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OBJECTIVES: The etiology of central precocious puberty (CPP) has expanded with identification of new genetic causes, including the monogenic deficiency of Makorin-Ring-Finger-Protein-3 (MKRN3). We aimed to assess the prevalence of CPP causes and the predictors of genetic involvement in this phenotype. DESIGN: A retrospective cohort study for an etiological survey of patients with CPP from a single academic center. METHODS: All patients with CPP had detailed medical history, phenotyping, and brain magnetic resonance imaging (MRI); those with negative brain MRI (apparently idiopathic) were submitted to genetic studies, mainly DNA sequencing studies, genomic microarray, and methylation analysis. RESULTS: We assessed 270 patients with CPP: 50 (18.5%) had CPP-related brain lesions (34 [68%] congenital lesions), whereas 220 had negative brain MRI. Of the latter, 174 (165 girls) were included for genetic studies. Genetic etiologies were identified in 22 patients (20 girls), indicating an overall frequency of genetic CPP of 12.6% (22.2% in boys and 12.1% in girls). The most common genetic defects were MKRN3, Delta-Like-Non-Canonical-Notch-Ligand-1 (DLK1), and Methyl-CpG-Binding-Protein-2 (MECP2) loss-of-function mutations, followed by 14q32.2 defects (Temple syndrome). Univariate logistic regression identified family history (odds ratio [OR] 3.3; 95% CI 1.3-8.3; P = .01) and neurodevelopmental disorders (OR 4.1; 95% CI 1.3-13.5; P = .02) as potential clinical predictors of genetic CPP. CONCLUSIONS: Distinct genetic causes were identified in 12.6% patients with apparently idiopathic CPP, revealing the genetic etiology as a relevant cause of CPP in both sexes. Family history and neurodevelopmental disorders were suggested as predictors of genetic CPP. We originally proposed an algorithm to investigate the etiology of CPP including genetic studies.

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INTRODUCTION: The prevalence of polycystic ovarian syndrome (PCOS) in adolescent girls is between 1 and 4.3%. It remains controversial whether women with a history of idiopathic central precocious puberty (ICPP) are at increased risk for PCOS. Our objective was to assess the prevalence of PCOS in adolescents with a history of ICPP compared with healthy adolescents and the prevalence of PCOS among ICPP girls who have received or not gonadotropin-releasing hormone analogue (GnRHa) treatment. METHODS: We assessed post-menarcheal girls with a history of ICPP. Girls were evaluated at gynecological age ≥2.5 years. Data collected were age at menarche, menstrual cycle characteristics, BMI, clinical hyperandrogenism (HA), total and free testosterone levels. PCOS diagnosis was defined by criteria for adolescents. Subjects were also analyzed regarding whether or not they had received GnRHa treatment. RESULTS: Ninety-four subjects were assessed, and 63 had been treated with GnRHa. Menstrual disorders were found in 29%, clinical HA in 36%, and biochemical HA in 23%. Twelve percent met the diagnostic criteria for PCOS. There was no difference in BMI or in the incidence of menstrual dysfunction or hyperandrogenemia between treated and untreated patients. A higher proportion of clinical HA was found in untreated patients when compared to treated girls. The relative risk (RR) of developing PCOS in ICPP girls was 2.5 compared to a population of healthy adolescents. This RR was not higher in patients who received treatment with GnRHa than in those who did not. CONCLUSION: Adolescent girls with a history of ICPP have an increased risk of PCOS. This risk seems not to be related to GnRHa treatment.

