Multiple forms of hypogonadism of central, peripheral or combined origin in males with Prader-Willi syndrome

Prostate-specific antigen (PSA) levels in men with Prader-Willi syndrome

Prader-Willi syndrome (PWS) is a rare genetic disorder typically characterized by body composition abnormalities, hyperphagia, behavioral challenges, cognitive dysfunction, and hormone deficiencies. Hypogonadism is common but knowledge on potential side effects of testosterone replacement is limited, in particular, the long-term effects on behavior and PSA.

PATIENTS AND METHODS

Retrospective case studies of seven men, median age 46 years, with genetically verified PWS, testosterone treated hypogonadism and available PSA values were included. Long-term follow-up of PSA was accessible in four patients. Medical records were reviewed for adverse effects.

RESULTS

Five men were treated with intramuscular testosterone undecanoate, two had no hypogonadism. Median PSA was 0.68 μg/L (0.23-1.3), median testosterone 15 nmol/L. After a median time of 17 years of testosterone replacement median PSA was 0.75 μg/L (range 0.46-1.4). Testosterone replacement was well tolerated, and no major behavioral changes were reported. Five were treated with growth hormone for >20 years.

CONCLUSION

Levels of PSA were low. Long-term treatment with testosterone was working well and did not result in any clinically meaningful increase in PSA. Our results indicate that testosterone replacement is neither associated with serious adverse events regarding changes in behavior or effect on PSA. However, larger studies are needed to confirm our results.

Endocrine features of Prader-Willi syndrome: a narrative review focusing on genotype-phenotype correlation

Prader-Willi syndrome (PWS) is a complex genetic disorder caused by three different types of molecular genetic abnormalities. The most common defect is a deletion on the paternal 15q11-q13 chromosome, which is seen in about 60% of individuals. The next most common abnormality is maternal disomy 15, found in around 35% of cases, and a defect in the imprinting center that controls the activity of certain genes on chromosome 15, seen in 1-3% of cases. Individuals with PWS typically experience issues with the hypothalamic-pituitary axis, leading to excessive hunger (hyperphagia), severe obesity, various endocrine disorders, and intellectual disability. Differences in physical and behavioral characteristics between patients with PWS due to deletion versus those with maternal disomy are discussed in literature. Patients with maternal disomy tend to have more frequent neurodevelopmental problems, such as autistic traits and behavioral issues, and generally have higher IQ levels compared to those with deletion of the critical PWS region. This has led us to review the pertinent literature to investigate the possibility of establishing connections between the genetic abnormalities and the endocrine disorders experienced by PWS patients, in order to develop more targeted diagnostic and treatment protocols. In this review, we will review the current state of clinical studies focusing on endocrine disorders in individuals with PWS patients, with a specific focus on the various genetic causes. We will look at topics such as neonatal anthropometry, thyroid issues, adrenal problems, hypogonadism, bone metabolism abnormalities, metabolic syndrome resulting from severe obesity caused by hyperphagia, deficiencies in the GH/IGF-1 axis, and the corresponding responses to treatment.

Premature adrenarche in Prader-Willi syndrome is associated with accelerated pre-pubertal growth and advanced bone age

OBJECTIVES

Prader-Willi syndrome (PWS) is characterized by obesity, growth hormone deficiency, hypogonadism, and a high prevalence of premature adrenarche despite reported hypothalamic-pituitary-adrenal axis dysfunction. While idiopathic premature adrenarche is associated with accelerated pre-pubertal growth and advanced bone age, the consequences of elevated adrenal androgens on growth and bone maturation in PWS remain unknown. This study therefore sought to describe age-related changes in dehydroepiandrosterone sulfate (DHEAS) and their effects on growth and bone maturation in PWS.

METHODS

This retrospective observational study included 62 children with PWS. Simple and multiple regression models were constructed to relate age and BMI-SDS with DHEAS levels. Height velocity was compared to age and sex-based norms with t-tests and two-way ANOVA. Patterns in bone age Z-score were examined with two-way ANOVA, and the contributions of age, BMI-SDS, and DHEAS to bone age Z-score were analyzed with multiple regression.

RESULTS

DHEAS levels rose earlier and were less strongly correlated with age in males and females with PWS (R²=0.12 and 0.30) compared to healthy controls (R²=0.89 and 0.88) in a pattern unrelated to BMI-SDS (adjusted R²=0.076, p=0.10 for age, and 0.29 for BMI-SDS). Mid-childhood height velocity was increased in males and preserved in females with PWS before declining at the age of expected puberty (p<0.0001). Peri-adrenarchal bone age was advanced in a manner associated with DHEAS but not BMI-SDS (p<0.0001; adjusted R²=0.48, p=0.0014 for DHEAS, and 0.78 for BMI-SDS).

CONCLUSIONS

An obesity-independent increase in adrenal androgens is associated with accelerated mid-childhood growth and bone maturation in PWS.

A rare occurrence of non-classic congenital adrenal hyperplasia and type 1 diabetes mellitus in a girl with Prader-Willi Syndrome: Case report and review of the literature

Prader-Willi syndrome (PWS) is a rare genetic disorder resulting from lack of expression of the paternally derived chromosome 15q11-13, associated with several complications, including pubertal disorders, short stature, hyperphagia, obesity, glucose metabolism abnormalities, scoliosis, obstructive sleep apnea syndrome (OSAS) and behavioral problems. We report the case of a girl affected by PWS who presented at the age of 5.9 with premature pubarche, accelerated linear growth and advanced bone age (BA). She was subsequently diagnosed with non-classic congenital adrenal hyperplasia (CAH) confirmed by genetic analysis. Considering the clinical, biochemical, and genetic findings, hydrocortisone therapy was started to prevent rapid BA acceleration and severe compromission of final height. During infancy, short stature and low levels of insulin-like growth factor-1 (IGF-1) for age and gender led to suspicion of growth hormone deficiency (GHD), confirmed by stimulation testing (arginine and clonidine). rhGH therapy was administered and continued until final height was reached. During endocrinological follow up she developed impaired glucose tolerance with positive markers of β-cell autoimmunity (anti-glutamic acid decarboxylase antibodies, GAD Ab), which evolved over time into type 1 diabetes mellitus and insulin therapy with a basal-bolus scheme and an appropriate diet were needed.

MKRN3 circulating levels in Prader-Willi syndrome: a pilot study

CONTEXT

Hypogonadism in Prader-Willi syndrome (PWS) is generally attributed to hypothalamic dysfunction or to primary gonadal defect. MKRN3, a maternal imprinted gene located on 15q11.2-q13 region, encodes makorin ring finger protein 3, whose deficiency causes precocious puberty, an extremely rare symptom in PWS.

OBJECTIVE

This study aimed to evaluate MKRN3 levels in patients with PWS and to analyze its correlation with sexual hormone levels, insulin resistance and Body Mass Index (BMI).

METHODS

We performed an observational cross-sectional study and enrolled 80 patients with genetically confirmed diagnosis of PWS with median age of 9.6 years.

RESULTS

MKRN3 levels were measurable in 49 PWS patients with a geometric mean of 34.9 ± 22 pg/ml (median: 28.4). Unmeasurable levels of MKRN3 were found in 31 patients. No statistically significant differences were found between patients with and without measurable MKRN3 levels for any clinical, biochemical, or genetic characteristics. However, MKRN3 levels were inversely correlated with HOMA-IR index (p: 0.005) and HbA1c (p: 0.046) values. No statistically significant correlations were found between MKRN3 and LH, estradiol and testosterone concentrations, pubertal development and genetic defect, whereas a direct correlation with FSH was found (p: 0.007).

CONCLUSIONS

The typical genetic defect of PWS should lead to unmeasurable levels of the MKRN3 protein due to the inactivation of the paternal allele. Measurable circulating MKRN3 could suggest the possible involvement of tissue-specific imprinting mechanisms and other regulatory factors in gene expression. Correlations with HOMA-IR index, HbA1c, and FSH suggest peripheral actions of MKRN3, but future studies are warranted to investigate this topic.

