Central precocious puberty: Recent advances in understanding the aetiology and in the clinical approach

Childhood Obesity, Hypothalamic Inflammation, and the Onset of Puberty: A Narrative Review

The onset of puberty, which is under the control of the hypothalamic-pituitary-gonadal (HPG) axis, is influenced by various factors, including obesity, which has been associated with the earlier onset of puberty. Obesity-induced hypothalamic inflammation may cause premature activation of gonadotropin-releasing hormone (GnRH) neurons, resulting in the development of precocious or early puberty. Mechanisms involving phoenixin action and hypothalamic microglial cells are implicated. Furthermore, obesity induces structural and cellular brain alterations, disrupting metabolic regulation. Imaging studies reveal neuroinflammatory changes in obese individuals, impacting pubertal timing. Magnetic resonance spectroscopy enables the assessment of the brain's neurochemical composition by measuring key metabolites, highlighting potential pathways involved in neurological changes associated with obesity. In this article, we present evidence indicating a potential association among obesity, hypothalamic inflammation, and precocious puberty.

Urinary gonadotropin assay on 24-h collections as a tool to detect early central puberty onset in girls: determination of predictive thresholds

STUDY QUESTION

Is the 24-h urinary gonadotropin assay an effective diagnostic tool in central precocious puberty (CPP) in girls?

SUMMARY ANSWER

This study is the first to provide 24-h urinary gonadotropin assay data, using an electrochemiluminescent immunoassay (CMIA), and to report its usefulness as a tool for the diagnosis of CPP.

WHAT IS KNOWN ALREADY

Data about the GnRH test in the diagnosis of CPP are variable and there is no consensus regarding its interpretation. The measurement of FSH and LH in urines was previously reported to be an alternative biological tool.

STUDY DESIGN, SIZE, DURATION

This is a retrospective two-cohort study, involving a setting and a validation cohort. A total of 516 girls, included between October 2012 and July 2015, and 632 urinary collections were analyzed in the setting cohort. In the validation cohort, 39 girls were included between January 2021 and May 2023, and 49 urinary collections were analyzed.

PARTICIPANTS/MATERIALS, SETTING, METHODS

This study included girls who consulted for an investigation of disturbed growth rate or a clinical suspicion of puberty onset in different medical centres across France (setting cohort). Girls with a suspicion of precocious puberty onset were addressed at the expert centre of paediatric endocrinology of the Groupement Hospitalier Lyon Est (validation cohort). Pelvic ultrasonography was performed and enabled their classification according to clinical and morphologic changes criteria (prepubertal or pubertal groups). The parents collected 24-h urine samples (u24) according to standardized instructions. FSH and LH (urinary or plasmatic) were measured using a current and automated CMIA.

MAIN RESULTS AND THE ROLE OF CHANCE

The area under the ROC curves for CPP prediction was 0.709 for u24FSH (P < 0.001), 0.767 for u24LH (P < 0.001), and 0.753 for the u24LH/u24FSH ratio (P < 0.001). We retained all possible combinations of the four thresholds in the validation cohort (u24FSH = 1.1 or 2.0 IU/24 h; u24LH = 0.035 or 0.08 IU/24 h). The combination of u24FSH > 1.1 IU/24 h and u24LH > 0.08 IU/24 h had a positive PV of 85.7% and a negative PV of 94.3%, a sensitivity of 85.7% and a specificity of 94.3%, for classifying prepubertal and pubertal girls in this cohort.

LIMITATIONS, REASONS FOR CAUTION

This is a retrospective study, in which a margin of error remains due to the inherent uncertainty regarding the clinical assessment of pubertal onset. It must be considered that the thresholds can only apply to the used reagents; measurements without extractions using other reagents are likely to show important heterogeneity.

WIDER IMPLICATIONS OF THE FINDINGS

The assay performed herein is a simple, non-invasive, and analytically robust technique meeting the criteria for an alternative to the GnRH test which could be used to supplement its lack of sensitivity.

STUDY FUNDING/COMPETING INTEREST(S)

No specific funding was used. All authors declared no conflict of interest.

TRIAL REGISTRATION NUMBER

In-house #23-5214 registered study.

Fifteen-minute consultation: The approach to the child with precocious puberty

Precocious puberty has traditionally been defined as the onset of secondary sexual characteristics occurring before age 8 years in girls and 9 years in boys. This earlier onset of puberty may have significant physical and psychological consequences if left untreated. Moreover, it should be excluded that pubertal signs are not secondary to malignancies, other organic aetiologies or associated syndromic phenotypes. Initial assessment involves a thorough medical history and physical examination; a hand and wrist X-ray to determine bone age, and hormonal tests might be indicated to confirm the diagnosis and to determine the origin of hormonal production. Treatment options depend on the underlying cause. Given the complexity of the differential diagnosis, this article aims to familiarise clinicians with the different steps that can be taken when precocious puberty is suspected.

Screening for central precocious puberty by single basal Luteinizing Hormone levels

PURPOSE

To identify cut-off for basal LH levels and for pelvic ultrasound uterine and ovarian parameters indicating an Hypotalamic-Pituitary-Gonadal (HPG) axis activation as diagnostic of Central Precocious Puberty (CPP).

METHODS

248 girls referred for suspected precocious/early puberty who had undergone a GnRH stimulation test were enrolled and divided into three groups: Premature Idiopathic Thelarche (PIT), CPP, and Early Puberty (EA). For every patient basal serum Luteinising Hormone (LH) and Follicle Stimulating Hormone (FSH), basal LH/FSH ratio and pelvic ultrasonographic parameters were also collected. Through the use of Receiver Operating Curves (ROCs) the sensitivity (Se) and specificity (Sp) of basal LH, FSH, LH/FSH ratio and ultrasonographic parameters were evaluated at each level and Area Under the Curve (AUC) was measured.

RESULTS

Basal LH model ≥0.14 mIU/mL reached the highest predictability (90.6% and 78.2%, Se and Sp, respectively). Basal LH/FSH ratio ≥0.1 showed a sensitivity of 85.90% and a specificity of 78.14%, while basal FSH cut-off (≥2.36 mIU/mL) had the lowest predictability, with a less favourable sensitivity (71%) and specificity (70.5%). Cut-off point for uterine length as 35 mm, (83.5% and 42.9% of Se and Sp, respectively) was calculated. For ovarian volumes, ROC curves showed very low sensitivity and specificity.

