Nutritional phases in Prader-Willi syndrome

Genetics of Prader-Willi and Angelman syndromes: 2024 update

PURPOSE OF REVIEW

Prader-Willi (PWS) and Angelman (AS) syndromes arise from errors in 15q11-q13 imprinting. This review describes recent advances in genomics and how these expand our understanding of these rare disorders, guiding treatment strategies to improve patient outcomes.

RECENT FINDINGS

PWS features include severe infantile hypotonia, failure to thrive, hypogonadism, developmental delay, behavioral and psychiatric features, hyperphagia, and morbid obesity, if unmanaged. AS presents severe intellectual disability, motor dysfunction, seizures, absent speech, and a characteristic happy demeanor. Standard-of-care testing involves SNRPN promoter methylation, microarray and genomic analyses for individuals presenting with these features. These tests identify syndromic-specific DNA methylation patterns and molecular genetic classes responsible for disease etiology. This review provides an update on studies of genotype-phenotype relationships and novel genomic technologies used for diagnostic purposes.

SUMMARY

We give an overview and update on the genetics and underlying mechanisms associated with symptoms and potential treatments with focus on features reported to be different between specific molecular genetic classes. The review also describes laboratory testing methods for diagnosis of these imprinting disorders with implications for clinical practice.

Early oxytocin treatment in infants with Prader-Willi syndrome is safe and is associated with better endocrine, metabolic and behavioral outcomes

BACKGROUND

Oxytocin (OT) plays an important role in modulating behavior, social interactions and feeding. Prader-Willi syndrome (PWS), a rare genetic neurodevelopmental disorder, is a model of hypothalamic disorder including OT dysfunction. We previously showed that infants with PWS who had received an early short course (7 days) of intranasal OT treatment improved their oral and social skills. We aim to document the long-term tolerance and effects of early intranasal OT treatment on the disease trajectory.

METHODS

We performed a comparative clinical trial including the 17 children who had received OT as infants in our previous study and compared them to 17 PWS non-exposed children at 3-4 years old. Primary endpoint was the total communication score on the Vineland Adaptive Behavior Scales-2nd edition (VABS-II). Secondary endpoints were the other domains of VABS-II, behavior scored by the Child Behavior Checklist, feeding skills, endocrine and metabolic profiles, and brain connectivity on functional magnetic resonance imaging.

RESULTS

We documented the long-term safety of early OT treatment. The VABS-II communication score was not different between the two groups, defined as OT-exposed and non-exposed, whereas a trend toward a higher socialization score was found in the OT-exposed children (p = 0.06). Circulating IGF-1 and HDL cholesterol were significantly higher in the OT-exposed group (p < 0.05). OT-exposed children had normal acylated ghrelin levels, which were lower than those observed in non-exposed children (p = 0.06), and they displayed higher connectivity of the orbitofrontal cortex brain region.

CONCLUSION

Early OT treatment in infants with PWS is safe up to 3-4 years of age. OT-exposed children display better social, endocrine and metabolic outcomes. This study documents for the first time in human the biological window of opportunity of early OT treatment, which may change the trajectory of the PWS condition.

TRIAL REGISTRATION

Clinical trial NCT03081832 Retrospectively registered https://clinicaltrials.gov/search?cond=NCT03081832 .

Comorbidities, Endocrine Medications, and Mortality in Prader-Willi Syndrome-A Swedish Register Study

Background: Prader-Willi Syndrome (PWS) is a rare, genetic, multi-systemic disorder. Its main characteristics are muscular hypotonia, behavioral problems, intellectual disability, endocrine deficiencies, hyperphagia, and a high risk of morbid obesity and related comorbidities. This study aimed to investigate the rate of comorbidity, prescription of endocrine medications, and mortality in individuals with PWS compared to the general population. Methods: The association between PWS and outcomes were investigated in a matched cohort study of individuals born in the period of 1930-2018 with data from Swedish national health and welfare registers. Each individual was matched with 50 non-PWS comparisons. The associations between PWS, outcomes and prescribed endocrine medications were estimated through Cox proportional hazard models, presented as Hazard Ratios (HR) with 95% Confidence Intervals (CIs). Results: Among 360 individuals (53% men) with PWS, 16% had diabetes mellitus, 6% heart failure, 4% vein thrombosis, 2% atrial fibrillation, 2% coronary heart disease, and 1% pulmonary embolism. Individuals with PWS had an increased rate of heart failure (HR: 23.85; 95% CI: 14.09-40.38), diabetes mellitus (HR: 17.49; 95% CI: 12.87-23.74), vein thrombosis (HR: 10.44; 95% CI: 5.69-19.13), pulmonary embolism (HR: 5.77; 95% CI: 2.27-14.67), atrial fibrillation (HR: 5.19; 95% CI: 2.48-10.86), and coronary heart disease (HR: 3.46; 95% CI: 1.50-7.97) compared to non-PWS individuals. Somatotropin was prescribed in 63%, antidiabetics in 18%, and thyroid hormones in 16% of the PWS individuals (<1%, 2%, and 3%, respectively, in non-PWS individuals). The rate of mortality was fifteen times higher in PWS than in non-PWS, with a mean age at death of 42 years. Conclusions: The rates of diabetes mellitus and cardiovascular comorbidities were higher in individuals with PWS. As expected, the prescription of somatotropin was high, but the endocrine prescription pattern also reflected the high prevalence of diabetes mellitus and thyroid illness. Although the mean age at death was older than previously reported, a higher awareness and intensified efforts to avoid obesity, as well as the prevention and early treatment of cardiovascular and endocrine comorbidity, are crucial aims in the care of people with PWS.

Validation of the Food Safe Zone questionnaire for families of individuals with Prader-Willi syndrome

BACKGROUND

Prader-Willi syndrome (PWS), a genetic neurodevelopmental disorder, is characterized by hyperphagia and significant behavioral problems. Hyperphagic individuals with PWS are chronically hungry yet rarely feel sated, and often engage in food-seeking behaviors. To avoid life-threatening obesity in their children, families implement food security strategies (e.g., locking food sources, constant supervision around food, alerting others). Although widely used, these strategies have yet to be systematically examined. We thus developed and analyzed the psychometric properties of a new measure of these diverse strategies, the Food Safe Zone, and evaluated them in relation to hyperphagic symptoms and demographic variables. In doing so, we also shine a light on the extraordinary efforts of families in managing their children's hyperphagia.