Single-center real-life experience with testosterone treatment in adult men with Prader-Willi syndrome

Hypogonadism is the most frequent hormonal deficiency in individuals with Prader-Willi syndrome (PWS). This often necessitates testosterone treatment, but limited data are available to guide testosterone treatment in adult men with PWS. We aimed to evaluate the serum testosterone concentrations and adverse effects of testosterone treatment in individuals with PWS attending a specialist obesity management service. A retrospective audit was undertaken at Austin Health, Melbourne between January 2010 and April 2021. Main outcome measures were testosterone formulation and dose, serum total testosterone concentration, and prevalence of polycythemia and behavioral disturbance. Data were available for eight individuals with median baseline age 19 years (range, 19-42) and BMI 37 kg/m² (range, 27-71). Six men had obstructive sleep apnea; none were smokers. Baseline testosterone concentration was 1.8 nmol/L (IQR, 1.1-3.3) with hematocrit 0.43. Testosterone formulations were intramuscular testosterone undecanoate (TU) 1000 mg (n = 5), transdermal testosterone gel 50 mg daily (n = 1), and oral TU 80-120 mg daily (n = 2). Median total testosterone concentration was 9.7 nmol/L (IQR, 8.5-14.7). Nine of 25 (36%) hematocrit results in six patients measured >0.50 (range, 0.50-0.56). Intramuscular TU was well tolerated and was the only formulation to achieve serum total testosterone concentrations in the adult male reference range. Worsening behavioral disturbance resulted in treatment discontinuation in one individual. Our experience reinforces the need to regular monitoring of hematocrit in men with PWS treated with testosterone. However, a worsening of behavior problems was uncommon in this series.

Approach to the Patient With Prader-Willi Syndrome

Prader-Willi syndrome (PWS) is a rare, multisystemic, genetic disorder involving the hypothalamus. It is caused by loss of expression of paternally inherited genes in chromosome 15 q11-13 region. The estimated incidence is around 1 in 20.000 births. PWS is characterized by a complex lifelong trajectory involving neurodevelopmental, nutritional, endocrine, metabolic, and behavioral changes. The major symptoms are hypotonia, short stature, hypogonadism, and eating disorders ranging from anorexia in infancy to hyperphagia, a deficit of satiety, and a high risk of severe obesity. The patients display intellectual disability comprising cognitive deficit, delayed motor and language development, learning deficits, impaired social skills, and emotional regulation. Behavioral features including temper outbursts, anxiety, obsessive-compulsive symptoms and rigidity are common and become more apparent with increasing age. Almost all have hypogonadism and growth hormone deficiency. Central adrenal insufficiency is rare whereas central hypothyroidism occurs in up to 30% of children with PWS. The prevalence of obesity increases with age from almost none in early childhood to more than 90% in adulthood. Up to 25% of adults with obesity have type 2 diabetes. Obesity and its complications are the major causes of comorbidity and mortality in PWS. As there is no specific treatment, care consists of comprehensive management of feeding disorders, a restricted, controlled diet, regular exercise, hormone substitution, and screening and treatment of comorbidities. Here we present the course of PWS from birth to adulthood in 2 patients and discuss their symptoms in relation to the literature.

Hypogonadism in Women with Prader-Willi Syndrome-Clinical Recommendations Based on a Dutch Cohort Study, Review of the Literature and an International Expert Panel Discussion

Prader-Willi syndrome (PWS) is a rare neuroendocrine genetic syndrome. Characteristics of PWS include hyperphagia, hypotonia, and intellectual disability. Pituitary hormone deficiencies, caused by hypothalamic dysfunction, are common and hypogonadism is the most prevalent. Untreated hypogonadism can cause osteoporosis, which is already an important issue in PWS. Therefore, timely detection and treatment of hypogonadism is crucial. To increase understanding and prevent undertreatment, we (1) performed a cohort study in the Dutch PWS population, (2) thoroughly reviewed the literature on female hypogonadism in PWS and (3) provide clinical recommendations on behalf of an international expert panel. For the cohort study, we retrospectively collected results of a systematic health screening in 64 female adults with PWS, which included a medical questionnaire, medical file search, medical interview, physical examination and biochemical measurements. Our data show that hypogonadism is frequent in females with PWS (94%), but is often undiagnosed and untreated. This could be related to unfamiliarity with the syndrome, fear of behavioral changes, hygienic concerns, or drug interactions. To prevent underdiagnosis and undertreatment, we provide practical recommendations for the screening and treatment of hypogonadism in females with PWS.

Hypogonadism in Adult Males with Prader-Willi Syndrome-Clinical Recommendations Based on a Dutch Cohort Study, Review of the Literature and an International Expert Panel Discussion

Prader-Willi syndrome (PWS) is a complex genetic syndrome characterized by hyperphagia, intellectual disability, hypotonia and hypothalamic dysfunction. Adults with PWS often have hormone deficiencies, hypogonadism being the most common. Untreated male hypogonadism can aggravate PWS-related health issues including muscle weakness, obesity, osteoporosis, and fatigue. Therefore, timely diagnosis and treatment of male hypogonadism is important. In this article, we share our experience with hypogonadism and its treatment in adult males with PWS and present a review of the literature. In order to report the prevalence and type of hypogonadism, treatment regimen and behavioral issues, we retrospectively collected data on medical interviews, physical examinations, biochemical measurements and testosterone replacement therapy (TRT) in 57 Dutch men with PWS. Fifty-six (98%) of the patients had either primary, central or combined hypogonadism. Untreated hypogonadism was associated with higher body mass index and lower hemoglobin concentrations. TRT was complicated by behavioral challenges in one third of the patients. Undertreatment was common and normal serum testosterone levels were achieved in only 30% of the patients. Based on the Dutch cohort data, review of the literature and an international expert panel discussion, we provide a practical algorithm for TRT in adult males with PWS in order to prevent undertreatment and related adverse health outcomes.

Hyperprolactinemia in Adults with Prader-Willi Syndrome

Prader-Willi syndrome (PWS) is a rare neurodevelopmental genetic disorder typically characterized by body composition abnormalities, hyperphagia, behavioural challenges, cognitive dysfunction, and hypogonadism. Psychotic illness is common, particularly in patients with maternal uniparental disomy (mUPD), and antipsychotic medications can result in hyperprolactinemia. Information about hyperprolactinemia and its potential clinical consequences in PWS is sparse. Here, we present data from an international, observational study of 45 adults with PWS and hyperprolactinemia. Estimated prevalence of hyperprolactinemia in a subset of centres with available data was 22%, with 66% of those related to medication and 55% due to antipsychotics. Thirty-three patients were men, 12 women. Median age was 29 years, median BMI 29.8 kg/m², 13 had mUPD. Median prolactin was 680 mIU/L (range 329–5702). Prolactin levels were higher in women and patients with mUPD, with only 3 patients having severe hyperprolactinemia. Thyroid function tests were normal, 24 were treated with growth hormone, 29 with sex steroids, and 20 with antipsychotic medications. One patient had kidney insufficiency, and one a microprolactinoma. In conclusion, severe hyperprolactinemia was rare, and the most common aetiology of hyperprolactinemia was treatment with antipsychotic medications. Although significant clinical consequences could not be determined, potential negative long-term effects of moderate or severe hyperprolactinemia cannot be excluded. Our results suggest including measurements of prolactin in the follow-up of adults with PWS, especially in those on treatment with antipsychotics.

Hypogonadism in the Prader-Willi syndrome from birth to adulthood: a 28-year experience in a single centre

BACKGROUND

Hypogonadism is a key feature of Prader-Willi syndrome (PWS) but clear strategies for hormone replacement are lacking.

OBJECTIVE

To evaluate gonadal status and outcome in patients attending a Scottish PWS clinic from 1991-2019.

METHODS

In 93 (35F:56M) patients, median follow-up 11.2 years, gonadal and pubertal status were assessed clinically. Pelvic ultrasound findings and basal/stimulated gonadotrophins were compared with age-matched controls.

