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.

Background Central precocious puberty (CPP) has been associated with loss-of-function mutations in two paternally expressed genes (MKRN3 and DLK1). Rare defects in the DLk1 were also associated with poor metabolic phenotype at adulthood. Objective Our aim was to investigate genetic and biochemical aspects of DLK1 in a Spanish cohort of children with CPP without MKRN3 mutations. Patients A large cohort of children with idiopathic CPP (Spanish PUBERE Registry) was studied. Genomic DNA was obtained from 444 individuals (168 index cases) with CPP and their close relatives. Automatic sequencing of MKRN3 and DLK1 genes were performed. Results Five rare heterozygous mutations of MKRN3 were initially excluded in girls with familial CPP. A rare allelic deletion (c.401_404+8del) in the splice site junction of DLK1 was identified in a Spanish girl with sporadic CPP. Pubertal signs started at 5.7 years. Her metabolic profile was normal. Familial segregation analysis showed that the DLK1 deletion was de novo in the affected child. Serum DLK1 levels were undetectable (<0.4 ng/mL), indicating that the deletion lead to complete lack of DLK1 production. Three others rare allelic variants of DLK1 were also identified (p.Asn134=; g.-222 C>A and g.-223 G>A) in two girls with CPP However, both had normal DLK1 serum levels. Conclusion Loss-of-function mutations of DLK1 represent a rare cause of CPP, reinforcing a significant role of this factor in human pubertal timing.

Context Loss-of-function mutations of makorin RING finger protein 3 (MKRN3) are the most common monogenic cause of familial central precocious puberty (CPP). Objective To describe the clinical and hormonal features of a large cohort of patients with CPP due to MKRN3 mutations and compare the characteristics of different types of genetic defects. Methods Multiethnic cohort of 716 patients with familial or idiopathic CPP screened for MKRN3 mutations using Sanger sequencing. A group of 156 Brazilian girls with idiopathic CPP (ICPP) was used as control group. Results Seventy-one patients (45 girls and 26 boys from 36 families) had 18 different loss-of-function MKRN3 mutations. Eight mutations were classified as severe (70% of patients). Among the 71 patients, first pubertal signs occurred at 6.2 ± 1.2 years in girls and 7.1 ± 1.5 years in boys. Girls with MKRN3 mutations had a shorter delay between puberty onset and first evaluation and higher follicle-stimulating hormone levels than ICPP. Patients with severe MKRN3 mutations had a greater bone age advancement than patients with missense mutations (2.3 ± 1.6 vs 1.6 ± 1.4 years, P = .048), and had higher basal luteinizing hormone levels (2.2 ± 1.8 vs 1.1 ± 1.1 UI/L, P = .018) at the time of presentation. Computational protein modeling revealed that 60% of the missense mutations were predicted to cause protein destabilization. Conclusion Inherited premature activation of the reproductive axis caused by loss-of-function mutations of MKRN3 is clinically indistinct from ICPP. However, the type of genetic defect may affect bone age maturation and gonadotropin levels.

Introduction: Loss-of-function mutation of MKRN3 represents the most frequent genetic cause of familial central precocious puberty (CPP). The outcomes of gonadotropin-releasing hormone analog (GnRHa) treatment in CPP patients with MKRN3 defects are unknown. Objective: To describe the clinical and hormonal features of patients with CPP with or without MKRN3 mutations after GnRHa treatment. Anthropometric, metabolic and reproductive parameters were evaluated. Patients and Methods: Twenty-nine female patients with CPP due to loss-of-function mutations in the MKRN3 and 43 female patients with idiopathic CPP were included. Their medical records were retrospectively evaluated for clinical, laboratory, and imaging study, before, during,

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 gonadotropin-releasing hormone (GnRH) and consequently, in the premature reactivation of hypothalamic-pituitary-gonadal (HPG) axis. The activation of excitatory factors or suppression of inhibitory factors during childhood represent the two 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 (e.g., hamartomas, gliomas), syndromic disorders associated with CPP (Temple, Prader-Willi, Silver-Russell, and Rett syndromes), and isolated CPP due to 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 since they are potentially associated with CPP.

Puberty is a crucial biological process normally occurring at a specific time during the lifespan, during which sexual and somatic maturation are completed, and reproductive capacity is reached. Pubertal timing is not only determined by genetics, but also by endogenous and environmental cues, including nutritional and metabolic signals. During the last decade, we have learned much regarding the essential roles of kisspeptins and the neuropeptide pathways that converge on these neurones to modulate kisspeptin signalling, as well as neurokinin B and dynorphin, the co‐transmitters of Kiss1 neurones in the arcuate nucleus, and the effects of melanocortins on puberty. Indeed, melanocortins are involved in transmitting the regulatory actions of metabolic cues on pubertal maturation. Intracellular metabolic sensors, such as the AMP‐activated protein kinase and the fuel‐sensing deacetylase SIRT1, have been shown to contribute to puberty. Further understanding of these signals and regulatory circuits will help uncover the intimacies of the central control of puberty, as well as how alterations in metabolic status, ranging from undernutrition to obesity, affect the pubertal process. Precocious puberty is rare and has a clear female predominance. Central precocious puberty (CPP) is diagnosed when premature activation of the hypothalamic‐pituitary axis occurs. Its causes are heterogeneous, with alterations of the central nervous system being of special interest, and with environmental factors also playing a role in some cases. During the last decade, several mutations in different genes (including KISS1, KISS1R, MKRN3 and DLK1) that cause CPP have been discovered. Loss‐of‐function mutations in MKRN3 are the most common monogenic cause of CPP known to date. Here, we review and update what is known regarding the genotype‐phenotype relationship in patients with CPP.

