Central precocious puberty in girls with Williams syndrome

Altered pubertal timing in 7q11.23 copy number variations and associated genetic mechanisms

Pubertal timing, including age at menarche (AAM), is a heritable trait linked to lifetime health outcomes. Here, we investigate genetic mechanisms underlying AAM by combining genome-wide association study (GWAS) data with investigations of two rare genetic conditions clinically associated with altered AAM: Williams syndrome (WS), a 7q11.23 hemideletion characterized by early puberty; and duplication of the same genes (7q11.23 Duplication syndrome [Dup7]) characterized by delayed puberty. First, we confirm that AAM-derived polygenic scores in typically developing children (TD) explain a modest amount of variance in AAM (R2 = 0.09; p = 0.04). Next, we demonstrate that 7q11.23 copy number impacts AAM (WS < TD < Dup7; p = 1.2x10-8, η2 = 0.45) and pituitary volume (WS < TD < Dup7; p = 3x10-5, ηp2 = 0.2) with greater effect sizes. Finally, we relate an AAM-GWAS signal in 7q11.23 to altered expression in postmortem brains of STAG3L2 (p = 1.7x10-17), a gene we also find differentially expressed with 7q11.23 copy number (p = 0.03). Collectively, these data explicate the role of 7q11.23 in pubertal onset, with STAG3L2 and pituitary development as potential mediators.

Precocious Puberty: Types, Pathogenesis and Updated Management

Precocious puberty (PP) means the appearance of secondary sexual characters before the age of eight years in girls and nine years in boys. Puberty is indicated in girls by the enlargement of the breasts (thelarche) in girls and in boys by the enlargement of the testes in either volume or length (testicular volume = 4 mL, testicular length = 25 mm, or both). Two types of PP are recognized - namely central PP (CPP) and peripheral PP (PPP). This paper aims to describe the clinical findings and laboratory workup of PP and to illustrate the new trends in the management of precocious sexual maturation. Gonadotropin-releasing hormone (GnRH)-independent type (PPP) refers to the development of early pubertal maturation not related to the central activation of the hypothalamic-pituitary-gonadal (HPG) axis. It is classified into genetic or acquired disorders. The most common forms of congenital or genetic causes involve McCune-Albright syndrome (MAS), familial male-limited PP, and congenital adrenal hyperplasia. The acquired causes include exogenous exposure to androgens, functioning tumors or cysts, and the pseudo-PP of profound primary hypothyroidism. On the other hand, CPP is the most common and it is a gonadotropin-dependent form. It is due to premature maturation of the HPG axis. CPP may occur as genetic alterations, such as MKRN3, DLK1, or KISS1;as a part of mutations in the epigenetic factors that regulate the HPG axis, such as Lin28b and let-7; or as a part of syndromes, central lesions such as hypothalamic hamartoma, and others. A full, detailed history and physical examination should be taken. Furthermore, several investigations should be conducted for both types of PP, including the estimation of serum gonadotropins such as luteinizing and follicle-stimulating hormones and sex steroids, in addition to a radiographic workup and thyroid function tests. Treatment depends on the type of PP: Long-acting GnRHa, either intramuscularly or implanted, is the norm of care for CPP management, while in PPP, especially in congenital adrenal hyperplasia, the goal of management is to suppress adrenal androgen secretion by glucocorticoids. In addition, anastrozole and letrozole - third-generation aromatase inhibitors - are more potent for MAS.

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

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

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

Central precocious puberty (CPP) results from early activation of the hypothalamic-pituitary-gonadal (HPG) axis. The current state of knowledge of the complex neural network acting at the level of the hypothalamus and the GnRH neuron to control puberty onset has expanded, particularly in the context of molecular interactions. Along with these advances, the knowledge of pubertal physiology and pathophysiology has also increased. This review focuses on regulatory abnormalities occurring at the hypothalamic level of the HPG axis to cause CPP. The clinical approach to diagnosis of puberty and pubertal disorders is also reviewed, with a particular focus on aetiologies of CPP. The recent identification of mutations in MKRN3 and DLK1 in familial as well sporadic forms of CPP has changed the state of the art of the approach to patients with CPP. Genetic advances have also had important repercussions beyond consideration of puberty alone. Syndromic disorders and central nervous system lesions associated with CPP are also discussed. If untreated, these conditions may lead to adverse physical, psychosocial and medical outcomes.