RESULTS

Females: Of 22 patients aged >11, 9 had reached B4-5, while 5 were still at B2-3, and 6 remained prepubertal. Eight patients experienced menarche aged 9.8-21.4 years, none with a normal cycle. Uterine length and ovarian volumes were normal but uterine configuration remained immature, with low follicular counts. Gonadotrophins were unremarkable, serum estradiol 129 (70 - 520) pmol/L. Only 5 patients received oestrogen replacement. Males: Fifty-four (96%) patients were cryptorchid (9 unilateral). Weekly hCG injections resulted in unilateral/bilateral descent in 2/1 of 25 patients. Of 37 boys aged >11, 14 (9 with failed/untreated bilateral cryptorchidism) failed to progress beyond G1, 15 arrested at G2-3 (testes 3-10 ml), and 8 reached G4-5. Gonadotrophins were unremarkable except in boys at G2-5 in whom FSH was elevated: 12.3/27.3 vs 3.25/6.26 U/L in controls (p<0.001). In males aged >13, testosterone was 3.1 (0.5-8.4) nmol/L. Androgen therapy, given from 13.5-29.2 years, was stopped in 4/24 patients owing to behavioural problems.

CONCLUSION

Despite invariable hypogonadism, few females and only half the males with PWS in this study received hormone replacement. Double-blind placebo-controlled crossover trials of sex steroids are required to address unproven behavioural concerns.

Prader-Willi syndrome: Hormone therapies

Prader-Willi syndrome (PWS) is a rare genetic neurodevelopmental disorder linked to the lack of expression of specific maternally imprinted genes located in the chromosomal region 15q11-q13. Impaired hypothalamic development and function explain most of the phenotype that is characterized by a specific trajectory from anorexia at birth to excessive weight gain at later ages, which is accompanied by hyperphagia and early severe obesity, as well as by other hormonal deficiencies, behavioral deficits, and dysautonomia. In almost all patients, their endocrine dysfunction involves growth hormone deficiency and hypogonadism, which originate from a combination of both peripheral and hypothalamic origin, central hypothyroidism in 40%, precocious adrenarche in 30% of the cases, and in rare cases, also adrenocorticotropin deficiency and precocious puberty. In addition, the oxytocin (OXT) and ghrelin systems are impaired in most patients and involved in a poor suckling response at birth, and hyperphagia with food addiction, poor social skills, and emotional dysregulation. Current hormonal replacement treatments are the same as used in classical hormonal deficiencies, and recombinant human GH treatment is registered since 2000 and has dramatically changed the phenotype of these children. OXT and OXT analogue treatments are currently investigated as well as new molecules targeting the ghrelin system. The severe condition of PWS can be seen as a model to improve the fine description and treatments of hypothalamic dysfunction.

Prader-Willi Syndrome with Angelman Syndrome in the Offspring

We report the second case, to the best of our knowledge, of a mother with Prader–Willi syndrome (PWS) who gave birth to a daughter with Angelman syndrome (AS). The menarche occurred when she was 16, and the following menstrual cycles were irregular, but she never took sexual hormone replacement therapy. At the age of 26, our patient with PWS became pregnant. The diagnosis was confirmed by molecular genetic testing that revealed a ~5.7 Mb deletion in the 15q11.1–15q13 region on the paternal allele in the mother with PWS and the maternal one in the daughter with AS, respectively. Both the mother with PWS and the daughter with AS showed peculiar clinical and genetic features of the two syndromes. Our case report reaffirms the possible fertility in PWS; therefore, it is very important to develop appropriate socio-sexual education programs and fertility assessments in order to guarantee the expression of a healthy sexuality.

An Adapted Model for Transition to Adult Care in Young Adults with Prader-Willi Syndrome

Background: Prader–Willi syndrome (PWS) is a rare, neurodevelopmental, genetic disease caused by the lack of expression of paternal genes in chromosome 15. The typical characteristics, including hyperphagia, muscular hypotonia, abnormal body composition, hormonal deficiencies, cognitive disabilities, and behavioral problems, appear or worsen in young adults, and the development of comorbidities increases. The transition of care of young adults with PWS is a challenge due to the complexity of the disease and the vulnerability of the patients. Multidisciplinary transition clinics are optimal but difficult to implement in clinics with few transitions. Methods: The description of transition care meetings was limited to the pediatric and adult endocrinologists and nurses. The presentation of our checklist was developed to optimize the organization of the transition of young adults with PWS. Results: Two to four patients with PWS are transferred to adult care every year in our hospital. Transition with the adapted program was more comfortable for patients and identification of the individual patient’s comorbidities and special needs could clearly be addressed. Conclusions: In smaller settings, an adapted model including a proper introduction and presentation of the adult team and clinic, careful information about comorbidities and special needs, together with a checklist can optimize the transition of care to adult care.

Endocrine disorders in Prader-Willi syndrome: a model to understand and treat hypothalamic dysfunction

Prader-Willi syndrome is a rare genetic neurodevelopmental disorder resulting from the loss of expression of maternally imprinted genes located in the paternal chromosomal region, 15q11-13. Impaired hypothalamic development and function is the cause of most of the phenotypes comprising the developmental trajectory of Prader-Willi syndrome: from anorexia at birth to excessive weight gain preceding hyperphagia, and early severe obesity with hormonal deficiencies, behavioural problems, and dysautonomia. Growth hormone deficiency, hypogonadism, hypothyroidism, premature adrenarche, corticotropin deficiency, precocious puberty, and glucose metabolism disorders are the main endocrine dysfunctions observed. Additionally, as a result of hypothalamic dysfunction, oxytocin and ghrelin systems are impaired in most patients. Standard pituitary and gonadal hormone replacement therapies are required. In this Review, we discuss Prader-Willi syndrome as a model of hypothalamic dysfunction, and provide a comprehensive description of the accumulated knowledge on genetics, pathophysiology, and treatment approaches of this rare disorder.

Benefits of multidisciplinary care in Prader-Willi syndrome

Introduction: Prader-Willi syndrome (PWS) is the most well-known condition of genetic obesity. Over the past 20 years, advances have been achieved in the diagnosis and treatment of PWS with a significant improvement in prognosis.Areas covered: This review focuses on the benefits of multidisciplinary approach in children and adolescents with PWS. In particular, the neonatologist and geneticist play a key role in early diagnosis and the clinical follow-up of the PWS patient must be guaranteed by a team including pediatric endocrinologist, psychologist, nutritionist/dietician, neurologist/neuropsychiatrist, sleep specialist, ears, nose and throat specialist (ENT), lung specialist, dentist, orthopedist and ophthalmologist and, eventually, gastroenterologist. We searched PubMed and critically summarized what has been reported in the last 10 years on PWS.Expert opinion: The multidisciplinary care in association with an early diagnosis and GH treatment postpones overweight development and decreases prevalence of obesity in individuals with PWS. Further prognostic improvements are expected through the selection of teams particularly experienced in the management of individuals with PWS and the discovery of new drugs.

Animal models for Prader-Willi syndrome

Prader-Willi syndrome (PWS) is a neurodevelopmental disorder characterized by hyperphagia, hypotonia, learning disability, as well as a range of psychiatric conditions. The conservation of the PWS genetic interval on chromosome 15q11-q13 in human, and a cluster of genes on mouse chromosome 7, has facilitated the use of mice as animal models for PWS. Some models faithfully mimic the loss of all gene expression from the paternally inherited PWS genetic interval, whereas others target smaller regions or individual genes. Collectively, these models have provided insight into the mechanisms, many of which lead to alterations in hypothalamic function, underlying the core symptoms of PWS, including growth retardation, hyperphagia and metabolism, reproductive maturation and endophenotypes of relevance to behavioral and psychiatric problems. Here we review and summarize these studies.

Delayed and Precocious Puberty: Genetic Underpinnings and Treatments

Delayed puberty may signify a common variation of normal development, or indicate the presence of a pathologic process. Constitutional delay of growth and puberty is a strongly familial type of developmental pattern and accounts for the vast majority of children who are "late bloomers." Individuals with sex chromosomal abnormalities frequently have hypergonadotropic hypogonadism. There are currently 4 known monogenic causes of central precocious puberty. The primary treatment goal in children with hypogonadism is to mimic normal pubertal progression, while the primary aims for the management of precocious puberty are preservation of height potential and prevention of further pubertal development.

