Search

Context Functional hypothalamic amenorrhea (HA) is a common, acquired form of hypogonadotropic hypogonadism that occurs in the setting of energy deficits and/or stress. Variability in individual susceptibility to these stressors, HA heritability, and previous identification of several rare sequence variants (RSVs) in genes associated with the rare disorder, isolated hypogonadotropic hypogonadism (IHH), in individuals with HA suggest a possible genetic contribution to HA susceptibility. Objective We sought to determine whether the burden of RSVs in IHH-related genes is greater in women with HA than controls. Design We compared patients with HA to control women. Setting The study was conducted at secondary referral centers. Patients and Other Participants Women with HA (n = 106) and control women (ClinSeq study; n = 468). Interventions We performed exome sequencing in all patients and controls. Main Outcome Measure(s) The frequency of RSVs in 53 IHH-associated genes was determined using rare variant burden and association tests. Results RSVs were overrepresented in women with HA compared with controls (P = .007). Seventy-eight heterozygous RSVs in 33 genes were identified in 58 women with HA (36.8% of alleles) compared to 255 RSVs in 41 genes among 200 control women (27.2%). Conclusions Women with HA are enriched for RSVs in genes that cause IHH, suggesting that variation in genes associated with gonadotropin-releasing hormone neuronal ontogeny and function may be a major determinant of individual susceptibility to developing HA in the face of diet, exercise, and/or stress.

Purpose Impaired function of gonadotropin-releasing hormone (GnRH) neurons can cause a phenotypic spectrum ranging from delayed puberty to isolated hypogonadotropic hypogonadism (IHH). We sought to identify a new genetic etiology for these conditions. Methods Exome sequencing was performed in an extended family with autosomal dominant, markedly delayed puberty. The effects of the variant were studied in a GnRH neuronal cell line. Variants in the same gene were sought in a large cohort of individuals with IHH. Results We identified a rare missense variant (F900V) in DLG2 (which encodes PSD-93) that co-segregated with the delayed puberty. The variant decreased GnRH expression in vitro. PSD-93 is an anchoring protein of NMDA receptors, a type of glutamate receptor that has been implicated in the control of puberty in laboratory animals. The F900V variant impaired the interaction between PSD-93 and a known binding partner, Fyn, which phosphorylates NMDA receptors. Variants in DLG2 that also decreased GnRH expression were identified in 3 unrelated families with IHH. Conclusion The findings indicate that variants in DLG2/PSD-93 cause autosomal dominant delayed puberty and may also contribute to IHH. The findings also suggest that the pathogenesis involves impaired NMDA receptor signaling and consequently decreased GnRH secretion.

Context Loss-of-function mutations in the imprinted genes MKRN3 and DLK1 cause central precocious puberty (CPP) but whole gene deletions have not been reported. Larger deletions of the chromosome 15q11-13 imprinted locus, including MKRN3, cause Prader-Willi syndrome (PWS). CPP has been reported in PWS but is not common, and the role of MKRN3 in PWS has not been fully elucidated. Objective To identify copy number variants in puberty-related, imprinted genes to determine their role in CPP. Methods Probands with idiopathic CPP had chromosomal microarray (CMA) and targeted deletion/duplication testing for MKRN3 and DLK1. Results Sixteen female probands without MKRN3 or DLK1 variants identified by Sanger sequencing were studied. Whole gene deletions of MKRN3 were identified in 2 subjects (13%): a complete deletion of MKRN3 in Patient A (pubertal onset at 7 years) and a larger deletion involving MAGEL2, MKRN3, and NDN in Patient B (pubertal onset 5.5 years). Both were paternally inherited. Patient B had no typical features of PWS, other than obesity, which was also present in her unaffected family. Conclusions We identified 2 cases of whole gene deletions of MKRN3 causing isolated CPP without PWS. This is the first report of complete deletions of MKRN3 in patients with CPP, emphasizing the importance of including copy number variant analysis for MKRN3 mutation testing when a genetic diagnosis is suspected. We speculate that there is a critical region of the PWS locus beyond MKRN3, MAGEL2, and NDN that is responsible for the PWS phenotype.

