Genetics of pubertal timing

Novel variants ensued genomic imprinting in familial central precocious puberty

INTRODUCTION

Central precocious puberty (CPP) is characterized by the early onset of puberty and is associated with the critical processes involved in the pubertal switch. The puberty-related gene pool in the human genome is considerably large though few have been described in CPP. Within those genes, the genomic imprinting features of the MKRN3 and DLK1 genes add additional complexity to the understanding of the pathologic pathways. This study aimed to investigate the molecular etiology in the CPP cohort.

METHODS

Eighteen familial CPP cases were investigated by Sanger sequencing for five CPP-related genes; DLK1, KISS1, KISS1R, MKRN3, and PROKR2. Segregation analysis was performed in all patients with pathogenic variants. Using an ELISA test, the functional pathogenicity of novel variants was also investigated in conjunction with serum delta-like 1 homolog (DLK1) concentrations.

RESULTS

In three probands, a known variant in the MKRN3 gene (c.982C>T/p.(Arg328Cys)) and two novel variants in the DLK1 gene (c.357C>G/p.(Tyr119Ter) and c.67+78C>T) were identified. All three were inherited from the paternal allele. The individuals carrying the DLK1 variants had low detectable DLK1 levels in their serum.

CONCLUSIONS

The frequencies were 5.5% (1/18) for MKRN3 11% (2/18) for DLK1, and none for either KISS1, KISS1R, and PROKR2. Low serum DLK1 levels in affected individuals supported the relationship between here described novel DLK1 gene variants with CPP. Nonsense nature of c.357C>G/p.(Tyr119Ter) and an alteration in the evolutionarily conserved nucleotide c.67+78C>T suggested the disruptive nature of the variant's compatibility with CPP.

Genetic and non-genetic factors in prediction of early pubertal development in Chinese girls

Objective

The objective of this study is to develop a combined predictive model for early pubertal development (EPD) in girls based on both non-genetic and genetic factors.

Methods

The case-control study encompassed 147 girls diagnosed with EPD and 256 girls who exhibited normal pubertal development. The non-genetic risk score (NGRS) was calculated based on 6 independent biochemical predictors screened by multivariate logistic regressions, and the genetic risk score (GRS) was constructed using 28 EPD related single-nucleotide polymorphisms (SNPs). Area under receiver operator characteristic curve (AROC), net reclassification optimization index (NRI) and integration differentiation index (IDI) were used to evaluate the improvement of adding genetic variants to the non-genetic risk model.

Results

Overweight (OR=2.74), longer electronic screen time (OR=1.79) and higher ratio of plastic bottled water (OR=1.01) were potential risk factors, and longer exercise time (OR=0.51) and longer day sleeping time (OR=0.97) were protective factors for EPD, and the AROC of NGRS model was 83.6% (79.3-87.9%). The GRS showed a significant association with EPD (OR=1.90), and the AROC of GRS model was 65.3% (59.7-70.8%). After adding GRS to the NGRS model, the AROC significantly increased to 85.7% (81.7-89.6%) (P=0.020), and the reclassification significantly improved, with NRI of 8.19% (P= 0.023) and IDI of 4.22% (P <0.001).

Conclusions

We established a combined prediction model of EPD in girls. Adding genetic variants to the non-genetic risk model brought modest improvement. However, the non-genetic factors such as overweight and living habits have higher predictive utility.

Behavioral and neural responses to social rejection: Individual differences in developmental trajectories across childhood and adolescence

Dealing with social rejection is challenging, especially during childhood when behavioral and neural responses to social rejection are still developing. In the current longitudinal study, we used a Bayesian multilevel growth curve model to describe individual differences in the development of behavioral and neural responses to social rejection in a large sample (n > 500). We found a peak in aggression following negative feedback (compared to neutral feedback) during late childhood, as well as individual differences during this developmental phase, possibly suggesting a sensitive window for dealing with social rejection across late childhood. Moreover, we found evidence for individual differences in the linear development of neural responses to social rejection in our three brain regions of interest: The anterior insula, the medial prefrontal cortex, and the dorsolateral prefrontal cortex. In addition to providing insights in the individual trajectories of dealing with social rejection during childhood, this study also makes a meaningful methodological contribution: Our statistical analysis strategy (and can be found in this study's online supplementary materials at https://jeroendmulder.github.io/social-emotion-regulation/) can be used as an example on how to take into account the many complexities of developmental neuroimaging datasets, while still enabling researchers to answer interesting questions about individual-level relationships.

