p <0.0001) and 16/36 (44%) FE men underwent spontaneous reversal of HH ( p <0.001). The FE group was enriched for protein-truncating variants (PTVs) in GNRHR and FGFR1 and 4/30 (13%) exhibited oligogenic PTVs. Findings suggest men with the FE variant exhibit the mildest neuroendocrine defects of HH men and the FE sub-type represents the first identified phenotypic predictor for reversible HH., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Dwyer, Stamou, McDonald, Anghel, Cox, Salnikov, Plummer, Seminara and Balasubramanian.)

Context: The genetic architecture of isolated hypogonadotropic hypogonadism (IHH) has not been completely defined., Objective: To determine the role of copy number variants (CNVs) in IHH pathogenicity and define their phenotypic spectrum., Methods: Exome sequencing (ES) data in IHH probands (n = 1394) (Kallmann syndrome [IHH with anosmia; KS], n = 706; normosmic IHH [nIHH], n = 688) and family members (n = 1092) at the Reproductive Endocrine Unit and the Center for Genomic Medicine of Massachusetts General Hospital were analyzed for CNVs and single nucleotide variants (SNVs)/indels in 62 known IHH genes. IHH subjects without SNVs/indels in known genes were considered "unsolved." Phenotypes associated with CNVs were evaluated through review of patient medical records. A total of 29 CNVs in 13 genes were detected (overall IHH cohort prevalence: ~2%). Almost all (28/29) CNVs occurred in unsolved IHH cases. While some genes (eg, ANOS1 and FGFR1) frequently harbor both CNVs and SNVs/indels, the mutational spectrum of others (eg, CHD7) was restricted to SNVs/indels. Syndromic phenotypes were seen in 83% and 63% of IHH subjects with multigenic and single gene CNVs, respectively., Conclusion: CNVs in known genes contribute to ~2% of IHH pathogenesis. Predictably, multigenic contiguous CNVs resulted in syndromic phenotypes. Syndromic phenotypes resulting from single gene CNVs validate pleiotropy of some IHH genes. Genome sequencing approaches are now needed to identify novel genes and/or other elusive variants (eg, noncoding/complex structural variants) that may explain the remaining missing etiology of IHH., (© The Author(s) 2022. Published by Oxford University Press on behalf of the Endocrine Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Purpose: To describe phenotype-genotype data of Asian-Indian normosmic congenital hypogonadotropic hypogonadism (nCHH) from our centre and perform a systematic review of genetic studies using next-generation sequencing (NGS) in nCHH., Methods: Sixty-eight nCHH probands from our center, and 370 nCHH probands from published studies were included. Per-patient genetic variants were analyzed as per ACMG guidelines. Molecular diagnosis was defined as presence of a pathogenic or likely pathogenic variant in a known CHH gene following zygosity status as per known mode of genetic inheritance., Result: At our centre molecular diagnosis was observed in 35.3% of probands {GNRHR:16.2%, FGFR1:7.3%, KISS1R:4.4%, GNRH1:2.9%, TACR3:2.9%, CHD7:1.4%}. Molecular diagnosis was observed more often (44.7% vs 14.3%, p = 0.026) with severe than partial reproductive-phenotype. The study adds 12 novel variants and suggests GNRHR p.Thr32Ala variant may have a founder effect. In per-patient systematic review (including our cohort), the molecular diagnosis was reached in 23.2%, ranging from 3.5 to 46.7% at different centers. The affected genes were FGFR1:6.4%, GNRHR:4.3%, PROKR2:3.6%, TACR3:1.8%, CHD7:1.6%, KISS1R:1.4%, GNRH1:1.4% and others (PROK2, SOX3, SOX10, SOX11, IL17RD, IGSF10, TAC3, ANOS1, oligogenic): < 1% each. FGFR1 was the most commonly affected gene in most cohorts except Asia, whereas PROKR2 (in China and Japan) and GNRHR (in India) were the commonest., Conclusion: (s): The global molecular diagnosis rate was 23.2% in nCHH cohorts whereas that in our cohort was 35% with a higher rate (44.7%) in those with severe reproductive-phenotype. The most commonly affected gene in nCHH patients was FGFR1 globally while it was PROKR2 in East Asia and GNRHR in India., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background and Aims: Budd Chiari syndrome (BCS) commonly affects adolescents and adults. With improved survival, important quality-of-life parameters such as sexual life and fertility become more relevant. This study was aimed to assess the gonadal function in male patients with BCS and the effect of treatment on gonadal function., Methods: Thirty male patients with newly diagnosed BCS were prospectively assessed for the presence of gonadal dysfunction. Erectile function was assessed using standardized International Index of Erectile Function questionnaire (IIEF). Follicular stimulating hormone (FSH), luteinizing hormone (LH), sex hormone-binding globulin (SHBG), estradiol, total testosterone (TT), calculated free testosterone (cFT), calculated bioavailable testosterone (cBT), sperm count, and sperm motility were compared at baseline and at 6 months of treatment for the assessment of gonadal function., Results: Sixteen (53.3%) out of 30 patients were sexually active at the time of study and 5/16 (31%) had erectile dysfunction. Hypogonadotropic hypogonadism (HH) was the most common pattern seen in 50% cases followed by hypergonadotropic hypogonadism (HyH) in 23% cases. 27% patients had eugonadism. At 6 months of treatment, 60% of patients in HH group became eugonadal as compared to only 14% in HyH group. Proportion of patients with erectile dysfunction reduced (5/16 vs 1/16) after 6 months of therapy. The improvement in sperm count and sperm motility was not significant., Conclusion: Gonadal dysfunction is common in male patients with BCS. HH remains the most common type of hypogonadism BCS and the type which improves significantly after treatment., (© 2022. Asian Pacific Association for the Study of the Liver.)