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BACKGROUND: Several rare loss-of-function mutations of delta-like noncanonical notch ligand 1 (DLK1) have been described in non-syndromic children with familial central precocious puberty (CPP). OBJECTIVE: We investigated genetic abnormalities of DLK1 gene in a French cohort of children with idiopathic CPP. Additionally, we explored the pattern of DLK1 serum levels in patients with CPP and in healthy children at puberty, as well as in wild-type female mice. PATIENTS AND METHODS: Genomic DNA was obtained from 121 French index cases with CPP. Automated sequencing of the coding region of the DLK1 gene was performed in all cases. Serum DLK1 levels were measured by enzyme linked immunosorbent assay (ELISA) in 209 individuals, including 191 with normal pubertal development and in female mice during postnatal pubertal maturation. RESULTS: We identified 2 rare pathogenic DLK1 allelic variants: A stop gain variant (c.372C>A; p.Cys124X) and a start loss variant (c.2T>G; p.Met1?, or p.0) in 2 French girls with CPP. Mean serum DLK1 levels were similar between healthy children and idiopathic CPP children. In healthy individuals, DLK1 levels correlated with pubertal stage: In girls, DLK1 decreased between Tanner stages III and V, whereas in boys, DLK1 decreased between Tanner stages II and V (P = .008 and .016, respectively). Serum levels of Dlk1 also decreased in wild-type female mice. CONCLUSIONS: Novel loss-of-function mutations in DLK1 gene were identified in 2 French girls with CPP. Additionally, we demonstrated a pattern of dynamic changes in circulating DLK1 serum levels in humans and mice during pubertal stages, reinforcing the role of this factor in pubertal timing.

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INTRODUCTION: Prior studies have found inconsistent results regarding the relationship between vitamin D status and Idiopathic Central Precocious Puberty (ICPP). OBJECTIVE: To assess the role of serum 25-hydroxyvitamin D (25 [OH]D) levels in ICPP development. METHOD: The authors retrospectively collected data from 221 girls with ICPP and 144 healthy girls between January 2017 and December 2019. The participants' serum 25(OH)D levels were measured using an automatic chemiluminescence method, and the association between serum 25(OH)D levels and the risk of ICPP was assessed using multivariate logistic regression analysis. Odds Ratios (OR) with 95% Confidence Intervals (95% CI) were calculated as effect estimates. RESULTS: Serum 25(OH)D levels in the ICPP group were significantly lower than those in healthy controls (p < 0.001). Multivariate analysis indicated that girls with insufficient vitamin D levels (OR = 0.201; 95% CI 0.094-0.428; p < 0.001) and sufficient vitamin D levels (OR = 0.141; 95% CI 0.053-0.375; p < 0.001) both had a lower risk of ICPP than girls with vitamin D deficiency. Moreover, the authors found that the height (p = 0.014), weight (p = 0.014), breast stage (p = 0.010), mother's height (p < 0.001), and luteinizing hormone/follicle-stimulating hormone ratio (p = 0.010) in girls with ICPP could be associated with levels of vitamin D. CONCLUSION: This study found that a low serum 25(OH)D level is an independent risk factor for ICPP, and several characteristics of girls with ICPP could be affected by their vitamin D status.

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CONTEXT: Central precocious puberty (CPP) can have a familial form in approximately one-quarter of the children. The recognition of this inherited condition increased after the identification of autosomal dominant CPP with paternal transmission caused by mutations in the MKRN3 and DLK1 genes. OBJECTIVE: We aimed to characterize the inheritance and estimate the prevalence of familial CPP in a large multiethnic cohort; to compare clinical and hormonal features, as well as treatment response to GnRH analogs (GnRHa), in children with distinct modes of transmission; and to investigate the genetic basis of familial CPP. METHODS: We retrospectively studied 586 children with a diagnosis of CPP. Patients with familial CPP (n = 276) were selected for clinical and genetic analysis. Data from previous studies were grouped, encompassing sequencing of MKRN3 and DLK1 genes in 204 patients. Large-scale parallel sequencing was performed in 48 individuals from 34 families. RESULTS: The prevalence of familial CPP was estimated at 22%, with a similar frequency of maternal and paternal transmission. Pedigree analyses of families with maternal transmission suggested an autosomal dominant inheritance. Clinical and hormonal features, as well as treatment response to GnRHa, were similar among patients with different forms of transmission of familial CPP. MKRN3 loss-of-function mutations were the most prevalent cause of familial CPP, followed by DLK1 loss-of-function mutations, affecting, respectively, 22% and 4% of the studied families; both affected exclusively families with paternal transmission. Rare variants of uncertain significance were identified in CPP families with maternal transmission. CONCLUSION: We demonstrated a similar prevalence of familial CPP with maternal and paternal transmission. MKRN3 and DLK1 loss-of-function mutations were the major causes of familial CPP with paternal transmission.