METHODS

Our team developed 20 FSZ items that were revised for clarity and completeness in an iterative feedback process with stakeholders, including parents, PWS specialists, and individuals with PWS. The FSZ was pilot tested, descriptive findings were reviewed by additional stakeholders, and then administered to 624 parents in a large-scale study. Based on an open-ended question, "Is there anything else you do to ensure food safety?" two additional items were added and evaluated in a follow-up study.

RESULTS

Principal component analyses revealed that 21 FSZ items loaded onto 5 factors that were readily interpretable, accounting for 67% of test variance: Alerting Others and Food Supervision in the Community; Locking or Restricting Food Sources; Checking for Food; At Home Supervision and Meals; and Avoiding Food Settings. Internal consistency and test-rest reliability were robust. Convergent validity analyses revealed that parents implemented FSZ strategies in response to the severity of their child's hyperphagia, and not their child's age, gender or PWS genetic subtype.

CONCLUSIONS

The psychometrically sound FSZ holds promise for future research, especially on the effects of food safety tactics on family members. In future clinical trials, the FSZ could also be used to help parents think critically about their food safety tactics in relation to their child's hyperphagia, or as an exploratory endpoint; if hyperphagia is lessened, so too may food safety tactics, thereby enhancing familial quality of life.

A review of Prader-Willi syndrome

ABSTRACT

Prader-Willi syndrome is a rare and complex genetic disorder with multiple physical and behavioral characteristics, affecting endocrine, metabolic, and neurologic systems and producing a plethora of medical complications. Early identification and diagnosis are paramount to providing timely and appropriate interventions to improve patient outcomes. Treatment should focus on neonatal feeding and growth, followed by hormonal therapy for hypothalamic dysfunction, and should then be directed at the prevention and treatment of obesity and obesity-related complications. Effective treatment requires a comprehensive multidisciplinary approach.

Pharmacological Aspects in the Management of Children and Adolescents with Prader-Willi Syndrome

Prader-Willi syndrome is a rare neurodevelopmental disorder that impacts the musculoskeletal, endocrine, pulmonary, neurologic, ocular, and gastrointestinal systems. In addition, individuals with Prader-Willi syndrome have issues with cognitive development, characteristic behavioral problems, and perhaps most profoundly, appetite control. Currently, the only US Food and Drug Administration-approved therapy for Prader-Willi syndrome is growth hormone, which has been Food and Drug Administration approved for > 20 years for the treatment of growth failure in Prader-Willi syndrome. Growth hormone has shown to improve many aspects of this syndrome, including final height, body composition, developmental milestones, and cognition, but it does not affect hyperphagia, which is the hallmark symptom of this condition. Over the past 15 years, there have been several medication trials for the treatment of hyperphagia in Prader-Willi syndrome, but thus far, all have failed to achieve Food and Drug Administration approval for a variety of reasons. However, hyperphagia is the most life-limiting symptom of Prader-Willi syndrome, thus new pharmacologic therapies are desperately needed. We review ongoing and recently completed clinical trials for hyperphagia. Other issues in Prader-Willi syndrome that significantly impact quality of life include excessive daytime sleepiness and severe behavioral problems. We examine the medication trials to address these issues.

Comparative study of emotional facial expression recognition among Prader-Willi syndrome subtypes

BACKGROUND

Prader-Willi syndrome (PWS) is a congenital disease caused by a rare and generally non-inherited genetic disorder. The inability to recognise facial expressions of emotion is an apparent social cognition deficit in people diagnosed with PWS. The main objective of the present study is to compare the ability to recognise emotional facial expression, in both non-contextualised and contextualised scenarios, among the main subtypes of PWS and a control group.

METHODS

The sample consisted of 46 children divided into three groups: deletion (n = 10), maternal uniparental disomy (mUPD) (n = 13) and control (n = 23). The protocol included the Facially Expressed Emotion Labeling and the Deusto-e-Motion 1.0.

RESULTS

The control group recognised facial emotions more accurately and quickly in both non-contextualised and contextualised scenarios than children with PWS, regardless of genetic subtype. Despite no differences being detected between PWS subtypes when non-contextualised scenarios were analysed, in contextualised situations, a longer reaction time was observed in children with the mUPD subtype.

CONCLUSIONS

This is the first study to assess the ability to recognise emotional facial expressions in contextualised situations among PWS subtypes and a control group. The findings suggest that some of the social cognitive deficits evidenced in children with mUPD PWS may be similar to those in autism spectrum disorder.

Aberrant behavior checklist in youth with Prader-Willi syndrome: Preliminary study of cross-sectional and longitudinal behavior characterization

Prader-Willi syndrome (PWS) is a rare genetic disorder caused by the loss of paternal genes on chromosome 15. The Aberrant Behavior Checklist (ABC) is a standardized rating scale for assessing problematic behaviors in persons with developmental disabilities. Our study aims to describe ABC scores in youth with PWS and track their change over time. The analysis included 69 patients. Mean ABC scores were compared in four age groups (5-8, 9-12, 13-16, and 17-22 years). A statistically significant difference was found only in the Irritability subscale, with lower scores in the 5-8 age group compared to the 9-12 age group. For change over time, scores for Irritability, Lethargy, Stereotypic Behavior, Hyperactivity subscales, and Total score were likely to decrease after age 12. Irritability subscale scores of males were predicted to increase more than those of females between ages of 5 and 12 . The Lethargy score in the nondeletion group had a greater reduction than the deletion group in the 12-20 year range. This study highlights the need for systematic collection and characterization of behavioral data given the burden of maladaptive behaviors that often persist for a lifetime.

GH Therapy in Non-Growth Hormone-Deficient Children

Before 1985, growth hormone (GH) was extracted from human pituitaries, and its therapeutic use was limited to children with severe GH deficiency (GHD). The availability of an unlimited amount of recombinant GH (rhGH) allowed for investigating the efficacy of its therapeutic use in a number of conditions other than GHD. Nowadays, patients with Turner syndrome, SHOX deficiency, Noonan syndrome, Prader-Willi syndrome, idiopathic short stature, chronic kidney disease, and children born small for gestational age can be treated with rhGH in order to improve adult height. In patients with Prader-Willi syndrome, rhGH therapy also improves body composition and cognitive function. Large post-marketing multinational studies in a large number of pediatric patients demonstrated a good safety profile for rhGH. Recently, long-acting formulations of rhGH have been approved and licensed for GHD, and clinical trials are ongoing for other conditions. In this paper, we review the rhGH therapy in children with conditions other than GHD.