Objective: As GNRH1 genotype-phenotype correlation in CHH is not well studied, we aim to describe the GNRH1 variants in our CHH cohort and present a systematic review as well as genotype-phenotype analysis of all mutation-positive cases reported in the world literature., Design: This is a retrospective study of GNRH1 mutation-positive patients from a western Indian center. PRISMA guidelines-based PubMed search of the published literature of all GNRH1 mutation-positive patients was conducted., Setting: This study was conducted in an academic medical center., Patient(s): This study included 2 probands from our cohort and 19 probands from the world literature., Main Outcome Measure(s): Demographic details, clinical presentation, biochemistry, imaging, treatment details, and genotypic data were recorded., Result(s): Two probands in our cohort carried two novel pathogenic biallelic GNRH1 variants (p.Glu24Leu, c.238-2A>G). Both had a severe reproductive phenotype. We report successful gonadotropin therapy and fertility in 1 proband. We included 19 probands from 12 studies after the literature review. Ten CHH probands (inclusive 2 from this study) with biallelic GNRH1 variants had severe reproductive phenotype, low gonadotropin levels, low/normal prolactin, normal pituitary imaging, and no extra-reproductive phenotype. Of seven biallelic variants reported, three were frameshift, two were splice-site, and two were missense mutations. All of them were pathogenic/likely pathogenic without oligogenicity. Of seven monoallelic GNRH1 variants reported in 11 probands, 4 had nonreproductive phenotype, 3 were benign/likely benign, and 4 were oligogenic., Conclusion(s): GNRH1 biallelic variants lead to severe reproductive phenotype, with low gonadotropin levels without nonreproductive features or oligogenicity. However, the role of GNRH1 monoallelic variants in CHH pathophysiology for reported variants remains questionable., (© 2021 S. Karger AG, Basel.)

Objective: To study the effect of prior testosterone replacement therapy (TRT) on the spermatogenic response to combined gonadotropin therapy (CGT) in severe and partial phenotype congenital hypogonadotropic hypogonadism (CHH) patients., Design: Retrospective cohort study., Setting: Tertiary care center., Patients: Patients of CHH without (n = 17) and with prior TRT (n = 18) were subdivided into severe and partial groups, based on mean testicular volume ≤ 3 cc and > 3 cc respectively., Intervention: Participants were treated with hMG at a dose of 75-150 U 3/week and gradually escalating doses of hCG until maximum dose (2000 U 3/week or 5000 U 2/week) or serum total testosterone of ≥ 3.5 ng/ml was reached., Main Outcome Measures: Final mean TV, trough serum testosterone (T), sperm concentration RESULTS: Thirty-five patients (20 severe, baseline mean TV of 3.6 ± 2.7 ml) were started on CGT at 24.8 ± 6.1 years. The median duration of prior TRT was 38 (IQR 10-63.75) months in the exposed group. After 33 ± 12 months, final mean TV was 8.9 ± 5.5 ml, 86% achieved serum testosterone > 3.5 ng/ml and 70% achieved spermatogenesis [median 5 (0-12.6) million/ml]. Patients without prior TRT had significantly higher peak sperm count than those with prior- TRT (median 9 vs 0.05 million/ml, p = 0.004). This effect of prior TRT was more pronounced in severe phenotype patients (median 7 vs 0 million/ml, p = 0.01)., Conclusion: Prior-TRT may interfere with spermatogenic response to CGT in CHH patients, especially in those with a severe phenotype.