CONCLUSION

A single basal LH measurement under the cut-off limit may be adequate to exclude an HPG axis activation as CPP.

[Recent advances in the genetic etiology of central precocious puberty]

Central precocious puberty (CPP) is a developmental disorder caused by early activation of the hypothalamic-pituitary-gonadal axis. The incidence of CPP is rapidly increasing, but the underlying mechanisms are not fully understood. Previous studies have shown that gain-of-function mutations in the KISS1R and KISS1 genes and loss-of-function mutations in the MKRN3, LIN28, and DLK1 genes may lead to early initiation of pubertal development. Recent research has also revealed the significant role of epigenetic factors such as DNA methylation and microRNAs in the regulation of gonadotropin-releasing hormone neurons, as well as the modulating effect of gene networks involving multiple variant genes on pubertal initiation. This review summarizes the genetic etiology and pathogenic mechanisms underlying CPP.

Polymorphism rs5780218, rs12998 and rs10158616 in KISS1 gene among the Hubei province Chinese girls with the central precocious puberty

PURPOSE

Central precocious puberty (CPP) results from early activation of the hypothalamic-pituitary-gonadal (HPG) axis. To elucidate the molecular genetic basis of CPP, we here investigated the effects of polymorphism rs5780218, rs12998 and rs10158616 in KISS1 gene on CPP susceptibility.

METHODS

The three KISS1 gene polymorphisms were genotyped by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and Sanger sequencing in 422 healthy Hubei Chinese girls and 384 Hubei Chinese girls with CPP.

RESULTS

Single-locus analysis demonstrated that rs5780218 and rs12998 were significantly associated with CPP susceptibility in Hubei Chinese girls. Haplotype analysis exhibited that the AGG carrying the risk allele A of rs5780218 and the -GG carrying the protective allele - of rs5780218 were associated with increased and decreased CPP susceptibility in Hubei Chinese girls, respectively. The following meta-analysis confirmed the contribution of rs5780218 and rs12998 on CPP susceptibility in Chinese girls.

CONCLUSIONS

rs5780218 and rs12998 in the KISS1 gene may participate in genetic susceptibility to CPP in Chinese girls, and the KISS1 gene rs5780218 may serve as a genetic biomarker of CPP. However, the present findings should be validated in future studies with larger sample sizes in other ethnic populations.

Pineal cysts may promote pubertal development in girls with central precocious puberty: a single-center study from China

Introduction

Pineal cysts have long been considered a benign intracranial variation. However, in our clinical practice, it has been observed that some children with central precocious puberty (CPP) who have pineal cysts experience rapid progression in adolescent development. In recent years, there has been a significant increase in the prevalence of CPP in girls, leading to more diagnoses of CPP among children with pineal cysts. Despite this, there is no consensus regarding whether pineal cysts contribute to CPP as one of its organic factors. This study aimed to analyze the clinical characteristics of pineal cysts in children with CPP and explore the potential effects of pineal cysts on puberty development.

Methods

This single-center study retrospectively analyzed clinical data from girls aged 3 to 10 years who underwent head/pituitary magnetic resonance imaging at the Children's Hospital Affiliated to Zhengzhou University between 2019 and 2022. The study categorized the detection rates of pineal cysts based on systematic disease classification and compared the rates of cyst detection between girls diagnosed with CPP and those without CPP. Subsequently, CPP-diagnosed girls with pineal cysts were examined. Among CPP-diagnosed girls meeting the study's criteria, those with pineal cysts formed the 'cyst group,' while those without cysts were matched in a 1:1 ratio based on age and body mass index to form the 'non-cyst group.' Comparative analyses were conducted to assess the clinical characteristics between these two groups. CPP-diagnosed girls with cysts were further subdivided into three groups according to cyst size (≤5 mm, 5.1-9.9 mm, and ≥10 mm) to investigate potential differences in clinical characteristics among these subgroups. The study involved an analysis of clinical data from girls diagnosed with CPP and included imaging follow-ups to explore the progression of pineal cysts over time.

Results

Among the 23,245 girls who underwent head/pituitary magnetic resonance imaging scans, the detection rate of pineal cysts was 3.6% (837/23,245), with most cases being associated with endocrine diseases. The detection rate of pineal cysts in CPP patients was 6.4% (262/4099), which was significantly higher than the 3.0% (575/19,146) in patients without CPP. In comparison to the non-cyst group, the cyst group exhibited statistically significant increases in estradiol levels, peak luteinizing hormone (LH) levels, peak LH/follicle-stimulating hormone (FSH) ratios, uterine body length, and cervix length (P < 0.001). As cyst size increased, there were significant rises in LH peak, peak LH/FSH ratio, uterine body length, and cervical length (P < 0.01). Estradiol levels and left ovarian volume also showed an increasing trend (P < 0.05). Among girls who underwent follow-up imaging, 26.3% (5/19) exhibited an increase in cyst size.

Conclusion

Pineal cysts are relatively common in children with CPP. They may affect the pubertal development process, with larger cysts correlating to faster pubertal development. Therefore, the authors hypothesize that pineal cysts may trigger CPP in some cases, especially when the cysts are larger than 5 mm in size, as indicated by our data.

A patient with X-linked adrenoleukodystrophy presenting with central precocious puberty: a case report

X-linked adrenoleukodystrophy (X-ALD) is a peroxisomal disorder caused by the variations in the ATP-binding cassette sub-family D member 1 (ABCD1) gene. This study is the first to report central precocious puberty (CPP) in individuals with X-ALD. A 6-year-old boy exhibited mucocutaneous pigmentation, increased plasma adrenocorticotropic hormone levels, and elevated very long-chain fatty acids (VLCFA). We identified a variant, c.1826A>G (p. Glu609Gly), in exon 8 of the ABCD1 gene in the proband. Additionally, he displayed rapid growth, testicular volume of 5-6 mL, the onset of pubic hair, and pubertal levels of luteinizing hormone (LH), all meeting the diagnostic criteria for CPP.