COVID-19 lockdown and the rate of central precocious puberty

PURPOSE

The aim of our study was to compare the incidence of idiopathic central precocious puberty (CPP) in our highly specialized Endocrinological Center before and after the onset of COVID-19 lockdown; we also aimed to identify any potential difference between girls with CPP from the two different time periods.

METHODS

We retrospectively analyzed the auxological profile of 49 girls with idiopathic CPP: 30 with pre-lockdown onset and 19 with post-lockdown onset of the disease. We collected patients' characteristics (medical history, physical examination, baseline and dynamic hormonal assessment, bone age, pelvic ultrasound) and compared them between the two groups.

RESULTS

We registered an almost threefold increase in CPP incidence in the 2020-2021 period compared to the previous six years. In post-lockdown patients we found a trend for an earlier diagnosis in terms of both chronological age (p 0.0866) and days between the onset of first pubertal signs and diagnosis (p 0.0618). We also found that post-lockdown patients had a significantly lower hypothalamus-pituitary-gonadal axis activation (lower ∆LH% after GnRH test, p 0.0497), a significantly lower increase in bone age calculated at RUS with TW3 method (p 0.0438) and a significantly reduced ovarian activation in females (lower delta-4-androstenedione levels, p 0.0115). Interestingly, post-lockdown patients were born from mothers with an older age at menarche (p 0.0039).

CONCLUSIONS

Besides confirming a significant increase in new diagnoses of CPP in the post-lockdown period, our findings among Post-lockdown girls also suggest a less progressive form of CPP and a stronger environmental influence compared to genetic background in determining the timing of pubertal onset.

Endocrine Health and Health Care Disparities in the Pediatric and Sexual and Gender Minority Populations: An Endocrine Society Scientific Statement

Endocrine care of pediatric and adult patients continues to be plagued by health and health care disparities that are perpetuated by the basic structures of our health systems and research modalities, as well as policies that impact access to care and social determinants of health. This scientific statement expands the Society's 2012 statement by focusing on endocrine disease disparities in the pediatric population and sexual and gender minority populations. These include pediatric and adult lesbian, gay, bisexual, transgender, queer, intersex, and asexual (LGBTQIA) persons. The writing group focused on highly prevalent conditions-growth disorders, puberty, metabolic bone disease, type 1 (T1D) and type 2 (T2D) diabetes mellitus, prediabetes, and obesity. Several important findings emerged. Compared with females and non-White children, non-Hispanic White males are more likely to come to medical attention for short stature. Racially and ethnically diverse populations and males are underrepresented in studies of pubertal development and attainment of peak bone mass, with current norms based on European populations. Like adults, racial and ethnic minority youth suffer a higher burden of disease from obesity, T1D and T2D, and have less access to diabetes treatment technologies and bariatric surgery. LGBTQIA youth and adults also face discrimination and multiple barriers to endocrine care due to pathologizing sexual orientation and gender identity, lack of culturally competent care providers, and policies. Multilevel interventions to address these disparities are required. Inclusion of racial, ethnic, and LGBTQIA populations in longitudinal life course studies is needed to assess growth, puberty, and attainment of peak bone mass. Growth and development charts may need to be adapted to non-European populations. In addition, extension of these studies will be required to understand the clinical and physiologic consequences of interventions to address abnormal development in these populations. Health policies should be recrafted to remove barriers in care for children with obesity and/or diabetes and for LGBTQIA children and adults to facilitate comprehensive access to care, therapeutics, and technological advances. Public health interventions encompassing collection of accurate demographic and social needs data, including the intersection of social determinants of health with health outcomes, and enactment of population health level interventions will be essential tools.