Objectives: To study the effect of combined gonadotropin therapy (CGT) on testicular descent ± spermatogenesis in congenital hypogonadotropic hypogonadism (CHH) patients with cryptorchidism beyond infancy., Methods: This retrospective cohort study included CHH patients with cryptorchidism [bilateral (n=5) or unilateral (n=1)] treated with CGT for testicular descent ± pubertal induction. All participants were treated with CGT [human menopausal gonadotropin (hMG) and human chorionic gonadotropin (hCG)] with hMG pretreatment in three and monitored for changes in testicular volume (TV), serum total testosterone (T), serum inhibin-B, and sperm concentration., Results: Complete testicular descent to the scrotal position was achieved in 5/6 patients (10/11 testes) after 4.7 ± 1.6 months of treatment. There was 44 ± 18%, 97.5% (IQR: 44-195), 10-fold (IQR: 3-19.6), and two-fold (IQR: 1.7-9.3) increase in stretched penile length, ultrasound measured TV, T level, and serum inhibin-B from baseline, respectively. In two pediatric cases, testicular descent occurred with isolated hMG therapy. At the last follow up (median: 23.5, IQR: 10.5-38.7 months), all the descended testes remained in scrotal position. In four pubertal/postpubertal age patients, continuous CGT (18-60 months) yielded T and inhibin-B levels of 16.64 ± 1.46 nmol/l and 106 ± 32.6 pg/mL, respectively. All the three patients with available semen analysis had sperm concentration of ≥5 million/mL and one of them achieved paternity., Conclusions: A trial of CGT before orchiopexy may be considered in CHH males with cryptorchidism even beyond the narrow age-window of infancy. CGT may also have beneficial effects on future spermatogenesis and fertility outcomes in these patients., (© 2021 Walter de Gruyter GmbH, Berlin/Boston.)

Purpose: SOX10 variants previously implicated in Waardenburg syndrome (WS) have now been linked to Kallmann syndrome (KS), the anosmic form of idiopathic hypogonadotropic hypogonadism (IHH). We investigated whether SOX10-associated WS and IHH represent elements of a phenotypic continuum within a unifying disorder or if they represent phenotypically distinct allelic disorders., Methods: Exome sequencing from 1,309 IHH subjects (KS: 632; normosmic idiopathic hypogonadotropic hypogonadism [nIIHH]: 677) were reviewed for SOX10 rare sequence variants (RSVs). The genotypic and phenotypic spectrum of SOX10-related IHH (this study and literature) and SOX10-related WS cases (literature) were reviewed and compared with SOX10-RSV spectrum in gnomAD population., Results: Thirty-seven SOX10-associated IHH cases were identified as follows: current study: 16 KS; 4 nIHH; literature: 16 KS; 1 nIHH. Twenty-three IHH cases (62%; all KS), had ≥1 known WS-associated feature(s). Moreover, five previously reported SOX10-associated WS cases showed IHH-related features. Four SOX10 missense RSVs showed allelic overlap between IHH-ascertained and WS-ascertained cases. The SOX10-HMG domain showed an enrichment of RSVs in disease states versus gnomAD., Conclusion: SOX10 variants contribute to both anosmic (KS) and normosmic (nIHH) forms of IHH. IHH and WS represent SOX10-associated developmental defects that lie along a unifying phenotypic continuum. The SOX10-HMG domain is critical for the pathogenesis of SOX10-related human disorders.