Evolving pituitary hormone deficits in primarily isolated GHD: a review and experts' consensus

Isolated growth hormone deficiency (GHD) is defined by growth failure in combination with retarded bone age, low serum insulin-like growth factor-1, and insufficient GH peaks in two independent GH stimulation tests. Congenital GHD can present at any age and can be associated with significant malformations of the pituitary-hypothalamic region or the midline of the brain. In rare instances, genetic analysis reveals germline mutations of transcription factors involved in embryogenesis of the pituitary gland and the hypothalamus. Acquired GHD is caused by radiation, inflammation, or tumor growth. In contrast to organic GHD, idiopathic forms are more frequent and remain unexplained.There is a risk of progression from isolated GHD to combined pituitary hormone deficiency (> 5% for the total group), which is clearly increased in children with organic GHD, especially with significant malformation of the pituitary gland. Therefore, it is prudent to exclude additional pituitary hormone deficiencies in the follow-up of children with isolated GHD by clinical and radiological observations and endocrine baseline tests. In contrast to primary disorders of endocrine glands, secondary deficiency is frequently milder in its clinical manifestation. The pituitary hormone deficiencies can develop over time from mild insufficiency to severe deficiency. This review summarizes the current knowledge on diagnostics and therapy of additional pituitary hormone deficits occurring during rhGH treatment in children initially diagnosed with isolated GHD. Although risk factors are known, there are no absolute criteria enabling exclusion of children without any risk of progress to combined pituitary hormone deficiency. Lifelong monitoring of the endocrine function of the pituitary gland is recommended in humans with organic GHD. This paper is the essence of a workshop of pediatric endocrinologists who screened the literature for evidence with respect to evolving pituitary deficits in initially isolated GHD, their diagnosis and treatment.

Premature Adrenarche in Children with Prader-Willi Syndrome Treated with Recombinant Human Growth Hormone Seems to Not Influence the Course of Central Puberty and the Efficacy and Safety of the Therapy

Puberty in children with Prader-Willi syndrome (PWS) is usually delayed and/or incomplete but in some patients premature/early adrenarche is observed. We assessed the premature adrenarche (PA) in PWS patients during the recombinant human growth hormone (rhGH) therapy and influence of PA on the course of central puberty (CP), rhGH efficacy and safety, and patients’ metabolic state. Forty-nine PWS patients were treated with rhGH, 11 presented with PA (group 1) and 14 had normal course of adrenarche (group 2). PA was observed in 22.5% of the PWS children treated with rhGH. The mean time between the rhGH start and the adrenarche, the rhGH dose, the growth velocity and the insulin-like growth factor 1 SD (IGF1 SD) during the treatment, as well as the time of CP, final height SD and BMI SD were similar in both groups. There were also no significant differences in the metabolic assessment—the oral glucose tolerance test (OGTT) and lipid profile results. PA may be a part of the clinical picture of PWS, apart from hypogonadotrophic hypogonadism and it seems to have no influence on CP in PWS patients. The rhGH efficacy and safety were comparable in the patients with PA and the normal course of adrenarche.

Prader-Willi syndrome: reflections on seminal studies and future therapies

Prader-Willi syndrome (PWS) is caused by the loss of function of the paternally inherited 15q11-q13 locus. This region is governed by genomic imprinting, a phenomenon in which genes are expressed exclusively from one parental allele. The genomic imprinting of the 15q11-q13 locus is established in the germline and is largely controlled by a bipartite imprinting centre. One part, termed the Prader-Willi syndrome imprinting center (PWS-IC), comprises a CpG island that is unmethylated on the paternal allele and methylated on the maternal allele. The second part, termed the Angelman syndrome imprinting centre, is required to silence the PWS_IC in the maternal germline. The loss of the paternal contribution of the imprinted 15q11-q13 locus most frequently occurs owing to a large deletion of the entire imprinted region but can also occur through maternal uniparental disomy or an imprinting defect. While PWS is considered a contiguous gene syndrome based on large-deletion and uniparental disomy patients, the lack of expression of only non-coding RNA transcripts from the SNURF-SNRPN/SNHG14 may be the primary cause of PWS. Patients with small atypical deletions of the paternal SNORD116 cluster alone appear to have most of the PWS related clinical phenotypes. The loss of the maternal contribution of the 15q11-q13 locus causes a separate and distinct condition called Angelman syndrome. Importantly, while much has been learned about the regulation and expression of genes and transcripts deriving from the 15q11-q13 locus, there remains much to be learned about how these genes and transcripts contribute at the molecular level to the clinical traits and developmental aspects of PWS that have been observed.

Ontogeny of Hypothalamus-Pituitary Gonadal Axis and Minipuberty: An Ongoing Debate?

The fetal hypothalamus-pituitary gonadal (HPG) axis begins to function during mid-gestation but its activity decreases during late pregnancy due to the suppressive effects of placental estrogens. Placental hormones drop immediately after birth, FSH and LH surge at around 1 week and peak between 1 and 3 months of life. The HPG axis is activated in both sexes, but a sexual dimorphism is evident with higher LH values in boys, while FSH prevails in girls. Both gonadotrophins decline in boys by around 6 months of age. In girls, LH declines at the same time as in boys, while FSH persists elevated up to 3 or 4 years of age. As a result of gonadotropin activation, testicular testosterone increases in males and ovarian estradiol rises in females. These events clinically translate into testicular and penile growth in boys, enlargement of uterus and breasts in girls. The functional impact of HPG axis activity in infancy on later reproductive function is uncertain. According to the perinatal programming theory, this period may represent an essential programming process. In boys, long-term testicular hormonal function and spermatogenesis seem to be, at least in part, regulated by minipuberty. On the contrary, the role of minipuberty in girls is still uncertain. Recently, androgen exposure during minipuberty has been correlated with later sex-typed behavior. Premature and/or SGA infants show significant differences in postnatal HPG axis activity in comparison to full-term infants and the consequences of these differences on later health and disease require further research. The sex-dimorphic HPG activation during mid-gestation is probably responsible for the body composition differences observed ad birth between boys and girls, with boys showing greater total body mass and lean mass, and a lower proportion of fat mass. Testosterone exposure during minipuberty further contributes to these differences and seems to be responsible for the significantly higher growth velocity observed in male infants. Lastly, minipuberty is a valuable "window of opportunity" for differential diagnosis of disorders of sex development and it represents the only time window before puberty when congenital hypogonadism can be diagnosed by the simple analysis of basal gonadotropin and gonadal hormone levels.

CENTRAL PRECOCIOUS PUBERTY IN TWO BOYS WITH PRADER-WILLI SYNDROME ON GROWTH HORMONE TREATMENT

Objective

Prader-Willi syndrome (PWS) is a rare genetic neuroendocrine disorder characterized by hypotonia, obesity, short stature, and mental retardation. Incomplete or delayed pubertal development as well as premature adrenarche are usually found in PWS, whereas central precocious puberty is rarely seen.

Methods

This study reports the clinical, biochemical, and histologic findings in 2 boys with PWS who developed central precocious puberty.

Results

Both boys were started on growth hormone therapy during the first years of life according to the PWS indication. They had both bilateral cryptorchidism at birth and had orchidopexy in early childhood. Retrospective histologic analysis of testicular biopsies demonstrated largely normal tissue architecture and germ cell maturation, but severely decreased number of prespermatogonia in one of the patients. Both boys had premature adrenarche around the age of 6. Precocious puberty was diagnosed in both boys with enlargement of testicular volume (>3 mL), signs of virilization and a pubertal response to a gonadotropin-releasing hormone (GnRH) test and they were both treated with GnRH analog.

Conclusion

The cases described here displayed typical characteristics for PWS, a considerable heterogeneity of the hypothalamic-pituitary function, as well as testicular histology. Central precocious puberty is extremely rare in PWS boys, but growth hormone treatment may play a role in the pubertal timing.

Prader- Willi syndrome: An uptodate on endocrine and metabolic complications

Prader-Willi syndrome (PWS) is a genetic disorder characterized by short stature, low lean body mass, muscular hypotonia, mental retardation, behavioral abnormalities, dysmorphic features, and excessive appetite with progressive obesity. It is caused by lack of expression of genes on the paternally inherited chromosome 15q11.2-q13. This genetic disorder has an estimated prevalence that ranges between 1/10,000-1/30,000. Hypothalamic dysfunction is a common finding in PWS and it has been implicated in several manifestations of this syndrome such as hyperphagia, temperature instability, high pain threshold, sleep disordered breathing, and multiple endocrine abnormalities. These include growth hormone deficiency, central adrenal insufficiency, hypogonadism, hypothyroidism, and obesity often complicated by type 2 diabetes. The aim of this manuscript is to overview the current literature on metabolic and endocrine complications of PWS, focusing on human studies and providing insights on the physio pathological mechanisms. A careful management of metabolic and endocrine complications can contribute to improve quality of life, prevent complications, and prolong life expectancy of PW patients.