Lack of correlation between asprosin serum levels and hyperphagic behavior in subjects with prader-Willi Syndrome

PURPOSE

Individuals with Prader-Willi syndrome (PWS) exhibit hyperphagic behavior, the severity of which varies throughout life. The mechanisms underlying this behavior are still unknown. Asprosin is a new discovered adipokine involved in the regulation of food intake, glucose homeostasis and energy balance. In this study we assessed asprosin serum levels in a cohort of children, adolescents and adults with PWS with the aim to correlate them with hyperphagic behavior, body mass index (BMI) and metabolic parameters, and to evaluate age-related changes.

METHODS

This cross-sectional study included 87 children and adolescents and 31 adults with PWS. Auxological data, fasting levels of glucose, insulin, total cholesterol, high-density lipoprotein-cholesterol (HDL-C), triglycerides (TG) and asprosin were collected, and the homeostasis model assessment for insulin resistance (HOMA-IR) was determined. The 11-item Italian version of the Hyperphagia Questionnaire (HQ) was administered to the parents/caregivers of the patients to assess hyperphagia.

RESULTS

Patients were analysed according to age (children < 10 years, adolescents between 10 and 17.9 years, adults ≥ 18 years) or BMI categories [normal weight (NW), overweight (OW), and obesity (OB)]. No significant correlations were found between asprosin levels and cardiometabolic risk factors in the whole cohort. Higher values of asprosin were found in adults compared with adolescents, as well as in the OB group compared to the NW group (p = 0.014). Hyperphagia total score and hyperphagic subdimensions were significantly lower in children compared to adults (p < 0.05). Similarly, hyperphagia total score and hyperphagic subdimensions were significantly lower in the NW group compared to the OB group. Asprosin levels were significantly higher in patients with deletion versus patients with uniparental disomy (p = 0.037). By logistic regression analysis, HQ total score and hyperphagic subdimensions were significantly associated with BMI-SDS independently of age, sex, and asprosin levels.

CONCLUSION

In conclusion, our data demonstrated higher asprosin levels in PWS individuals with OB compared to NW, while differences by age and sex were inconsistent. The lower levels of hyperphagia, BMI-SDS, and metabolic variables in children with PWS compared to adults underline that prevention of obesity should start very early in life and should be maintained over time.

A bibliometric analysis of Prader-Willi syndrome from 2002 to 2022

Background

Prader-Willi Syndrome (PWS) is a rare disorder that was initially documented by Prader and Willi in 1956. Despite significant advancements in the understanding of PWS over recent decades, no bibliometric studies have been reported on this field. We aimed to analyze and explore the research trends and hotspots of PWS using a bibliometric analysis to understand the future development of basic and clinical research.

Methods

The literature regarding PWS was retrieved from the Web of Science Core Collection Science Citation Index Expanded (SCI-Expanded) database. Data were extracted from the articles or review articles, and analyzed using CiteSpace and VOSviewer software.

Results

A total of 1,895 related studies have been published in 64 countries or regions. The United States has published the most articles, followed by the United Kingdom, Italy, Netherlands, and France. University of Florida (The United States), University of Kansas (The United States), University of Alberta (Canada), University of Cambridge (the United Kingdom), and Dutch Growth Research Foundation (Netherlands) were the top five most productive institutions. Butler, Merlin G. and his colleagues have made the most outstanding contributions in the field of PWS research. Keyword co-occurrence analysis showed that genomic imprinting, uniparental disomy, obesity, hyperphagia, hypothalamus, growth hormone treatment, and ghrelin appeared with the higher frequency. Furthermore, oxytocin, magel2, and management were the latest bursts keywords.

Conclusion

Our findings indicated that genetic mechanism, diagnose, and emerging therapies will be the hotspots and frontiers in PWS research.

Trapped fat: Obesity pathogenesis as an intrinsic disorder in metabolic fuel partitioning

Our understanding of the pathophysiology of obesity remains at best incomplete despite a century of research. During this time, two alternative perspectives have helped shape thinking about the etiology of the disorder. The currently prevailing view holds that excessive fat accumulation results because energy intake exceeds energy expenditure, with excessive food consumption being the primary cause of the imbalance. The other perspective attributes the initiating cause of obesity to intrinsic metabolic defects that shift fuel partitioning from pathways for mobilization and oxidation to those for synthesis and storage. The resulting reduction in fuel oxidation and trapping of energy in adipose tissue drives a compensatory increase in energy intake and, under some conditions, a decrease in expenditure. This theory of obesity pathogenesis has historically garnered relatively less attention despite its pedigree. Here, we present an updated comprehensive formulation of the fuel partitioning theory, focused on evidence gathered over the last 80 years from major animal models of obesity showing a redirection of fuel fluxes from oxidation to storage and accumulation of excess body fat with energy intake equal to or even less than that of lean animals. The aim is to inform current discussions about the etiology of obesity and by so doing, help lay new foundations for the design of more efficacious approaches to obesity research, treatment and prevention.

The influence of genotype makeup on the effectiveness of growth hormone therapy in children with Prader-Willi syndrome

BACKGROUND

Prader-Willi syndrome (PWS) is a rare multisystemic hereditary illness. Recombinant human growth hormone (rhGH) therapy is widely recognized as the primary treatment for PWS. This study aimed to examine how different PWS genotypes influence the outcome of rhGH treatment in children with PWS.

METHODS

A review was conducted on 146 Chinese children with PWS, genetically classified and monitored from 2017 to 2022. Unaltered and modified generalized estimating equations (GEE) were employed to examine the long-term patterns in primary outcomes (growth metrics) and secondary outcomes (glucose metabolism metrics and insulin-like growth factor-1 (IGF-1)) during rhGH therapy. The study also evaluated the prevalence of hypothyroidism, hip dysplasia, and scoliosis before and after rhGH treatment.

RESULTS

Children with PWS experienced an increase in height/length standard deviation scores (SDS) following rhGH administration. The impact of rhGH therapy on growth measurements was similar in both the deletion and maternal uniparental diploidy (mUPD) cohorts. Nevertheless, the deletion group was more prone to insulin resistance (IR) compared to the mUPD group. No significant variations in growth metrics were noted between the two groups (P > 0.05). At year 2.25, the mUPD group showed a reduction in fasting insulin (FINS) levels of 2.14 uIU/ml (95% CI, -4.26, -0.02; P = 0.048) and a decrease in homeostasis model assessment of insulin resistance (HOMA-IR) of 0.85 (95% CI, -1.52, -0.17; P = 0.014) compared to the deletion group. Furthermore, there was a decrease in the IGF standard deviation scores (SDS) by 2.84 (95% CI, -4.84, -0.84; P = 0.005) in the mUPD group during the second year. The frequency of hip dysplasia was higher in the mUPD group compared to the deletion group (P < 0.05).

