Body composition, endocrine and metabolic profiles in adults with Prader-Willi syndrome

Puberty in girls with Prader-Willi syndrome: cohort evaluation and clinical recommendations in a Latin American tertiary center

Introduction

Prader-Willi syndrome (PWS) is a genetic disorder characterized by hypothalamic-pituitary deficiencies including hypogonadism. In girls with PWS, hypogonadism can present early in childhood, leading to genital hypoplasia, delayed puberty, incomplete pubertal development, and infertility. In contrast, girls can present with premature activation of the adrenal axis leading to early pubarche and advanced bone age. We aim to evaluate the progression of puberty and adrenarche signals in girls with PWS.

Methodology

A longitudinal retrospective cohort study included girls with PWS followed at a Pediatric Endocrinology Outpatient Clinic in a Tertiary University Hospital in Sao Paulo, Brazil from 2002 to 2022. Data collected via chart review included clinical information on birth history, breast and pubic hair Tanner stages, presence of genital hypoplasia, age at menarche, regularity of menstrual cycles, body mass index (BMI) z-score, final height, age of initiation of estrogen replacement and growth hormone replacement, as well as results for PWS genetic subtype; biochemical investigation (LH, FSH, estradiol, DHEA-S); radiographic bone age and pelvic ultrasound.

Results

A total of 69 girls were included in the study and the mean age of puberty onset was 10.2 years in those who started puberty after the age of 8 years. Breast Tanner stage IV was reached by 29.1% girls at a mean age of 14.9 years. Spontaneous menarche was present in 13.8% and only one patient had regular menstrual cycles. Early adrenarche was seen in 40.4% of cases.

Conclusion

Our study demonstrated in a large sample that girls with PWS often present with delayed onset of puberty despite frequent premature adrenarche. Based on our results, we suggest an estrogen replacement protocol for girls with PWS to be started at the chronological age or bone age of 12-13 years, taking into consideration the uterus size. Further prospective studies are needed.

Body Fat Distribution Contributes to Defining the Relationship between Insulin Resistance and Obesity in Human Diseases

The risk for metabolic and cardiovascular complications of obesity is defined by body fat distribution rather than global adiposity. Unlike subcutaneous fat, visceral fat (including hepatic steatosis) reflects insulin resistance and predicts type 2 diabetes and cardiovascular disease. In humans, available evidence indicates that the ability to store triglycerides in the subcutaneous adipose tissue reflects enhanced insulin sensitivity. Prospective studies document an association between larger subcutaneous fat mass at baseline and reduced incidence of impaired glucose tolerance. Case-control studies reveal an association between genetic predisposition to insulin resistance and a lower amount of subcutaneous adipose tissue. Human peroxisome proliferator-activated receptorgamma (PPAR-γ) promotes subcutaneous adipocyte differentiation and subcutaneous fat deposition, improving insulin resistance and reducing visceral fat. Thiazolidinediones reproduce the effects of PPAR-γ activation and therefore increase the amount of subcutaneous fat while enhancing insulin sensitivity and reducing visceral fat. Partial or virtually complete lack of adipose tissue (lipodystrophy) is associated with insulin resistance and its clinical manifestations, including essential hypertension, hypertriglyceridemia, reduced HDL-c, type 2 diabetes, cardiovascular disease, and kidney disease. Patients with Prader Willi syndrome manifest severe subcutaneous obesity without insulin resistance. The impaired ability to accumulate fat in the subcutaneous adipose tissue may be due to deficient triglyceride synthesis, inadequate formation of lipid droplets, or defective adipocyte differentiation. Lean and obese humans develop insulin resistance when the capacity to store fat in the subcutaneous adipose tissue is exhausted and deposition of triglycerides is no longer attainable at that location. Existing adipocytes become large and reflect the presence of insulin resistance.

Multicentric Italian case-control study on 25OH vitamin D levels in children and adolescents with Prader-Willi syndrome

PURPOSE

25OHD levels in patients with Prader-Willi Syndrome (PWS), the most frequent cause of genetic obesity with a peculiar fat mass distribution, are still debated. Insulin resistance (IR), Body Mass Index-SDS (BMI-SDS), Growth Hormone Therapy (GHT), and puberty onset seem to interact with 25OHD levels. The objectives of the study are: (1) To analyze 25OHD levels in pediatric PWS patients in comparison with a control group (CNT) (2) To evaluate a possible correlation between BMI-SDS, HOMA-IR, puberty, GHT, and 25OHD levels.

METHODS

This is a retrospective case-control, multicenter study. Data were collected among 8 different Italian Hospitals (outpatient clinics), over a period of four years (2016-2020). We included 192 genetically confirmed PWS and 192 CNT patients, aged 3-18 years, matched 1:1 for age, gender, BMI-SDS, Tanner stage, sun exposure, and month of recruitment.

RESULTS

No statistically significant differences in 25OHD levels were observed between the PWS population and the CNT (PWS 24.0 ng/mL vs CNT 22.5 ng/mL, p > 0.05), OR = 0.89 (95% CI 0.58-1.35). We observed a slight, although non-significant, reduction in 25OHD levels comparing NW and OB populations. HOMA-IR, puberty onset, genotype and GHT (previous or ongoing) did not show statistically significant correlation with 25OHD levels.

CONCLUSIONS

Our findings could be useful for clinicians to optimize the therapeutic management as well as to increase awareness of PWS.

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.

Food-Related Brain Activation Measured by fMRI in Adults with Prader-Willi Syndrome

(1) Background: Prader–Willi syndrome (PWS) is characterized by hyperphagia, resulting in morbid obesity if not controlled. The primary aim of this study was to investigate whether PWS patients show altered activation of brain areas involved in hunger. As a secondary objective, we assessed whether there is an association between these brain areas and several endocrine and metabolic factors in the fasting state. (2) Methods: 12 PWS adults and 14 healthy controls (siblings) performed a food-related experimental task after an overnight fast while brain activation in regions of interest was measured by functional MRI. (3) Results: In controls, significantly more activation was found in the left insula (p = 0.004) and the bilateral fusiform gyrus (p = 0.003 and 0.013) when the individuals were watching food as compared to non-food pictures, which was absent in PWS patients. Moreover, in PWS adults watching food versus non-food pictures a significant negative correlation for glucose and right amygdala activation (p_fwe = 0.007) as well as a positive correlation for leptin and right anterior hippocampus/amygdala activation (p_fwe = 0.028) was demonstrated. No significant associations for the other hormonal and metabolic factors were found. (4) Conclusions: PWS individuals show aberrant food-related brain activation in the fasting state. Leptin is associated with activation within the neural motivation/reward circuitry, while the opposite is true for glucose.

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.

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.

Adults with Prader-Willi syndrome exhibit a unique microbiota profile

Objective

Adults with Prader–Willi syndrome (PWS) require less energy intake to maintain body weight than the general adult population. This, combined with their altered gastrointestinal transit time, may impact microbiota composition. The aim of the study was to determine if the fecal microbiota composition of adults with PWS differed from non-affected adults. Using usual diet/non-interventional samples, fecal microbiota composition was analyzed using 16S rRNA gene amplicon sequencing and data from adults with PWS were merged with four other adult cohorts that differed by geographical location and age. QIIME 2™ sample-classifier, machine learning algorithms were used to cross-train the samples and predict from which dataset the taxonomic profiles belong. Taxa that most distinguished between all datasets were extracted and a visual inspection of the R library PiratePlots was performed to select the taxa that differed in abundance specific to PWS.

Results

Fecal microbiota composition of adults with PWS showed low Blautia and enhanced RF39 (phyla Tenericutes), Ruminococcaceae, Alistipes, Erysipelotrichacaea, Parabacteriodes and Odoribacter. Higher abundance of Tenericutes, in particular, may be a signature characteristic of the PWS microbiota although its relationship, if any, to metabolic health is not yet known.

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.