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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.

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Abstract Introduction Prior studies have found inconsistent results regarding the relationship between vitamin D status and Idiopathic Central Precocious Puberty (ICPP). Objective To assess the role of serum 25-hydroxyvitamin D (25 [OH]D) levels in ICPP development. Method The authors retrospectively collected data from 221 girls with ICPP and 144 healthy girls between January 2017 and December 2019. The participants' serum 25(OH)D levels were measured using an automatic chemiluminescence method, and the association between serum 25(OH)D levels and the risk of ICPP was assessed using multivariate logistic regression analysis. Odds Ratios (OR) with 95% Confidence Intervals (95% CI) were calculated as effect estimates. Results Serum 25(OH)D levels in the ICPP group were significantly lower than those in healthy controls (p < 0.001). Multivariate analysis indicated that girls with insufficient vitamin D levels (OR = 0.201; 95% CI 0.094-0.428; p < 0.001) and sufficient vitamin D levels (OR = 0.141; 95% CI 0.053-0.375; p < 0.001) both had a lower risk of ICPP than girls with vitamin D deficiency. Moreover, the authors found that the height (p = 0.014), weight (p = 0.014), breast stage (p = 0.010), mother's height (p < 0.001), and luteinizing hormone/follicle-stimulating hormone ratio (p = 0.010) in girls with ICPP could be associated with levels of vitamin D. Conclusion This study found that a low serum 25(OH)D level is an independent risk factor for ICPP, and several characteristics of girls with ICPP could be affected by their vitamin D status.

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Although gonadotropin-releasing hormone analogs are the standard of care for the treatment of central precocious puberty, they are not approved for children/< age 2 years. We reviewed experience with the use of gonadotropin-releasing hormone analogs in 47 children younger than age 2 years, which revealed efficacy and safety comparable with that in older children.

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OBJECTIVE: The aim of this study is to determine the cutoff values of gonadotropin response to gonadotropin-releasing hormone analogs (GnRHas) corresponding to the activation of the hypothalamic-pituitary-gonadal axis that could differentiate central precocious puberty (CPP) from premature thelarche (PT) and using the electrochemiluminescence assay method. METHODS: A total of 49 girls underwent the stimulation test with an intramuscular injection of 3.75 mg leuprolide acetate. Based on the clinical and laboratory characteristics, they were divided into two groups: CPP (n = 22) and PT (n = 27). Baseline estradiol, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) were collected before GnRHa administration and LH and FSH at 60 and 120 min, respectively, after GnRHa administration. RESULTS: The girls with CPP presented an increased height Z-score, advanced bone age, and higher baseline LH, FSH, estradiol, and LH/FSH ratio in relation to PT (p < 0.001). Stimulated LH differed significantly between the two groups, and the LH cutoff values were ≥4.29 IU/L (p < 0.001) and ≥3.95 IU/L at 60 and 120 min, respectively (p < 0.001). The LH peak was found at 60 min after stimulation. CONCLUSIONS: The GnRHa test is effective in distinguishing CPP from PT, and a single sampling, at 60 min, with LH concentrations above 4.29 may be the parameter of choice with the advantage of greater convenience and practicality.