MKRN3 Mutations in Central Precocious Puberty: A Systematic Review and Meta-Analysis

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

Pediatric endocrinology through syndromes

In everyday practice, a pediatric endocrinologist will face a variety of different endocrine issues (such as short or tall stature, dysthyroidism, abnormal pubertal timing or impaired glucose metabolism), which relevantly contribute to the global care of a number of syndromic conditions. On the other hand, the presence of endocrine features may assist in the diagnostic process, leading to final diagnosis of a syndromic disorder. The intention of this review is to provide a referenced overview of different genetic syndromes characterized by endocrine features, and to present a possible classification, based on whether the endocrinopathy or the syndrome is typically recognized first. Thus, the first part of the manuscript deals with the most common syndromes associated with endocrine dysfunctions, while the second part describes the conditions by which a syndrome is most frequently diagnosed after an endocrine finding. The aim is to provide a practical overview of the assessment of syndromic patients, so that they can be recognized and managed in an integrated, multidisciplinary fashion.

Gonadal function and testicular histology in males with Prader-Willi syndrome

CONTEXT

Cryptorchidism is common in Prader-Willi syndrome (PWS) males, but the testicular histology in childhood remains uncertain. The association between testicular histology and long-term gonadal function in PWS males is also unknown.

OBJECTIVES

To evaluate the relationship between testicular histology in childhood and long-term gonadal function in PWS males.

PATIENTS AND METHODS

Forty men with PWS were assessed longitudinally at our institute over the past 24 years. Clinical examinations and blood tests for LH, FSH and testosterone levels were compared with normal reference values. Tissue specimens were collected during orchiopexy and analyzed based on Nistal categories.

RESULTS

Of nine testes available for pathological assessments, two showed favourable histology (Nistal I) and seven showed unfavourable histology (Nistal II or III). Of five postpubertal males with histology available, four reached puberty spontaneously, but only one reached Tanner stage 5. In a male with favourable histology, LH and FSH were high, but testosterone was normal, though below the average of the reference range. In three males with unfavourable histology, LH was normal, but FSH was highly elevated, and testosterone was at the lower limit of normal. One patient took hCG treatment to induce puberty; this patient showed favourable histology, but LH, FSH and testosterone were not elevated in adolescence.

CONCLUSIONS

Testicular histology of PWS men in childhood varies from normal to Sertoli Cell-Only Syndrome. Regardless of the testicular histology in childhood, hypogonadism in PWS adults arises as a consequence of primary testicular dysfunction with highly elevated FSH and insufficient testosterone levels.

Review of Prader-Willi syndrome: the endocrine approach

Prader-Willi syndrome (PWS) is a complex genetic disorder with implications on the endocrine and neurologic systems, metabolism, and behavior. Early in life, PWS is characterized by hypotonia and failure to thrive, followed by obesity and hyperphagia. Patients with PWS develop hypothalamic dysfunction which may lead growth hormone deficiency (GHD), hypogonadism, hypothyroidism, adrenal insufficiency, and poor bone mineral density (BMD). In addition to hypothalamic dysfunction, individuals with PWS have increased risk for obesity which may be complicated by metabolic syndrome and type 2 diabetes mellitus (T2DM). In this paper, we will review the current literature pertaining to the endocrine concerns of PWS and current recommendations for screening and management of these conditions.

Anthropometric adjustments are helpful in the interpretation of BMD and BMC Z-scores of pediatric patients with Prader-Willi syndrome

Anthropometric adjustments of bone measurements are necessary in Prader-Willi syndrome patients to correctly assess the bone status of these patients. This enables physicians to get a more accurate diagnosis of normal versus abnormal bone, allow for early and effective intervention, and achieve better therapeutic results.

INTRODUCTION

Bone mineral density (BMD) is decreased in patients with Prader-Willi syndrome (PWS). Because of largely abnormal body height and weight, traditional BMD Z-scores may not provide accurate information in this patient group. The goal of the study was to assess a cohort of individuals with PWS and characterize the development of low bone density based on two adjustment models applied to a dataset of BMD and bone mineral content (BMC) from dual-energy X-ray absorptiometry (DXA) measurements.

METHODS

Fifty-four individuals, aged 5-20 years with genetically confirmed PWS, underwent DXA scans of spine and hip. Thirty-one of them also underwent total body scans. Standard Z-scores were calculated for BMD and BMC of spine and total hip based on race, sex, and age for all patients, as well as of whole body and whole-body less head for those patients with total-body scans. Additional Z-scores were generated based on anthropometric adjustments using weight, height, and percentage body fat and a second model using only weight and height in addition to race, sex, and age.

RESULTS

As many PWS patients have abnormal anthropometrics, addition of explanatory variables weight, height, and fat resulted in different bone classifications for many patients. Thus, 25-70 % of overweight patients, previously diagnosed as normal, were subsequently diagnosed as below normal, and 40-60 % of patients with below-normal body height changed from below normal to normal depending on bone parameter.

CONCLUSIONS

This is the first study to include anthropometric adjustments into the interpretation of BMD and BMC in children and adolescents with PWS. This enables physicians to get a more accurate diagnosis of normal versus abnormal BMD and BMC and allows for early and effective intervention.

A boy with Prader-Willi syndrome: unmasking precocious puberty during growth hormone replacement therapy

Prader-Willi syndrome (PWS) is a genetic disorder frequently characterized by obesity, growth hormone deficiency, genital abnormalities, and hypogonadotropic hypogonadism. Incomplete or delayed pubertal development as well as premature adrenarche are usually found in PWS, whereas central precocious puberty (CPP) is very rare. This study aimed to report the clinical and biochemical follow-up of a PWS boy with CPP and to discuss the management of pubertal growth. By the age of 6, he had obesity, short stature, and many clinical criteria of PWS diagnosis, which was confirmed by DNA methylation test. Therapy with recombinant human growth hormone (rhGH) replacement (0.15 IU/kg/day) was started. Later, he presented psychomotor agitation, aggressive behavior, and increased testicular volume. Laboratory analyses were consistent with the diagnosis of CPP (gonadorelin-stimulated LH peak 15.8 IU/L, testosterone 54.7 ng/dL). The patient was then treated with gonadotropin-releasing hormone analog (GnRHa). Hypothalamic dysfunctions have been implicated in hormonal disturbances related to pubertal development, but no morphologic abnormalities were detected in the present case. Additional methylation analysis (MS-MLPA) of the chromosome 15q11 locus confirmed PWS diagnosis. We presented the fifth case of CPP in a genetically-confirmed PWS male. Combined therapy with GnRHa and rhGH may be beneficial in this rare condition of precocious pubertal development in PWS.

Prader-Willi Syndrome: A spectrum of anatomical and clinical features

Prader-Willi Syndrome (PWS) is estimated to affect 400,000 people worldwide. First described clinically in 1956, PWS is now known to be a result of a genetic mutation, involving Chromosome 15. The phenotypical appearance of individuals with the syndrome follows a similar developmental course. During infancy, universal hypotonia accompanied by feeding problems, hypogonadism, and dolichocephaly are evident. Characteristic facial features such as narrow bifrontal diameter, almond-shaped eyes, and small mouth (with downturned corners and thin upper lip) may also be evident at this stage. In early childhood, the craniofacial features become more obvious and a global developmental delay is observed. Simultaneously, individuals develop hyperphagia that leads to excessive or rapid weight gain, which, if untreated, exists throughout their lifespan and may predispose them to numerous, serious health issues. The standard tool for differential diagnosis of PWS is genetic screening; however, clinicians also need to be aware of the characteristic features of this disorder, including differences between the genetic subtypes. As the clinical manifestations of the syndrome vary between individuals and become evident at different developmental time points, early assessment is hindered. This article focuses on the clinical and anatomical manifestations of the syndrome and highlights the areas of discrepancy and limitations within the existing literature. Clin. Anat. 29:590-605, 2016. © 2016 Wiley Periodicals, Inc.