CONCLUSIONS

rhGH treatment effectively increased height/length SDS in children with PWS, with similar effects observed in both deletion and mUPD genotypes. Children with mUPD genetype receiving rhGH treatment may experience enhanced therapeutic effects in managing PWS.

Management of food socialization for children with Prader-Willi Syndrome: An exploration study in Malaysia

This study aims to explore the food management strategies among caregivers/family members of children with Prader-Willi Syndrome (PWS) using the lens of 'familialisation' of a health problem and the sociology of food socialization. Food intake among individuals with PWS is a main concern for parents, caregivers, and medical practitioners as it affects their physical, mental, and social well-being throughout their lives. Earlier studies on PWS and food intake centered around dietary management, dietary intake and growth, nutritional treatment and pharmacological approaches, nutritional phases, and weight gain. However, little has been done to understand the challenges of managing children with PWS from the sociological lens of food management strategies and socialization among families in Malaysia. This study is based on an investigation involving eight children with PWS and 46 family members and caregivers through lab observations and reflexive interviews. Ten food management strategies were identified that were adopted by the caregivers and families, which were influenced by cultural factors, family norms, and formal and informal support systems. The findings will influence future behavioral interventions to ensure the empowerment and well-being of individuals with PWS and their families.

Pathological analysis of Prader-Willi syndrome using adipocytes

Prader-Willi syndrome (PWS) is a complex epigenetic disorder caused by the deficiency of paternally expressed genes in chromosome 15q11-q13. This syndrome also includes endocrine dysfunction, leading to short stature, hypogonadism, and obscure hyperphagia. Although recent progress has been made toward understanding the genetic basis for PWS, the molecular mechanisms underlying its pathology in obesity remain unclear. In this study, we examined the adipocytic characteristics of two PWS-induced pluripotent stem cell (iPSC) lines: those with the 15q11-q13 gene deletion (iPWS cells) and those with 15q11-q13 abnormal methylation (M-iPWS cells). The transcript levels of the lipid-binding protein aP2 were decreased in iPWS and M-iPWS adipocytes. Flow-cytometry analysis showed that PWS adipocytes accumulated more lipid droplets than did normal individual adipocytes. Furthermore, glucose uptake upon insulin stimulation was attenuated compared to that in normal adipocytes. Overall, our results suggest a significantly increased lipid content and defective in glucose metabolism in PWS adipocytes.

Is Oxytocin a Contributor to Behavioral and Metabolic Features in Prader-Willi Syndrome?

Prader-Willi Syndrome (PWS) is a rare genetic disorder typically characterized by decreased social interaction, hyperphagia, poor behavioral control and temper tantrums, together with a high risk of morbid obesity unless food intake is controlled. The genetic defects that cause PWS include paternal 15q deletion (estimated in 60% of cases), chromosome 15 maternal uniparental disomy (UPD) (estimated in 35% of cases) and imprinting defects and translocations. Several studies indicate an oxytocin deficiency in PWS. Oxytocin is a hypothalamic nonapeptide with receptors located in the brain and in various other tissues in the body. It acts as a neuropeptide in several brain areas of great importance for behavioral and metabolic effects, as well as a neurohypophyseal hormone released into the circulation. Oxytocin in both rats and humans has strong and long-lasting behavioral and metabolic effects. Thus, an oxytocin deficiency might be involved in several of the behavioral and metabolic symptoms characterizing PWS. Treatment with oxytocin has, in some studies, shown improvement in psycho-social behavior and hyperphagia in individuals with PWS. This review focus on the behavioral and metabolic effects of oxytocin, the symptoms of a potential oxytocin deficiency in PWS and the effects of oxytocin treatment.

Feasibility, safety, and efficacy of dietary or lifestyle interventions for hypothalamic obesity: A systematic review

BACKGROUND & AIMS

A dysfunctional hypothalamus may result in decreased feelings of satiety (hyperphagia), decreased energy expenditure, and increased fat storage as a consequence of hyperinsulinemia. Hypothalamic dysfunction may thus lead to morbid obesity and can be encountered in childhood as a consequence of congenital, genetic, or acquired disorders. There is currently no effective treatment for hypothalamic obesity (HO). However, comparable to alimentary obesity, dietary and lifestyle interventions may be considered the cornerstones of obesity treatment. We questioned the effect of dietary or lifestyle interventions for HO and systematically searched the literature for evidence on feasibility, safety, or efficacy of dietary or lifestyle interventions for childhood hypothalamic overweight or obesity.

METHODS

A systematic search was conducted in MEDLINE (including Cochrane Library), EMBASE, and CINAHL (May 2023). Studies assessing feasibility, safety, or efficacy of any dietary or lifestyle intervention in children with hypothalamic overweight or obesity, were included. Animal studies, studies on non-diet interventions, and studies with no full text available were excluded. Because the number of studies to be included was low, the search was repeated for adults with hypothalamic overweight or obesity. Risk of bias was assessed with an adapted Cochrane Risk of Bias Tool. Level of evidence was assessed using the GRADE system. Descriptive data were described, as pooled-data analysis was not possible due to heterogeneity of included studies.

RESULTS

In total, twelve studies were included, with a total number of 118 patients (age 1-19 years) of whom one with craniopharyngioma, one with ROHHAD-NET syndrome, 50 with monogenic obesity, and 66 with Prader-Willi syndrome (PWS). Four studies reported a dietary intervention as feasible. However, parents did experience difficulties with children still stealing food, and especially lowering carbohydrates was considered to be challenging. Seven studies reported on efficacy of a dietary intervention: a well-balanced restrictive caloric diet (30% fat, 45% carbohydrates, and 25% protein) and various hypocaloric diets (8-10 kcal/cm/day) were considered effective in terms of weight stabilization or decrease. No negative effect on linear growth was reported. Four studies reported on specific lifestyle interventions, of which three also included a dietary intervention. Combined dietary and lifestyle intervention resulted in decreased BMI, although BMI returned to baseline values on long-term. One additional study was identified in adults after brain trauma and showed a significant reduction in BMI in one out of eight patients after a combined dietary and lifestyle intervention.