Growth hormone treatment for Prader-Willi syndrome: A review

The Prader-Willi Syndrome (PWS) is a rare developmental disorder that contributed by multiple genes. Phenotypically, infants with PWS exhibit hypotonia and developmental delay, whilst older children and adults have cognitive impairments, neuropsychiatric symptoms, impaired motor development, neurological anomalies, endocrine dysfunctions like growth hormone (GH) deficiency, and hyperphagia that leads to obesity. Although mechanisms remain elusive, GH treatment has been recommended as the standard treatment for PWS children. In addition to better motor development, improved body composition and linear growth have been well established, but mental flexibility and behavioural problems remained largely untouched. This review will systemically analyze the recent clinical trials of GH treatment on PWS patients. The emphasis is on the mental and behavioural improvements by GH treatment, and a few concerns to initiate GH treatment. This review will finally propose possible future explorations on basic studies that may shed new light on clinical trials of GH treatment on PWS.

Three years of growth hormone treatment in young adults with Prader-Willi Syndrome previously treated with growth hormone in childhood: Effects on glucose homeostasis and metabolic syndrome

CONTEXT

Growth hormone (GH) has been approved for children with Prader-Willi syndrome (PWS) and significantly improves body composition in adults with PWS. Adults with PWS are predisposed to develop impaired glucose tolerance (IGT) and diabetes mellitus type 2 (DMT2). Continuation of GH maintains body composition, but GH is known to induce insulin resistance, which might affect glucose homeostasis. Studies on long-term effects of GH treatment in adults are very limited.

OBJECTIVE

To investigate effects of 3 years of GH treatment on glucose homeostasis and prevalence of metabolic syndrome (MS) in adults with PWS.

DESIGN

Open-label, prospective study.

PATIENTS

43 young adults with PWS.

SETTING

Dutch PWS Reference Center.

MAIN OUTCOME MEASURES

Glucose and insulin during oral glucose tolerance test.

RESULTS

Estimated mean (95% CI) fasting glucose and insulin levels remained stable during 3 years of GH treatment. Glucose being 4.6 (4.4-4.8) mmol/l at start and 4.7 (4.6-4.9) mmol/l after 3 years (P = .07); insulin being 59.5 (45.2-75.8) pmol/l and 56.7 (45.2-69.6) pmol/l resp. (P = .72). Sex, ethnicity and fat mass percentage were significantly associated with fasting glucose levels, while IGF-I or GH-dose were not. Blood pressure, lipids and prevalence of MS remained stable during 3 years of GH. IGT prevalence was variable over time, six patients had IGT at start and eleven after 3 years of GH. One patient developed DMT2. However, prevalence of IGT or DMT2 was not significantly higher after 3 years than at study start.

CONCLUSIONS

Three years of GH treatment in adults with PWS does not impair glucose homeostasis and does not lead to an increased prevalence of DMT2.

Sleep-disordered breathing and genetic findings in children with Prader-Willi syndrome in China

Background

Sleep-related breathing disorders are common in individuals with Prader-Willi syndrome (PWS), and can include hypersomnolence and obstructive sleep apnea, as well as central sleep breathing abnormalities that are present from infancy. Here we describe the sleep-disordered breathing (SDB) and genetic findings in patients with PWS in China.

Methods

In all, 48 patients confirmed by genetic tests were enrolled, 32 were under 2 years of age and 16 were older children. There were 37 (77.1%) patients with paternal 15q11-13 deletions, 11 (22.9%) patients with maternal uniparental disomy (mUPD), and no patients with imprinting defect (ID).

Results

Compared with infants, a significantly higher proportion of older children with PWS were overweight or obese (15/16 children vs. 4/32 infants) and children had a higher serum level of free thyroxine (FT4) (0.9±0.2 vs. 0.7±0.7) and thyroxine (T4) (9.0±2.5 vs. 7.5±1.7). Age was correlated significantly with body mass index (BMI), T4, and FT4 (r=0.626, P=0.000; r=0.426, respectively). Overall, 42 of 48 (87.5%) patients had sleep apnea on polysomnography (PSG). Infants, when compared with older children, were more likely to experience central sleep apnea (71.8% vs. 25%). In infants, there were no significant differences in the prevalence of SDB between the deletion group and the mUPD group.

Conclusions

Being overweight or obese was more common in older children with PWS. Compared with infants, a higher proportion children were overweight or obese and had higher serum levels of FT4 and T4. The prevalence of SDB was high in those with PWS, and central sleep apnea was found to be prevalent in infants. The pattern of SDB in infants with PWS was not significantly associated with the genotypes.

Gut microbiota of obese subjects with Prader-Willi syndrome is linked to metabolic health

OBJECTIVE

The gut microbiota has been implicated in the aetiology of obesity and associated comorbidities. Patients with Prader-Willi syndrome (PWS) are obese but partly protected against insulin resistance. We hypothesised that the gut microbiota of PWS patients differs from that of non-genetically obese controls and correlate to metabolic health. Therefore, here we used PWS as a model to study the role of gut microbiota in the prevention of metabolic complications linked to obesity.

DESIGN

We conducted a case-control study with 17 adult PWS patients and 17 obese subjects matched for body fat mass index, gender and age. The subjects were metabolically characterised and faecal microbiota was profiled by 16S ribosomal RNA gene sequencing. The patients' parents were used as a non-obese control group. Stool samples from two PWS patients and two obese controls were used for faecal microbiota transplantations in germ-free mice to examine the impact of the microbiota on glucose metabolism.

RESULTS

The composition of the faecal microbiota in patients with PWS differed from that of obese controls, and was characterised by higher phylogenetic diversity and increased abundance of several taxa such as Akkermansia, Desulfovibrio and Archaea, and decreased abundance of Dorea. Microbial taxa prevalent in the PWS microbiota were associated with markers of insulin sensitivity. Improved insulin resistance of PWS was partly transmitted by faecal microbiota transplantations into germ-free mice.

CONCLUSION

The gut microbiota of PWS patients is similar to that of their non-obese parents and might play a role for the protection of PWS patients from metabolic complications.

Prader-Willi syndrome: endocrine manifestations and management

Prader-Willi syndrome (PWS) is a genetic disorder caused by the absence of gene expression in the 15q11.2-q13 paternal chromosome. Patients with PWS develop hypothalamic dysfunction that can lead to various endocrine changes such as: obesity, growth hormone deficiency, hypogonadism, hypothyroidism, adrenal insufficiency and low bone mineral density. In addition, individuals with PWS have increased risk of developing type 2 diabetes mellitus. This review summarizes and updates the current knowledge about the prevention, diagnosis and treatment of endocrine manifestations associated with Prader Willi syndrome, especially diagnosis of growth hormone deficiency, management and monitoring of adverse effects; diagnosis of central adrenal insufficiency and management in stressful situations; screening for central hypothyroidism; research and treatment of hypogonadism; prevention and treatment of disorders of glucose metabolism. Careful attention to the endocrine aspects of PWS contributes significantly to the health of these individuals. Arch Endocrinol Metab. 2020;64(3):223-34.

The Sun's Vitamin in Adult Patients Affected by Prader-Willi Syndrome

Prader-Willi syndrome (PWS) is a genetic disorder characterized by hyperphagia with progressive, severe obesity, and an increased risk of obesity-related comorbidities in adult life. Although low dietary vitamin D intake and low 25-hydroxy vitamin D (25OHD) levels are commonly reported in PWS in the context of bone metabolism, the association of low 25OHD levels with fat mass has not been extensively evaluated in PWS adults. The aims of this study were to investigate the following in PWS adults: (1) 25OHD levels and the dietary vitamin D intake; (2) associations among 25OHD levels with anthropometric measurements and fat mass; (3) specific cut-off values for body mass index (BMI) and fat mass predictive of the 25OHD levels. In this cross-sectional, single-center study we enrolled 30 participants, 15 PWS adults (age 19-41 years and 40% males) and 15 control subjects matched by age, sex, and BMI from the same geographical area (latitude 40° 49' N; elevation 17 m). Fat mass was assessed using a bioelectrical impedance analysis (BIA) phase-sensitive system. The 25OHD levels were determined by a direct competitive chemiluminescence immunoassay. Dietary vitamin D intake data was collected by three-day food records. The 25OHD levels in the PWS adults were constantly lower across all categories of BMI and fat mass compared with their obese counterpart. The 25OHD levels were negatively associated with BMI (p = 0.04), waist circumference (p = 0.03), fat mass (p = 0.04), and dietary vitamin D intake (p < 0.001). During multiple regression analysis, dietary vitamin D intake was entered at the first step (p < 0.001), thus explaining 84% of 25OHD level variability. The threshold values of BMI and fat mass predicting the lowest decrease in the 25OHD levels were found at BMI ≥ 42 kg/m2 (p = 0.01) and fat mass ≥ 42 Kg (p = 0.003). In conclusion, our data indicate that: (i) 25OHD levels and dietary vitamin D intake were lower in PWS adults than in the control, independent of body fat differences; (ii) 25OHD levels were inversely associated with BMI, waist circumference, and fat mass, but low dietary vitamin D intake was the major determinant of low vitamin D status in these patients; (iii) sample-specific cut-off values of BMI and fat mass might help to predict risks of the lowest 25OHD level decreases in PWS adults. The presence of trained nutritionists in the integrated care teams of PWS adults is strongly suggested in order to provide an accurate nutritional assessment and tailored vitamin D supplementations.