The Emerging Therapeutic Potential of Kisspeptin and Neurokinin B

Kisspeptin (KP) and neurokinin B (NKB) are neuropeptides that govern the reproductive endocrine axis through regulating hypothalamic gonadotropin-releasing hormone (GnRH) neuronal activity and pulsatile GnRH secretion. Their critical role in reproductive health was first identified after inactivating variants in genes encoding for KP or NKB signaling were shown to result in congenital hypogonadotropic hypogonadism and a failure of pubertal development. Over the past 2 decades since their discovery, a wealth of evidence from both basic and translational research has laid the foundation for potential therapeutic applications. Beyond KP's function in the hypothalamus, it is also expressed in the placenta, liver, pancreas, adipose tissue, bone, and limbic regions, giving rise to several avenues of research for use in the diagnosis and treatment of pregnancy, metabolic, liver, bone, and behavioral disorders. The role played by NKB in stimulating the hypothalamic thermoregulatory center to mediate menopausal hot flashes has led to the development of medications that antagonize its action as a novel nonsteroidal therapeutic agent for this indication. Furthermore, the ability of NKB antagonism to partially suppress (but not abolish) the reproductive endocrine axis has supported its potential use for the treatment of various reproductive disorders including polycystic ovary syndrome, uterine fibroids, and endometriosis. This review will provide a comprehensive up-to-date overview of the preclinical and clinical data that have paved the way for the development of diagnostic and therapeutic applications of KP and NKB.

A Short-Duration Gonadotropin-Releasing Hormone Stimulation Test for the Diagnosis of Central Precocious Puberty

Background and Objectives: The gonadotropin-releasing hormone (GnRH) stimulation test is the gold standard method for diagnosing central precocious puberty (CPP), although it requires multiple blood samplings over 120 min. This study aimed to evaluate if a shorter test may have an equivalent diagnostic accuracy. Materials and Methods: We retrospectively reviewed the GnRH tests of 188 consecutive pediatric patients (169 females) referred for signs of early pubertal development. The diagnostic accuracy of the hormonal levels was evaluated at different time points (15, 0, 60, 90, and 120 min after the GnRH stimulus). Results: A diagnosis of CPP was made in 130 cases (69%), with 111 (85%) being female. Sensitivity and specificity ratings higher than 99% for the diagnosis of CPP were achieved for LH levels ≥4.7 mU/mL at 30 and 60 min after the stimulus (area under the ROC curve (AUC) = 1), with no further increase in the diagnostic accuracy in the remaining time points. No sex differences in diagnostic accuracy were found. The LH/FSH ratio at 30 min showed a sensitivity of 94.9%, with an AUC of 0.997 and a value ≥0.76. Conclusions: A short-duration GnRH test of 60 min provided optimal results for the diagnosis of CPP. Extending the test for an extra hour is therefore unnecessary and inadvisable.

Central precocious puberty: a review of diagnosis, treatment, and outcomes

Central precocious puberty (CPP) refers to early activation of the hypothalamic-pituitary-gonadal (HPG) axis and is manifested by breast development in girls or testicular enlargement in boys before the normal physiological age ranges. CPP can be precipitated by intracranial pathology, exposure to high levels of sex steroids, or environmental risk factors, but most cases are idiopathic. Monogenic causes have also been identified. In this Review, we summarise pathophysiology, risk factors, diagnosis, and management of CPP. Concern for CPP should prompt referral to paediatric endocrinology where diagnosis is confirmed by clinical, biochemical, radiological, and genetic testing. CPP is treated with a gonadotropin-releasing hormone analogue, the primary aims of which are to increase adult height and postpone development of secondary sexual characteristics to an age that is more commensurate with peers. Although long-term outcomes of treatment with gonadotropin-releasing hormone analogues are reassuring, additional research on the psychological effect of CPP is needed.

Alterations in Appetite-Regulating Hormones in Girls with Central Early or Precocious Puberty

The prevalence of central precocious puberty (CPP) in girls has increased worldwide and is often associated with obesity in childhood as well as high fat/high glycemic index diets. Evidence suggests that subjects with obesity present with alterations in appetite-regulating hormones. The arcuate and paraventricular nuclei of the hypothalamus are the centers of action of appetite hormones, as well as the location of gonadotropin-releasing hormone (GnRH) neurons, the activation of which results in the onset of puberty. This anatomical proximity raises the question of possible alterations in appetite-regulating hormones in patients with CPP. Furthermore, diet-induced hypothalamic inflammation constitutes a probable mechanism of the pathophysiology of CPP, as well as alterations in appetite-regulating hormones in young children. In this article, we summarize the evidence investigating whether girls with CPP present with alterations in appetite-regulating hormones. We present evidence that leptin concentrations are elevated in girls with CPP, ghrelin concentrations are lower in girls with CPP, nesfatin-1 and orexin-A concentrations are elevated among girls with premature thelarche, and insulin concentrations are increased in girls with early menarche.

Efficacy and Safety of Triptorelin 3-Month Formulation in Chinese Children with Central Precocious Puberty: A Phase 3, Open-Label, Single-Arm Study

INTRODUCTION

Triptorelin is available as 1- and 3-month prolonged-release (PR) formulations; at the time of the study, only the former was approved for central precocious puberty (CPP) in China. This study assessed the efficacy and safety of the triptorelin 3-month PR formulation in Chinese children with CPP.

METHODS

In this 12-month, prospective, open-label, multicentre, single-arm study (NCT04736602), Chinese children (mean age [standard deviation (SD)], 7.6 ± 0.8 years) with CPP received triptorelin pamoate 15 mg on day 1 and at months 3, 6 and 9. The primary endpoint was the proportion with luteinizing hormone (LH) suppression (stimulated peak LH ≤ 3 IU/L after gonadotropin-releasing hormone [GnRH] stimulation) at month 3. Secondary endpoints included changes from baseline in hormone levels and clinical parameters, as well as safety assessments.

RESULTS

Overall, 32 children were enrolled, including three boys. LH suppression to prepubertal levels (≤ 3 IU/L) after GnRH stimulation was observed in 100%, 93.5% and 93.5% of participants at months 3, 6 and 12, respectively. Basal and peak LH and follicle-stimulating hormone levels were substantially suppressed at months 3, 6 and 12, and most participants showed sex hormone suppression. At months 6 and 12 respectively 92.9% and 89.3% of girls had stable breast development, and all boys had stable genital development. There was a decrease in mean growth velocity from baseline (8.96 cm/year) to months 3, 6 and 12 (8.07, 5.24 and 6.94 cm/year, respectively). The mean difference between bone and chronological age decreased from baseline (2.85 years) to month 12 (2.39 years). In girls, uterine length was stable or reduced at month 12; in boys, testicular volume was reduced. Triptorelin was well tolerated.