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OBJECTIVES: Longer-acting gonadotropin-releasing hormone analogs (GnRHa) have been widely used for central precocious puberty (CPP) treatment. However, the follow-up of patients after this treatment are still scarce. Our aim was to describe anthropometric, metabolic, and reproductive follow-up of CPP patients after treatment with leuprorelin acetate 3-month depot (11.25 mg). METHODS: Twenty-two female patients with idiopathic CPP were treated with leuprorelin acetate 3-month depot (11.25 mg). Their medical records were retrospectively evaluated regarding clinical, hormonal, and imaging aspects before, during, and after GnRHa treatment until adult height (AH). RESULTS: At the diagnosis of CPP, the mean chronological age (CA) was 8.2 ± 1.13 year, and mean bone age (BA) was 10.4 ± 1.4 year. Mean height SDS at the start and the end of GnRHa treatment was 1.6 ± 0.8 and 1.3 ± 0.9, respectively. The mean duration of GnRHa treatment was 2.8 ± 0.8 year. Mean predicted adult heights (PAH) at the start and the end of GnRH treatment was 153.2 ± 8.6 and 164.4 ± 7.3 cm, respectively (p<0.05). The mean AH was 163.2 ± 6.2 cm (mean SDS: 0.1 ± 1). All patients were within their target height (TH) range. There was a decrease in the percentage of overweight and obesity from the diagnosis until AH (39-19% p>0.05). At the AH, the insulin resistance and high LDL levels were identified in 3/17 patients (17.6%) and 2/21 patients (9.5%), respectively. The mean CA of menarche was 12.2 ± 0.5 years. At the AH, PCOS was diagnosed in one patient (4.8%). CONCLUSIONS: Long-term anthropometric, metabolic, and reproductive follow-up of patients with CPP treated with longer-acting GnRHa revealed effectivity, safety, and favorable outcomes.

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OBJECTIVE: The determinants of an increased risk of an organic pathology underlying central precocious puberty (CPP) in girls remain contentious. The present study aimed to determine the clinical and hormonal findings that can be used to differentiate organic and idiopathic CPP in girls as a screening method so that only those considered likely to have organic CPP undergo cranial magnetic resonance imaging (MRI). METHODS: The medical records of 286 girls that received GnRH agonist (GnRHa) therapy for CPP were retrospectively evaluated. Chronological and bone age, height, pubertal stage, and basal/stimulated gonadotropin and estradiol (E2) levels, as well as cranial MRI findings at the time CPP was diagnosed were recorded. Clinical and hormonal parameters that can be used to differentiate between girls with organic and idiopathic CPP were identified using ROC curves. RESULTS: Organic CPP was noted in 6.3% of the participants. Puberty started before age 6 years in 88.9% of the girls with organic CPP. Mean E2 and peak luteinizing hormone (LH) levels were higher in the girls with organic CPP than in those with idiopathic CPP that were matched for pubertal stage, as follows: early stage puberty (Tanner 2 and 3): E2: 62.4 ± 19.8 pg/mL vs. 29.1 ± 9.5 pg/mL; peak LH: 16.8 ± 3.2 IU/L vs. 12.2 ± 3.7 IU/L; advanced stage puberty (Tanner 4): mean E2: 87.6 ± 3.4 pg/mL vs. 64.6 ± 21.2 pg/mL; peak LH: 20.8 ± 0.4 IU/L vs. 16.6 ± 5.8 IU/L (P < 0.001 for all). Thresholds for differentiating organic and idiopathic CPP in girls with early-stage puberty were 38.1 pg/mL for E2 (100% sensitivity and 80.4% specificity) and 13.6 IU/L for peak LH (100% sensitivity and 66.4% specificity). CONCLUSION: Pubertal symptoms and signs generally begin before age 6 years and hormone levels are much higher than expected for pubertal stage in girls with organic CPP. Based on the present findings, cranial MRI is recommended for girls aged < 6 years, as the risk of diagnosing an organic pathology is highest in this age group. Hormone levels higher than expected for pubertal stage might be another indication for cranial MRI, regardless of patient age. Cranial MRI should be performed in girls with early-stage puberty, and an E2 level > 38 pg/mL and/or a peak LH level > 13.6 IU/L.