CONCLUSIONS

Hypocaloric diet or restrictive macronutrient diet with lower percentage of carbohydrates seems feasible and effective for childhood HO, although most of the studies had a high risk of bias, small cohorts without control groups, and were conducted in children with PWS only, compromising the generalizability. Lifestyle interventions only resulted in BMI decrease in short-term, indicating that additional guidance is needed to sustain its effect in the long-term. Literature on feasibility and efficacy of a dietary or lifestyle intervention for hypothalamic overweight or obesity is scarce, especially in children with acquired HO (following treatment for a suprasellar tumor). There is need for prospective (controlled) studies to determine which dietary and lifestyle intervention are most helpful for this specific patient group.

Prader-Willi syndrome: guidance for children and transition into adulthood

Prader-Willi syndrome (PWS) is a rare orphan disease and complex genetic neurodevelopmental disorder, with a birth incidence of approximately 1 in 10,000-30,000. Management of people with PWS requires a multi-disciplinary approach, ideally through a multi-disciplinary team (MDT) clinic with community support. Hypotonia, poor feeding and faltering growth are characteristic features in the neonatal period, followed by hyperphagia and risk of rapid weight gain later in childhood. Children and adolescents (CA) with PWS usually display developmental delay and mild learning disability and can develop endocrinopathies, scoliosis, respiratory difficulties (both central and obstructive sleep apnoea), challenging behaviours, skin picking, and mental health issues, especially into adulthood. This consensus statement is intended to be a reference document for clinicians managing children and adolescents (up to 18 years of age) with PWS. It considers the bio-psycho-social domains of diagnosis, clinical assessment, and management in the paediatric setting as well as during and after transition to adult services. The guidance has been developed from information gathered from peer-reviewed scientific reports and from the expertise of a range of experienced clinicians in the United Kingdom and Ireland involved in the care of patients with PWS.

Exploring the Diagnostic Complexity of Diabetes Subtypes in Pediatric Obesity: A Case Report of an Adolescent With Prader-Willi Phenotype and Literature Review

Obesity among adolescents poses a significant global health concern with profound short- and long-term impact on physical and mental well-being. The intricate relationship between obesity and the onset of diabetes remains ambiguous, particularly in cases where the manifestation may differ from that observed in individuals with uncomplicated obesity. Herein, we present the case of a 14-year-old male adolescent with Prader-Willi phenotype and subsequent obesity, exhibiting symptoms of polyuria and polydipsia over a 10-day period, indicative of potential diabetes mellitus (DM). Laboratory assessments revealed a hemoglobin A1c level of 10%, confirming the suspected diagnosis. Notably, despite the absence of ketosis, elevated C-peptide levels and the presence of slightly positive islet-cell antibodies warranted further investigation. While the presence of antibodies typically aligns with a diagnosis of type 1 DM, recent research has highlighted the occurrence of anti-insulin pancreatic cell antibodies in type 2 DM cases. This article aims to delve into the multifaceted issues surrounding adolescent obesity, atypical presentations of DM with positive antibodies, and the long-term management of patients with genetic syndromes.

Diagnosis of Two Unrelated Syndromes of Prader-Willi and Calpainopathy: Insight from Trio Whole Genome Analysis and Isodisomy Mapping

PURPOSE

An investigation for the co-occurrence of two unrelated genetic disorders of muscular dystrophy and Prader-Willi syndrome (PWS) (OMIM#176270) using joint whole genome sequencing (WGS).

METHODS

Trio WGS joint analysis was performed to investigate the genetic etiology in a proband with PWS, prolonged muscular hypotonia associated hyperCKemia, and early-onset obesity. The parents were unaffected.

RESULTS

Results showed maternal isodisomy uniparental disomy (UPD) in chromosome 15, expanding from 15q11.2 to 15q22.2, including PWS regions at 15q11.2-15q13. Maternal heterodisomy was detected from 15q22.2 to 15q26.3. A pathogenic variant, NM_000070.3(CAPN3):c.550del (p.Thr184fs), was identified at 15q15.1 in a heterozygous state in the mother that was homozygous in the proband due to maternal isodisomy.

CONCLUSION

This is the first study of the concurrent molecular etiology of PWS and calpainopathy (OMIM#253600) in the same patient. This report highlights the utility of joint analysis and the need for the assessment of autosomal recessive disease in regions of isodisomy in patients with complex and unexplained phenotypes.

Mothering a Child With Complexity and Rarity: A Narrative Inquiry Exploring Prader-Willi Syndrome

Daily experiences of mothers caring for children with Prader-Willi syndrome (PWS) are largely unknown and unvoiced. Knowledge of PWS has generally focused on pathology of the disorder. This emphasis overlooks the challenging moments of everyday life caring for children with PWS. Storied accounts of mothers caring for children with PWS offer expanded narratives to medicalized descriptions of experience. An understanding of everyday challenges in managing physical and mental health issues of PWS including hyperphagia and anxiety may create shifts in social and clinical perspectives. This understanding could improve practices in health and social care for families with PWS. This narrative inquiry studied everyday experience using storied accounts. Participants were mothers caring for children aged 3-17 years with genetically confirmed PWS who were experiencing hyperphagia. Four participants were recruited, and each interviewed 8-12 times over 12 months. Field texts and narrative accounts were co-composed through a collaborative process of analysis. Engaging with participants' day-to-day experiences offered insights into their work of nurturing, caring, and contributing to the care of a child with PWS. Narrative threads focused on complexity and rarity and include the desire to be normal, how ordinary becomes extraordinary, isolation, behaviors and normative standards, and alternative stories of mothering. Recommendations for practice and policy include (a) challenges of mothering a child with complexity, (b) moving beyond functionality and impairment to participation and quality of life, (c) re-storying narratives and supports for families, and (d) engaging with mothers to determine care priorities.

Blind to the perils of pursuing food: Behaviors of individuals with Smith-Magenis Syndrome

Purpose

Discrepancies exist between the need to lock food away and satiety scores in the Smith-Magenis syndrome (SMS) population. This study sought to uncover food-related behaviors within this unique group of individuals.

Methods

Caregivers (N = 24) representing 21 individuals with SMS, recruited from the Parents and Researchers Interested in SMS national meeting and social media platforms, participated in semistructured interviews. Interviews were digitally recorded, transcribed verbatim, coded, and analyzed using hybrid thematic analysis.