[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.

Neighborhood Racial and Economic Privilege and Timing of Pubertal Onset in Girls

PURPOSE

Early puberty is associated with adverse health outcomes over the life course, and Black and Hispanic girls experience puberty earlier than girls of other racial/ethnic backgrounds. Neighborhood racial and economic privilege may contribute to these disparities by conferring differential exposure to mechanisms (e.g., stress, obesity, endocrine disruptors) underlying early puberty. We examined associations between neighborhood privilege, measured by the Index of Concentration at the Extremes (ICE), and age at pubic hair onset (pubarche) and breast development onset (thelarche) in a large multiethnic cohort.

METHODS

A cohort of 46,299 girls born 2005-2011 at Kaiser Permanente Northern California medical facilities were followed until 2021. Pubertal development was assessed routinely by pediatricians using the Sexual Maturity Rating scale. ICE quintiles for race/ethnicity, income, and income + race/ethnicity were calculated using American Community Survey 2010 5-year estimates and linked to census tract at birth. We fit multilevel Weibull regression models accommodating left, right, and interval censoring for all analyses.

RESULTS

ICE measures were monotonically associated with pubertal onset, with the strongest associations observed for ICE-race/ethnicity. Adjusting for maternal education, age at delivery, and parity, girls from the least versus most privileged ICE-race/ethnicity quintiles were at increased risk for earlier pubarche (hazard ratio: 1.30, 95% confidence interval: 1.21, 1.38) and thelarche (hazard ratio: 1.45, 95% confidence interval: 1.36, 1.54). These associations remained significant after adjusting for girls' race/ethnicity and childhood body mass index. Additionally, adjustment for ICE partially attenuated Black-White and Hispanic-White disparities in pubertal onset.

DISCUSSION

Neighborhood privilege may contribute to pubertal timing and related disparities.

Gene-Environment Interplay Linking Peer Victimization With Adolescents' Trajectories of Depressive Symptoms

OBJECTIVE

This study examined to what extent genetic and environmental factors explain-either additively or interactively with peer victimization-different trajectories of adolescents' depressive symptoms and whether genetic factors related to distinct trajectories are correlated with peer victimization.

METHOD

Participants included 902 twins (52% girls) who self-reported peer victimization and depressive symptoms in grades 6, 7, 8, 9, and 11.

RESULTS

Growth mixture modeling revealed 3 trajectories of depressive symptoms: low (69.2% of participants), increasing (19.5%), and high-decreasing-increasing (11.3%). Biometric modeling showed that, for both sexes, genetic factors explained roughly half (52.6%, 47.5%) of the probability of following either a low or an increasing trajectory. Genetic influences (41%) were also observed for the high-decreasing-increasing trajectory, albeit only for girls. Nonshared environmental influences explained the remaining variances, along with shared environmental influences (27%) on the high-decreasing-increasing trajectory. Only for the low and the increasing trajectories, nonshared environmental influences increased with more frequent peer victimization (b_low = 0.206, 95% CI [0.094, 0.325]; b_increasing = 0.246, 95% CI [0.143, 0.356]). Moreover, peer victimization was associated with a lower probability of a low trajectory and a higher probability of an increasing or high-decreasing-increasing trajectory, and these associations were mostly explained by common underlying genetic factors.

CONCLUSION

Youth expressing (partly inherited) depressive symptoms may be at risk of peer victimization. However, increasing depressive symptoms in victims may be mitigated by other environmental factors except for those who enter adolescence with already high levels of depressive symptoms.

