Context: Puberty is initiated by a complex interaction of suppressing and stimulating factors. Genetic studies of familial central precocious puberty have suggested makorin ring finger protein 3 (MKRN3) as a major inhibitor of GnRH secretion during childhood. Furthermore, genetic variation near MKRN3 (rs12148769) affects age at menarche in healthy girls.
Objective: The purpose of this study was to evaluate whether serum levels of MKRN3 declined before pubertal onset in healthy girls.
Design: This was a population-based longitudinal study of healthy Danish girls and a cohort study of early maturing girls.
Setting: The study was performed in the general community and in a tertiary referral center for pediatric endocrinology.
Patients Or Other Participants: Healthy girls (n = 38) aged 9.3 years (range, 5.9-11.3 years) at baseline and followed for 6.0 years (2.7-7.6 years) (2006-2014) with blood sampling every 6 months and early maturing girls (n = 13) with breast development ay <8.3 years of age were included.
Main Outcome Measures: Serum levels of MKRN3 were measured in 354 samples (median, 9 per girl; range, 2-14 per girl), and genotyping of variants near MKRN3 (rs12148769 and rs12439354) was performed.
Results: MKRN3 concentrations declined preceding pubertal onset; the geometric mean (95% confidence interval) 3 years before pubertal onset vs the last visit before pubertal onset was 304 pg/mL (264-350 pg/mL) vs 257 pg/mL (243-273 pg/mL), corresponding to a reduction of 15% (1-27%) (P = .033). In prepubertal girls, circulating MKRN3 correlated negatively with gonadotropin levels: for FSH, r = -0.262 (P = .015) and for LH, r = -0.226 (P = .037). After adjustment, MKRN3 levels were lower in early maturing girls than in age-matched prepubertal girls: 171 pg/mL (<25-333 pg/mL) vs 262 pg/mL (94-624 pg/mL) (P = .051). Genetic variants near MKRN3 did not correlate with serum levels of MKRN3.
Conclusions: Declining levels of circulating MKRN3 preceded pubertal onset. The negative correlation between MKRN3 and gonadotropins further supports MKRN3 as a major regulator of hypothalamic GnRH secretion during childhood. Undetectable or low MKRN3 levels were observed in a subgroup of patients with early onset of puberty.
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http://dx.doi.org/10.1210/jc.2014-4462 | DOI Listing |
Cureus
December 2024
Pediatric Endocrinology Unit, Department of Pediatrics, Centro Hospitalar Universitário de Santo António, Unidade Local de Saúde de Santo António, Centro Materno-Infantil do Norte Albino Aroso, Porto, PRT.
Introduction: In light of the recent evidence suggesting an increase in idiopathic central precocious puberty (ICPP) during the COVID-19 pandemic, this study aimed to assess the incidence of newly diagnosed ICPP cases and compare differences in demographic, anthropometric, and clinical characteristics pre-pandemic and during the pandemic.
Methods: We conducted a retrospective study at a national reference pediatric endocrinology unit in Portugal to evaluate the proportion of referrals for precocious puberty (PP) and, within this group, the number of ICPP cases diagnosed before (group 1: January 2018 to March 2020) and during the pandemic (group 2: April 2020 to June 2022). Additionally, we compared the demographic, anthropometric, and clinical characteristics of ICPP patients between the two groups.
Oral contraceptives (OCs) are approved for use after onset of menarche, which is well before brain maturation is complete. OC use may induce biochemical changes in the brain, especially during the neurobiologically dynamic adolescent/young adult years. MicroRNA cargo in L1CAM-associated extracellular vesicles was measured from serum samples collected from young women using the miRCURY LNA miRNA Focus PCR Panel (Qiagen) and validated using quantitative PCR.
View Article and Find Full Text PDFVitam Horm
January 2025
Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi, Uttar pradesh, India.
The discovery of Kisspeptin (Kiss) has opened a new direction in research on neuroendocrine control of reproduction in vertebrates. Belonging to the RF amide family of peptides, Kiss and its cognate receptor Gpr54 (Kissr) have a long and complex evolutionary history. Multiple forms of Kiss and Kissr are identified in non-mammalian vertebrates, with the exception of birds, and monotreme mammals.
View Article and Find Full Text PDFChildren (Basel)
January 2025
Department of Pediatrics, Division of Pediatric Endocrinology, Demiroğlu Bilim University, 34394 Istanbul, Türkiye.
This review examines the inconsistent effects of endocrine-disrupting chemicals (EDCs) and pollutants on pubertal timing, emphasizing the methodological challenges contributing to variability in findings. Data from nine key studies reveal that chemicals such as BPA, phthalates, and PFAS impact pubertal onset differently based on exposure timing, dosage, and sex. For instance, BPA is linked to earlier puberty in girls but delayed onset in boys, while other EDCs show mixed effects across populations.
View Article and Find Full Text PDFJ Pediatr Endocrinol Metab
January 2025
Department of Paediatrics, School of Medical Sciences, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
Objectives: Kisspeptin plays a major role in the onset of puberty by stimulating the gonadotropin-releasing hormone (GnRH) neurons. The aim of this study was to investigate whether GnRH inhibits kisspeptin secretion via a negative feedback mechanism and potential associations between kisspeptin levels and other hormones of importance for pubertal onset.
Methods: Thirteen girls with suspected central precocious puberty underwent a GnRH stimulation test twice in a randomized, placebo-controlled manner.
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