Prader-Willi syndrome: a review of clinical, genetic, and endocrine findings

INTRODUCTION

Prader-Willi syndrome (PWS) is a multisystemic complex genetic disorder caused by lack of expression of genes on the paternally inherited chromosome 15q11.2-q13 region. There are three main genetic subtypes in PWS: paternal 15q11-q13 deletion (65-75 % of cases), maternal uniparental disomy 15 (20-30 % of cases), and imprinting defect (1-3 %). DNA methylation analysis is the only technique that will diagnose PWS in all three molecular genetic classes and differentiate PWS from Angelman syndrome. Clinical manifestations change with age with hypotonia and a poor suck resulting in failure to thrive during infancy. As the individual ages, other features such as short stature, food seeking with excessive weight gain, developmental delay, cognitive disability and behavioral problems become evident. The phenotype is likely due to hypothalamic dysfunction, which is responsible for hyperphagia, temperature instability, high pain threshold, hypersomnia and multiple endocrine abnormalities including growth hormone and thyroid-stimulating hormone deficiencies, hypogonadism and central adrenal insufficiency. Obesity and its complications are the major causes of morbidity and mortality in PWS.

METHODS

An extensive review of the literature was performed and interpreted within the context of clinical practice and frequently asked questions from referring physicians and families to include the current status of the cause and diagnosis of the clinical, genetics and endocrine findings in PWS.

CONCLUSIONS

Updated information regarding the early diagnosis and management of individuals with Prader-Willi syndrome is important for all physicians and will be helpful in anticipating and managing or modifying complications associated with this rare obesity-related disorder.

Sexual dichotomy of gonadal function in Prader-Willi syndrome from early infancy through the fourth decade

STUDY QUESTION

At what age does the type of hypogonadism, namely hypothalamic or primary gonadal defect, become established in men and women with Prader-Willi syndrome (PWS)?

SUMMARY ANSWER

The type of hypogonadism becomes established only in late adolescence and early adulthood.

WHAT IS KNOWN ALREADY

The etiology of hypogonadism in PWS is heterogeneous and the clinical expression is variable. Primary testicular failure is common in PWS men, while combinations of ovarian dysfunction and gonadotrophin deficiency are seen in women.

STUDY DESIGN, SIZE, DURATION

This is a prospective study of a cohort of 106 PWS patients followed for a mean duration of 4.5 years. Serial blood samples were obtained and assayed for gonadotrophins, inhibin B, anti-Mullerian hormone (AMH), dehydroepiandrosterone sulfate (DHEAS), testosterone (males), and estradiol (females). Results were compared with normal reference values obtained from the literature. For the purpose of this study, we defined the following age groups: infants <1 year; children 1-10 years; adolescents 11-20 years and adults >20 years.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Study participants were 49 males (aged 2 months to 36 years) and 57 females (aged 1 month to 37 years) with genetically confirmed diagnoses of PWS (deletions 60, uniparental disomy 54, imprinting center defect 2) followed in the Israel national multidisciplinary PWS clinic.

MAIN RESULTS AND THE ROLE OF CHANCE

Serum LH levels were in the normal range (1.0-6.0 mIU/ml) for 7/10 adult men, and high in 3, while FSH (normal range 1.0-6.1 mIU/ml) was elevated (34.4 ± 11.5 mIU/ml) in 6 and normal (3.5 ± 1.6 mIU/ml) in 4 men. Testosterone was low (5.7 ± 3.4 nmol/l) compared with the normal range of 12.0-34.5 nmol/l in the reference population in all men >20 years. AMH showed a normal decrease with age, despite low testosterone levels. Inhibin B was normal (241 ± 105 pg/ml) in infant boys, but low or undetectable in most adult men. Hormonal profiles were more heterogeneous in women than in men. Estradiol was consistently detectable in only 7/13 adult women. Inhibin B was low or undetectable in all PWS females although occasional samples showed levels within the normal range of 15-95 pg/ml. Vaginal bleeding was reported to occur for the first time in eight women at a median age of 20 years (13-34 years), but only one had regular monthly menses. The type of hypogonadism (primary or secondary) in PWS can be determined only after age 20 years.

LIMITATIONS, REASONS FOR CAUTION

The study cohort was heterogeneous, showing variability in BMI, cognitive disability and medical treatment.

WIDER IMPLICATIONS OF THE FINDINGS

Demonstration of the natural history of reproductive hormone development in PWS suggests that androgen replacement may be indicated for most PWS boys in mid-adolescence. Recommendations for hormone replacement in PWS women need to be individually tailored, serial measurements of inhibin B should be performed, and contraception should be considered in those women who may have the potential for fertility.

Characterization of minipuberty in infants with Prader-Willi syndrome

BACKGROUND

Minipuberty describes transient activation of the hypothalamic-pituitary-gonadal axis occurring during the first few months of life. Hormone levels during minipuberty were described in only a few Prader-Willi syndrome (PWS) infant boys and have not been reported in PWS infant girls.

OBJECTIVES

To measure gonadotropins and gonadal hormones in PWS male and female infants and assess gender-specific patterns of hormone secretion.

METHODS

Hormone levels in 14 (9 male, 5 female) PWS infants ages 1-3 months were compared with reference ranges for normal infants and in 44 prepubertal PWS children (27 female, 17 male).

RESULTS

Compared to prepubertal boys, hormone levels (median and range) for PWS infant boys were increased: LH 2.8 mIU/ml (1.2-6.2), FSH 4.4 mIU/ml (1.0-19.5), testosterone 4.0 nmol/l (3.0-7.0), inhibin B 219 pg/ml (141-325), and AMH 79 ng/ml (45-157). Hormone levels in infant girls were not significantly different from levels in prepubertal girls. LH, inhibin B, and AMH were higher in male infants than in female infants. LH/FSH ratios were 0.56 (0.24-1.77) in boys versus 0.09 (0.04-0.17) in girls (p = 0.003).

CONCLUSIONS

Hormone levels in PWS infant boys are in the expected minipuberty range. By contrast, reproductive hormones in most PWS infant girls did not differ from levels in prepubertal girls.

MKRN3 mutations in familial central precocious puberty

Loss-of-function mutations in the gene encoding the makorin RING finger protein 3 (MKRN3) have recently been reported to underlie familial cases of central precocious puberty (CPP). The imprinted MKRN3 gene is expressed only from the paternal allele, and mutations inherited from the father affect boys and girls equally, which is in contrast to the known female preponderance in idiopathic CPP. By screening a series of 6 families and 1 male patient with idiopathic CPP, we identified 2 further families carrying loss-of-function mutations in MKRN3, the previously reported variant c.475_476insC (p.Ala162Glyfs*14) and a novel one, c.331G>T (p.Glu111*). We conclude that MKRN3 mutations appear to be a frequent cause of familial CPP and, considering the imprinted mode of inheritance, may also account for a certain proportion of isolated CPP cases. Remarkably, four out of six MKRN3 mutations described so far encode either a stop codon or a frameshift followed by a premature stop codon. Consequently, there may be less severe mutations that possibly associate with more subtle phenotypes, which could even explain variation within the physiological range. Mutation screening in larger cohorts is necessary in order to estimate the real prevalence of MKRN3 mutations in idiopathic CPP.

Medical, psychological and social features in a large cohort of adults with Prader-Willi syndrome: experience from a dedicated centre in France

BACKGROUND

Prader-Willi syndrome (PWS) is a developmental genetic disorder characterised by a variable expression of medical, cognitive and behavioural symptoms. In adulthood, the prevalence and severity of these symptoms determine the quality of life of the affected persons. Because of their rare disease condition, data on health and social problems in adults with PWS are scarce. In this research, we present medical, psychological and social features of a large cohort of adults admitted to a specialised PWS centre in France and analyse the differences according to genotype, gender and age.

METHODS

Data from 154 patients (68 men/86 women), with a median age of 27 years (range 16-54), were collected during their stay in our centre. Clinical histories were completed using information from parents or main caregivers, and the same medical team performed the diagnosis of different clinical conditions. Statistical analyses were performed to determine the influence of factors such as genotype, age or gender.