Update on Diabetes Mellitus and Glucose Metabolism Alterations in Prader-Willi Syndrome

PURPOSE OF REVIEW

This review summarizes our current knowledge on type 2 diabetes mellitus (T2DM) and glucose metabolism alterations in Prader-Willi syndrome (PWS), the most common syndromic cause of obesity, and serves as a guide for future research and current best practice.

RECENT FINDINGS

Diabetes occurs in 10-25% of PWS patients, usually in adulthood. Severe obesity is a significant risk factor for developing of T2DM in PWS. Paradoxically, despite severe obesity, a relative hypoinsulinemia, without the expected insulin resistance, is frequently observed in PWS. The majority of PWS subjects with T2DM are asymptomatic and diabetes-related complications are infrequent. Long-term growth hormone therapy does not adversely influence glucose homeostasis in all ages, if weight gain does not occur. Early intervention to prevent obesity and the regular monitoring of glucose levels are recommended in PWS subjects. However, further studies are required to better understand the physiopathological mechanisms of T2DM in these patients.

Prevalence of growth hormone (GH) deficiency in previously GH-treated young adults with Prader-Willi syndrome

OBJECTIVE

Some features of subjects with Prader-Willi syndrome (PWS) resemble those seen in growth hormone deficiency (GHD). Children with PWS are treated with growth hormone (GH), which has substantially changed their phenotype. Currently, young adults with PWS must discontinue GH after attainment of adult height when they do not fulfil the criteria of adult GHD. Limited information is available about the prevalence of GHD in adults with PWS. This study aimed to investigate the GH/insulin-like growth factor (IGF-I) axis and the prevalence of GHD in previously GH-treated young adults with PWS.

DESIGN

Cross-sectional study in 60 young adults with PWS.

MEASUREMENTS

Serum IGF-I and IGFBP-3 levels, GH peak during combined growth hormone-releasing hormone (GHRH)-arginine stimulation test.

RESULTS

Serum IGF-I was <-2 standard deviation scores (SDS) in 2 (3%) patients, and IGFBP-3 was within the normal range in all but one patient. Median (IQR) GH peak was 17.8 μg/L (12.2; 29.7) [~53.4 mU/L] and below 9 μg/L in 9 (15%) patients. Not one patient fulfilled the criteria for adult GHD (GH peak < 9 μg/L and IGF-I < -2 SDS), also when BMI-dependent criteria were used. A higher BMI and a higher fat mass percentage were significantly associated with a lower GH peak. There was no significant difference in GH peak between patients with a deletion or a maternal uniparental disomy (mUPD).

CONCLUSIONS

In a large group of previously GH-treated young adults with PWS, approximately 1 in 7 exhibited a GH peak <9 μg/L during a GHRH-arginine test. However, none of the patients fulfilled the consensus criteria for adult GHD.

Treatment with growth hormone in the prader-willi syndrome

INTRODUCTION

The Prader-Willi syndrome (PWS) is a rare genetic disorder caused by absence of expression of the paternal alleles in región 15q11.2-q13. Obesity and hormonal deficiencies, especially of growth hormone (GH), are the most important signs from the therapeutic viewpoint. Recombinant GH (rGH) is effective in children and represents the mainstay in treatment; by contrast, little evidence in available in adult patients.

OBJECTIVE

To review the reported evidence on the beneficial and adverse effects of treatment with rGH in children and adults.

DESIGN

A review was made of 62 original articles published between 2000 and 2017 using the PubMed database.

RESULTS

In pediatric and adult PWS, rGH improves body morphology and composition, physical performance, cognition, psychomotor development, respiratory function, and quality of life with few adverse effects.

CONCLUSIONS

Treatment with rGH is effective and safe and improves quality of life in both children and adults with PWS.

Body composition, adipokines, bone mineral density and bone remodeling markers in relation to IGF-1 levels in adults with Prader-Willi syndrome

Background

In patients with Prader-Willi syndrome (PWS) body composition is abnormal and alterations in appetite regulating factors, bone mineral density and insulin-like growth factor-1 (IGF-1) levels have been described. Studies in PWS adults are limited. In this study, we investigated body composition, appetite regulating peptides, bone mineral density and markers of bone remodeling in an adult PWS population. Furthermore, we investigated the association between these different parameters and IGF-1 levels because of the described similarities with growth hormone deficient patients.

Methods

In this cross-sectional observational cohort study in a university hospital setting we studied fifteen adult PWS patients. Anthropometric and metabolic parameters, IGF-1 levels, bone mineral density and bone metabolism were evaluated. The homeostasis model assessment of insulin resistance (HOMA2-IR) was calculated. Fourteen healthy siblings served as a control group for part of the measurements.

Results

In the adult PWS patients, height, fat free mass, IGF-1 and bone mineral content were significantly lower when compared to controls; body mass index (BMI), waist, waist-to-hip ratio and fat mass were higher. There was a high prevalence of osteopenia and osteoporosis in the PWS patients. Also, appetite regulating peptides and bone remodelling markers were aberrant when compared to reference values. Measurements of body composition were significantly correlated to appetite regulating peptides and high-sensitive C-reactive protein (hs-CRP), furthermore HOMA was correlated to BMI and adipokines.

Conclusion

In adults with Prader-Willi syndrome alterations in body composition, adipokines, hs-CRP and bone mineral density were demonstrated but these were not associated with IGF-1 levels. Further investigations are warranted to gain more insight into the exact pathophysiology and the role of these alterations in the metabolic and cardiovascular complications seen in PWS, so these complications can be prevented or treated as early as possible.

Mechanisms of obesity in Prader-Willi syndrome

Obesity is the most common cause of metabolic complications and poor quality of life in Prader-Willi syndrome (PWS). Hyperphagia and obesity develop after an initial phase of poor feeding and failure to thrive. Several mechanisms for the aetiology of obesity in PWS are proposed, which include disruption in hypothalamic pathways of satiety control resulting in hyperphagia, aberration in hormones regulating food intake, reduced energy expenditure because of hypotonia and altered behaviour with features of autism spectrum disorder. Profound muscular hypotonia prevents PWS patients from becoming physically active, causing reduced muscle movements and hence reduced energy expenditure. In a quest for the aetiology of obesity, recent evidence has focused on several appetite-regulating hormones, growth hormone, thyroid hormones and plasma adipocytokines. However, despite advancement in understanding of the genetic basis of PWS, there are contradictory data on the role of satiety hormones in hyperphagia and data regarding dietary intake are limited. Mechanistic studies on the aetiology of obesity and its relationship with disease pathogenesis in PWS are required. . In this review, we focused on the available evidence regarding mechanisms of obesity and potential new areas that could be explored to help unravel obesity pathogenesis in PWS.