The Role of Genetics in Central Precocious Puberty: Confirmed and Potential Neuroendocrine Genetic and Epigenetic Contributors and Their Interactions with Endocrine Disrupting Chemicals (EDCs)

Despite the growing prevalence of central precocious puberty (CPP), most cases are still diagnosed as “idiopathic” due to the lack of identifiable findings of other diagnostic etiology. We are gaining greater insight into some key genes affecting neurotransmitters and receptors and how they stimulate or inhibit gonadotropin-releasing hormone (GnRH) secretion, as well as transcriptional and epigenetic influences. Although the genetic contributions to pubertal regulation are more established in the hypogonadotropic hypogonadism (HH) literature, cases of CPP have provided the opportunity to learn more about its own genetic influences. There have been clinically confirmed cases of CPP associated with gene mutations in kisspeptin and its receptor (KISS1, KISS1R), Delta-like noncanonical Notch ligand 1 (DLK1), and the now most commonly identified genetic cause of CPP, makorin ring finger protein (MKRN3). In addition to these proven genetic causes, a number of other candidates continue to be evaluated. After reviewing the basic clinical aspects of puberty, we summarize what is known about the various genetic and epigenetic causes of CPP as well as discuss some of the potential effects of endocrine disrupting chemicals (EDCs) on some of these processes.

Psychosocial and energetic factors on human female pubertal timing: a systematized review

Childhood psychosocial stressors have been proposed to favour fast life history strategies promoting earlier puberty in females. However, studies demonstrating this association often do not elucidate causal mechanisms, nor account for greater childhood energetic availability - also known to promote rapid growth and earlier puberty. To assess the extent to which such confounding has been considered, we conducted a systematized review to identify studies examining measures of both prepubertal growth (e.g. weight, height) and psychosocial stressors (e.g. adversity, father absence) in relation to female pubertal timing. A total of 1069 non-duplicated studies were identified across five databases. Twenty studies met selection criteria for critical review following independent screening of titles, abstracts and manuscripts. Within these studies, measures indicative of rapid childhood growth were more consistently associated with earlier pubertal timing than were measures of psychosocial stress. We discuss future research directions to investigate the impact of psychosocial stress on pubertal timing more robustly, including methodological and mechanistic considerations, and contextualization of findings by socioecological environments.

Analysis of Early-Life Growth and Age at Pubertal Onset in US Children

Importance

Earlier pubertal onset may be associated with an increased risk of chronic diseases. However, the extent to which growth in the first 5 years of life-an important developmental life stage that lays the foundation for later health outcomes-is associated with pubertal onset remains understudied.

Objective

To assess whether changes in weight, length or height, and body mass index (BMI, calculated as weight in kilograms divided by height in meters squared) during the first 5 years of life are associated with earlier pubertal onset.

Design, Setting, and Participants

This cohort study used data from 36 cohorts participating in the Environmental Influences on Child Health Outcomes program from January 1, 1986, to December 31, 2015. Participant inclusion required at least 1 anthropometric measure in the first 5 years of life and at least 1 measure of pubertal onset. Data were analyzed from January 1 to June 30, 2021.

Exposures

Standardized velocities of weight, length or height, and BMI gain in early infancy (0-0.5 years), late infancy (0.5-2 years), and early childhood (2-5 years).

Main Outcomes and Measures

Markers of pubertal onset for boys and girls, including age at peak height velocity (APHV), time to puberty score greater than 1, time to Tanner pubic hair stage greater than 1, and time to menarche. Multivariable regression models were used to estimate mean differences in APHV by growth periods.