[Clinical guidelines «Precocious puberty»]

The precocious puberty is an urgent problem of pediatric endocrinology characterized by clinical and pathogenetic heterogeneity. The appearance of secondary sex characteristics before the age of 8 years in girls and 9 years in boys requires timely diagnosis and the appointment of pathogenetically justified treatment in order to achieve the target indicators of final growth and prevent social deprivation. The developed clinical guidelines are the main working tool of the practitioner. They briefly and structurally present the main information about the epidemiology and modern classification of рrecocious puberty, methods of its diagnosis and treatment based on the principles of evidence-based medicine.

Growth, body composition, and endocrine issues in Williams syndrome

PURPOSE OF REVIEW

Williams syndrome is a multisystem disorder caused by a microdeletion on chromosome 7q. Throughout infancy, childhood, and adulthood, abnormalities in body composition and in multiple endocrine axes may arise for individuals with Williams syndrome. This review describes the current literature regarding growth, body composition, and endocrine issues in Williams syndrome with recommendations for surveillance and management by the endocrinologist, geneticist, or primary care physician.

RECENT FINDINGS

In addition to known abnormalities in stature, calcium metabolism, and thyroid function, individuals with Williams syndrome are increasingly recognized to have low bone mineral density, increased body fat, and decreased muscle mass. Furthermore, recent literature identifies a high prevalence of diabetes and obesity starting in adolescence, and, less commonly, a lipedema phenotype in both male and female individuals. Understanding of the mechanisms by which haploinsufficiency of genes in the Williams syndrome-deleted region contributes to the multisystem phenotype of Williams syndrome continues to evolve.

SUMMARY

Multiple abnormalities in growth, body composition, and endocrine axes may manifest in individuals with Williams syndrome. Individuals with Williams syndrome should have routine surveillance for these issues in either the primary care setting or by an endocrinologist or geneticist.

Insights from the genetic characterization of central precocious puberty associated with multiple anomalies

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.

Social, neurodevelopmental, endocrine, and head size differences associated with atypical deletions in Williams-Beuren syndrome

Williams-Beuren syndrome (WBS) is a multisystem disorder caused by a hemizygous deletion on 7q11.23 encompassing 26-28 genes. An estimated 2-5% of patients have "atypical" deletions, which extend in the centromeric and/or telomeric direction from the WBS critical region. To elucidate clinical differentiators among these deletion types, we evaluated 10 individuals with atypical deletions in our cohort and 17 individuals with similarly classified deletions previously described in the literature. Larger deletions in either direction often led to more severe developmental delays, while deletions containing MAGI2 were associated with infantile spasms and seizures in patients. In addition, head size was notably smaller in those with centromeric deletions including AUTS2. Because children with atypical deletions were noted to be less socially engaged, we additionally sought to determine how atypical deletions relate to social phenotypes. Using the Social Responsiveness Scale-2, raters scored individuals with atypical deletions as having different social characteristics to those with typical WBS deletions (p = .001), with higher (more impaired) scores for social motivation (p = .005) in the atypical deletion group. In recognizing these distinctions, physicians can better identify patients, including those who may already carry a clinical or FISH WBS diagnosis, who may benefit from additional molecular evaluation, screening, and therapy. In addition to the clinical findings, we note mild endocrine findings distinct from those typically seen in WBS in several patients with telomeric deletions that included POR. Further study in additional telomeric deletion cases will be needed to confirm this observation.