CONCLUSION

The triptorelin 3-month PR formulation demonstrated similar efficacy to that previously reported in non-Chinese patients with CPP and had an acceptable safety profile. This supports triptorelin 3-month PR as a viable option for Chinese children with CPP.

In vivo magnetic resonance spectroscopy for the differential diagnosis of a cerebral mass in a boy with precocious puberty: a case report and review of the literature

PURPOSE

To highlight the role of in vivo magnetic resonance spectroscopy (MRS) as a non-invasive tool that can clarify the etiology of sellar tumors by presenting the case of a boy with central precocious puberty (CPP) and to review the current literature.

METHODS

A 4-year-old boy was admitted to our hospital due to repeated episodes of focal and gelastic seizures in the previous year. Clinical examination (testicular volume 4-5 ml bilaterally, penile length of 7.5 cm, and absence of axillary or pubic hair) and laboratory tests (FSH, LH, and testosterone) were indicative of CPP. The combination of gelastic seizures with CPP in a 4-year-old boy raised the suspicion of hypothalamic hamartoma (HH). Brain MRI revealed a lobular mass in the suprasellar-hypothalamic region. The differential diagnosis included glioma, HH, and craniopharyngioma. To further investigate the CNS mass, an in vivo brain MRS was performed.

RESULTS

Οn conventional MRI, the mass demonstrated isointensity to gray matter on T1 weighted images but slight hyperintensity on T2-weighted images. It did not show restricted diffusion or contrast enhancement. On MRS, it showed reduced N-acetyl aspartate (NAA) and slightly elevated myoinositol (MI) compared with values in normal deep gray matter. The MRS spectrum, in combination with the conventional MRI findings, were consistent with the diagnosis of a HH.

CONCLUSION

MRS is a state-of-the-art, non-invasive imaging technique that compares the chemical composition of normal tissue to that of abnormal regions by juxtaposing the frequency of measured metabolites. MRS, in combination with clinical evaluation and classic MRI, can provide identification of CNS masses, thus eliminating the need for an invasive biopsy.

Role of luteinizing hormone urinary levels in the diagnostic and therapeutic management of female central precocious puberty

BACKGROUND

Diagnosing central precocious puberty (CPP) requires an integrated approach based on clinical, biochemical and instrumental data. The diagnostic gold standard is represented by GnRH (gonadotropin-releasing hormone) stimulation test. Some undoubted limitations of this procedure led the international scientific community to look for cheaper and less invasive alternative diagnostic methods, such as luteinizing hormone urinary levels (uLH) measurement. This study aims to define the reliability of urinary LH levels as a biomarker of pubertal development, both concerning the initial diagnostic management and the monitoring of patients with central precocious puberty undergoing therapy with GnRH analogues. Furthermore, the study plans to detect the potential association between LH peak serum (pLH) and urinary LH in patients undergoing diagnostic tests with GnRH and to identify a possible cut-off of uLH that may be suggestive of ensued successful hormonal stimulation.

METHODS

The study includes 130 female patients with suspected precocious puberty or in follow-up during suppressive therapy. After the collection of the informed consent, the patients underwent clinical evaluation, auxological assessment, and hormone assays (basal levels of LH, FSH, and oestradiol; GnRH stimulating test in patients with suspected precocious puberty; urinary LH assay on the first-morning urine sample, collected after waking up).

RESULTS

Two uLH cut-off values have been identified: the first of 0.25 UI/L [C.I. 95% 0.23-0.27], able to distinguish between pubertal and pre-pubertal patients, the second of 0.45 UI/L [C.I. 95% 0,20 - 0,70] suggestive of occurred hormonal stimulation in patients with diagnosis of CPP at GnRH test. All 30 patients with CPP in follow-up during suppressive therapy presented uLH values ≤ 0.45 IU/L (pU < 0.05), and uLH collected in prepubertal group control.

CONCLUSIONS

uLH assays on the first morning urine specimen could be considered a low-cost and minimally invasive tool for precocious puberty diagnosing and monitoring, making possible to be easily performed even by a general pediatrician. Thus, this could help referring only selected patients to pediatric endocrinologists. After an appropriate validation, this approach could reasonably reduce hospital attendance and costs of performing more invasive procedures, with a more significant emotional impact on the pediatric patient.

Clinical significance of serum MBD3 detection in girls with central precocious puberty

Diagnosis of central precocious puberty (CPP) in girls remains a huge challenge. The current study was to measure the serum expression of methyl-DNA bind protein 3 (MBD3) in CPP girls and assess its diagnostic efficacy. To begin with, we enrolled 109 CPP girls and 74 healthy pre-puberty girls. Then, MBD3 expression in their serum samples was measured via reverse transcription-quantitative polymerase chain reaction, and its diagnostic efficacy on CPP was assessed via the receiver operating characteristic (ROC) curve, followed by correlation analysis between serum MBD3 and patient age, gender, bone age, weight, height, body mass index, basal luteinizing hormone (LH), peak LH, basal follicle-stimulating hormone (FSH), peak FSH, and ovarian size using bivariate correlations method. Finally, independent predictors of MBD3 expression were confirmed using multivariate linear regression analysis. MBD3 was highly expressed in sera of CPP patients. The area under the ROC curve of MBD3 diagnosing CCP was 0.9309, with 1.475 cut-off value (92.66% sensitivity and 86.49% specificity). MBD3 expression positively correlated with basal LH, peak LH, basal FSH, and ovarian size, among which basal LH was considered the strongest independent predictor of MBD3, followed by basal FSH and peak LH. In summary, serum MBD3 could act as a biomarker in aiding CPP diagnosis.

Prosopagnosia (face blindness) and child health during the COVID-19 pandemic

Prosopagnosia or 'face blindness' is the inability to recognise people's faces. There are two types: congenital or developmental prosopagnosia, which is the most common, and acquired prosopagnosia, which may occur secondary to brain tumours, stroke or other brain disorders. The authors of this article explored if mask wearing as a result of the restrictions imposed by the coronavirus disease 2019 (COVID-19) pandemic may affect social and developmental outcomes in children, including the development of prosopagnosia. Limited research on this topic is available and, although some relevant publications were found, no definitive evidence of mask-induced prosopagnosia in children was identified. However, nurses should be aware of this issue and discuss coping strategies to support children with the condition. Longitudinal studies on outcomes in children from different age groups who grew up during the COVID-19 pandemic will provide further insight.