Results

Of 7495 children included in the study, 3772 (50.3%) were girls, 4505 (60.1%) were White individuals, and 6307 (84.1%) were born during or after the year 2000. Girls had a younger APHV (10.8 vs 12.9 years) than boys. In boys, faster weight gain (per 1-SD increase) in early infancy (β, -0.08 years; 95% CI, -0.10 to -0.06), late infancy (β, -0.10 years; 95% CI, -0.12 to -0.08), and early childhood (β, -0.07 years; 95% CI, -0.08 to -0.05) was associated with younger APHV after adjusting for the child's birth year, race, and Hispanic ethnicity as well as maternal age at delivery; educational level during pregnancy; annual household income during pregnancy; prenatal cigarette smoking; whether the mother was nulliparous; whether the mother had gestational diabetes, hypertension, or preeclampsia; mode of delivery; prepregnancy BMI; gestational weight gain; and gestational age at delivery. Similar associations were observed for length or height and BMI gains during the same age periods. In girls, faster gains (per 1-SD increase) in weight (β, -0.03 years; 95% CI, -0.05 to -0.01) and height (β, -0.02 years; 95% CI, -0.04 to 0.00) in early childhood were associated with younger APHV. Faster BMI gain in late infancy was associated with earlier time to menarche, whereas faster BMI gain in early childhood was associated with earlier time to Tanner pubic hair stage greater than 1.

Conclusions and Relevance

This cohort study found that faster gains in weight, length or height, or BMI in early life were associated with earlier pubertal onset. The results suggest that children who experience faster early growth should be monitored closely for earlier onset of puberty and referred as appropriate for supportive services.

Gene Polymorphisms Associated with Central Precocious Puberty and Hormone Levels in Chinese Girls

Central precocious puberty (CPP) is associated with adverse health outcomes in females; however, CPP pathogenesis remains unclear. In this study, we investigated the association of 20 single nucleotide polymorphisms (SNPs) in eight genes with CPP risk and hormone levels. A case-control study on 247 and 243 girls with and without CPP, respectively, was conducted at Kunming Children's Hospital, China, from September 2019 to August 2020. The genotype of the SNPs and their haplotypes were identified. Additionally, the effects of the polymorphisms on hormone levels were investigated. Three variants (rs10159082, rs7538038, and rs5780218) in KISS1 and two variants (rs7895833 and rs3758391) in SIRT1 were related to an increased CPP risk (odds ratio (OR) = 1.524, 1.507, 1.409, 1.348, and 1.737; 95% confidence interval (CI) = 1.176-1.974, 1.152-1.970, 1.089-1.824, 1.023-1.777, and 1.242-2.430, respectively). Rs3740051in SIRT1 and rs1544410 in VDR reduced CPP risk (OR = 0.689, 0.464; 95% CI, 0.511-0.928, 0.232-0.925, respectively). Rs1544410, rs7975232, and rs731236 in VDR were negatively correlated with peak follicle-stimulating hormone (FSH; β = -2.181; P=0.045), basal FSH (β = -0.391; P=0.010), and insulin-like growth factor (β = -50.360; P=0.041) levels, respectively. KISS1, SIRT1, and VDR variants were associated with CPP susceptibility, and VDR SNPs influenced hormonal levels in Chinese females with CPP. In particular, VDR polymorphism rs1544410 was associated with both CPP risk and GnRH-stimulated peak FSH levels. Further functional research and large-scale genetic studies of these loci and genes are required to confirm our findings.

Genetic and Epigenetic Control of Puberty

Puberty is a complex transitional phase in which reproductive capacity is achieved. There is a very wide variation in the age range of the onset of puberty, which follows a familial, ethnic, and sex pattern. The hypothalamic-pituitary-gonadal axis and several genetic, environmental, and nutritional factors play an important role in the onset of and throughout puberty. Recently, there has been significant progress in identifying factors that affect normal pubertal timing. Different studies have identified single nucleotide polymorphisms (SNPs) that affect pubertal timing in both sexes and across ethnic groups. Single genes are implicated in both precocious and delayed puberty, and epigenetic mechanisms have been suggested to affect the development and function of the GnRH neuronal network and responsiveness of end organs. All these factors can influence normal puberty timing, precocious puberty, and delayed puberty. The objective of this review is to describe recent findings related to the genetic and epigenetic control of puberty and highlight the need to deepen the knowledge of the regulatory mechanisms of this process in the normal and abnormal context.