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The classic definition of precocious sexual maturation is the development of secondary sexual characteristics before 8 years of age in girls and before 9 years of age in boys. It is classified as central precocious puberty when premature maturation of the hypothalamic-pituitary-gonadal axis occurs, and as peripheral precocious puberty when there is excessive secretion of sex hormones, independent of gonadotropin secretion. Precocious sexual maturation is more common in girls, generally central precocious puberty of idiopathic origin. In boys, it tends to be linked to central nervous system abnormalities. Clinical evaluation should include a detailed history and physical examination, including anthropometric measurements, calculation of growth velocity, and evaluation of secondary sexual characteristics. The main sign to suspect the onset of puberty is breast tissue development (thelarche) in girls and testicular enlargement (≥4 mL) in boys. Hormonal assessment and imaging are required for diagnosis and identification of the etiology. Genetic testing should be considered if there is a family history of precocious puberty or other clinical features suggestive of a genetic syndrome. Long-acting gonadotropin-releasing hormone analogs are the standard of care for central precocious puberty management, while peripheral precocious puberty management depends on the etiology.Conclusion: The aim of this review is to address the epidemiology, etiology, clinical assessment, and management of precocious sexual maturation. What is Known: • The main sign to suspect the onset of puberty is breast tissue development (thelarche) in girls and testicular enlargement (≥4 mL) in boys. The classic definition of precocious sexual maturation is the development of secondary sexual characteristics before 8 years of age in girls and before 9 years of age in boys. • Long-acting gonadotropin-releasing hormone agonist (GnRHa) is the standard of care for CPP management, and adequate hormone suppression results in the stabilization of pubertal progression, a decline in growth velocity, and a decrease in bone age advancement. What is New: • Most cases of precocious sexual maturation are gonadotropin-dependent and currently assumed to be idiopathic, but mutations in genes involved in pubertal development have been identified, such as MKRN3 and DLK1. • A different preparation of long-acting GnRHa is now available: 6-month subcutaneous injection.