Health Care Supervision for Children With Williams Syndrome

This set of recommendations is designed to assist the pediatrician in caring for children with Williams syndrome (WS) who were diagnosed by using clinical features and with chromosome 7 microdeletion confirmed by fluorescence in situ hybridization, chromosome microarray, or multiplex ligation-dependent probe amplification. The recommendations in this report reflect review of the current literature, including previously peer-reviewed and published management suggestions for WS, as well as the consensus of physicians and psychologists with expertise in the care of individuals with WS. These general recommendations for the syndrome do not replace individualized medical assessment and treatment.

Williams Syndrome, Human Self-Domestication, and Language Evolution

Language evolution resulted from changes in our biology, behavior, and culture. One source of these changes might be human self-domestication. Williams syndrome (WS) is a clinical condition with a clearly defined genetic basis which results in a distinctive behavioral and cognitive profile, including enhanced sociability. In this paper we show evidence that the WS phenotype can be satisfactorily construed as a hyper-domesticated human phenotype, plausibly resulting from the effect of the WS hemideletion on selected candidates for domestication and neural crest (NC) function. Specifically, we show that genes involved in animal domestication and NC development and function are significantly dysregulated in the blood of subjects with WS. We also discuss the consequences of this link between domestication and WS for our current understanding of language evolution.

Precocious and Early Central Puberty in Children With Pre-existing Medical Conditions: A Single Center Study

Background: Precocious and early puberty are reported findings in children with pre-existing medical conditions including certain syndromes. Series pertaining to such situations are limited. Methods: A retrospective, single-center study was conducted on children with central precocious puberty (onset before the age of 8 years in girls and 9 years in boys) or early puberty (onset between 8 and 9 years in girls and between 9 and 10.5 years in boys) diagnosed on the background of a known pre-existing chronic significant medical condition. Patients with a CNS tumor and those exposed to cranial irradiation were excluded. Results: Precocious puberty was diagnosed in 13 patients and early puberty in 12. Mean age at onset of puberty was 6.65 ± 2.3 years in girls (n = 15) and 9.4 ± 0.84 years in boys (n = 10). The most common disorders were psychomotor delay (n = 12), psychiatric disorders (n = 7) and/or epilepsy (n = 5). Precocious or early puberty was among the symptoms experienced by patients with a variety of syndromes including lipofuscinosis (2 siblings), Dravet syndrome and Silver-Russel syndrome. Pituitary stalk interruption with agenesis of olfactory bulbs and optic nerve atrophy was found on imaging in one patient who presented with blindness, epilepsy, and autism spectrum disorder. The other diseases associated with precocious or early puberty are adrenocorticotropic deficiency, dyspraxia and bone abnormalities, glomerulopathy with complete renal failure, and repeated intra-fetal deaths in the mother. Karyotype analysis revealed chromosomal duplication (chromosome 15 in 2 cases; chromosomes 17 and 11 in one case each) in 4 of 8 patients evaluated. Conclusions: Data from patients with complex disease who experience precocious or early puberty may provide clues regarding the genetic determinants of pubertal development.

High prevalence of syndromic disorders in patients with non-isolated central precocious puberty

Objective Non-idiopathic CPP is caused by acquired or congenital hypothalamic lesions visible on MRI or is associated with various complex genetic and/or syndromic disorders. This study investigated the different types and prevalence of non-isolated CPP phenotypes. Design and Methods This observational cohort study included all patients identified as having non-idiopathic CPP in the database of a single academic pediatric care center over a period of 11.5 years. Patients were classified on the basis of MRI findings for the CNS as having either hypothalamic lesions or complex syndromic phenotypes without structural lesions of the hypothalamus. Results In total, 63 consecutive children (42 girls and 21 boys) with non-isolated CPP were identified. Diverse diseases were detected, and the hypothalamic lesions visible on MRI (n = 28, 45% of cases) included hamartomas (n = 17; either isolated or with an associated syndromic phenotype), optic gliomas (n = 8; with or without neurofibromatosis type 1), malformations (n = 3) with interhypothalamic adhesions (n = 2; isolated or associated with syndromic CNS midline abnormalities, such as optic nerve hypoplasia, ectopic posterior pituitary) or arachnoid cysts (n = 1). The patients with non-structural hypothalamic lesions (n = 35, 55% of cases) had narcolepsy (n = 9), RASopathies (n = 4), encephalopathy or autism spectrum disorders with or without chromosomal abnormalities (n = 15) and other complex syndromic disorders (n = 7). Conclusion Our findings suggest that a large proportion (55%) of patients with non-isolated probable non-idiopathic CPP may have complex disorders without structural hypothalamic lesions on MRI. Future studies should explore the pathophysiological relevance of the mechanisms underlying CPP in these disorders.