Biological basis of child health 12: the endocrine system and common childhood endocrinopathies

This article, the 12th in a series on the biological basis of child health, focuses on the endocrine system. This system works alongside the nervous system to regulate the functioning of the human body using chemical mediators called hormones. It is composed of several glands secreting a wide range of hormones that act on target cells in organs and tissues. Various functions of the human body are controlled by the endocrine system, including growth, puberty, metabolism and bone health. This article explores the anatomy and pathophysiology of the endocrine system, the effects of hormonal excesses or deficiencies on the body, and the presentation and management of endocrinopathies commonly seen in children.

The role of the hypothalamus and pituitary epigenomes in central activation of the reproductive axis at puberty

Puberty is programmed through a multifactorial gene network which works to activate the pulsatile secretion of the gonadotropin releasing hormone (GnRH), and subsequently elevate circulating levels of the pituitary gonadotropins that stimulate gonadal activity. Although this developmental transition normally occurs at a limited age-range in individuals of the same genetic background and environment, pubertal onset can occur prematurely or be delayed following changes in ambient conditions, or due to genetic variations or mutations, many of which have remained elusive due to their location in distal regulatory elements. Growing evidence is pointing to a pivotal role for the epigenome in regulating key genes in the reproductive hypothalamus and pituitary at this time, which might mediate some of the plasticity of pubertal timing. This review will address epigenetic mechanisms which have been demonstrated in the KNDy neurons that increase the output of pulsatile GnRH, and those involved in activation of the GnRH gene and its receptor, and describes how GnRH utilizes epigenetic mechanisms to stimulate transcription of the pituitary gonadotropin genes in the context of the chromatin landscape.

Adolescent Sport Participation and Age at Menarche in Relation to Midlife Body Composition, Bone Mineral Density, Fitness, and Physical Activity

This study aimed to investigate the associations of competitive sport participation in adolescence and age at menarche (AAM) with body composition, femoral neck bone mineral density (BMD), physical performance, and physical activity (PA) in middle-aged women. 1098 women aged 47–55 years formed the sample of this retrospective study. Participants self-reported their PA level at age 13–16 years and AAM. The protocol also included dual-energy X-ray absorptiometry, physical performance tests, and accelerometer-measured PA. Participants were divided into three groups according to their PA level at the age of 13–16 (no exercise, regular PA, and competitive sport) and according to their AAM (≤12, 13, and ≥14 years). After adjusting for potential confounding factors, participation in competitive sport at age 13–16 was associated with higher midlife lean mass and BMD, and better physical performance compared to groups with no exercise or regular PA. Individuals with AAM ≥ 14 years had lower midlife BMI and fat mass than participants in the other AAM groups and pre- and perimenopausal women with AAM ≥ 14 years had lower BMD than those with AAM ≤ 12. The findings indicate that participation in competitive sport in adolescence is associated with healthier body composition, higher BMD, and better physical performance in midlife, but BMD might be impaired if menarche occurs late.

Menarche at an Earlier Age: Results from Two National Surveys of Israeli Youth, 2003 and 2016

STUDY OBJECTIVE

To assess emergent changes in the age at menarche and investigate associated factors in Israeli adolescents in 2003 and 2016.

DESIGN

Cross-sectional study.

SETTING

Two national representative school-based surveys (first and second "Mabat Youth").

PARTICIPANTS

Both surveys included female students in 7th-12th grades (ages 11-19 years). The first (N = 3328) was conducted between the years 2003 and 2004, and the second (N = 2535) from 2015 to 2016.

INTERVENTIONS

The survey questionnaire was self-administered and anthropometric measurements were performed by trained personnel.

MAIN OUTCOME MEASURES

The current age at menarche in Israeli girls was determined and independent factors (demographic, clinical, and lifestyle) examined. Changes that occurred since the past national survey more than a decade ago were documented.