Context: Data are limited regarding prevalence, predictors, and mechanisms of persistent hypogonadotropic hypogonadism (HH) in males with a macroprolactinoma who achieve normoprolactinemia on dopamine-agonist therapy. None of the previous studies provide cutoffs to predict the achievement of eugonadism., Objective: The objective of this work is to evaluate the prevalence of persistent HH and its determinants in men with a macroprolactinoma who achieve normoprolactinemia on cabergoline monotherapy., Design and Setting: This retrospective study with prospective cross-sectional evaluation took place at a tertiary health care center., Patients: Study participants included men with a macroprolactinoma and baseline HH who achieved normoprolactinemia on cabergoline monotherapy., Main Outcome Measures: Outcome measures of this study included the prevalence of persistent HH and its predictors., Results: Thirty participants (age, 38.3 ± 10.1 years) with baseline tumor size of 4.08 ± 1.48 cm and median (interquartile range) prolactin of 2871 ng/mL (range, 1665-8425 ng/mL) were included. Eight of 30 participants achieved eugonadism after a median follow-up of 3 years. Patients with persistent HH had suppression of the luteinizing hormone (LH)-testosterone axis with sparing of other anterior pituitary hormonal axes, including follicle-stimulating hormone-inhibin B. Baseline prolactin (1674 vs 4120 ng/mL; P = .008) and maximal tumor diameter (2.55 ± 0.36 vs 4.64 ± 1.32 cm; P = .003) were lower in patients who achieved eugonadism. Baseline maximal tumor diameter less than or equal to 3.2 cm (sensitivity: 75%, specificity: 63.6%) and serum prolactin less than or equal to 2098 ng/mL (sensitivity: 87.5%, specificity: 77.3%) best predicted reversal of HH., Conclusion: Recovery of the LH-testosterone axis occurred in 26.7% of men with a macroprolactinoma who achieved normoprolactinemia on cabergoline monotherapy. Higher baseline tumor size and serum prolactin predict persistent HH. Our data favor chronic functional modification of the hypothalamic-pituitary-gonadal axis over gonadotroph damage as the cause of persistent HH., (© Endocrine Society 2020. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Biallelic pathogenic variants in RAB3GAP2 cause Warburg Micro syndrome (WARBM) and Martsolf syndrome (MS), two rare, phenotypically overlapping disorders characterized by congenital cataracts, intellectual disability, and hypogonadism. Although the initial report documented hypergonadotropic hypogonadism (implying a gonadal defect), an adolescent girl with WARBM/MS was subsequently reported to have hypogonadotropic hypogonadism (implying a central defect in either the hypothalamus or anterior pituitary). However, in adult MS, hypogonadotropism has not been convincingly demonstrated. Additionally, the correlation between the pathogenic severity of variants in RAB3GAP2 and the phenotypic severity also remains unclear. Here we present a clinical report of a woman with congenital cataracts, apparent intellectual disability, and pubertal failure who underwent exome sequencing (ES) to determine a precise molecular diagnosis. Reproductive phenotypes reported previously in individuals with MS and the genotypic spectrum of previous RAB3GAP2 variants were also reviewed. The ES identified pathogenic compound heterozygous RAB3GAP2 variants (c.387-2A > G; p.(Arg428Glu)) combined with her phenotypic features, which enabled a unifying molecular diagnosis of MS. Reproductive evaluation confirmed a normosmic idiopathic hypogonadotropic hypogonadism. Review of the RAB3GAP2 allelic spectrum in WARBM/MS suggests that although variants resulting in complete abrogation of RAB3GAP2 protein function cause severe WARBM, variants associated with partially preserved RAB3GAP2 function cause milder MS. This report expands the genotypic and phenotypic spectrum of MS and demonstrates hypogonadotropic hypogonadism as a key pathophysiologic abnormality in MS. Genotype-phenotype associations of previously reported RAB3GAP2 variants indicate that variants that fully abolish RAB3GAP2 function result in WARBM, whereas MS is associated with variants of lesser severity with residual RAB3GAP2 function., (© 2020 Xu et al.; Published by Cold Spring Harbor Laboratory Press.)

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., (Copyright © 2019 Endocrine Society.)

Context: Loss of prokineticin 2 (PROK2) signaling in mice disrupts circadian rhythms, but the role of PROK2 signaling in the regulation of circadian rhythms in humans is undetermined., Objective: The aim of the study was to examine the circadian rhythms of humans with a complete loss-of-function PROK2 mutation using an inpatient constant routine (CR) protocol., Design and Setting: We conducted a case study in an academic medical center., Subjects and Methods: Two siblings (one male and one female, ages 67 and 62 y, respectively) with isolated GnRH deficiency (IGD) due to a biallelic loss-of-function PROK2 mutation were studied using an inpatient CR protocol. Historical data from inpatient CR protocols conducted in healthy controls (ages 65-81 y) were used for comparison., Main Outcome Measures: We measured circadian phase markers (melatonin, cortisol, and core body temperature) and neurobehavioral performance (psychomotor vigilance task [PVT] and subjective alertness scale)., Results: Circadian waveforms of melatonin and cortisol did not differ between the IGD participants with PROK2 mutation and controls. In both IGD participants, neurobehavioral testing with PVT showed disproportionate worsening of PVT lapses and median reaction time in the second half of the CR., Conclusions: Humans with loss of PROK2 signaling lack abnormalities in circadian phase markers, indicating intact central circadian pacemaker activity in these patients. These results suggest that PROK2 signaling in humans is not required for central circadian pacemaker function. However, impaired PVT in the PROK2-null participants despite preserved endocrine rhythms suggests that PROK2 may transmit circadian timing information to some neurobehavioral neural networks.