Endocrine manifestations in children with Williams-Beuren syndrome

AIM

Endocrine abnormalities in Williams-Beuren syndrome (WBS) include growth retardation, precocious puberty, hypercalcaemia and thyroid disorders. We aimed to characterise these abnormalities in a national cohort of children with WBS.

METHODS

A retrospective study comprising a national cohort of individuals with WBS in Israel (16 males, 18 females) followed between 2010 and 2016.

RESULTS

The age at diagnosis of WBS was 1.4 ± 1.0 years. Height standard deviation score (SDS) at last visit was correlated with the midparental height SDS (r = 0.46 p = 0.007). Yet, participants did not reach their midparental height, with a difference of 1.40 ± 0.85SD (p < 0.001). Short stature below the 3rd percentile was found in 14 participants (41%). Mean insulin-like growth factor 1 SDS was low (-0.61 ± 1.64) and was correlated with the mean height SDS (r = 0.63 p = 0.038). Two participants were diagnosed with growth hormone deficiency, and initiation of growth hormone treatment improved their height velocity. A total of eight participants (23.5%) had mild hypercalcaemia, five girls (14.7%) had precocious puberty and five participants (14.7%) had thyroid abnormalities.

CONCLUSION

Individuals with WBS had a distinct growth pattern consisting of growth restriction at all ages, resulting in final adult height in the low-normal range. Precocious puberty, hypercalcaemia and thyroid abnormalities should be screened for and treated as needed.

Williams Syndrome and 15q Duplication: Coincidence versus Association

Williams syndrome is a multisystem disorder caused by contiguous gene deletion in 7q11.23, commonly associated with distinctive facial features, supravalvular aortic stenosis, short stature, idiopathic hypercalcemia, developmental delay, joint laxity, and a friendly personality. The clinical features of 15q11q13 duplication syndrome include autism, mental retardation, ataxia, seizures, developmental delay, and behavioral problems. We report a rare case of a girl with genetically confirmed Williams syndrome and coexisting 15q duplication syndrome. The patient underwent treatment for central precocious puberty and later presented with primary amenorrhea. The karyotype revealed 47,XX,+mar. FISH analysis for the marker chromosome showed partial trisomy/tetrasomy for proximal chromosome 15q (15p13q13). FISH using an ELN-specific probe demonstrated a deletion in the Williams syndrome critical region in 7q11.23. To our knowledge, a coexistence of Williams syndrome and 15q duplication syndrome has not been reported in the literature. Our patient had early pubertal development, which has been described in some patients with Williams syndrome. However, years later after discontinuing gonadotropin-releasing hormone analogue treatment, she developed primary amenorrhea.

Seven cases with Williams-Beuren syndrome: endocrine evaluation and long-term follow-up

BACKGROUND

Endocrine evaluation and long-term follow-up of seven (six male) patients with Williams-Beuren syndrome (WBS) are given.

METHOD

Data were obtained from patients' medical records. All patients underwent hormonal analyses and four of them underwent oral glucose tolerance test (OGTT).

RESULTS

They all had mild hypercalcemia. Three of them had overt hypothyroidism while subclinical hypothyroidism was detected in three patients. Four patients had thyroid hypoplasia and one had thyroid agenesis. Growth hormone deficiency (GHD) was determined in one patient. Impaired glucose tolerance (IGT) was found in three adolescents. All adolescents had early-onset puberty. The follow-up duration was 5.7±2.1 years. The mean growth velocity (GV) was 12.9±7.2 cm and 7.6±2 cm at the end of the first and second years of therapy, respectively. All patients had neurodevelopment retardation and were continuing to special education.