[Gonadotropin-dependent precocious puberty: genetic and clinical characteristics]

BACKGROUND

In 90% cases of girls and 25-60% cases of boys the cause of gonadotropin-dependent precocious puberty (PP) is unclear. Up to 25-27.5% of gonadotropin-dependent PP cases are monogenic and suggest autosomal-dominant inheritance with incomplete sex-dependent penetrance. To date, mutations in genes KISS1, KISS1R, MKRN3, DLK1 have been described as causal variants leading to precocious hypothalamic-pituitary axis activation in childhood. Genetic testing in patients with hereditary forms of PP can expand our knowledge of underlying molecular mechanisms of the disease and it  is also necessary for genetic counselling.

AIM

To study clinical features and genetic characteristics of patients with idiopathic gonadotropin-dependent precocious puberty.

MATERIALS AND METHODS

A group of patients with idiopathic gonadotropin-dependent precocious puberty and positive family history (early or precocious puberty) was examined. Laboratory and instrumental diagnostic tests, full-exome sequencing (NGS, next-generation sequencing) were provided for all patients.

RESULTS

The study included 30 patients (29 girls, 1 boy) with idiopathic gonadotropin-dependent precocious puberty. The median of patients age at the time of the examination was 7,2 years [6,5; 7,7]. Positive family history presented in all cases: in 40% of patients on father's side, in 37% - on mother's side, in 23% of patients PP was diagnosed in siblings. The fullexome sequencing was conducted to 21 patients: in 61,9% of cases (95% CI [40;79]) nucleotide variants were identified   in genes, associated with gonadotropin-dependent precocious puberty. MKRN3 gene defect was detected in most cases (77% cases (95% CI [49; 92]), which consistent with international data on its highest prevalence in the monogenic forms of PP. In 23% of cases (95% CI [7; 50]) nucleotide variants were identified in other candidate genes associated with neuroontogenesis and neuroendocrine regulation mechanisms of hypothalamic-pituitary axis.

CONCLUSION

Our study confirms that detailed family history data in children with PP provides a rational approach to molecular-genetic testing. Data of inheritance pattern and clinical manifestations will simplify the diagnosis of hereditary forms of disease and enhance genetic counselling of families, followed by timely examination and administration of pathogenetic therapy.

Central precocious puberty in Prader-Willi syndrome: a narrative review

Prader-Willi syndrome (PWS, OMIM176270) is a rare genetic disorder with recognizable dysmorphic features and multisystemic consequences such as endocrine, neurocognitive and metabolic ones. Although most patients with Prader-Willi syndrome exhibit hypogonadotropic hypogonadism, there is variability regarding sexual maturation, with precocious puberty occurring in rare cases. Our aim is to elaborate a thorough review of Prader-Willi patients with central precocious puberty, in order to raise awareness of such cases and to enhance our knowledge regarding the diagnosis and prompt treatment of this particular PWS patients.

Differential diagnosis of precocious puberty in girls during the COVID-19 pandemic: a pilot study

BACKGROUND

To investigate the differential diagnosis of girls aged 6 to 8 years with idiopathic premature thelarche (IPT) and central precocious puberty (CPP) during the COVID-19 pandemic. We explored predicted adult height (PAH) discrepancy to guide appropriate diagnosis and treatment.

METHODS

From January 2020 to December 2021, Chinese girls aged 6 to 8 years with precocious puberty were recruited. They were divided into IPT and CPP groups. Clinical characteristics, including height, weight, body mass index (BMI), basal luteinizing hormone (LH), oestradiol, uterine length and volume, follicle numbers (d > 4 mm) and bone age (BA) were recorded. We analysed differential diagnosis and PAH discrepancy in both groups. Binary logistic regression analysis was used to explore risk factors for CPP, and receiver operating characteristic (ROC) curves were generated to evaluate the diagnostic value of related indexes.

RESULTS

Sixty patients, including 40 girls with IPT and 20 girls with CPP, were recruited. The prevalence of overweight and obesity in the entire cohort was 25% (15/60) and was significantly higher in IPT than CPP, 32.5% (13/40) vs. 10% (2/20), respectively (P=0.045). There were significant differences in LH, uterine volume, follicle numbers and BA (P<0.05). The impaired PAH of IPT and CPP was 0.01 ± 1.19 SD and 0.62 ± 0.94 SD with significant differences (P=0.047). Logistic regression analysis showed that LH and follicle numbers were independent risk factors for CPP. The ROC curve showed that the area under the curve (AUC) of LH and follicle numbers were 0.823 and 0.697. The sensitivity and specificity of LH with a cut off of 0.285 IU/L were 78.9% and 77.8%. The sensitivity and specificity of follicle numbers with a cut off of 3.5 were 89.5% and 52.8%.

CONCLUSION

The prevalence of overweight and obesity in 6- to 8-year-old girls with precocious puberty was high. Auxological data should not be used in the differential diagnosis of IPT and CPP. Basal LH above 0.285 IU/L and follicle numbers greater than 4 were important features suggestive of CPP. PAH was impaired in individuals with CPP, but it was not impaired in individuals with IPT.

When it doesn't run in the blood(vessels) - events involved in vascular disorders

In the current issue of the Biomedical Journal the underlying pathology of hemodynamic compromise in acute small subcortical infarction are elucidated. A follow-up study in patients with childhood Kawasaki disease is presented, as well as an insight into the gradually decreasing antigen expression in cases of acute myeloid leukemia. Furthermore this issue provides an exciting update concerning COVID-19 and the use of CRISPR-Cas, a review about computational approaches in the research of kidney stone formation, factors connected to central precocious puberty, and why a rock star of paleogenetics recently received a Nobel Prize. Additionally, this issue contains an article proposing the repurposing of the lung cancer drug Capmatinib, a study of how the gut microbiome develops in neonates, an impulse about the role of the transmembrane protein TMED3 in esophageal carcinoma, and the revelation about how competing endogenous RNA influences ischemic stroke. Lastly, genetic reasons for male infertility are discussed, as well as the relation between non-alcoholic fatty liver disease and chronic kidney disease.