RESULTS

The estimated median age at menarche declined from 13.0 (interquartile range, 12.0-14.0) years in 2003-2004 to 12.5 (interquartile range, 12.0-13.0) years in 2015-2016 (P < .0001). Jewish girls reached menarche earlier than Arab girls, but both populations experienced a similar downward trend in the past approximately 14 years. Greater body mass index, higher socioeconomic status, and immigrant status were associated with younger menarche onset (P < .001). Age at menarche remained lower in 2015-2016 vs 2003-2004, even after adjustment for these potential confounders, with a high hazard ratio (HR), which decreased as a function of survival time (t): HR_t = 15.417 × 0.813^t.

CONCLUSION

This study confirms the decline in age at menarche in Israel. Findings were associated with body mass index and population group but also indicated that other factors are likely involved.

Recent pubertal timing trends in Northern Taiwanese children: Comparison with skeletal maturity

BACKGROUND

International studies have reported an early age of onset of puberty in girls and boys. However, the current situation of puberty onset in Taiwanese children is unknown. In this study, the timing of menarche and pubertal change in testicular volume (TV) in Taiwanese children was examined, and bone age (BA) was used as an internal somatic maturity scale and compared with the chronological age (CA) at pubertal timing.

METHODS

Clinical data from October 1, 2010, to March 31, 2018, were retrospectively collected from a general hospital in Taipei. The data of patients who were diagnosed with endocrine/genetic disorders were excluded. Clinical data included CA, timing of menarche, and X-ray images of TV and BA. BA was determined by a senior pediatrician and a senior pediatric radiologist. The reliability and validity of BA readings were tested. Collected data were analyzed statistically.

RESULTS

Overall, TV records of 241 boys and the menarche timing data of 98 girls were collected from 1823 children. CA for menarche was 11.35 ± 1.06 years (mean ± SD), and BA for menarche was 12.95 ± 0.80 years. CA and BA at TV = 15 mL in male puberty was 12.32 ± 1.22 and 13.46 ± 0.68 years, respectively. A stronger correlation was observed between TV and BA than between TV and CA during the pubertal period.

CONCLUSION

The secular trend of earlier puberty timing continues. The decline rate of menarche timing was approximately 0.43 years per decade in the past 30 years. Among boys, an advance of more than 1 year in pubertal timing age was observed over the past 20 years. BA and TV showed high correlation during puberty.

Transcription Profiles of Age-at-Maturity-Associated Genes Suggest Cell Fate Commitment Regulation as a Key Factor in the Atlantic Salmon Maturation Process

Despite recent taxonomic diversification in studies linking genotype with phenotype, follow-up studies aimed at understanding the molecular processes of such genotype-phenotype associations remain rare. The age at which an individual reaches sexual maturity is an important fitness trait in many wild species. However, the molecular mechanisms regulating maturation timing processes remain obscure. A recent genome-wide association study in Atlantic salmon (Salmo salar) identified large-effect age-at-maturity-associated chromosomal regions including genes vgll3, akap11 and six6, which have roles in adipogenesis, spermatogenesis and the hypothalamic-pituitary-gonadal (HPG) axis, respectively. Here, we determine expression patterns of these genes during salmon development and their potential molecular partners and pathways. Using Nanostring transcription profiling technology, we show development- and tissue-specific mRNA expression patterns for vgll3, akap11 and six6. Correlated expression levels of vgll3 and akap11, which have adjacent chromosomal location, suggests they may have shared regulation. Further, vgll3 correlating with arhgap6 and yap1, and akap11 with lats1 and yap1 suggests that Vgll3 and Akap11 take part in actin cytoskeleton regulation. Tissue-specific expression results indicate that vgll3 and akap11 paralogs have sex-dependent expression patterns in gonads. Moreover, six6 correlating with slc38a6 and rtn1, and Hippo signaling genes suggests that Six6 could have a broader role in the HPG neuroendrocrine and cell fate commitment regulation, respectively. We conclude that Vgll3, Akap11 and Six6 may influence Atlantic salmon maturation timing via affecting adipogenesis and gametogenesis by regulating cell fate commitment and the HPG axis. These results may help to unravel general molecular mechanisms behind maturation.