Knockout mice for the kisspeptin receptor, Kiss1r (Kiss1r−/−) and its ligand kisspeptin, Kiss1 (Kiss1−/−) replicate the phenotype of isolated hypogonadotropic hypogonadism (IHH) associated with variants of these genes in humans. A recent report suggests that kisspeptin may be involved in human fetal adrenocortical development and function. Herein, we characterized the adrenal function and morphology in Kiss1−/− mice that do not go through normal puberty. Two fetal markers were expressed in eosinophilic cells potentially derived from the X-zone that should disappear at puberty in male mice and during the first pregnancy in female animals. Although the hypercorticosteronism observed in Kiss1−/− females corrected overtime, hyperaldosteronism persisted at 14 months and correlated with the overexpression of Star. To determine if KISS1 and KISS1R genes are involved in the development of primary aldosteronism (PA) and hypercortisolism [Cushing’s syndrome (CS)] in humans, we sequenced these 2 genes in 65 patients with PA and/or CS. Interestingly, a patient with CS presented with a germline KISS1 variant (p.H90D, rs201073751). We also found three rare variants in the KISS1R gene in three patients with PA: p.C95W (rs141767649), p.A189T (rs73507527) and p.R229R (rs115335009). The two missense variants have been previously associated with IHH. Our findings suggest that KISS1 may play a role in adrenal function in mice and possibly adrenocortical steroid hormone secretion in humans, beyond its recently described role in human fetal adrenocortical development.

Sex hormone–binding globulin (SHBG) in the blood is a major determinant of bioactivity for key sex steroids such as testosterone and estradiol. Low serum levels of SHBG have been associated with obesity, polycystic ovaries, and metabolic syndrome, and other states associated with hyperandrogenemia. A 9-year, 6-month-old girl presented with a history of peripheral precocious puberty and aggressive behavior. The patient’s SHBG level was remarkably low for her age, at less than 5 nmol/L (reference range for a girl with a bone age of 10 years, 73 nmol/L [SEM = 10]) [1]. On genetic and protein analysis, the patient was found to have a homozygous missense potentially pathogenic variant in the SHBG gene (c.554C>T, p.P185L); her parents were asymptomatic heterozygote carriers. Laboratory investigations supported the possible involvement of this genetic alteration in the patient’s phenotype. Various analyses of this variant support its pathogenicity, although the exact mechanism remains unclear. In conclusion, we present a genetic SHBG variant in the homozygote state that may have been associated with gonadotropin-independent precocious puberty in a young girl.

Ovarian estrogens may influence the development of the human brain and behavior, but there are few opportunities to test this possibility. Isolated GnRH deficiency (IGD) is a rare endocrine disorder that could provide evidence for the role of estrogens in organizing sexually differentiated phenotypes: Unlike typical development, development in individuals with IGD is characterized by low or absent gonadal hormone production after the first trimester of gestation. Because external genitalia develop in the first trimester, external appearance is nevertheless concordant with gonadal sex in people with IGD. We therefore investigated the effects of gonadal hormones on sexual orientation by comparing participants with IGD (n = 97) to controls (n = 1670). Women with IGD reported lower male-attraction compared with typically developing women. In contrast, no consistent sexuality differences between IGD and typically developing men were evident. Ovarian hormones after the first trimester appear to influence female-typical dimensions of sexual orientation.

Context Individuals with idiopathic hypogonadotropic hypogonadism (IHH), even those with evidence of some hypothalamic reproductive endocrine activity, fail to complete puberty and fail to respond to physiologic doses of kisspeptin. Objective This case series examined whether treatment with sex steroids could stimulate kisspeptin responsiveness in patients with IHH. Design This was a case series. Setting This study was conducted at an academic medical center. Participants Seven patients with IHH were studied. Interventions Participants, both on and off sex steroid therapy, underwent frequent blood sampling to measure LH at baseline, in response to kisspeptin and GnRH. Main outcome measures The main outcome measure was LH responses to kisspeptin on and off sex steroids. Results All participants responded to exogenous GnRH, but no participant responded to exogenous kisspeptin. Sex steroid treatment did not modify responsiveness to kisspeptin. Conclusions The functional impairment of the GnRH neuronal network in patients with IHH, as evidenced by their inability to respond to a physiologic dose of kisspeptin, is observed in both sex steroid- deficient and sex steroid-replete states. In this case series, a normalized sex steroid milieu does not appear capable of overcoming the kisspeptin resistance of these patients.

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.

Context The reproductive axis is controlled by a network of gonadotropin-releasing hormone (GnRH) neurons born in the primitive nose that migrate to the hypothalamus alongside axons of the olfactory system. The observation that congenital anosmia (inability to smell) is often associated with GnRH deficiency in humans led to the prevailing view that GnRH neurons depend on olfactory structures to reach the brain, but this hypothesis has not been confirmed. Objective The objective of this work is to determine the potential for normal reproductive function in the setting of completely absent internal and external olfactory structures. Methods We conducted comprehensive phenotyping studies in 11 patients with congenital arhinia. These studies were augmented by review of medical records and study questionnaires in another 40 international patients. Results All male patients demonstrated clinical and/or biochemical signs of GnRH deficiency, and the 5 men studied in person had no luteinizing hormone (LH) pulses, suggesting absent GnRH activity. The 6 women studied in person also had apulsatile LH profiles, yet 3 had spontaneous breast development and 2 women (studied from afar) had normal breast development and menstrual cycles, suggesting a fully intact reproductive axis. Administration of pulsatile GnRH to 2 GnRH-deficient patients revealed normal pituitary responsiveness but gonadal failure in the male patient. Conclusions Patients with arhinia teach us that the GnRH neuron, a key gatekeeper of the reproductive axis, is associated with but may not depend on olfactory structures for normal migration and function, and more broadly, illustrate the power of extreme human phenotypes in answering fundamental questions about human embryology.