RESULTS

Paternal deletion genotype was the most frequent (65%) at all ages. Most patients had mild or moderate intellectual disability (87%). Only 30% had studied beyond primary school and 70% were in some special educational or working programme. Most of them lived in the family home (57%). The most prevalent somatic comorbidities were scoliosis (78%), respiratory problems (75%), dermatological lesions (50%), hyperlipidaemia (35%), hypothyroidism (26%), Type 2 diabetes mellitus (25%) and lymph oedema (22%). Some form of psychotropic treatment was prescribed in 58% of subjects, and sex hormones in 43%. Patients with deletion had a higher body mass index (44 vs. 38.9 kg/m(2)) and displayed higher frequency of sleep apnoeas. Non-deletion patients received insulin treatment (19% vs. 4%) and antipsychotic treatment (54.8% vs. 32.7%) more frequently. No difference was observed in the prevalence of Type 2 diabetes between the two genotype groups. Patients >27 years of age had a higher rate of comorbidities (Type 2 diabetes, hypertension, respiratory problems and lymph oedema). Gender differences were minor.

CONCLUSIONS

Adult patients with PWS showed high prevalence of comorbid health problems that need to be monitored for early treatment. Some of them are influenced by genotype and age. Another salient problem concerns the lack of adapted structures for better social integration. Further data about the real life and health conditions of adults with PWS are necessary to further our knowledge of the natural history of the disease and to design appropriate care strategies.

Prader-Willi syndrome: a case report with atypical developmental features

OBJECTIVE

To describe the case of a male Prader-Willi syndrome (PWS) patient with atypical development features.

DESCRIPTION

We report the case of a male adolescent with confirmed diagnosis of PWS which presents atypical phenotype. The patient progressed with spontaneous and complete pubertal development, stature in the normal range, and weight control without any pharmacological treatment, except metformin.

COMMENTS

PWS is an imprinting paternally inherited disorder of 15q11-13 characterized by hypotonia in infant age, hyperphagia, varied degrees of mental retardation, behavior problems, hypogonadism, short stature, and other less common findings.

Testes in infants with Prader-Willi syndrome: human chorionic gonadotropin treatment, surgery and histology

PURPOSE

Boys with Prader-Willi syndrome often have undescended testes. Prospective studies on the treatment of cryptorchidism in these patients are lacking. We evaluated the effects of human chorionic gonadotropin administration on testis position in 16 males with Prader-Willi syndrome. In patients who subsequently underwent orchiopexy biopsy was taken and testis histology was evaluated.

MATERIALS AND METHODS

A total of 16 boys (median age 1.6 years, IQR 1.2 to 1.8) with Prader-Willi syndrome and cryptorchidism underwent human chorionic gonadotropin stimulation test. After a positive test human chorionic gonadotropin treatment was initiated. Patients received 250 to 500 IU (depending on age) intramuscularly twice weekly for 6 weeks.

RESULTS

We found 1 testis in a stable scrotal position, 1 vanished testis and 1 atrophic abdominal testis. Of 29 testes responding to human chorionic gonadotropin 23% reached a stable scrotal position, 62% reached a lower position and 14% did not change position. Thus, 22 testes required orchiopexy. Of 17 obtained biopsies in 12 patients 2 showed germ cells in more than 60% of seminiferous tubules, 3 in 30% to 60% and 7 in less than 30%. In addition, 4 boys had Sertoli cell only syndrome and 1 had a vanished testis. In patients undergoing orchiopexy younger age and increased inhibin B and testosterone levels after human chorionic gonadotropin stimulation were associated with a greater number of germ cell containing tubules.

CONCLUSIONS

Human chorionic gonadotropin administration resulted in an anatomically lower testis position in most of our patients with Prader-Willi syndrome, and 23% of testes reached a stable scrotal position. Of the cases 76% required orchiopexy to ensure a stable position in the scrotum.

Spreading the clinical window for diagnosing fetal-onset hypogonadism in boys

In early fetal development, the testis secretes - independent of pituitary gonadotropins - androgens and anti-Müllerian hormone (AMH) that are essential for male sex differentiation. In the second half of fetal life, the hypothalamic-pituitary axis gains control of testicular hormone secretion. Follicle-stimulating hormone (FSH) controls Sertoli cell proliferation, responsible for testis volume increase and AMH and inhibin B secretion, whereas luteinizing hormone (LH) regulates Leydig cell androgen and INSL3 secretion, involved in the growth and trophism of male external genitalia and in testis descent. This differential regulation of testicular function between early and late fetal periods underlies the distinct clinical presentations of fetal-onset hypogonadism in the newborn male: primary hypogonadism results in ambiguous or female genitalia when early fetal-onset, whereas it becomes clinically undistinguishable from central hypogonadism when established later in fetal life. The assessment of the hypothalamic-pituitary-gonadal axis in male has classically relied on the measurement of gonadotropin and testosterone levels in serum. These hormone levels normally decline 3-6 months after birth, thus constraining the clinical evaluation window for diagnosing male hypogonadism. The advent of new markers of gonadal function has spread this clinical window beyond the first 6 months of life. In this review, we discuss the advantages and limitations of old and new markers used for the functional assessment of the hypothalamic-pituitary-testicular axis in boys suspected of fetal-onset hypogonadism.

Endocrine manifestations and management of Prader-Willi syndrome

Prader-Willi syndrome (PWS) is a complex genetic disorder, caused by lack of expression of genes on the paternally inherited chromosome 15q11.2-q13. In infancy it is characterized by hypotonia with poor suck resulting in failure to thrive. As the child ages, other manifestations such as developmental delay, cognitive disability, and behavior problems become evident. Hypothalamic dysfunction has been implicated in many manifestations of this syndrome including hyperphagia, temperature instability, high pain threshold, sleep disordered breathing, and multiple endocrine abnormalities. These include growth hormone deficiency, central adrenal insufficiency, hypogonadism, hypothyroidism, and complications of obesity such as type 2 diabetes mellitus. This review summarizes the recent literature investigating optimal screening and treatment of endocrine abnormalities associated with PWS, and provides an update on nutrition and food-related behavioral intervention. The standard of care regarding growth hormone therapy and surveillance for potential side effects, the potential for central adrenal insufficiency, evaluation for and treatment of hypogonadism in males and females, and the prevalence and screening recommendations for hypothyroidism and diabetes are covered in detail. PWS is a genetic syndrome in which early diagnosis and careful attention to detail regarding all the potential endocrine and behavioral manifestations can lead to a significant improvement in health and developmental outcomes. Thus, the important role of the provider caring for the child with PWS cannot be overstated.

Deconvolution-based assessment of pituitary GH secretion stimulated with GHRH+arginine in Prader-Willi adults and obese controls

OBJECTIVE

The assessment of GH deficiency in adult patients with Prader-Willi syndrome (PWS) has been previously assessed through the evaluation of quantitative parameters, such as the peak value of GH response to exogenous stimuli. A comprehensive description of the pattern of secretory response obtainable by deconvolution analysis is still lacking. The aim of our study was to characterize the time evolution of responses of PWS subjects compared with obese controls.

DESIGN AND SUBJECTS

GH responsiveness was measured following the combined administration of GHRH+arginine to 65 PWS adults (24 males, 41 females) aged 18-41·2 years, and 17 age-, gender- and body mass index-matched obese controls. PWS subjects were analysed considering the stratification on different genotypes.

MEASUREMENTS

GH response to GHRH+arginine was analysed in terms of peak values, standard area under the curves (AUCs), AUCs due to the stimulus, AUCs of the Instantaneous Secretion Rate signal and Secretion Response Analysis.

RESULTS

In terms of both peak values and AUC, GH responses were statistically different between PWS UPD15 and PWS DEL15 subjects as well as between PWS UPD15 and obese controls. PWS subjects showed a lower and a more delayed GH response compared with obese controls. Moreover, PWS UPD15 subjects had the most delayed GH response.

CONCLUSIONS

Our findings demonstrate that impaired GH secretion in PWS subjects compared with obese controls regards not only amplitude parameters such as peak value and AUC, but also the shape of the secretory response, which is more delayed, especially for UPD15 subjects.