Background: Hyperglycemic hypoglycemia (HH) is most commonly caused by a single, sporadic insulinoma. Insulinomatosis is a rare cause of HH. The histology is characterized by several tumors and grouping of neuroendocrine cells that produce exclusively insulin. (1) Case report: A 52 year old woman, with no known disease, presented to a tertiary hospital with a 1 year record of several, recurrent hypoglycemic episodes. During one of this episodes the laboratory workout revealed: glucose 26 mg/dL (1.44 mmol/L), insulin 13.4 µU/mL (< 3 µg/dL), C-peptide 2,7 ng/dL (<0,6 ng/dL), negative cetonemia and negative sulfonylurea hypoglycemia panel, which confirmed a HH case. Subsequently she performed abdominal magnetic resonance imaging (MRI) and endoscopic ultrasonography, which were normal, and a pancreatic arteriography with intra-arterial calcium stimulation that revealed a 6.2 insulin gradient in the splenic artery consistent with a higher insulin production in the pancreatic body/tail. Another directed MRI scan revealed a small (1 cm) T2-Hyperintense lesion which was previously unnoted in the pancreatic tail. This lesion was enucleated, with histology showing a insulin positive neuroendocrine tumor. Unexpectedly, enucleation of the lesion did not lead to symptoms remission, and the patient relapsed on hypoglycemic episodes, which were confirmed by a second fasting test. MRI was repeated and showed a new pancreatic tail lesion (1.0 cm). Distal pancreatectomy was performed, and detailed histopathological examination revealed several small (< 0.5cm) tumors along the pancreatic body with positive immunohistochemistry staining for insulin, chromogranin A, synaptophysin and negative for glucagon. After the second surgical procedure, the patient showed symptomatic remission with no further hypoglycemia. Conclusion: We have described a rare case of HH caused by insulinomatosis. Although initial presentation could point out to an insulinoma, the recurrence of hypoglycemia after enucleation of the suspected lesion suggested another etiology. Subsequent surgery and histologic study confirmed the insulinomatosis hypothesis. Its histology is characterized by multiple neuroendocrine tumors producing exclusively insulin, which could comprise the concurrence of different lesions, including macrotumors, microadenomas (<0,5cm), and/or small proliferative insulin-expressing monohormal endocrine cell clusters (IMECCs). This represents a rare cause of HH, and literature is scarce on the management of this condition. It has been described high recurrence of hypoglycemic episodes. The patient is currently being followed in our service with no further hypoglycemic episodes.

Context No consensus has been reached regarding the glucocorticoid (GC) to use for congenital adrenal hyperplasia (CAH) during adulthood. Dexamethasone (DEX), because of its longer half-life, could improve compliance; however, no data are available regarding the long-term effects of DEX therapy. Objective To analyze the metabolic effect of DEX therapy for adults with CAH. Design Retrospective analysis of a CAH cohort receiving DEX therapy. Setting Medical School Hospital, São Paulo University, Brazil. Participants Sixty patients with well-controlled classic CAH (41 women; 30 with salt-wasting) receiving DEX after achievement of final height. Interventions None. Main Outcome Measures Clinical, laboratory, and metabolic data were compared immediately before DEX and at the last evaluation. Results The mean age at the last evaluation was 31.9 ± 9.6 years, and the duration of DEX therapy was 11.5 ± 4.9 years. The mean DEX dose was 0.18 ± 0.07 mg/m2/d. The body mass index SD score (1.6 ± 1.6 vs 1.5 ± 1.5 mg/m2; P = 0.65) and obesity prevalence (27% vs 27%) did not differ between evaluations. However, the waist/height ratio (WtHR) had increased from 0.54 ± 0.08 to 0.56 ± 0.1 (P = 0.001). An increase in the homeostatic model assessment for insulin resistance index (2.5 ± 1.3 vs 2.8 ± 1.7; P = 0.03) was observed and positively correlated with the WtHR (r = 0.54). The prevalence of metabolic syndrome (7% vs 10%; P = 0.7) and hypertension (15% vs 13.3%; P = 0.8) did not differ significantly between the two evaluations. Conclusions Long-term and low-dose DEX therapy did not lead to increases in obesity or metabolic syndrome, although it was associated with an increased WtHR and greater homeostatic model assessment for insulin resistance observed with chronic use of GCs. DEX appears to be an acceptable option to treat adult CAH.