CONCLUSIONS

Thyroid hypoplasia is common and agenesis can be seen in patients with WBS; therefore, thyroid hormones should be measured in the newborn period and annually. GHD should be kept in mind in patients with decreased GV. IGT might be detected in patients with WBS even in adolescence.

Array CGH - A Powerful Tool in Molecular Diagnostic of Pathogenic Microdeletions - Williams-Beuren Syndrome - A Case Report

ABSTRACT: Williams-Beuren syndrome (WBS) (OMIM 194050) is caused by interstitial deletions or duplications of the 7q11.23 chromosomal region and characterised through a complex phenotype. We described a case diagnosed clinically and genetically confirmed through aCGH. Genetic assessment identified three microdeletions with a total size of 1.35 Mb located at 7q11.23. The deleted regions encompasses more than 30 genes including several protein coding genes such as ELN, LIMK1, FZDS, WBSCR22, WBSCR27, WBSCR28, STX1A, CLDN3, CLDN4, LAT2, ABHD11 or EIF4H .

Causes, diagnosis, and treatment of central precocious puberty

Central precocious puberty results from the premature activation of the hypothalamic-pituitary-gonadal axis. It mimics physiological pubertal development, although at an inappropriate chronological age (before 8 years in girls and 9 years in boys). It can be attributable to cerebral congenital malformations or acquired insults, but the cause in most cases in girls remains unknown. MKRN3 gene defects have been identified in familial disease, with important basic and clinical results. Indeed, genetic analysis of this gene should be included in the routine clinical investigation of familial and idiopathic cases of central precocious puberty. Gonadotropin-releasing hormone agonists are the gold-standard treatment. The assessment and management of this disease remain challenging for paediatric endocrinologists. In this Series paper, we describe current challenges involving the precise diagnosis and adequate treatment of this disorder.

Endocrine dysfunctions in children with Williams-Beuren syndrome

PURPOSE

Williams-Beuren syndrome (WBS) is caused by a hemizygous microdeletion of chromosome 7q11.23 and is characterized by global cognitive impairment, dysmorphic facial features, and supravalvular aortic stenosis. Endocrine dysfunctions have been reported in patients with WBS. This study was performed to investigate the frequency, clinical features, and outcomes of endocrine dysfunctions in children with WBS.

METHODS

One hundred two patients were included. The diagnosis was confirmed by chromosome analysis and fluorescent in situ hybridization. Medical charts were reviewed retrospectively to analyze endocrine dysfunctions such as short stature, precocious puberty, thyroid dysfunctions, and hypocalcemia.

RESULTS

The age at diagnosis was 3.7±4.4 years (one month to 19 years). Height- and weight-standard deviation score (SDS) were -1.1±1.1 and -1.4±1.4 at presentation, respectively. Short stature was found in 26 patients (28.3%) among those older than 2 years. Body mass index-SDS increased as the patients grew older (P<0.001). Two males and one female (2.9%) were diagnosed with central precocious puberty. Nine patients (8.8%) were diagnosed with primary hypothyroidism at age 4.0±4.3 years (one month to 12.1 years); their serum thyroid stimulating hormone and free T4 levels were 15.2±5.4 µU/mL and 1.2±0.2 ng/dL, respectively. Hypercalcemia was observed in 12 out of 55 patients under age 3 (22%) at the age of 14.3±6.6 months (7 to 28 months) with a mean serum calcium level of 13.1±2.1 mg/dL.

CONCLUSION

Endocrine dysfunctions are not uncommon causes of morbidity in patients with WBS. The severity and outcomes of their endocrine manifestations were heterogeneous. Long-term follow-up is needed to predict the prognosis of endocrine features.