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STUDY QUESTION: Is there an (epi)genetic basis in patients with central precocious puberty (CPP) associated with multiple anomalies that unmasks underlying mechanisms or reveals novel genetic findings related to human pubertal control? SUMMARY ANSWER: In a group of 36 patients with CPP associated with multiple phenotypes, pathogenic or likely pathogenic (epi)genetic defects were identified in 12 (33%) patients, providing insights into the genetics of human pubertal control. WHAT IS KNOWN ALREADY: A few studies have described patients with CPP associated with multiple anomalies, but without making inferences on causalities of CPP. Genetic-molecular studies of syndromic cases may reveal disease genes or mechanisms, as the presentation of such patients likely indicates a genetic disorder. STUDY DESIGN, SIZE, DURATION: This translational study was based on a genetic-molecular analysis, including genome-wide high throughput methodologies, for searching structural or sequence variants implicated in CPP and DNA methylation analysis of candidate regions. PARTICIPANTS/MATERIALS, SETTING, METHODS: A cohort of 197 patients (188 girls) with CPP without structural brain lesions was submitted to a detailed clinical evaluation, allowing the selection of 36 unrelated patients (32 girls) with CPP associated with multiple anomalies. Pathogenic allelic variants of genes known to cause monogenic CPP (KISS1R, KISS1, MKRN3 and DLK1) had been excluded in the entire cohort (197 patients). All selected patients with CPP associated with multiple anomalies (n = 36) underwent methylation analysis of candidate regions and chromosomal microarray analysis. A subset (n = 9) underwent whole-exome sequencing, due to presenting familial CPP and/or severe congenital malformations and neurocognitive abnormalities. MAIN RESULTS AND THE ROLE OF CHANCE: Among the 36 selected patients with CPP, the more prevalent associated anomalies were metabolic, growth and neurocognitive conditions. In 12 (33%) of them, rare genetic abnormalities were identified: six patients presented genetic defects in loci known to be involved with CPP (14q32.2 and 7q11.23), whereas the other six presented defects in candidate genes or regions. In detail, three patients presented hypomethylation of DLK1/MEG3:IG-DMR (14q32.2 disruption or Temple syndrome), resulting from epimutation (n = 1) or maternal uniparental disomy of chromosome 14 (n = 2). Seven patients presented pathogenic copy number variants: three with de novo 7q11.23 deletions (Williams-Beuren syndrome), three with inherited Xp22.33 deletions, and one with de novo 1p31.3 duplication. Exome sequencing revealed potential pathogenic variants in two patients: a sporadic female case with frameshift variants in TNRC6B and AREL1 and a familial male case with a missense substitution in UGT2B4 and a frameshift deletion in MKKS. LIMITATIONS, REASONS FOR CAUTION: The selection of patients was based on a retrospective clinical characterization, lacking a longitudinal inclusion of consecutive patients. In addition, future studies are needed, showing the long-term (mainly reproductive) outcomes in the included patients, as most of them are not in adult life yet. WIDER IMPLICATIONS OF THE FINDINGS: The results highlighted the relevance of an integrative clinical-genetic approach in the elucidation of mechanisms and factors involved in pubertal control. Chromosome 14q32.2 disruption indicated the loss of imprinting of DLK1 as a probable mechanism of CPP. Two other chromosomal regions (7q11.23 and Xp22.33) represented new candidate loci potentially involved in this disorder of pubertal timing. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by grant number 2018/03198-0 (to A.P.M.C.) and grant number 2013/08028-1 (to A.C.V.K) from the São Paulo Research Foundation (FAPESP), and grant number 403525/2016-0 (to A.C.L.) and grant number 302849/2015-7 (to A.C.L.) and grant number 141625/2016-3 (to A.C.V.K) from the National Council for Scientific and Technological Development (CNPq). The authors have nothing to disclose. TRIAL REGISTRATION NUMBER: N/A.

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ABSTRACT Objectives The determinants of an increased risk of an organic pathology underlying central precocious puberty (CPP) in girls remain contentious. The present study aimed to determine the clinical and hormonal findings that can be used to differentiate organic and idiopathic CPP in girls as a screening method so that only those considered likely to have organic CPP undergo cranial magnetic resonance imaging (MRI). Subjects and methods The medical records of 286 girls that received GnRH agonist (GnRHa) therapy for CPP were retrospectively evaluated. Chronological and bone age, height, pubertal stage, and basal/stimulated gonadotropin and estradiol (E2) levels, as well as cranial MRI findings at the time CPP was diagnosed were recorded. Clinical and hormonal parameters that can be used to differentiate between girls with organic and idiopathic CPP were identified using ROC curves. Results Organic CPP was noted in 6.3% of the participants. Puberty started before age 6 years in 88.9% of the girls with organic CPP. Mean E2 and peak luteinizing hormone (LH) levels were higher in the girls with organic CPP than in those with idiopathic CPP that were matched for pubertal stage, as follows: early stage puberty (Tanner 2 and 3): E2: 62.4 ± 19.8 pg/mL vs. 29.1 ± 9.5 pg/mL; peak LH: 16.8 ± 3.2 IU/L vs. 12.2 ± 3.7 IU/L; advanced stage puberty (Tanner 4): mean E2: 87.6 ± 3.4 pg/mL vs. 64.6 ± 21.2 pg/mL; peak LH: 20.8 ± 0.4 IU/L vs. 16.6 ± 5.8 IU/L (P < 0.001 for all). Thresholds for differentiating organic and idiopathic CPP in girls with early-stage puberty were 38.1 pg/mL for E2 (100% sensitivity and 80.4% specificity) and 13.6 IU/L for peak LH (100% sensitivity and 66.4% specificity). Conclusion Pubertal symptoms and signs generally begin before age 6 years and hormone levels are much higher than expected for pubertal stage in girls with organic CPP. Based on the present findings, cranial MRI is recommended for girls aged < 6 years, as the risk of diagnosing an organic pathology is highest in this age group. Hormone levels higher than expected for pubertal stage might be another indication for cranial MRI, regardless of patient age. Cranial MRI should be performed in girls with early-stage puberty, and an E2 level > 38 pg/mL and/or a peak LH level > 13.6 IU/L.