Medical management for adults with Prader-Willi syndrome

BACKGROUND

Prader-Willi syndrome (PWS) is a genetic disorder characterized by morbid obesity resulting from insatiable appetite. Complications like diabetes mellitus or other cardiovascular diseases typically occur during lifetime. Lifestyle advice and education as well as limited caloric intake are the major concepts in assistance of PWS patients.

METHODS

A 12.9-month follow-up study, which included 8 formerly genetically diagnosed PWS patients, was conducted. Physical and laboratory examinations were done at the beginning and at the end of the follow-up. Improved medical care and lifestyle advice were given. The participants lived in an assisted living environment with a fixed daily schedule and limited caloric intake.

RESULTS

The group of patients consisted of manifest diabetics (n=6) as well as nondiabetics (n=2). Therapeutic concepts were simplified in 2 patients by switching from insulin to oral antidiabetics. The reduction in body weight was moderate, but attributable to a loss of fat mass. A significant reduction in blood cholesterol and triglyceride content was achieved along the observational period as well as a significant reduction of glycosylated hemoglobin (HbA1c) in the group of diabetic PWS patients. Systolic blood pressure improved during the study.

CONCLUSION

A combination of an assisted living environment following conservative treatments as well as consistent patient care improved the daily and medical situation of PWS patients. Weight loss and, as a consequence, improvements in terms of metabolic condition and blood pressure were observed. A combination of medical and daily routine management should be established in PWS patients to improve their quality of life.

The prepubertal testis: biomarkers and functions

PURPOSE OF REVIEW

Biomarkers of prepubertal testicular function have become widely available only in recent years. The aim of this review is to update the knowledge on key biomarkers used to assess hypogonadism in boys.

RECENT FINDINGS

Sertoli cells are the most representative cells of the prepubertal testis. Anti-Müllerian hormone and inhibin B are essential biomarkers of Sertoli cell function. Also, INSL3 arises as an additional marker of Leydig cell dysfunction.

SUMMARY

The widespread use of these biomarkers has enhanced our knowledge on the pathophysiology and diagnosis of prepubertal male hypogonadism. Beyond their well known germ-cell toxicity, oncologic treatments may also affect Sertoli cell function. Pathophysiology is not the same in all aneuploidies leading to infertility: while hypogonadism is not evident until mid-puberty in Klinefelter syndrome, it is established in early infancy in Down syndrome. In Noonan syndrome, the occurrence of primary hypogonadism depends on the existence of cryptorchidism, and Prader-Willi syndrome may present with either primary or combined forms of hypogonadism. Prepubertal testicular markers have also provided insights into the effects of environmental disruptors on gonadal function from early life, and helped dissipate concerns about testicular function in boys born preterm or small for gestational age or conceived by assisted reproductive technique procedures.

Recent updates on recombinant human growth hormone outcomes and adverse events

PURPOSE OF REVIEW

To provide up-to-date information on outcomes and adverse events associated with the use of recombinant human growth hormone (rhGH). We will focus on patients with Prader Willi Syndrome and Idiopathic Short Stature. We will also discuss recent reports on long-term adverse events from the European database.

RECENT FINDINGS

Prader Willi Syndrome is associated with hypogonadism, which does not appear to be affected by treatment with rhGH. However, there is new evidence that treatment may improve cognition. For patients with Idiopathic Short Stature, the gain in near adult height with treatment with rhGH appears to be 3-4 cm. Although a recent analysis of this group shows that certain patient characteristics may help identify those most likely to have a good response to treatment. Additionally, the safety and appropriateness of growth hormone treatments in Europe study released preliminary data from patients treated in two separate locations that showed conflicting information on risk of mortality from treatment with rhGH.

SUMMARY

Although we will continue to receive new information regarding the safety and effects of treatment with rhGH, it is important to discuss the risks and benefits with our patients. Additionally, it is incumbent on us to help guide the treatment to those most likely to benefit.

Anti-müllerian hormone: a valuable addition to the toolbox of the pediatric endocrinologist

Anti-Müllerian hormone (AMH), secreted by immature Sertoli cells, provokes the regression of male fetal Müllerian ducts. FSH stimulates AMH production; during puberty, AMH is downregulated by intratesticular testosterone and meiotic germ cells. In boys, AMH determination is useful in the clinical setting. Serum AMH, which is low in infants with congenital central hypogonadism, increases with FSH treatment. AMH is also low in patients with primary hypogonadism, for instance in Down syndrome, from early postnatal life and in Klinefelter syndrome from midpuberty. In boys with nonpalpable gonads, AMH determination, without the need for a stimulation test, is useful to distinguish between bilaterally abdominal gonads and anorchism. In patients with disorders of sex development (DSD), serum AMH determination helps as a first line test to orientate the etiologic diagnosis: low AMH is indicative of dysgenetic DSD whereas normal AMH is suggestive of androgen synthesis or action defects. Finally, in patients with persistent Müllerian duct syndrome (PMDS), undetectable serum AMH drives the genetic search to mutations in the AMH gene, whereas normal or high AMH is indicative of an end organ defect due to AMH receptor gene defects.

Ovarian function and reproductive hormone levels in girls with Prader-Willi syndrome: a longitudinal study

CONTEXT

The etiology of hypogonadism in girls with Prader-Willi syndrome (PWS) remains uncertain.

OBJECTIVES

The aim of the study was to evaluate gonadal function longitudinally in girls and female adolescents with PWS.

MEASUREMENTS

We performed a longitudinal assessment of anti-müllerian hormone (AMH), gonadotropins, estradiol (E(2)), inhibin B and A, and pubertal development in girls and female adolescents with PWS.

PATIENTS AND METHODS

Sixty-one girls participating in the Dutch PWS Cohort study participated in the study. Serum AMH, gonadotropins, E(2), and inhibin B and A levels were compared with reference values.

RESULTS

AMH levels in girls and female adolescents with PWS were comparable to reference levels between 6 months and 22 yr of age. From 10 yr of age, FSH and LH levels increased to above the 5th percentile compared to reference levels. E(2) and inhibin B levels were in the low normal range in the majority, and inhibin A levels were low but detectable in almost half the female adolescents with PWS. The median age at puberty onset was comparable, but the median ages at attaining Tanner M3 (P = 0.05) and M4 (P < 0.0001) were significantly higher in girls with PWS than in healthy references.

CONCLUSION

Our study shows that the primordial follicle pool and number of small antral follicles are conserved in girls and female adolescents with PWS. We found no classical hypogonadotropic hypogonadism. However, maturation of follicles and progression of pubertal development are impaired, which might be due to dysregulation of LH secretion. Because these impairments are not absolute, ovulation and thus conception cannot be ruled out in individual female adolescents with PWS.

The FSH-inhibin axis in prader-willi syndrome: heterogeneity of gonadal dysfunction

BACKGROUND

We characterized the spectrum and etiology of hypogonadism in a cohort of Prader-Willi syndrome (PWS) adolescents and adults.

METHODS

Reproductive hormonal profiles and physical examination were performed on 19 males and 16 females ages 16-34 years with PWS. Gonadotropins, sex-steroids, inhibin B (INB) and anti-Mullerian hormone (AMH) were measured. We defined 4 groups according to the relative contribution of central and gonadal dysfunction based on FSH and INB levels: Group A: primary hypogonadism (FSH >15 IU/l and undetectable INB (<10 pg/ml); Group B: central hypogonadism (FSH <0.5 IU/l, INB <10 pg/ml); Group C: partial gonadal & central dysfunction (FSH 1.5-15 IU/l, INB >20 pg/ml); Group D: mild central and severe gonadal dysfunction (FSH 1.5-15 IU/l, INB < 10 pg/ml.

RESULTS

There were 10, 8, 9 and 8 individuals in Groups A-D respectively; significantly more males in group A (9, 4, 4 and 2; P = 0.04). Significant differences between the groups were found in mean testosterone (P = 0.04), AMH (P = 0.003) and pubic hair (P = 0.04) in males and mean LH (P = 0.003) and breast development (P = 0.04) in females. Mean age, height, weight, BMI and the distribution of genetic subtypes were similar within the groups.

CONCLUSIONS

Analysis of FSH and inhibin B revealed four distinct phenotypes ranging from primary gonadal to central hypogonadism. Primary gonadal dysfunction was common, while severe gonadotropin deficiency was rare. Longitudinal studies are needed to verify whether the individual phenotypes are consistent.