Parent-of-origin-specific allelic associations among 106 genomic loci for age at menarche

Age at menarche is a marker of timing of puberty in females. It varies widely between individuals, is a heritable trait and is associated with risks for obesity, type 2 diabetes, cardiovascular disease, breast cancer and all-cause mortality. Studies of rare human disorders of puberty and animal models point to a complex hypothalamic-pituitary-hormonal regulation, but the mechanisms that determine pubertal timing and underlie its links to disease risk remain unclear. Here, using genome-wide and custom-genotyping arrays in up to 182,416 women of European descent from 57 studies, we found robust evidence (P < 5 × 10(-8)) for 123 signals at 106 genomic loci associated with age at menarche. Many loci were associated with other pubertal traits in both sexes, and there was substantial overlap with genes implicated in body mass index and various diseases, including rare disorders of puberty. Menarche signals were enriched in imprinted regions, with three loci (DLK1-WDR25, MKRN3-MAGEL2 and KCNK9) demonstrating parent-of-origin-specific associations concordant with known parental expression patterns. Pathway analyses implicated nuclear hormone receptors, particularly retinoic acid and γ-aminobutyric acid-B2 receptor signalling, among novel mechanisms that regulate pubertal timing in humans. Our findings suggest a genetic architecture involving at least hundreds of common variants in the coordinated timing of the pubertal transition.

Arterial hypertension during treatment with triptorelin in a child with Williams-Beuren syndrome

BACKGROUND

Arterial hypertension (AHT) is a common finding in children with Williams-Beuren syndrome (WBS). Although cardiovascular and renal abnormalities can explain the AHT in some patients with WBS, its etiology is not fully understood and most cases are considered idiopathic.

CASE-DIAGNOSIS/TREATMENT

The case is reported of a 10-year-old girl with WBS who developed severe AHT during treatment with triptorelin, a long-lasting gonadotropin-releasing hormone (GnRH) analog, administered because of early normal puberty. Comprehensive diagnostic studies ruled out other known causes of AHT associated with WBS. After discontinuation of triptorelin, the blood pressure remained within the normal range for her age and height with no antihypertensive treatment on long-term follow-up. To the best of the authors' knowledge, this is the first report of AHT associated with triptorelin administration in a child with WBS.

CONCLUSIONS

Clinicians should be aware of the possibility, although rare, of AHT developing during triptorelin administration in childhood, specifically in patients at increased risk of AHT, such as those with WBS.

New causes of central precocious puberty: the role of genetic factors

A pivotal event in the onset of puberty in humans is the reemergence of the pulsatile release of the gonadotropin-releasing hormone (GnRH) from hypothalamic neurons. Pathways governing GnRH ontogeny and physiology have been discovered by studying animal models and humans with reproductive disorders. Recent human studies implicated the activation of kisspeptin and its cognate receptor (KISS1/KISS1R) and the inactivation of MKRN3 in the premature reactivation of GnRH secretion, causing central precocious puberty (CPP). MKRN3, an imprinted gene located on the long arm of chromosome 15, encodes makorin ring finger protein 3, which is involved in ubiquitination and cell signaling. The MKRN3 protein is derived only from RNA transcribed from the paternally inherited copy of the gene due to maternal imprinting. Currently, MKRN3 defects represent the most frequent known genetic cause of familial CPP. In this review, we explored the clinical, hormonal and genetic aspects of children with sporadic or familial CPP caused by mutations in the kisspeptin and MKRN3 systems, essential genetic factors for pubertal timing.

Sex and genes, part 1: sexuality and Down, Prader-Willi, and Williams syndromes

Specific genetic syndromes affect individuals' sexual development, experiences, and fertility. Individuals with specific syndromes can also display inappropriate sexual behavior resulting from vulnerabilities presented by their genetic makeup. Using clinical case studies, we discuss the specific impact that Down, Prader-Willi, and Williams syndromes can have on sexual development and behavior. Applying a biopsychosocial approach, we present the primary sexual effects, such as delayed sexual development and infertility. These genetic syndromes are also associated with challenges that are not specifically sexual in nature but that affect sexual expression, such as self-injury, mental health issues, or epilepsy. Medication side effects are also discussed. We conclude with treatment recommendations for individuals with sexual challenges, considering the unique effects of these three syndromes on sexuality.