Anthropometric dimensions provide reliable estimates of abdominal adiposity: A validation study

Abdominal fat accumulation is a major risk factor for cardiometabolic morbidity and mortality. The purpose of the study is to assess the possibility of developing accurate estimation equations based on body measurements to determine total abdominal (TFA), subcutaneous (SFA) and visceral fat area (VFA). Hungarian volunteers (n=198) aged between 20 and 81 years were enrolled in the study, which was conducted between July and November 2014. All persons underwent anthropometric measurements and computer tomographic (CT) scanning. Sex-specific multiple linear regression analyses were conducted in a subgroup of 98 participants to generate estimation models, then Bland-Altman's analyses were applied in the cross-validation group to compare their predictive efficiency. The variables best predicting VFA were hip circumference, calf circumference and waist-to-hip ratio (WHR) for males (R²=0.713; SEE=5602.1mm²) and sagittal abdominal diameter (SAD), WHR, thigh circumference and triceps skinfold for females (R²=0.845; SEE=3835.6mm²). The SFA prediction equation included SAD, thigh circumference and abdominal skinfold for males (R²=0.848; SEE=4124.1mm²), body mass index and thigh circumference for females (R²=0.861; SEE=5049.7mm²). Prediction accuracy was the highest in the case of TFA: hip circumference and WHR for males (R²=0.910; SEE=5637.2mm²), SAD, thigh circumference and abdominal skinfold for females (R²=0.915; SEE=6197.5mm²) were used in the equations. The results suggested that deviations in the predictions were independent of the amount of adipose tissue. Estimation of abdominal fat depots based on anthropometric traits could provide a cheap, reliable method in epidemiologic research and public health screening to evaluate the risk of cardiometabolic events.

Visceral adipose tissue area measurement at a single level: can it represent visceral adipose tissue volume?

OBJECTIVE

Measurement of visceral adipose tissue (VAT) needs to be accurate and sensitive to change for risk monitoring. The purpose of this study is to determine the CT slice location where VAT area can best reflect changes in VAT volume and body weight.

METHODS

60 plain abdominal CT images from 30 males [mean age (range) 51 (41-68) years, mean body weight (range) 71.1 (101.9-50.9) kg] who underwent workplace screenings twice within a 1-year interval were evaluated. Automatically calculated and manually corrected areas of the VAT of various scan levels using "freeform curve" region of interest on CT were recorded and compared with body weight changes.

RESULTS

The strongest correlations of VAT area with VAT volume and body weight changes were shown in a slice 3 cm above the lower margin of L3 with r values of 0.853 and 0.902, respectively.

CONCLUSION

VAT area measurement at a single level 3 cm above the lower margin of the L3 vertebra is feasible and can reflect changes in VAT volume and body weight. Advances in knowledge: As VAT area at a CT slice 3cm above the lower margin of L3 can best reflect interval changes in VAT volume and body weight, VAT area measurement should be selected at this location.

The use of magnetic resonance imaging to characterize abnormal body composition phenotypes in youth with Prader-Willi syndrome

INTRODUCTION

Magnetic resonance imaging (MRI) provides detailed assessment of body composition compartments. No studies have employed state-of-the-art MRI methods to accurately examine abdominal adipose tissue (AT) and skeletal muscle in youth with Prader-Willi syndrome (PWS). Therefore, this study aimed to describe AT distribution and skeletal muscle in the abdominal region of youth with PWS using MRI.

METHODS

Anthropometric measures and whole-abdominal T1-weighted MRI were performed in sixteen (5 males and 11 females) youth diagnosed with PWS, and seventeen (10 males and 7 females) youth who did not have PWS (controls). Volume of subcutaneous, visceral, intermuscular, and total AT, and skeletal muscle in the abdominal region were quantified using a semiautomatic procedure. Results were summarized using median and interquartile range (IQR, 25th-75th), and ANCOVA test was used (with age and sex as covariates) to examine differences in body composition compartments between PWS and control group.

RESULTS

PWS group had similar age (10.5, 6.6-13.9 vs. 12.8, 10.0-14.4years; P=0.14) and BMI z-score (0.5, 0.2-1.3 vs. 0.2, -0.3 to 1.0; P=0.33) when compared with controls. Significant differences were observed in absolute volumes of total AT (PWS: 4.1, 2.0-6.6L; control: 2.9, 2.0-4.5L; P=0.01), subcutaneous AT (PWS: 2.8, 1.4-4.8L; control: 1.8, 1.1-3.2L; P=0.01), and intermuscular AT (PWS: 0.3, 0.1-0.4L; control: 0.3, 0.2-0.3L; P<0.005). Visceral AT/subcutaneous AT was lower in PWS (0.4, 0.3-0.5) compared to controls (0.5, 0.4-0.6), P=0.01. In addition, skeletal muscle volume was lower in PWS (1.5, 1.0-2.6L) compared to controls (3.1, 1.6-3.9L), P=0.03. Ratios of abdominal AT compartments to skeletal muscle were all higher in PWS compared to controls (all P<0.005).

CONCLUSIONS

PWS youth have greater abdominal adiposity, particularly subcutaneous AT and intermuscular AT, and lower volume of skeletal muscle compared to controls. The decreased ratio of visceral AT/subcutaneous AT in youth with PWS suggests an improved metabolic profile for the level of adiposity present; however, elevated ratios of AT to skeletal muscle suggest a sarcopenic obesity-like phenotype, which could lead to worse health outcomes.

Diagnosis and treatment of GH deficiency in Prader-Willi syndrome

Prader-Willi syndrome (PWS) results from under-expression of the paternally-derived chromosomal region 15q11-13. Growth failure is a recognized feature of PWS, and both quantitative and qualitative defects of the GH/IGF-I axis revealing GH deficiency (GHD) have been demonstrated in most children with PWS. In PWS adults, criteria for GHD are biochemically fulfilled in 8-38% of the studied cohorts. Published data support benefits of early institution of GH therapy (GHT) in PWS children, with positive effects on statural growth, body composition, metabolic homeostasis, and neurocognitive function. Like in pediatric PWS, GHT also yields beneficial effects on lean and body fat, exercise capacity, and quality of life of PWS adults. Although GHT has been generally administered safely in PWS children and adults, careful surveillance of risks is mandatory during prolonged GH replacement for all PWS individuals.

Bridging the gap: metabolic and endocrine care of patients during transition

OBJECTIVE

Seamless transition of endocrine patients from the paediatric to adult setting is still suboptimal, especially in patients with complex disorders, i.e., small for gestational age, Turner or Prader-Willi syndromes; Childhood Cancer Survivors, and those with childhood-onset growth hormone deficiency.

METHODS

An expert panel meeting comprised of European paediatric and adult endocrinologists was convened to explore the current gaps in managing the healthcare of patients with endocrine diseases during transition from paediatric to adult care settings.

RESULTS

While a consensus was reached that a team approach is best, discussions revealed that a 'one size fits all' model for transition is largely unsuccessful in these patients. They need more tailored care during adolescence to prevent complications like failure to achieve target adult height, reduced bone mineral density, morbid obesity, metabolic perturbations (obesity and body composition), inappropriate/inadequate puberty, compromised fertility, diminished quality of life and failure to adapt to the demands of adult life. Sometimes it is difficult for young people to detach emotionally from their paediatric endocrinologist and/or the abrupt change from an environment of parental responsibility to one of autonomy. Discussions about impending transition and healthcare autonomy should begin in early adolescence and continue throughout young adulthood to ensure seamless continuum of care and optimal treatment outcomes.

CONCLUSIONS

Even amongst a group of healthcare professionals with a great interest in improving transition services for patients with endocrine diseases, there is still much work to be done to improve the quality of healthcare for transition patients.

Disorders of glucose metabolism in Prader-Willi syndrome: Results of a multicenter Italian cohort study

BACKGROUND AND AIMS

Prader-Willi syndrome (PWS) is characterized by a high incidence of altered glucose metabolism (AGM). However, epidemiological data on impaired fasting glucose (IFG), impaired glucose tolerance (IGT) and type 2 diabetes mellitus (T2DM) are still discordant.

METHODS AND RESULTS

We performed a multicenter study based on 274 PWS patients [144 females, aged 20.3 ± 10.4 yrs (range: 8.1-50.1 years)] evaluating the prevalence for AGM in the entire group, and according to age (children <10 yrs; adolescents 10-18 yrs, and adults >18 yrs), Body Mass Index (BMI = kg/m(2)), gender, genotypes (deletion or uniparental disomy for chromosome 15), and GH therapy (GHT) (untreated, previously or currently treated). Altogether, AGM was detected in 67 (24.4%) of patients (0.7% IFG, 10.2% IGT, 13.5% T2DM). The prevalence of AGM was correlated to age (p = 0.001), BMI (p = 0.001) and HOMA-IR (p = 0.001). However, gender, genotype, and GHT did not influence AGM development in univariate analysis. These data were confirmed as positive predictors when inserted in a multivariate analysis model.