Clinical and Genetic Characterization of a Constitutional Delay of Growth and Puberty Cohort

INTRODUCTION

Constitutional delay of growth and puberty (CDGP) is the most prevalent cause of delayed puberty in both sexes. Family history of delayed puberty (2 or more affected members in a family) has been evidenced in 50-75% of patients with CDGP and the inheritance is often consistent with autosomal dominant pattern, with or without complete penetrance. However, the molecular basis of CDGP is not completely understood.

OBJECTIVE

To characterize the clinical and genetic features of a CDGP cohort.

METHODS

Fifty-nine patients with CDGP (48 boys and 11 girls) underwent careful and long-term clinical evaluation. Genetic analysis was performed using a custom DNA target enrichment panel designed to capture 36 known and candidate genes implicated with pubertal development.

RESULTS

All patients had spontaneous or induced pubertal development (transient hormonal therapy) prior to 18 years of age. The mean clinical follow-up time was 46 ± 28 months. Male predominance (81%), short stature (91%), and family history of delayed puberty (59%) were the main clinical features of this CDGP -cohort. Genetic analyses revealed 15 rare heterozygous missense variants in 15 patients with CDGP (25%) in seven different genes (IGSF10, GHSR, CHD7, SPRY4, WDR11, SEMA3A,and IL17RD). IGSF10 and GHSR were the most prevalent affected genes in this group.

CONCLUSIONS

Several rare dominant variants in genes implicated with GnRH migration and metabolism were identified in a quarter of the patients with familial or sporadic CDGP, suggesting genetic heterogeneity in this frequent pediatric condition.

The Makorin lep-2 and the lncRNA lep-5 regulate lin-28 to schedule sexual maturation of the C. elegans nervous system

Sexual maturation must occur on a controlled developmental schedule. In mammals, Makorin3 (MKRN3) and the miRNA regulators LIN28A/B are key regulators of this process, but how they act is unclear. In C. elegans, sexual maturation of the nervous system includes the functional remodeling of postmitotic neurons and the onset of adult-specific behaviors. Here, we find that the lin-28-let-7 axis (the 'heterochronic pathway') determines the timing of these events. Upstream of lin-28, the Makorin lep-2 and the lncRNA lep-5 regulate maturation cell-autonomously, indicating that distributed clocks, not a central timer, coordinate sexual differentiation of the C. elegans nervous system. Overexpression of human MKRN3 delays aspects of C. elegans sexual maturation, suggesting the conservation of Makorin function. These studies reveal roles for a Makorin and a lncRNA in timing of sexual differentiation; moreover, they demonstrate deep conservation of the lin-28-let-7 system in controlling the functional maturation of the nervous system.

Early-life exposure to endocrine-disrupting chemicals and pubertal development in girls

Over the last decades, the onset of puberty in girls has occurred earlier, but the tempo of pubertal progression has been relatively slower, resulting in a younger age at puberty onset without a change in age at menarche. Sufficient energy availability and adiposity contribute to early pubertal development, and environmental factors, such as endocrine-disrupting chemicals (EDCs), may affect not only the control of energy balance, but also puberty and reproduction. EDCs are hormonally active substances that can perturb puberty by acting both peripherally on target organs, such as adipose tissue or adrenal glands, and/or centrally on the hypothalamic-pituitary-gonadal (HPG) axis. Depending on whether the exposure takes place earlier during fetal and neonatal life or later during early childhood, EDCs can lead to different outcomes through different mechanisms. Evidence of associations between exposures to EDCs and altered pubertal timing makes it reasonable to support their relationship. However, human epidemiologic data are limited or inconsistent and cannot provide sufficient evidence for a causal relationship between EDC exposure and changes in pubertal timing. Further investigation is warranted to determine the overall or different effects of EDCs exposure during prenatal or childhood windows on pubertal milestones and to reveal the underlying mechanisms, including epigenetic marks, whereby early-life exposure to EDCs affect the HPG-peripheral tissue axis.