Background: Kallmann Syndrome (KS) is characterized by hypogonadotropic hypogonadism (HH) due to isolated GnRH deficiency (IGD) and anosmia. While reversal of KS has been described, predominantly in males, few cases have been described in females. We report a female with KS who demonstrated spontaneous recovery of her HPG axis. Case Report: A 34-year-old woman with a history of KS was referred to the NIH Clinical Center for evaluation. She was evaluated for absent thelarche and primary amenorrhea at age 18 when, due to her history of vigorous exercise and low BMI, she was assumed to have hypothalamic amenorrhea. At age 22, she was first noted to be anosmic by her endocrinologist who diagnosed her with KS. She underwent bilateral breast augmentation, and oral contraceptive pills (OCPs) induced regular menstrual bleeding. OCPs were self-discontinued after 1 year and amenorrhea recurred. By her late 20s, her level of exercise had decreased and her BMI normalized. She reported 3 episodes of spontaneous menstrual spotting in the six months preceding her visit, cyclical but irregular breast tenderness and emotional lability in the absence of hormonal treatment. Her medications included only fluoxetine. Physical examination revealed a BMI of 19.1 kg/m2, bilateral breast implants, a high-arched palate and bilateral fifth digit clinodactyly. Her laboratory evaluation revealed a serum LH of 8 U/L, FSH of 9 U/L and E2 of 19 pg/mL; all other anterior pituitary hormones were normal. Frequent blood sampling revealed a high-frequency pattern of LH pulsatility (24 pulses/24 hrs) with sleep augmentation and mean LH of 6.8 U/L. Formal smell testing confirmed anosmia. Her pelvic ultrasound revealed normal ovaries with follicles and normal uterus with a 4 mm endometrial stripe. A brain MRI was normal except for absent olfactory bulbs. Clinical testing of 14 IGD genes showed a novel heterozygous ANOS1 variant (c.298C>A p.Q100K) of unknown significance that was also present in her unaffected mother. A maternal half-uncle was reportedly anosmic but is now deceased. Discussion: This KS female exhibited spontaneous recovery of her HPG axis, which has been reported in very few cases. Her olfactory bulb aplasia is consistent with a congenital defect in GnRH neuronal development given their common ontogeny, suggesting that her HH and recovery were not simply due to changes in body weight nor exercise. Although females with heterozygous ANOS1 variants have been reported to demonstrate features of HH, the role of this novel ANOS1 variant remains unclear due lack of functional data and the presence of the same variant in her asymptomatic mother. Conclusions: Reversal of the reproductive phenotype in women with KS is rare with little known about their genetic abnormalities and long-term outcomes. Further study of such cases is warranted to gain insight into the mechanisms required for activation of the HPG axis.

Experiments in male rodents demonstrate that sensitivity to the organizational effects of steroid hormones decreases across the pubertal window, with earlier androgen exposure leading to greater masculinization of the brain and behavior. Similarly, some research suggests the timing of peripubertal exposure to sex steroids influences aspects of human psychology, including visuospatial cognition. However, prior studies have been limited by small samples and/or imprecise measures of pubertal timing. We conducted 4 studies to clarify whether the timing of peripubertal hormone exposure predicts performance on male-typed tests of spatial cognition in adulthood. In Studies 1 (n = 1095) and 2 (n = 173), we investigated associations between recalled pubertal age and spatial cognition in typically developing men, controlling for current testosterone levels in Study 2. In Study 3 (n = 51), we examined the relationship between spatial performance and the age at which peripubertal hormone replacement therapy was initiated in a sample of men with Isolated GnRH Deficiency. Across Studies 1–3, effect size estimates for the relationship between spatial performance and pubertal timing ranged from. −0.04 and −0.27, and spatial performance was unrelated to salivary testosterone in Study 2. In Study 4, we conducted two meta-analyses of Studies 1–3 and four previously published studies. The first meta-analysis was conducted on correlations between spatial performance and measures of the absolute age of pubertal timing, and the second replaced those correlations with correlations between spatial performance and measures of relative pubertal timing where available. Point estimates for correlations between pubertal timing and spatial cognition were −0.15 and −0.12 (both p < 0.001) in the first and second meta-analyses, respectively. These associations were robust to the exclusion of any individual study. Our results suggest that, for some aspects of neural development, sensitivity to gonadal hormones declines across puberty, with earlier pubertal hormone exposure predicting greater sex-typicality in psychological phenotypes in adulthood. These results shed light on the processes of behavioral and brain organization and have implications for the treatment of IGD and other conditions wherein pubertal timing is pharmacologically manipulated.