CONCLUSION

This study is the first report on the prevalence of AGM in a large population of PWS. Overall, PWS subjects show a high prevalence of AGM that appears more common in obese and adult subjects. Our data confirm the main role of obesity on the individual metabolic risk clustering in PWS, and thus reinforce the concept that improvement in weight control remains the most important goal of any PWS treatment program.

Growth hormone therapy for Prader-willi syndrome: challenges and solutions

Prader-Willi syndrome (PWS) is characterized by a dysregulation of growth hormone (GH)/insulin-like growth factor I axis, as the consequence of a complex hypothalamic involvement. PWS' clinical picture seems to resemble the classic non-PWS GH deficiency (GHD), including short stature, excessive body fat, decreased muscle mass, and impaired quality of life. GH therapy is able to ameliorate the phenotypic appearance of the syndrome, as well as to improve body composition, physical strength, and cognitive level. In this regard, however, some pathophysiologic and clinical questions still remain, representing a challenge to give the most appropriate care to PWS patients. Data about the prevalence of GHD in PWS children are not unequivocal, ranging from 40% to 100%. In this context, to establish whether the presence (or not) of GHD may have a different effect on clinical course during GH therapy may be helpful. In addition, the comparison of GH effects in PWS children diagnosed as small for gestational age with those obtained in subjects born appropriate for gestational age is of potential interest for future trials. Emerging information seems to demonstrate the maintenance of beneficial effects of GH therapy in PWS subjects after adolescent years. Thus, GH retesting after achievement of final height should be taken into consideration for all PWS patients. However, it is noteworthy that GH administration exerts positive effects both in PWS adults with and without GHD. Another critical issue is to clarify whether the genotype-phenotype correlations may be relevant to specific outcome measures related to GH therapy. Moreover, progress of our understanding of the role of GH replacement and concomitant therapies on bone characteristics of PWS is required. Finally, a long-term surveillance of benefits and risks of GH therapy is strongly recommended for PWS population, since most of the current studies are uncontrolled and of short duration.

Does segmental body composition differ in women with Prader-Willi syndrome compared to women with essential obesity?

BACKGROUND

Subjects with Prader-Willi syndrome (PWS) have a higher fat mass and a lower fat-free mass compared to subjects with essential obesity. However, few data are presently available on the segmental body composition (BC) of PWS subjects.

AIM

To evaluate whether women with PWS and women with essential obesity, matched for age and percent body fat, differ in segmental fat distribution and surrogate markers of cardiometabolic disease (CMD).

SUBJECTS AND METHODS

35 women with PWS and 50 women with essential obesity were matched for age and percent body fat using coarsened exact matching. BC was measured by dual-energy X-ray absorptiometry. Oral glucose tolerance testing and measurements of cholesterol, triglycerides, C-reactive protein, and blood pressure were performed. Comparisons between PWS and obese women were performed using generalized linear models.

RESULTS

Trunk fat was lower in PWS than in obese women on both absolute [-7.3 (95% confidence interval -9.4 to -5.2) kg] and relative [-4.1 (-6.9 to -1.4)% of body fat] grounds. PWS and obese women had similar surrogate markers of CMD, with the exception of HDL-cholesterol, which was higher in PWS women.

CONCLUSION

Trunk fat is lower in obese women with PWS than in those with essential obesity. Surrogate markers of CMD are, however, mostly similar in the two groups.

Growth Hormone Therapy in Adults with Prader-Willi Syndrome

Prader-Willi syndrome (PWS) is characterized by hyperphagia, obesity if food intake is not strictly controlled, abnormal body composition with decreased lean body mass and increased fat mass, decreased basal metabolic rate, short stature, low muscle tone, cognitive disability, and hypogonadism. In addition to improvements in linear growth, the benefits of growth hormone therapy on body composition and motor function in children with PWS are well established. Evidence is now emerging on the benefits of growth hormone therapy in adults with PWS. This review summarizes the current literature on growth hormone status and the use of growth hormone therapy in adults with PWS. The benefits of growth hormone therapy on body composition, muscle strength, exercise capacity, certain measures of sleep-disordered breathing, metabolic parameters, quality of life, and cognition are covered in detail along with potential adverse effects and guidelines for initiating and monitoring therapy.

Growth hormone treatment of Prader-Willi syndrome has long-term, positive effects on body composition

AIM

Growth hormone (GH) treatment is a relatively new concept in adults, and the knowledge of its long-term effects is limited. We studied ten men with Prader-Willi Syndrome (PWS) after more than 5 years of GH treatment.

METHODS

Study participants underwent a detailed physical examination, including blood tests. Five had received GH as childhood and five had started GH as adults.

RESULTS

The total duration of GH treatment was 16 ± 4 years in the childhood PWS group and 15 ± 1 years in the adulthood PWS group. Their respective mean ages were 27 ± 4 years and 44 ± 4 years, mean heights were 178 ± 11 cm and 156 ± 5 cm, and mean body mass indexes were 32.4 ± 10.3 kg/m(2) and 28.9 ± 4.6 kg/m(2) . There were no differences in body composition between the groups and all lipids and insulin-like growth factor 1 were normal or close to normal. Four had well-controlled type 2 diabetes. The GH doses in the childhood and adulthood groups were 0.4 mg and 0.3 mg, respectively.

CONCLUSION

Men with PWS who received GH treatment displayed positive effects on body composition independent of when the GH treatment had started. Only patients who gained weight developed diabetes. The duration of GH treatment should balance the benefits and observed side effects.

Growth charts for non-growth hormone treated Prader-Willi syndrome

OBJECTIVE

The goal of this study was to generate and report standardized growth curves for weight, height, head circumference, and BMI for non-growth hormone-treated white male and female US subjects with Prader-Willi syndrome (PWS) between 3 and 18 years of age and develop standardized growth charts.

METHODS

Anthropometric measures (N = 133) were obtained according to standard methods from 120 non-growth hormone-treated white subjects (63 males and 57 females) with PWS between 3 and 18 years of age. Standardized growth curves were developed for the third, 10th, 25th, 50th, 75th, 90th, and 97th percentiles by using the LMS method for weight, height, head circumference, and BMI for PWS subjects along with the normative third, 50th, and 97th percentiles from national and international growth data. The LMS smoothing procedure summarized the distribution of the anthropometric variables at each age using three parameters: power of the Box-Cox transformation λ (L), median μ (M) and coefficient of variation δ (S).

RESULTS

Weight, height, head circumference, and BMI standardized growth charts representing 7 percentile ranges were developed from 120 non-growth hormone-treated white male and female US subjects with PWS (age range: 3-18 years) and normative third, 50th, and 97th percentiles from national and international data.

CONCLUSIONS

We encourage the use of syndrome-specific growth standards to examine and evaluate subjects with PWS when monitoring growth patterns and determining nutritional and obesity status. These variables can be influenced by culture, individual medical care, diet intervention, and physical activity plans.

Dual-energy X-ray absorptiometry is a valid method to estimate visceral adipose tissue in adult patients with Prader-Willi syndrome during treatment with growth hormone

CONTEXT

Visceral adipose tissue (VAT) is established as a risk factor for type 2 diabetes and cardiovascular disease, but the radiation exposure and cost of computed tomography (CT) measurements limits its daily clinical use.

OBJECTIVE

The main objective of this study was to compare the degree of agreement between VAT measurements by a new dual-energy X-ray absorptiometry (DXA) application and one of the standard methods, CT, in a population of patients with Prader-Willi syndrome (PWS) before and after GH treatment. Furthermore, we tested whether VAT estimations by these two methods are equivalent in assessing the metabolic risk in this population.