The Congenital and Acquired Mechanisms Implicated in the Etiology of Central Precocious Puberty

The etiology of central precocious puberty (CPP) is multiple and heterogeneous, including congenital and acquired causes that can be associated with structural or functional brain alterations. All causes of CPP culminate in the premature pulsatile secretion of hypothalamic GnRH and, consequently, in the premature reactivation of hypothalamic-pituitary-gonadal axis. The activation of excitatory factors or suppression of inhibitory factors during childhood represent the 2 major mechanisms of CPP, revealing a delicate balance of these opposing neuronal pathways. Hypothalamic hamartoma (HH) is the most well-known congenital cause of CPP with central nervous system abnormalities. Several mechanisms by which hamartoma causes CPP have been proposed, including an anatomical connection to the anterior hypothalamus, autonomous neuroendocrine activity in GnRH neurons, trophic factors secreted by HH, and mechanical pressure applied to the hypothalamus. The importance of genetic and/or epigenetic factors in the underlying mechanisms of CPP has grown significantly in the last decade, as demonstrated by the evidence of genetic abnormalities in hypothalamic structural lesions (eg, hamartomas, gliomas), syndromic disorders associated with CPP (Temple, Prader-Willi, Silver-Russell, and Rett syndromes), and isolated CPP from monogenic defects (MKRN3 and DLK1 loss-of-function mutations). Genetic and epigenetic discoveries involving the etiology of CPP have had influence on the diagnosis and familial counseling providing bases for potential prevention of premature sexual development and new treatment targets in the future. Global preventive actions inducing healthy lifestyle habits and less exposure to endocrine-disrupting chemicals during the lifespan are desirable because they are potentially associated with CPP.

Precocious puberty under stressful conditions: new understanding and insights from the lessons learnt from international adoptions and the COVID-19 pandemic

Neuro-biological variations in the timing of sexual maturation within a species are part of an evolved strategy that depend on internal and external environmental conditions. An increased incidence of central precocious puberty (CPP) has been described in both adopted and "covid-19 pandemic" children. Until recently, it was hypothesised that the triggers for CPP in internationally adopted children were likely to be better nutrition, greater environmental stability, and improved psychological wellbeing. However, following data collected during and after the coronavirus (COVID-19) global pandemic, other possibilities must be considered. In a society with high levels of child wellbeing, the threat to life presented by an unknown and potentially serious disease and the stressful environment created by lockdowns and other public health measures could trigger earlier pubertal maturation as an evolutionary response to favour early reproduction. The main driver for increased rates of precocious and rapidly progressive puberty during the pandemic could have been the environment of "fear and stress" in schools and households. In many children, CPP may have been triggered by the psychological effects of living without normal social contact, using PPE, being near adults concerned about financial and other issues and the fear of getting ill. The features and time of progression of CPP in children during the pandemic are similar to those observed in adopted children. This review considers the mechanisms regulating puberty with a focus on neurobiological and evolutionary mechanisms, and analyses precocious puberty both during the pandemic and in internationally adopted children searching for common yet unconsidered factors in an attempt to identify the factors which may have acted as triggers. In particular, we focus on stress as a potential factor in the early activation of the hypothalamic-pituitary-gonadal axis and its correlation with rapid sexual maturation.

Oestrogenic Activity in Girls with Signs of Precocious Puberty as Exposure Biomarker to Endocrine Disrupting Chemicals: A Pilot Study

The relationship between endocrine disrupting chemical (EDC) exposure and Precocious Puberty (PP) was investigated in this pilot study, involving girls with signs of PP (P) and pre-pubertal girls (C). Risk factors for PP were assessed through questionnaires, while 17β-oestradiol (E2) levels and oestrogenic activity were quantified on sera. The oestrogenic activity, expressed as E2 equivalent concentration (EEQ), was applied as EDC exposure biomarker. Questionnaires showed a low EDC knowledge, a high EDC exposure, and a potential relationship between some habits at risk for EDC exposure and PP. EEQs were similar between C and P; however, they were significantly higher in girls living in an urban environment than in girls living in a rural environment, suggesting a potential higher EDC exposure in cities. The results of this pilot study highlighted the need to raise awareness on EDCs and can be considered a starting point to clarify the relationship between EDC exposure and PP.

Investigation on the Correlation of Anxiety Degree with Family Atmosphere in Children with Precocious Puberty

Objective

This research sets out to explore the correlation of anxiety degree with family atmosphere in children with precocious puberty (PP), so as to provide a reference for future treatment of PP.

Methods

Eighty-one cases of PP were visited between January 2021 and March 2021, and their direct relatives were selected as the research population for retrospective analysis. After admission, children and their direct relatives completed a questionnaire survey on the quality of life and social anxiety of children with PP. Children were assigned to the research group and the control group based on their anxiety scores. The intergroup differences in daily activities, diet, and family status, as well as children's and parents' psychological status, were identified, and the relationship between anxiety degree in PP children and family atmosphere was discussed.

Results

The children's anxiety score was (6.17 ± 4.26), and they were divided into groups according to the median, with 30 cases in the research group and 51 cases in the control group. The two cohorts were similar in dietary status and children's physiological status (P > 0.05); however, the research group exhibited a greater number of cases who used electronic products for 2-3 h daily and watched romantic TV series (movies). The daily exercise time of the research group is lower than that of the control group (P < 0.05). In the research group, the monthly family income and the number of family companions and very harmonious families were significantly lower, while the number of divorces or remarriages increased (P < 0.05). The survey results on parents' psychological status also showed better psychological states in patients in the control group (P < 0.05).

Conclusion

The anxiety level of PP children is closely related to the family atmosphere. In future clinical treatment of children with PP, it will also be necessary to pay attention to and adjust the family relationship of the children, which is of great significance for relieving PP-associated anxiety.