Precocious puberty in two girls with PEHO syndrome: a clinical feature not previously described

The authors present 2 girls with progressive encephalopathy, hypsarrhythmia, and optic atrophy syndrome. They describe a novel finding, precocious puberty, a feature not previously reported in this syndrome. The authors also present their clinical features and the results of investigations, including radiological findings, and compare the patients of this report to previously reported cases.

Presenting phenotype and clinical evaluation in a cohort of 22 Williams-Beuren syndrome patients

Williams-Beuren syndrome (WS) is a rare multi-system genomic disorder, caused by 7q11.23 microdeletion with a prevalence of 1/7500-1/20,000 live births. Clinical phenotype includes typical facial dysmorphism (elfin face), mental retardation associated with a peculiar neuropsychological profile and congenital heart defects. We investigated 22 WS patients (mean age of 9.7 years, range 1 day to 39 years) with a multi-specialist follow-up protocol comprehensive of neuropsychological, cardiologic, nephrologic, ophthalmologic, endocrinologic, gastroenterologic, odontostomatologic and orthopaedic evaluations. The mean age at diagnosis was 5.38 years, being 1.02 years when genetic evaluation was requested for congenital heart defects (CHD) and 10.68 years in case of mental retardation and/or abnormal neuropsychological profile without an evident CHD. All patients showed facial dysmorphisms, with supravalvular aortic stenosis (SVAS) as the most common cardiovascular anomaly (12/22), followed by peripheral pulmonary stenosis (9/22); interestingly, in one patient we detected a total anomalous pulmonary venous return (TAPVR), confirming the possible association of this rare CHD with WS. Hypertension was detected by 24-h ambulatory blood pressure monitoring in 7/22 cases. A cognitive assessment was performed in 13 patients older than 6 years, showing various degrees of mental retardation in 12 and a normal intelligence quotient (IQ) in a single patient; evaluation of developmental milestones revealed various grades of developmental delay in all the patients younger than 6 years. Chiari malformation type 1 was found in 3 patients. Our study underlines a remarkable diagnostic delay in patients who present to genetic evaluation because of mental retardation and/or peculiar neuropsychological profile lacking an evident cardiopathy and confirms the multi-systemic nature of WS leading to a high clinical presentation's variability and complex follow-up strategies.

Central precocious puberty in a girl with Williams syndrome: the result of treatment with GnRH analogue

Williams syndrome (WS) is a well-known microdeletion syndrome characterized by specific facial features, retardation in growth and development, typical personality and cardiac defects. Poor growth potential is further affected by central precocious puberty (CPP) which is frequent in these patients. A WS patient with CPP is presented, whose pubertal development and bone age progression were arrested by administration of GnRH analogues. The case is reported to discuss the role of GnRH analogues for management of CPP in patients with WS.

Clinical manifestations and molecular investigation of 50 patients with Williams syndrome in the Greek population

Williams syndrome (WS) is a well-recognized neurodevelopmental disorder manifested by both connective tissue and CNS abnormalities. The study depicts the 8-y experience and follow-up of 50 Greek children with the clinical diagnosis of WS. Clinical data on the facial features and cardiovascular, endocrinologic, and neurodevelopmental evaluation are presented. The most consistent findings were dysmorphic features (100%), followed by dental anomalies (90%) and hyperacousis (90%). Only eight of 50 children had severe cardiovascular defects that required surgical intervention during the first year of life. Supravalvular aortic stenosis was less frequent (28%) than shown in the literature. Severe hypertension was noticed in 22% of our patients, and infantile hypercalcemia was noticed in 6%. Twelve percent of our patients showed an elevation of CPK. Most children presented with moderate to severe mental retardation with IQ ranging from 20 to 85. Elastin hemizygosity was detected by fluorescence in situ hybridization. Dinucleotide repeat polymorphism analysis was performed in an attempt to correlate phenotype with genotype. The origin of deletions was more frequently maternal (59%), and a more severe phenotype seemed to be associated with those deletions. This is the first report on WS patients in the Greek population.