Results

This study identified a global theme of "Blind to the perils while pursuing their goals," supported by 5 organizing themes: (1) Biology-impacting behaviors, (2) Need for personalized strategies, (3) Controlling food experiences, (4) Need for parents to orchestrate life, and (5) Surprising resourcefulness. Subthemes within these organizing themes highlighted that individuals with SMS have unique food-related behaviors and often fixate on certain types of foods. Their constant obsession with food for many of them is driven by hunger, obsessive characteristics, a need for autonomy, and a need for fairness. Caregivers must put multiple guardrails in place and remain constantly vigilant to prevent overeating in these individuals.

Conclusion

Individuals with SMS often perseverate on food and display unique food-related behaviors. Treating obesity in this population is likely to be ineffective without multicomponent, individualized strategies. Additionally, research in this population will likely require targeted instruments for the SMS population to more clearly define the underlying etiologies and to track changes over time in therapeutic trials.

Feeding tube use and complications in Prader-Willi syndrome: Data from the Global Prader-Willi Syndrome Registry

Guidance on indications for, and types of, feeding tubes recommended in Prader-Willi syndrome (PWS) is needed. A Global PWS Registry survey was developed to investigate nasogastric (NG) and gastrostomy (G) tube use and associated complications. Of 346 participants, 242 (69.9%) had NG-tubes, 17 (4.9%) had G-tubes, and 87 (25.1%) had both NG- and G-tubes. Primary indication for placement was "feeding difficulties and/or poor weight gain" for both NG- (90.2%) and G-tubes (71.2%), while "aspiration/breathing difficulties" was the procedural indication for 6.4% of NG-tubes and 23.1% of G-tubes. NG-tubes were generally removed by age 6 months (NG Only: 82.9%; NG/G: 98.8%), while G-tubes were often removed by age 2 years (G Only: 85.7%; NG/G: 70.5%). The severe complication rate from G-tubes was 31.7% and from NG-tubes was 1.2%. Overall, caregivers indicated the presence of an NG- or G-tube had a positive effect on quality of life. Feeding difficulties in PWS are largely managed by NG-tube alone. The severe complication rate from G-tubes was about 25 times higher than from NG-tubes; yet, G-tube placement rates have generally increased. G-tube placement puts individuals with PWS at risk for anesthesia and surgery-related complications and should be considered judiciously by a multidisciplinary team.

Appetite- and Weight-Regulating Neuroendocrine Circuitry in Hypothalamic Obesity

Since hypothalamic obesity (HyOb) was first described over 120 years ago by Joseph Babinski and Alfred Fröhlich, advances in molecular genetic laboratory techniques have allowed us to elucidate various components of the intricate neurocircuitry governing appetite and weight regulation connecting the hypothalamus, pituitary gland, brainstem, adipose tissue, pancreas, and gastrointestinal tract. On a background of an increasing prevalence of population-level common obesity, the number of survivors of congenital (eg, septo-optic dysplasia, Prader-Willi syndrome) and acquired (eg, central nervous system tumors) hypothalamic disorders is increasing, thanks to earlier diagnosis and management as well as better oncological therapies. Although to date the discovery of several appetite-regulating peptides has led to the development of a range of targeted molecular therapies for monogenic obesity syndromes, outside of these disorders these discoveries have not translated into the development of efficacious treatments for other forms of HyOb. This review aims to summarize our current understanding of the neuroendocrine physiology of appetite and weight regulation, and explore our current understanding of the pathophysiology of HyOb.

Prader-Willi syndrome in a large sample from Spain: general features, obesity and regular use of psychotropic medication

BACKGROUND

Prader-Willi syndrome (PWS), a genetically determined disorder, the most frequent cause of early onset obesity, is associated with physical and cognitive dysfunctions and behavioural disturbances; these disturbances are frequently treated with psychotropic medication. The aim of this cross-sectional study was to describe the characteristics of the first large national sample of persons with PWS in Spain and analyse the relationships of those characteristics with key demographic and clinical factors, particularly with obesity and the regular use of psychotropic medication.

METHODS

Participants were recruited among all members of the Spanish Prader-Willi Association who agreed to take part in the study and fulfilled its inclusion criteria. Family and patient demographic features, family size and birth order, intelligence quotient (IQ), anthropometric measures, lifestyle habits, behavioural disturbances (with the Aberrant Behavior Checklist) and clinical data, as well as use of psychotropic drugs and their side effects (with the UKU scale), were collected in genetically confirmed cases of PWS. Bivariate and logistic regression analyses were used for determining the associations of demographic and clinical factors with both obesity and the regular use of psychotropic medication.

RESULTS

The cohort included 177 participants (aged 6-48 years), that is, 90 (50.8%) males and 87 (49.2%) females. Behavioural disturbances were present in a range of 75% to 93% of participants; psychotropic medication was prescribed to 81 (45.8%) of them. Number of siblings showed a direct correlation with IQ, especially among males, and inappropriate speech was more intense in only-child females. Obesity was, in parallel, strongly associated with ascending age and with not being currently under growth hormone (GH) treatment. Participants taking any psychotropic medication were characterised by more frequent age ≥30 years, high level of hyperactivity and a psychiatric diagnosis.

CONCLUSIONS

Characterisation of persons with PWS in Spain confirms their physical and behavioural phenotype and supports the long-term application of GH therapy and the rational use of psychotropic medication.

Prader-Willi Syndrome: The More We Know, the Less We Know

Prader-Willi syndrome (PWS) is a complex genetic neurodevelopmental disorder with multisystem impact and a unique behavior profile that evolves over the life span. Beyond the primary care needs of all children and adults, the unique medical concerns and management needs of those with PWS are best served in a multidisciplinary academic center. Our PWS center has provided care for individuals with PWS and their families since 1981. Our growth hormone studies contributed to growth hormone supplementation becoming standard of care in this country. Here, in collaboration with the primary care provider, early childhood intervention programs, schools and local parent organizations, solid, patient-centered care for affected individuals and their families can be provided across the life-span. The purpose of this article is to provide a brief overview of PWS and the attendant medical and behavior management challenges attendant to the disorder.