Daily GnRH agonist treatment effectively delayed puberty in female rats without long-term effects on sexual behavior or estrous cyclicity

The present study examined the long-term effects of suppressing puberty with a GnRH agonist on reproductive physiology and behavior in female rats. We have recently reported that administration of the GnRH agonist leuprolide acetate (25 µg/kg) daily between postnatal day (PD) 25-50 delayed puberty and disrupted the development of copulatory behavior and sexual motivation in male rats. However, pilot data from our lab suggest that this low dose of leuprolide acetate (25 µg/kg) was not high enough to significantly delay puberty in female rats. Therefore, we injected female Long-Evans rats with leuprolide acetate at a higher dose (50 µg/kg) or 0.9% sterile saline, daily , starting on PD 25 and ending on PD 50. Vaginal opening was monitored daily starting on PD 30 for signs of pubertal onset and first estrous cycle. In addition, we measured estrous cyclicity starting approximately 2 weeks after the last injection of leuprolide (∼PD 64). Immediately after monitoring estrous cyclicity, the female rats were mated on their first day in behavioral estrus using the partner-preference paradigm, with and without physical contact (PD 95-110). We found that this dose of leuprolide (50 µg/kg) significantly delayed puberty; however, neither estrous cyclicity nor sexual motivation was significantly affected by periadolescent exposure to leuprolide. Together with our findings in male rats, these results add to our understanding of the developmental effects of chemically suppressing puberty in rats.

Diagnostic Value of LH Peak Value of the GnRH Stimulation Test for Girls with Precocious Puberty and Its Correlation with Body Mass Index

Objective

To analyze the diagnostic value of luteinizing hormone (LH) peak value of the gonadotropin-releasing hormone (GnRH) stimulation test for girls with precocious puberty and its correlation with body mass index (BMI).

Methods

A total of 230 girls with precocious puberty who came to our hospital for testing from June 2019 to June 2021 were selected and divided into a true group (n = 130) and sham group (n = 100) according to the results of the GnRH stimulation test. According to the BMI, the true group was further divided into a normal group (48 cases), overweight group (43 cases), and obese group (39 cases). The GnRH stimulation test was performed on all subjects, and the basal value and peak value of LH and the basal value and peak value of follicle-stimulating hormone (FSH) were recorded. The general data and serological indexes of the true group and the sham group were compared. Indicators of the GnRH stimulation test, breast stage, bone age, BMI, uterine volume, ovarian volume, and serological indicators (leptin, sex hormone-binding protein (SHBG), and adiponectin (APN)) were compared among the normal group, the overweight group, and the obese group.

Results

There were no significant differences in age and breast stage between the true group and the sham group (P > 0.05). There were statistically significant differences in bone age, BMI, uterine volume, and ovarian volume between the two groups (P < 0.05). The LH base value, LH peak value, FSH base value, and FSH peak value in the true group were higher than those in the sham group, and the differences were statistically significant (P < 0.05). ROC curve analysis showed that the AUC of LH peak value in diagnosing girls with precocious puberty was 0.973, which was higher than 0.895, 0.875, and 0.912 of LH base value, FSH base value, and FSH peak value, respectively. There were statistically significant differences in LH base value, LH peak value, FSH base value, breast development stage, bone age, BMI, SHBG, leptin, and APN among the normal group, overweight group, and obese group (P < 0.05), but there were no significant differences in FSH peak value, uterine volume, and ovarian volume among the three groups (P > 0.05). There was a negative correlation between BMI, LH peak value, and FSH base value (P < 0.05), but there was no significant correlation between BMI and FSH peak value (P > 0.05).

Conclusion

The LH peak value of the GnRH stimulation test has high diagnostic value for girls with precocious puberty, and BMI is negatively correlated with the LH peak value of CPP children.

The Possible Association between Phthalates and Bisphenol A Exposure and Idiopathic Precocious Puberty in Egyptian Girls

BACKGROUND: Bisphenol A (BPA) and phthalates are utilized in large spectrum of plastics, as polyvinyl chloride as well as personal products, medical equipment, and epoxy resins. Phthalate and bisphenol A are the most common endocrine disrupting chemicals that interrupt the endocrine system and cause developmental, reproductive, neurological, and immune disturbances in humans. However, the relation between phthalates and bisphenol A and precocious puberty (PP) in human is still controversial. AIM: Consequently, the present study aimed to detect and investigate the association between exposure to bisphenol A and monobutyl phthalate (MBP) and precocious puberty in Egyptian girls. METHODS: Urine samples were collected from 100 young females. The subjects were divided into two major groups, precocious puberty group consisted of 60 young females diagnosed by an endocrine pediatric specialist and controls consisted of 40 normal young females matched in age and demographic characters. In urine, MBP and bisphenol A (BPA) were measured with high-performance liquid chromatography. RESULTS: The mean concentration of MBP level was 22.758 ± 6.216 for the PP group and 15.283 ± 6.262 for controls with statistical difference between the studied groups (p < 0.001). Furthermore, the mean concentration of BPA was 405.02 ± 223.54 for the PP group and 97.95 ± 55 for controls with significant difference between groups (p < 0.001). CONCLUSION: The present study found that idiopathic precocious puberty in young females was associated with high phthalate metabolites and bisphenol A levels in urine.

Genetic causes of central precocious puberty

Central precocious puberty (CPP) is a condition in which the hypothalamus–pituitary–gonadal system is activated earlier than the normal developmental stage. The etiology includes organic lesions in the brain; however, in the case of idiopathic diseases, environmental and/or genetic factors are involved in the development of CPP. A genetic abnormality in KISS1R, that encodes the kisspeptin receptor, was first reported in 2008 as a cause of idiopathic CPP. Furthermore, genetic alterations in KISS1, MKRN3, DLK1, and PROKR2 have been reported in idiopathic and/or familial CPP. Of these, MKRN3 has the highest frequency of pathological variants associated with CPP worldwide; but, abnormalities in MKRN3 are rare in patients in East Asia, including Japan. MKRN3 and DLK1 are maternal imprinting genes; thus, CPP develops when a pathological variant is inherited from the father. The mechanism of CPP due to defects in MKRN3 and DLK1 has not been completely clarified, but it is suggested that both may negatively control the progression of puberty. CPP due to such a single gene abnormality is extremely rare, but it is important to understand the mechanisms of puberty and reproduction. A further development in the genetics of CPP is expected in the future.