DESIGN AND PATIENTS

Data from the Norwegian population of a multicenter study in adults with genetically proven PWS were used. Subjects with complete anthropometry, biochemical, and imagistic measurements at all study visits (baseline and after 12 and 24 months of GH treatment) (n = 14, six men) were included. VAT was quantified both using CT scans (GE Lightspeed 16 Pro) of the abdomen at L2-L3 level and a total body DXA scan (GE Healthcare Lunar Prodigy).

RESULTS

VAT DXA was strongly associated with VAT CT at baseline (r = 0.97) and after 12 (r = 0.90) and 24 months (r = 0.89) of GH treatment (all P < .001). We found moderate to strong positive correlations between VAT by both methods, and blood pressure, weight, body mass index, waist circumference, glucose metabolism, and other fat depots (arms, legs, android, trunk, total body) but no association with age, gender, blood lipids, and IGF-I. Adiponectin was negatively associated with the amount of VAT. At baseline, the highest correlation with homeostasis model assessment of insulin resistance (HOMA-IR) was found for VAT DXA (r = 0.76, P = .001) and VAT CT (r = 0.75, P = .002), respectively.

CONCLUSION

VAT can be accurately estimated by DXA, in patients with PWS, and might contribute to the assessment of the metabolic risk.

Skeletal muscle characteristics and motor performance after 2-year growth hormone treatment in adults with prader-willi syndrome

CONTEXT

In adults with Prader-Willi syndrome (PWS), abnormal body composition with decreased lean body mass and skeletal muscle (SM) volume has been related to altered GH secretion and may possibly contribute to greatly reduced motor capacity.

OBJECTIVE

The scope of the study was to test the hypothesis that GH treatment has favorable effects on SM characteristics and motor performance in adults with PWS.

DESIGN, SETTING, AND PARTICIPANTS

Fifteen obese PWS subjects (nine males and six females; age range, 19-35 y; body mass index, 37.7-59.9 kg/m(2)) were investigated before and after 12 (GH12) and 24 (GH24) months of GH treatment.

MAIN OUTCOME MEASURES

SM cross-sectional area and SM attenuation were determined with computed tomography at the lumbar and midthigh levels. Maximal isometric handgrip strength and isokinetic knee extension peak torque were measured. Motor performance was evaluated with different indoor walking tests, whereas exercise endurance was assessed with a treadmill incremental test to exhaustion.

RESULTS

A condition of severe GH deficiency was found in six patients (40%). GH treatment significantly increased lean body mass (GH12, P < .05; GH24, P < .05), reduced percentage of body fat (GH12, P < .05; GH24, P < .05), and augmented SM cross-sectional area and SM attenuation of both lumbar (GH12, P < .01; GH24, P < .001) and thigh muscles (GH24, P < .05). Handgrip strength increased by 7% at GH12 (P < .05) and by 13% at GH24 (P < .001). Peak torque of knee extension extrapolated at zero angular velocity was significantly higher at GH24 (P < .01), and exercise endurance rose by 13% (P < .05) and 17% (P < .05) before exhaustion at GH12 and GH24, respectively, whereas no change was detected with walking tests. No significant difference in the response to GH treatment was detected between patients with and without GH deficiency.

CONCLUSION

Long-term GH treatment in adult PWS patients improves body composition and muscle size and quality and increases muscle strength and exercise tolerance independently from the GH secretory status.

Glucose homeostasis in adults with Prader-Willi syndrome during treatment with growth hormone: results from a 12-month prospective study

OBJECTIVES

To investigate glucose homeostasis in relation to body mass index (BMI) in adults with PWS before and after GH therapy.

DESIGN

We prospectively investigated the effects of a 12-month GH treatment on body composition and glucose homeostasis in relation to BMI in 39 adults, mean (±SD) age=28.6 (6.5) years with genetically verified PWS. We compared the results for different BMI categories (<25 kg/m²; 25-30 kg/m²; >30 kg/m²) and performed a regression analysis to detect predictors for homeostasis model of assessment-insulin resistance (HOMA-IR).

RESULTS

The baseline HOMA-IR was higher, with BMI of >30 kg/m². Our main findings were as follows: i) GH treatment (mean final dose, 0.6 (0.25) mg) was associated with small increases in fasting p-glucose, 2-h p-glucose by oral glucose load tolerance test, HOMA-IR and lean mass, and a reduction in fat mass. ii) Whereas the baseline HOMA-IR was associated with increased BMI (>30 kg/m²), we found no differences in HOMA-IR among the BMI categories after 12 months of GH. iii) Stepwise linear regression identified the triglyceride level as the strongest predictor of HOMA-IR at baseline, whereas an increase in VAT was the strongest predictor of the increase in HOMA-IR after therapy.

CONCLUSIONS

GH treatment for 12 months in adults with PWS resulted in an increase in HOMA-IR, irrespective of BMI, confirming that control of HbA1c is essential during GH treatment in PWS.

The GHRH + arginine stimulated pituitary GH secretion in children and adults with Prader-Willi syndrome shows age- and BMI-dependent and genotype-related differences

OBJECTIVE

The quantitative and qualitative aspects of the pituitary response in children and adults with Prader-Willi syndrome (PWS) are compared in order to verify the possible age-dependent and genotype-related differences in terms of GH secretion.

DESIGN

29 young subjects (21 males and 8 females) and 65 adults (24 males and 41 females) with PWS were studied. All subjects underwent a standard GH Releasing Hormone (GHRH 1-29, 1 μg/kg as i.v. bolus at 0 minutes)+arginine (0.5 g/kg) test. Peak GH values, standard GH area under the curve (AUC), AUC of the instantaneous secretion rate (ISR), and secretion response analysis (i.e. half-secretion time) were evaluated. A regression analysis was performed to investigate which are the patient characteristics that affect the amplitude and shape of the GH secretion response.

RESULTS

Peak GH values and AUCGH were significantly higher in PWS children than in PWS adults, these differences being also significant both in PWS DEL15 (only peak GH value) and PWS UPD15. Moreover, PWS children showed significantly lower half secretion time than PWS adults, this delayed response being present both in PWS DEL15 and PWS UPD15. Significant negative correlations between AUCGH and BMISDS were observed in the two groups (adults and children), as well as in adults and children DEL15, but not in adults and children PWS UPD15. A regression analysis performed on the whole dataset showed that for PWS DEL15 the statistically significant variable explaining GH responsiveness was BMISDS (p<0.0001), while for UPD15 no statistically significant covariate was found. Conversely, when the delay of the secretion response was considered, the regression model yielding the best performances was the one with only age as a regressor (p<0.001).

CONCLUSIONS

The quantitative and qualitative analyses of GH responsiveness to GHRH+arginine highlight relevant differences between PWS children and PWS adults and genotype-related traits. The negative influence of BMISDS on GH secretion reinforces the need for an early start of life-long weight management in PWS subjects.

Current status of growth hormone therapy in Prader-Willi syndrome

Prader-Willi syndrome (PWS) is a complex genetic disorder characterized by muscular hypotonia, hypogonadism, short stature, hyperphagia, obesity, cognitive disabilities and behavioral problems. Body composition is abnormal and growth hormone (GH) secretion is insufficient with more body fat than lean body mass. In children with PWS treatment with GH improves height, head size, body composition and psychomotor functioning. In adults with PWS treatment with GH improves body composition, physical activity and quality of life. However, restricted diet and regular physical exercise are cornerstone treatments in PWS also during GH treatment. GH treatment should be considered in PWS patients with a genetically confirmed diagnosis. Cognitive disabilities and scoliosis are not contraindications to GH treatment. Adverse effects to GH treatment in PWS are few, but glucose metabolism and changes in respiration must be monitored carefully, especially in individuals with predispositions. GH treatment should be continued as long as benefits outweigh the risks.

Metabolic syndrome in adult patients with Prader-Willi syndrome

BACKGROUND AND AIMS

Prader-Willi syndrome (PWS), the most common genetic cause of obesity, is characterized by elevated morbility and mortality in all ages. In this context, non-obese PWS children showed low frequency of metabolic syndrome (MetS), while a comparable prevalence was observed in obese PWS and obese controls. Aim of this study was to estimate the occurrence of MetS and its components in a large group of PWS adults, according to obesity status.