A genetic condition that spans both extremes of the nutritional spectrum

Prader-Willi syndrome (PWS) is a complex genetic disorder caused by lack of expression of genes on the paternally inherited chromosome 15q11.2-q13 region, known as the Prader Willi critical region. Nutritional clinical manifestations change with age and are described in four different phases. The phases span both extremes of the nutritional spectrum, beginning with an infant with poor sucking reflexes and failure to thrive then progressing to an adolescent who may have hyperphagia and be at risk for obesity. The phenotype is likely due to hypothalamic dysfunction due to genetic changes in the Prader Willi critical region. Researchers are examining the pathological mechanisms that determine the disease course.

Specificity of Early Childhood Hyperphagia Profiles in Neurogenetic Conditions

Hyperphagia is highly penetrant in Prader-Willi syndrome (PWS) and has increasingly been reported in other neurogenetic conditions (NGC). The Hyperphagia Questionnaire (HQ) was completed by caregivers of 4-8-year-olds with PWS (n = 17), Angelman syndrome (AS; n = 22), Williams syndrome (WS; n = 25), or low-risk controls (LRC; n = 35). All NGC groups were significantly elevated in HQ Total and Behavior scores compared to LRC. Only AS and WS were significantly elevated in the Drive domain, and only PWS in the Severity domain. After controlling for externalizing behavior, HQ Total scores were higher for PWS relative to other groups. Hyperphagic symptoms may not differentiate PWS from other NGCs in early childhood. However, hyperphagic phenotypes may be most severe in PWS. Further investigation of these profiles may inform etiology and syndrome-specific treatments.

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.

Behavioral changes in patients with Prader-Willi syndrome receiving diazoxide choline extended-release tablets compared to the PATH for PWS natural history study

BACKGROUND

Prader-Willi syndrome (PWS) is a rare neurobehavioral-metabolic disease caused by the lack of paternally expressed genes in the chromosome 15q11-q13 region, characterized by hypotonia, neurocognitive problems, behavioral difficulties, endocrinopathies, and hyperphagia resulting in severe obesity if energy intake is not controlled. Diazoxide choline extended-release (DCCR) tablets have previously been evaluated for their effects on hyperphagia and other behavioral complications of people with PWS in a Phase 3 placebo-controlled study of participants with PWS, age 4 and older with hyperphagia (C601) and in an open label extension study, C602.

METHODS

To better understand the longer-term impact of DCCR, a cohort from PATH for PWS, a natural history study that enrolled participants with PWS age 5 and older, who met the C601 age, weight and baseline hyperphagia inclusion criteria and had 2 hyperphagia assessments ≥ 6 months apart, were compared to the C601/C602 cohort. Hyperphagia was measured using the Hyperphagia Questionnaire for Clinical Trials (HQ-CT, range 0-36). The primary analysis used observed values with no explicit imputation of missing data. A sensitivity analysis was conducted in which all missing HQ-CT assessments in the C601/C602 cohort were assigned the highest possible value (36), representing the worst-case scenario. Other behavioral changes were assessed using the Prader-Willi Syndrome Profile questionnaire (PWSP).

RESULTS

Relative to the PATH for PWS natural history study cohort, the DCCR-treated C601/C602 cohort showed significant improvements in HQ-CT score at 26 weeks (LSmean [SE] -8.3 [0.75] vs. -2.5 [0.43], p < 0.001) and 52 weeks (LSmean [SE] -9.2 [0.77] vs. -3.4 [0.47], p < 0.001). The comparison between the cohorts remained significant in the worst-case imputation sensitivity analysis. There were also significant improvements in all domains of the PWSP at 26 weeks (all p < 0.001) and 52 weeks (all p ≤ 0.003) for C601/C602 participants compared to the PATH for PWS participants.

CONCLUSION

Long-term administration of DCCR to people with PWS resulted in changes in hyperphagia and other behavioral complications of PWS that are distinct from the natural history of the syndrome as exemplified by the cohort from PATH for PWS. The combined effects of administration of DCCR should reduce the burden of the syndrome on the patient, caregivers and their families, and thereby may benefit people with PWS and their families.

TRIAL REGISTRATION

Clinical study C601 was originally registered on ClinicalTrials.gov on February 22, 2018 (NCT03440814). Clinical study C602 was originally registered on ClinicalTrials.gov on October 22, 2018 (NCT03714373). PATH for PWS was originally registered on ClinicalTrials.gov on October 24, 2018 (NCT03718416).

Bardet-Biedl syndrome: A clinical overview focusing on diagnosis, outcomes and best-practice management

Bardet-Biedl syndrome (BBS) is a genetic disorder characterized by early-onset obesity, polydactyly, genital and kidney anomalies, developmental delay and vision loss due to rod-cone dystrophy. BBS is an autosomal recessive disorder with >20 implicated genes. The genotype-phenotype relationship in BBS is not clear, and there may be additional modifying factors. The underlying mechanism is dysfunction of primary cilia. In BBS, receptor trafficking in and out of the cilia is compromised, affecting multiple organ systems. Along with early-onset obesity, hyperphagia is a prominent symptom and contributes significantly to clinical morbidity and caregiver burden. While there is no cure for BBS, setmelanotide is a new pharmacotherapy approved for treatment of obesity in BBS. The differential diagnosis for BBS includes other ciliopathies, such as Alstrom syndrome, and other genetic obesity syndromes, such as Prader-Willi syndrome. Careful clinical history and genetic testing can help determine the diagnosis and a multidisciplinary team is necessary to guide clinical management.

Neuromodulation for the treatment of Prader-Willi syndrome - A systematic review

Prader-Willi syndrome (PWS) is a complex, genetic disorder characterized by multisystem involvement, including hyperphagia, maladaptive behaviors and endocrinological derangements. Recent developments in advanced neuroimaging have led to a growing understanding of PWS as a neural circuit disorder, as well as subsequent interests in the application of neuromodulatory therapies. Various non-invasive and invasive device-based neuromodulation methods, including vagus nerve stimulation (VNS), transcranial direct current stimulation (tDCS), repetitive transcranial magnetic stimulation (rTMS), and deep brain stimulation (DBS) have all been reported to be potentially promising treatments for addressing the major symptoms of PWS. In this systematic literature review, we summarize the recent literature that investigated these therapies, discuss the underlying circuits which may underpin symptom manifestations, and cover future directions of the field. Through our comprehensive search, there were a total of 47 patients who had undergone device-based neuromodulation therapy for PWS. Two articles described VNS, 4 tDCS, 1 rTMS and 2 DBS, targeting different symptoms of PWS, including aberrant behavior, hyperphagia and weight. Multi-center and multi-country efforts will be required to advance the field given the low prevalence of PWS. Finally, given the potentially vulnerable population, neuroethical considerations and dialogue should guide the field.