Implicating factors in the increase in cases of central precocious puberty (CPP) during the COVID-19 pandemic: Experience of a tertiary centre of pediatric endocrinology and review of the literature

Sexual development is a complex mechanism activated by the hypothalamic-pituitary-gonadal axis. Over the last one hundred years there has been a decline in the age at puberty onset in industrialised countries. Some Italian studies showed an increase in diagnoses of Central Precocious Puberty (CPP) during the COVID-19 pandemic. It is thus supposed that in this period there was an increased impact of factors that can influence pubertal development. Our retrospective monocentric study aimed to confirm the existence of this phenomenon and analysed possible related factors. We retrospectively evaluated clinical, laboratory, radiological and ultrasound (US) data of 154 girls referred to our Tertiary Centre of Paediatric Endocrinology from January 2019 to April 2021 for different forms of Precocious Puberty. We subdivided the cases into subgroups according to the final diagnosis: CPP, Early Puberty (EP), isolated thelarche and isolated pubarche. The observation period was subdivided into: Period 1, before lockdown (1 January 2019 - 8 March 2020) and Period 2, lockdown and the following months (9 March 2020 - 30 April 2021). Period 2 was further divided into "restrictive lockdown period" (Period 2.1) (March 2020 - 14 June 2020, in which the schools were closed) and "less restrictive lockdown period" (Period 2.2) (15 June 2020 - 30 April 2021). We analysed data regarding the use of electronic devices before and during lockdown in a group of girls with CPP diagnosed in Period 2 and we compared the data with that of a control group. Our data show an increase in the number of new diagnoses of CPP during lockdown and in the following months, compared with the previous period. We also detected a higher use of PCs and smartphones in girls with CPP diagnosed in Period 2, compared with the control group. The percentage of the presence of endometrial rhyme detected during the pelvic ultrasound was higher in girls with CPP in Period 2, compared with the previous period. Based on our data we assume there was an environmental effect on pubertal timing that calls our attention to factors such as food, use of electronic devices and stress. We will need further studies to better understand this data.

An Approach to the Evaluation and Management of the Obese Child With Early Puberty

With the declining age at onset of puberty and increasing prevalence of childhood obesity, early breast development in young obese girls has become a more frequent occurrence. Here, we examine available literature to answer a series of questions regarding how obesity impacts the evaluation and management of precocious puberty. We focus on girls as the literature is more robust, but include boys where literature permits. Suggestions include: (1) Age cutoffs for evaluation of precocious puberty should not differ substantially from those used for nonobese children. Obese girls with confirmed thelarche should be evaluated for gonadotropin-dependent, central precocious puberty (CPP) to determine if further investigation or treatment is warranted. (2) Basal luteinizing hormone (LH) levels remain a recommended first-line test. However, if stimulation testing is utilized, there is a theoretical possibility that the lower peak LH responses seen in obesity could lead to a false negative result. (3) Advanced bone age (BA) is common among obese girls even without early puberty; hence its diagnostic utility is limited. (4) Obesity does not eliminate the need for magnetic resonance imaging in girls with true CPP. Age and clinical features should determine who warrants neuroimaging. (5) BA can be used to predict adult height in obese girls with CPP to inform counseling around treatment. (6) Use of gonadotropin-releasing hormone analogues (GnRHa) leads to increased adult height in obese girls. (7) Obesity should not limit GnRHa use as these agents do not worsen weight status in obese girls with CPP.

Diet-Induced Hypothalamic Inflammation, Phoenixin, and Subsequent Precocious Puberty

Recent studies have shown a rise in precocious puberty, especially in girls. At the same time, childhood obesity due to overnutrition and energy imbalance is rising too. Nutrition and fertility are currently facing major challenges in our societies, and are interconnected. Studies have shown that high-fat and/or high-glycaemic-index diet can cause hypothalamic inflammation and microglial activation. Molecular and animal studies reveal that microglial activation seems to produce and activate prostaglandins, neurotrophic factors activating GnRH (gonadotropin-releasing hormone expressing neurons), thus initiating precocious puberty. GnRH neurons’ mechanisms of excitability are not well understood. In this review, we study the phenomenon of the rise of precocious puberty, we examine the physiology of GnRH neurons, and we review the recent literature regarding the pathophysiological mechanisms that connect diet-induced hypothalamic inflammation and diet-induced phoenixin regulation with precocious puberty.

Disorders of Puberty in Girls

Puberty is the process through which reproductive competence is achieved and comprises gonadarche and adrenarche. Breast development is the initial physical finding of pubertal onset in girls and typically occurs between 8 and 13 years. Menarche normally occurs 2 to 3 years after the onset of breast development. Pubertal onset is controlled by the gonadotropin-releasing hormone pulse generator in the hypothalamus; however, environmental factors such as alterations in energy balance and exposure to endocrine-disrupting chemicals can alter the timing of pubertal onset. Improvement in nutritional and socioeconomic conditions over the past two centuries has been associated with a secular trend in earlier pubertal onset. Precocious puberty is defined as onset of breast development prior to 8 years and can be central or peripheral. Delayed puberty can be hypogonadotropic or hypergonadotropic and is defined as lack of breast development by 13 years or lack of menarche by 16 years. Both precocious and delayed puberty may have negative effects on self-esteem, potentially leading to psychosocial stress. Patients who present with pubertal differences require a comprehensive assessment to determine the underlying etiology and to devise an effective treatment plan.

Biological clock and heredity in pubertal timing: what is new?

Puberty represents a milestone during a person's life and is characterized by several physical and psychological changes which end with the achievement of sexual maturation and of fertility. Puberty onset depends on a series of sophisticated, not completely understood, mechanisms certainly involving Gonadotropin-Releasing Hormone (GnRH) and its effects on pituitary gonadotropins. As recent evidence has demonstrated that pubertal timing deeply affects future adult health life, much efforts have been performed in order to clarify the exact actors involved in the onset and progression of puberty. Genetic factors are undoubtedly essential players in the regulation of pubertal development, accounting for approximately 50-80% of its variability. Mutations in genes such as KISS1, MKRN3 and DLK1 have been associated with central precocious puberty. Interestingly, a possible involvement of epigenetic mechanisms has been proposed as additional element able to affect pubertal phase. Environmental factors have recently attracted much attention. Indeed, an overall decrease in the age of puberty has been observed in the last decades. As genetic factors require long time to exert their effect, other players, such as environmental ones, may be involved. Special focus has been posed on nutritional status, endocrine-disrupting chemicals with non-conclusive results. Pubertal timing deeply affects future life, suggesting the need to clarify mechanisms driving pubertal onset and progression, in order to identify tailored therapeutic strategies and targets.