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BACKGROUND: Idiopathic central precocious puberty (iCPP) presents a disproportionate advancement of bone age and maturation, as well as metabolic and endocrinological changes that may be related to effects on telomere biology. OBJECTIVE: To investigate the telomere length in iCPP girls treated with GnRHa. STUDY DESIGN: Observational case-control study with 85 girls, including 45 iCPP treated with GnRHa and 40 controls. It was analyzed age, height, weight and body mass index (BMI), insulin, triglycerides, testosterone, insulin resistance by HOMA, and telomere length by real-time PCR. Statistical analyses were determined by Wilcoxon test and Spearman correlation was carried out. RESULTS: Weight, BMI, insulin level and HOMA index were higher in the iCPP than in the control group (p < .01); without difference between mean ages. The telomere length did not differ between iCPP and control group. However, a negative correlation was observed between the telomere length and age in iCPP (p = .0009) and control group (p = .014), and weight in the iCPP (p = .017). CONCLUSIONS: We did not observe any difference in the telomere length in the iCPP and control group. Even though, some characteristics of the disease, such as increased weight and body fat, negatively influence the telomere biology.

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BACKGROUND/AIMS: Kisspeptin (KP) is a key player in the regulation of the release of gonadotropin-releasing hormone (GnRH), which increases the secretion of gonadotropin during puberty to establish reproductive function and regulate the hypothalamic-pituitary-gonadal axis. Premature activation of GnRH secretion leads to idiopathic/central gonadotropin-dependent precocious puberty (CPP). We aimed to compare the blood KP concentrations in girls with CPP and healthy controls. METHODS: A systematic review and meta-analysis was performed. We searched MEDLINE, EMBASE, The Cochrane Library, and SciELO. Random-effects model and standardized mean difference (SMD) were used. Heterogeneity was assessed through I2. Meta-regression considered patient age, KP fraction, and analytical method for KP measurement. RESULTS: The 11 studies included comprised 316 CPP patients and 251 controls. Higher KP levels in the CPP group were found (SMD 1.53; CI 95% = 0.56-2.51). Subgroup analysis revealed association with patient age (p = 0.048), indicating a positive correlation between elevation in KP concentration and age in CPP group. A group of patients with precocious thelarche (PT) from 5 of the included studies comprising 121 patients showed higher levels of KP (1.10; -0.25-2.45: CI 95%) and high heterogeneity (I2 = 91%). The CPP/PT ratio for KP level indicates KP 36% higher on CPP than PT patients. CONCLUSIONS: A consistent difference in KP levels between girls with CPP and controls was identified. While there are important limitations in KP assays which argue against its use as a diagnostic tool, the KP levels in CPP versus control and PT children are consistent with the predicted mechanisms and pathophysiology of CPP.