METHODS AND RESULTS

A cross-sectional study was performed in 108 PWS aged 18.0-43.2 years (87 obese and 21 non-obese) and in 85 controls with nonsyndromic obesity matched for age, gender, and BMI with obese PWS. Non-obese PWS showed lower waist circumference, insulin, HOMA-index, triglycerides, diastolic blood pressure, and higher HDL-C than both obese PWS and obese controls (p < 0.017). Obese PWS showed higher glucose and systolic blood pressure than both non-obese PWS and obese controls (p < 0.017). MetS was found in 1/21 (4.8%) non-obese PWS, 36/87 (41.4%) obese PWS and 39/85 (45.9%) obese controls. Non-obese PWS showed lower frequency for each MetS component as compared with obese PWS and obese controls. PWS patients with deletion of the chromosome 15q11-13 showed a lower risk for low HDL-C (p < 0.01) and a trend towards a lower MetS risk (p < 0.06) compared to subjects without deletion.

CONCLUSION

Our findings suggest the main role that obesity status plays on the individual metabolic risk clustering in PWS adults. Early identification of MetS could be helpful to improve morbidity and prevent mortality in such patients.

GrowthHormone Research Society workshop summary: consensus guidelines for recombinant human growth hormone therapy in Prader-Willi syndrome

CONTEXT

Recombinant human GH (rhGH) therapy in Prader-Willi syndrome (PWS) has been used by the medical community and advocated by parental support groups since its approval in the United States in 2000 and in Europe in 2001. Its use in PWS represents a unique therapeutic challenge that includes treating individuals with cognitive disability, varied therapeutic goals that are not focused exclusively on increased height, and concerns about potential life-threatening adverse events.

OBJECTIVE

The aim of the study was to formulate recommendations for the use of rhGH in children and adult patients with PWS.

EVIDENCE

We performed a systematic review of the clinical evidence in the pediatric population, including randomized controlled trials, comparative observational studies, and long-term studies (>3.5 y). Adult studies included randomized controlled trials of rhGH treatment for ≥ 6 months and uncontrolled trials. Safety data were obtained from case reports, clinical trials, and pharmaceutical registries.

METHODOLOGY

Forty-three international experts and stakeholders followed clinical practice guideline development recommendations outlined by the AGREE Collaboration (www.agreetrust.org). Evidence was synthesized and graded using a comprehensive multicriteria methodology (EVIDEM) (http://bit.ly.PWGHIN).

CONCLUSIONS

Following a multidisciplinary evaluation, preferably by experts, rhGH treatment should be considered for patients with genetically confirmed PWS in conjunction with dietary, environmental, and lifestyle interventions. Cognitive impairment should not be a barrier to treatment, and informed consent/assent should include benefit/risk information. Exclusion criteria should include severe obesity, uncontrolled diabetes mellitus, untreated severe obstructive sleep apnea, active cancer, or psychosis. Clinical outcome priorities should vary depending upon age and the presence of physical, mental, and social disability, and treatment should be continued for as long as demonstrated benefits outweigh the risks.

Effects of growth hormone treatment in adults with Prader-Willi syndrome

OBJECTIVE

Since limited data exist on adults with Prader-Willi syndrome (PWS) and growth hormone (GH) treatment, we report our experience on the effects of treatment for one year on body composition, physical activity, strength and energy expenditure, diet, general chemistry and endocrine data with quality of life measures.

DESIGN

We studied 11 adults with PWS (6F:5M; average age=32 yrs) over a 2 year period with GH treatment during the first year only. Electrolytes, IGF-I, glucose, thyroid, insulin, lipids, body composition, physical activity and strength, diet, energy expenditure and quality of life data were collected and analyzed statistically using linear modeling at baseline, at 12 months following GH therapy and at 24 months after treatment cessation for 12 months.

RESULTS

Total lean muscle mass was significantly increased (p<0.05) during GH treatment along with moderate-vigorous physical activity and plasma IGF-I and HDL levels, but returned to near baseline after treatment. Percent body fat decreased during the 12 months of GH treatment but increased after treatment.

CONCLUSIONS

Previously reported beneficial effects of GH treatment in children with PWS were found in our adults regarding body composition, physical activity and plasma HDL and IGF-I levels. Several beneficial effects diminished to near baseline after cessation of GH treatment for 12 months supporting the continuation of treatment in PWS into adulthood and possibly adults not previously treated during childhood.

Two years of growth hormone treatment in adults with Prader-Willi syndrome do not improve the low BMD

BACKGROUND

Bone mineral density (BMD) in adult patients with Prader-Willi syndrome (PWS) might be low due to high bone turnover.

OBJECTIVES

The objective of the study was to investigate bone mass in a group of adult PWS subjects and study the effects of GH treatment on BMD and markers of bone turnover.

DESIGN

Forty-six adults with genetically verified PWS were randomized to GH or placebo for 12 months, followed by open prospective GH for 24 additional months. BMD at the lumbar spine (LS) L1-4, the total hip, and the total body was assessed by dual-energy x-ray absorptiometry at baseline and every 12th month thereafter. Markers of bone turnover were measured at baseline and at the end of the controlled study.

RESULTS

In this cohort of adult subjects with PWS, baseline BMD was reduced in all compartments compared with the reference (Z-scores). Men had lower Z-scores BMD than women in LS and total body (P < .05). With 12 months of GH, LS-BMD was significantly reduced compared with placebo. No changes in BMD were observed with continuous GH treatment for 24 months. The bone formation markers increased with GH therapy compared with placebo, whereas the resorption marker did not change.

CONCLUSIONS

Adult PWS subjects, especially the men, have low bone mass that was not improved with GH treatment for 2 years. Because PWS subjects are short, BMD might be underestimated and should be adjusted for. Further studies, with adequate GH and sex hormone replacement throughout puberty and early adult life, are needed to better characterize PWS.

Comparison of body composition, basal metabolic rate and metabolic outcomes of adults with Prader Willi syndrome or lesional hypothalamic disease, with primary obesity

CONTEXT

The care of patients with hypothalamic obesity is challenging.

OBJECTIVE

To compare body composition, basal metabolic rate (BMR) and metabolic outcomes of adults, with lesional or genetic hypothalamic obesity, with obese patients suffering from primary obesity, once matched for body mass index (BMI).

DESIGN AND PATIENTS

Adults with hypothalamic obesity of genetic origin (Prader Willi syndrome (PWS)) or acquired hypothalamic damage (HD), such as craniopharygioma, were compared with obese control candidates awaiting bariatric surgery (C), with a BMI between 35 and 65 kg m(-)(2), and aged between 18 and 50 years.

MAIN OUTCOME MEASURES

Body composition measured by whole-body dual-energy X-ray absorptiometry scanning, BMR using indirect calorimetry, hormonal and metabolic assessments.

RESULTS

A total of 27 adults with a genetic diagnosis of PWS, 15 obese subjects with HD and 206 obese controls with similar BMI were studied. Compared with the control group, PWS patients had an increased percentage of fat mass (FM), and a decreased percentage of android FM. The BMR of PWS patients was significantly lower than controls and highly correlated with lean body mass in PWS and C patients. Body composition of HD was similar with those of obese patients. A trend toward an increased prevalence of diabetes in HD patients and of cytolysis in PWS was observed in comparison with primary obese patients.

CONCLUSION

Genetic and lesional hypothalamic obesities have different consequences for phenotypic features such as body composition or BMR compared with primary obese patients. The mechanisms of adipose tissue development and metabolic complications may be different between genetic and lesional obesities.

Effects of recombinant human growth hormone therapy in adults with Prader-Willi syndrome: a meta-analysis

OBJECTIVE

Prader-Willi syndrome (PWS) is associated with GH deficiency, deleterious changes in body composition and function. As the effects of recombinant human GH (rhGH) in PWS adults have not been well established, we sought to conduct a meta-analysis of pertinent studies.

DESIGN

Meta-analysis of studies examining the effects of rhGH therapy in PWS adults.

PATIENTS

One hundred and thirty four PWS adults (75 men, 59 women).