Body size varies enormously among mammalian species. In small mammals, body growth is typically suppressed rapidly, within weeks, whereas in large mammals, growth is suppressed slowly, over years, allowing for a greater adult size. We recently reported evidence that body growth suppression in rodents is caused in part by a juvenile genetic program that occurs in multiple tissues simultaneously and involves the downregulation of a large set of growth-promoting genes. We hypothesized that this genetic program is conserved in large mammals but that its time course is evolutionarily modulated such that it plays out more slowly, allowing for more prolonged growth. Consistent with this hypothesis, using expression microarray analysis, we identified a set of genes that are downregulated with age in both juvenile sheep kidney and lung. This overlapping gene set was enriched for genes involved in cell proliferation and growth and showed striking similarity to a set of genes downregulated with age in multiple organs of the juvenile mouse and rat, indicating that the multiorgan juvenile genetic program previously described in rodents has been conserved in the 80 million years since sheep and rodents diverged in evolution. Using microarray and real-time PCR, we found that the pace of this program was most rapid in mice, more gradual in rats, and most gradual in sheep. These findings support the hypothesis that a growth-regulating genetic program is conserved among mammalian species but that its pace is modulated to allow more prolonged growth and therefore greater adult body size in larger mammals.

Context: Some patients with idiopathic hypogonadotropic hypogonadism (IHH) undergo spontaneous activation of their hypothalamic-pituitary-gonadal axis resulting in normalization of steroidogenesis and/or gametogenesis, a phenomenon termed reversal. Objective: To assess the responsiveness of the GnRH neuronal network to exogenous kisspeptin administration in IHH patients who have undergone reversal. Participants: Six men with congenital IHH and evidence for reversal. Intervention: Subjects underwent q10 min blood sampling to measure GnRH-induced LH secretion at baseline and in response to iv boluses of kisspeptin (0.24–2.4 nmol/kg) and GnRH (75 ng/kg). Results: Individuals with sustained reversal of their hypogonadotropism (spontaneous LH pulses) responded to exogenous kisspeptin with a GnRH-induced LH pulse. Individuals who had reversal but then subsequently suffered relapse of their IHH (loss of spontaneous LH pulsatility) did not respond to kisspeptin. Conclusions: The ability of kisspeptin to stimulate a GnRH-induced LH pulse correlates with the presence of endogenous LH pulses. These data suggest that reversal of hypogonadotropism, and by extension sexual maturation, may be due to the acquisition of kisspeptin responsiveness.

OBJECTIVE—The purpose of this study was to screen adolescents with type 1 diabetes using ambulatory blood pressure monitoring (ABPM) to 1) test the hypothesis that using a preset sleep time results in an overdiagnosis of abnormal nocturnal dipping in systolic blood pressure and 2) assess the reproducibility of an abnormal nocturnal systolic blood pressure dip. RESEARCH DESIGN AND METHODS—For aim 1, ABPM from 53 adolescent patients with type 1 diabetes was reviewed. Nocturnal dips in systolic blood pressure calculated by actual sleep time were compared with those from a preset sleep time. For aim 2, blood pressure monitoring from 98 patients using actual reported sleep time was reviewed. Reproducibility of the nocturnal dip in systolic blood pressure was assessed in a subset of “nondippers.” RESULTS—For aim 1, the actual mean ± SE decline in nocturnal systolic blood pressure was 11.6 ± 4.7%, whereas the mean decline in nocturnal systolic blood pressure calculated using the preset sleep time was 8.8 ± 4.9% (P < 0.0001). For aim 2, 64% of patients had a normal nocturnal decline in systolic blood pressure (14.9 ± 3.1% mmHg), whereas 36% had an abnormal dip (5.7 ± 2.8% mmHg). Repeat ABPM performed in 22 of the 35 nondippers revealed that only 36% had abnormal systolic dipping confirmed on the repeat ABPM. CONCLUSIONS—The use of actual reported sleep time is required to accurately determine the nocturnal dip in systolic blood pressure. Repeating ABPM in nondippers is essential to confirm this abnormality.