Context: A subset of patients diagnosed with idiopathic hypogonadotropic hypogonadism (IHH) later achieves activation of their hypothalamic-pituitary-gonadal axis with normalization of steroidogenesis and/or gametogenesis, a phenomenon termed reversal., Objective: The objective of this study was to determine the natural history of reversal and to identify associated phenotypes and genotypes., Design, Setting, and Subjects: This was a retrospective review of clinical, biochemical, and genetic features of patients with IHH evaluated at an academic medical center., Main Outcome Measures: History of spontaneous fertility, regular menses, testicular growth, or normalization of serum sex steroids, LH secretory profiles, brain imaging findings, and sequences of 14 genes associated with IHH were reviewed., Results: Of 308 patients with IHH, 44 underwent reversal. Time-to-event analysis estimated a lifetime incidence of reversal of 22%. There were no differences in the rates of cryptorchidism, micropenis, or partial pubertal development in patients with reversal vs IHH patients without reversal. Fifteen patients with reversal (30%) had Kallmann syndrome (IHH and anosmia); one had undetectable olfactory bulbs on a brain magnetic resonance imaging scan. Subjects with reversal were enriched for mutations affecting neurokinin B signaling compared with a cohort of IHH patients without reversal (10% vs 3%, P = .044), had comparable frequencies of mutations in FGFR1, PROKR2, and GNRHR, and had no mutations in KAL1. Five men did not sustain their reversal and again developed hypogonadotropism., Conclusions: Reversal of IHH may be more widespread than previously appreciated and occurs across a broad range of genotypes and phenotypes. Enrichment for mutations that disrupt neurokinin B signaling in patients who reversed indicates that, despite the importance of this signaling pathway for normal pubertal timing, its function is dispensable later in life. The occurrence of reversal in a patient with no olfactory bulbs demonstrates that these structures are not essential for normal reproductive function. Patients with IHH require lifelong monitoring for reversal and, if reversal occurs, subsequent relapse also may occur.

Context: The olfactory phenotype in patients with idiopathic hypogonadotropic hypogonadism (IHH) ranges from complete anosmia (Kallmann syndrome) to normosmia (normosmic IHH). However, the true prevalence of intermediary olfactory phenotypes (hyposmia) in IHH patients has not yet been assessed, and systematic correlations with anatomical and genetic abnormalities have not been reported., Objective: The objective of this study was to evaluate olfactory function in a large IHH cohort and correlate these findings with olfactory magnetic resonance imaging (MRI) and underlying genetic etiology., Design and Setting: We conducted a cross-sectional case-control study at an academic referral center., Patients: A total of 286 IHH patients (201 males and 85 females) and 2183 healthy historic controls (1011 males and 1172 females) were studied., Main Outcome Measures: We measured olfactory function using the University of Pennsylvania Smell Identification Test; in 208 subjects, the genetic etiology of IHH was ascertained by DNA sequencing; in a minor subset [39 of 286 subjects (13%)], olfactory structures were determined by MRI., Results: In the IHH cohort, 31.5% were anosmic, 33.6% were hyposmic, and 34.9% were normosmic. Most hyposmic (seven of 11) subjects with MRI data exhibited olfactory structure abnormalities. Of hyposmic subjects, 39.5% harbored mutations in genes involved in either GnRH neuronal migration or GnRH secretion., Conclusions: IHH subjects display a broad spectrum of olfactory function, with a significant hyposmic phenotype in nearly one third of subjects. The hyposmic subjects harbor mutations in genes affecting GnRH neuronal migration and its secretion, suggesting a pathophysiological overlap between Kallmann syndrome and normosmic IHH. Accurate olfactory phenotyping in IHH subjects will inform the pathophysiology of this condition and guide genetic testing.