MEASUREMENTS

Literature searches, including publications (PubMed, EMBASE and the Cochrane Register), and abstracts presented at meetings through July 2011 describing studies of rhGH therapy in PWS adults; 8/1194 articles, describing unique cohorts, were included. Two authors independently extracted data and examined study quality.

RESULTS

rhGH therapy for 12 months led to [weighted mean difference (95% CI)] decreased body fat [-2·91% (-3·90, -1·91)], visceral [-32·97 cm(2) (-55·67, -10·26)] and subcutaneous adiposity [-55·24 cm(2) (-89·05, -21·44)], and increased lean body mass (LBM) [2·41 Kg (1·32, 3·49)]. Similar changes in body fat [-2·89% (-4·69, -1·07)] and LBM [2·82 Kg (1·31, 4·33)] were found in longer studies. There were no changes in body mass index (BMI) or lipids. There was a small increase in fasting glucose [0·27 mmol/l (0·05, 0·49)] and trends towards higher fasting insulin [20·24 pmol/l (-0·55, 41·02)] and insulin resistance [HOMA: 0·60 (-0·04, 1·24)] after rhGH therapy for 12 months.

CONCLUSIONS

In PWS adults, rhGH therapy led to decreased body adiposity and increased LBM without changes in BMI or lipids. There was a small increase in fasting glucose and trends towards higher insulin and insulin resistance.

Growth hormone treatment in adults with Prader-Willi syndrome: the Scandinavian study

Prader-Willi syndrome (PWS) is characterized by short stature, muscular hypotonia, cognitive dysfunction, and hyperphagia usually leading to severe obesity. Patients with PWS share similarities with growth hormone deficiency (GHD). Few studies have dealt with growth hormone (GH) treatment in PWS adults. The purpose of the Scandinavian study was to evaluate the effects of GH on body composition, lipid and glucose metabolism, physical performance and safety parameters in adults with PWS. Twenty-five women and 21 men with PWS were randomized to treatment with GH or placebo during 1 year followed by 2 years of open labeled GH treatment. At baseline 1/3 had normal BMI, six patients severe GHD, ten impaired glucose tolerance and seven diabetes. At 1 year insulin-like growth factor I (IGF-I) SDS had increased by 1.51 (P < 0.001) and body composition improved in the GH treated group. Visceral fat decreased by 22.9 ml (P = 0.004), abdominal subcutaneous fat by 70.9 ml (P = 0.003) and thigh fat by 21.3 ml (P = 0.013), whereas thigh muscle increased 6.0 ml (P = 0.005). Lean body mass increased 2.25 kg (P = 0.005), and total fat mass decreased 4.20 kg (P < 0.001). The positive effects on body composition were maintained after 2 years of GH treatment. Peak expiratory flow increased by 12% (P < 0.001) at 2 years of GH treatment. Lipid and glucose metabolism were unchanged, however, three patients developed diabetes at 2 years of GH treatment. In conclusion GH treatment had beneficial effects on the abnormal body composition without serious adverse events making it a logic treatment option in adults with PWS.

Growth hormone treatment for two years is safe and effective in adults with Prader-Willi syndrome

OBJECTIVE

Prader-Willi syndrome (PWS) shares similarities with the growth hormone (GH) deficiency syndrome in regards to reduced lean body mass and increased fat mass and several short-term trials with GH treatment have demonstrated beneficial effects on body composition. The aim of the present study was to evaluate the effects and safety of two years of GH therapy in adults with PWS.

DESIGN

Forty-three adults (24 women) with genetically verified PWS were included. Blood samples, body composition as measured by computed tomography (CT) and dual-energy x-ray absorptiometry (DXA) were performed at baseline and during two years of continued GH treatment.

RESULTS

Thirty-nine patients completed treatment for two years. The GH dosage averaged 0.61 mg/day (range 0.2-1.6). Based upon CT, body composition improved at two years; thigh muscle volume increased 6.7 mL (3.7 to 9.7; P<0.001) whereas abdominal subcutaneous fat volume decreased by 53.3 mL (13.8 to 92.9; P=0.01). By DXA, lean body mass improved 2.8 kg (1.9 to 3.6; P<0.001), whereas fat mass decreased by 3.0 kg (1.1 to 4.8; P=0.003). Lung function as evaluated by peak expiratory flow increased 12% (p<0.001) - indicating improved muscle function. Adverse effects were few. Fifteen out of 39 patients had diabetes (DM; n=4) or impaired glucose tolerance (IGT; n=11) prior to GH treatment. Among the 11 patients with IGT, three reverted to normal glucose tolerance, while three progressed to overt DM at two years of GH treatment.

CONCLUSION

The known beneficial effects of GH treatment upon body composition in PWS are maintained during two years continuous treatment. With appropriate control, GH is a safe treatment option in adults with PWS.

In adults with Prader-Willi syndrome, elevated ghrelin levels are more consistent with hyperphagia than high PYY and GLP-1 levels

OBJECTIVE

Prader-Willi syndrome (PWS) is a leading genetic cause of obesity, characterized by hyperphagia, endocrine and developmental disorders. It is suggested that the intense hyperphagia could stem, in part, from impaired gut hormone signaling. Previous studies produced conflicting results, being confounded by differences in body composition between PWS and control subjects.

DESIGN

Fasting and postprandial gut hormone responses were investigated in a cross-sectional cohort study including 10 adult PWS, 12 obese subjects matched for percentage body fat and central abdominal fat, and 10 healthy normal weight subjects.

METHODS

PYY[total], PYY[3-36], GLP-1[active] and ghrelin[total] were measured by ELISA or radioimmunoassay. Body composition was assessed by dual energy X-ray absorptiometry. Visual analog scales were used to assess hunger and satiety.

RESULTS

In contrast to lean subjects (p<0.05), PWS and obese subjects were similarly insulin resistant and had similar insulin levels. Ghrelin[total] levels were significantly higher in PWS compared to obese subjects before and during the meal (p<0.05). PYY[3-36] meal responses were higher in PWS than in lean subjects (p=0.01), but not significantly different to obese (p=0.08), with an additional non-significant trend in PYY[total] levels. There were no significant differences in self-reported satiety between groups, however PWS subjects reported more hunger throughout (p=0.003), and exhibited a markedly reduced meal-induced suppression of hunger (p=0.01) compared to lean or obese subjects.

CONCLUSIONS

Compared to adiposity-matched control subjects, hyperphagia in PWS is not related to a lower postprandial GLP-1 or PYY response. Elevated ghrelin levels in PWS are consistent with increased hunger and are unrelated to insulin levels.

Impaired hypothalamic regulation of endocrine function and delayed counterregulatory response to hypoglycemia in Magel2-null mice

Hypothalamic dysfunction may underlie endocrine abnormalities in Prader-Willi syndrome (PWS), a genetic disorder that features GH deficiency, obesity, and infertility. One of the genes typically inactivated in PWS, MAGEL2, is highly expressed in the hypothalamus. Mice deficient for Magel2 are obese with increased fat mass and decreased lean mass and have blunted circadian rhythm. Here, we demonstrate that Magel2-null mice have abnormalities of hypothalamic endocrine axes that recapitulate phenotypes in PWS. Magel2-null mice had elevated basal corticosterone levels, and although male Magel2-null mice had an intact corticosterone response to restraint and to insulin-induced hypoglycemia, female Magel2-null mice failed to respond to hypoglycemia with increased corticosterone. After insulin-induced hypoglycemia, Magel2-null mice of both sexes became more profoundly hypoglycemic, and female mice were slower to recover euglycemia, suggesting an impaired hypothalamic counterregulatory response. GH insufficiency can produce abnormal body composition, such as that seen in PWS and in Magel2-null mice. Male Magel2-null mice had Igf-I levels similar to control littermates. Female Magel2-null mice had low Igf-I levels and reduced GH release in response to stimulation with ghrelin. Female Magel2-null mice did respond to GHRH, suggesting that their GH deficiency has a hypothalamic rather than pituitary origin. Female Magel2-null mice also had higher serum adiponectin than expected, considering their increased fat mass, and thyroid (T(4)) levels were low. Together, these findings strongly suggest that loss of MAGEL2 contributes to endocrine dysfunction of hypothalamic origin in individuals with PWS.