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ABSTRACT Pubertal timing in humans is determined by complex interactions including hormonal, metabolic, environmental, ethnic, and genetic factors. Central precocious puberty (CPP) is defined as the premature reactivation of the hypothalamic-pituitary-gonadal axis, starting before the ages of 8 and 9 years in girls and boys, respectively; familial CPP is defined by the occurrence of CPP in two or more family members. Pioneering studies have evidenced the participation of genetic factors in pubertal timing, mainly identifying genetic causes of CPP in sporadic and familial cases. In this context, rare activating mutations were identified in genes of the kisspeptin excitatory pathway (KISS1R and KISS1 mutations). More recently, loss-of-function mutations in two imprinted genes (MKRN3 and DLK1) have been identified as important causes of familial CPP, describing novel players in the modulation of the hypothalamic-pituitary-gonadal axis in physiological and pathological conditions. MKRN3 mutations are the most common cause of familial CPP, and patients with MKRN3 mutations present clinical features indistinguishable from idiopathic CPP. Meanwhile, adult patients with DLK1 mutations present high frequency of metabolic alterations (overweight/obesity, early onset type 2 diabetes and hyperlipidemia), indicating that DLK1 may be a novel link between reproduction and metabolism. Arch Endocrinol Metab. 2019;63(4):438-44

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MKRN3 mutations represent the most common genetic cause of central precocious puberty (CPP) but associations between genotype and clinical features have not been extensively explored. This systematic review and meta-analysis investigated genotype-phenotype associations and prevalence of MKRN3 mutations in CPP. The search was conducted in seven electronic databases (Cochrane, EMBASE, LILACS, LIVIVO, PubMed, Scopus, and Web of Science) for articles published until 4 September 2018. Studies evaluating MKRN3 mutations in patients with CPP were considered eligible. A total of 22 studies, studying 880 subjects with CPP, fulfilled the inclusion criteria. Eighty-nine subjects (76 girls) were identified as harboring MKRN3 mutations. Girls, compared with boys, exhibited earlier age at pubertal onset (median, 6.0 years; range, 3.0 to 7.0 vs 8.5 years; range, 5.9 to 9.0; P < 0.001), and higher basal FSH levels (median, 4.3 IU/L; range, 0.7 to 13.94 IU/L vs 2.45 IU/L; range, 0.8 to 13.70 IU/L; P = 0.003), and bone age advancement (ΔBA; median, 2.3 years; range, -0.9 to 5.2 vs 1.2 years; range, 0.0 to 2.3; P = 0.01). Additional dysmorphisms were uncommon. A total of 14 studies evaluating 857 patients were included for quantitative analysis, with a pooled overall mutation prevalence of 9.0% (95% CI, 0.04 to 0.15). Subgroup analysis showed that prevalence estimates were higher in males, familial cases, and in non-Asian countries. In conclusion, MKRN3 mutations are associated with nonsyndromic CPP and manifest in a sex-dimorphic manner, with girls being affected earlier. They represent a common cause of CPP in western countries, especially in boys and familial cases.

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Background Puberty is associated with a physiological decline in insulin sensitivity (IS). Overweight (OW) and obesity (OB) are common among girls with central precocious puberty (CPP). CPP is considered a risk factor for metabolic diseases. The aim of this study was to assess surrogate measures of IS, body mass index (BMI) and other metabolic parameters in CPP girls at diagnosis and during treatment with gonadotropin-releasing hormone analogues (GnRHa). Methods We present a prospective longitudinal study of CPP girls. The standard oral glucose tolerance test, homeostatic model assessment of insulin resistance (HOMA-IR), whole-body IS index (ISI) and fasting lipid profiles were evaluated at diagnosis, and at 6 and 12 months of treatment. Results Nineteen CPP girls were included; 17 were evaluable. At baseline, seven patients had normal weight (NW), five were OW and five were OB. During GnRHa treatment no significant changes were observed in BMI, HOMA-IR or ISI when considering the whole group. Whereas, when we analyzed patients according to BMI status, in NW patients, BMI increased significantly with no changes in HOMA-IR or ISI along treatment. In the OW/OB group, no significant differences were observed in BMI, HOMA-IR or ISI. Conclusions Girls with CPP showed a high frequency of OW/OB and a high prevalence of IR. GnRHa did not affect BMI, IS or the lipid profile when considering the whole cohort of patients. However, there was an increase in BMI in NW girls but not in OW/OB patients.

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