Microglial phagolysosome dysfunction and altered neural communication amplify phenotypic severity in Prader-Willi Syndrome with larger deletion

Prader-Willi Syndrome (PWS) is a rare neurodevelopmental disorder of genetic etiology, characterized by paternal deletion of genes located at chromosome 15 in 70% of cases. Two distinct genetic subtypes of PWS deletions are characterized, where type I (PWS T1) carries four extra haploinsufficient genes compared to type II (PWS T2). PWS T1 individuals display more pronounced physiological and cognitive abnormalities than PWS T2, yet the exact neuropathological mechanisms behind these differences remain unclear. Our study employed postmortem hypothalamic tissues from PWS T1 and T2 individuals, conducting transcriptomic analyses and cell-specific protein profiling in white matter, neurons, and glial cells to unravel the cellular and molecular basis of phenotypic severity in PWS sub-genotypes. In PWS T1, key pathways for cell structure, integrity, and neuronal communication are notably diminished, while glymphatic system activity is heightened compared to PWS T2. The microglial defect in PWS T1 appears to stem from gene haploinsufficiency, as global and myeloid-specific Cyfip1 haploinsufficiency in murine models demonstrated. Our findings emphasize microglial phagolysosome dysfunction and altered neural communication as crucial contributors to the severity of PWS T1's phenotype.

Hyperphagia and impulsivity: use of self-administered Dykens' and in-house impulsivity questionnaires to characterize eating behaviors in children with severe and early-onset obesity

BACKGROUND

The determinants of early-onset obesity (< 6 years) are not completely elucidated, however eating behavior has a central role. To date no study has explored eating behavior in children with severe, early-onset obesity. Self-administered questionnaire data from these children were examined to evaluate eating behavior and the etiology of early-onset obesity.

METHODS

Children with severe, early-onset obesity (body mass index [BMI] > International Obesity Task Force [IOTF] 30) of different etiologies (hypothalamic obesity [HO], intellectual disability with obesity [IDO], common polygenic obesity [CO]) were prospectively included. BMI history and responses from the Dykens' Hyperphagia Questionnaire and an in-house Impulsivity Questionnaire at first visit were compared between groups.

RESULTS

This cohort of 75 children (39 girls; mean age ± standard deviation [SD] 10.8 ± 4.4 years) had severe, early-onset obesity at an age of 3.8 ± 2.7 years, with a BMI Z-score of 4.9 ± 1.5. BMI history varied between the 3 groups, with earlier severe obesity in the HO group versus 2 other groups (BMI > IOTF40 at 3.4 ± 1.6 vs. 4.6 ± 1.6 and 8.4 ± 4.1 years for the IDO and CO groups, respectively [P < 0.01]). Absence of adiposity rebound was more prevalent in the HO group (87% vs. 63% and 33% for the IDO and CO groups, respectively [P < 0.01]). The Dykens' mean total score for the cohort was 22.1 ± 7.2 with no significant between-group differences. Hyperphagia (Dykens' score > 19) and impulsivity (score > 7) were found in 50 (67%) and 11 children (15%), respectively, with no difference between the HO, IDO and CO groups regarding the number of patients with hyperphagia (10 [67%], 14 [74%], and 26 [63%] children, respectively) or impulsivity (2 [13%], 1 [7%], and 8 [19%] children, respectively). Children with food impulsivity had significantly higher total and severity scores on the Dykens' Questionnaire versus those without impulsivity.

CONCLUSION

The Dykens' and Impulsivity questionnaires can help diagnose severe hyperphagia with/without food impulsivity in children with early-onset obesity, regardless of disease origin. Their systematic use can allow more targeted management of food access control in clinical practice and monitor the evolution of eating behavior in the case of innovative therapeutic targeting hyperphagia.

Diazoxide choline extended-release tablet in people with Prader-Willi syndrome: results from long-term open-label study

OBJECTIVE

This study assessed the effect of 1-year administration of diazoxide choline extended-release tablet (DCCR) on hyperphagia and other complications of Prader-Willi syndrome (PWS).

METHODS

The authors studied 125 participants with PWS, age ≥ 4 years, who were enrolled in the DESTINY PWS Phase 3 study and who received DCCR for up to 52 weeks in DESTINY PWS and/or its open-label extension. The primary efficacy endpoint was Hyperphagia Questionnaire for Clinical Trials (HQ-CT) score. Other endpoints included behavioral assessments, body composition, hormonal measures, and safety.

RESULTS

DCCR administration resulted in significant improvements in HQ-CT (mean [SE] -9.9 [0.77], p < 0.0001) and greater improvements in those with more severe baseline hyperphagia (HQ-CT > 22). Improvements were seen in aggression, anxiety, and compulsivity (all p < 0.0001). There were reductions in leptin, insulin, and insulin resistance, as well as a significant increase in adiponectin (all p < 0.004). Lean body mass was increased (p < 0.0001). Disease severity was reduced as assessed by clinician and caregiver (both p < 0.0001). Common treatment-emergent adverse events included hypertrichosis, peripheral edema, and hyperglycemia. Adverse events infrequently resulted in discontinuation (7.2%).

CONCLUSIONS

DCCR administration to people with PWS was well tolerated and associated with broad-ranging improvements in the syndrome. Sustained administration of DCCR has the potential to reduce disease severity and the burden of care for families.

Mental health impact on primary and secondary Prader-Willi syndrome caregivers

INTRODUCTION

Caring for individuals with rare diseases can be challenging and represent a burden. Nevertheless, this has been scarcely explored in Prader-Willi syndrome (PWS). Therefore, we sought to explore the psychological impact of caregiving, as well as the differences between main caregivers and other family members.

METHODS

Different evaluation tools and scales were used taking into consideration the impact on caregivers. The scales were administered to those relatives who are immersed in the usual dynamics of the patient, differentiating between the main caregiver and other relatives living in the family home.

RESULTS

A total of 33 families of patients with genetic confirmation of PWS were included. In this survey, 32% of primary caregivers reported a high probability of anxiety, compared with 19% of non-primary caregivers (p = 0.27). Concerning depression, 40% of primary caregivers related possible or probable cases of depression compared with non-primary caregivers 13% (p = 0.04). Regarding caregiver burden evaluated using the Zarit scale, 61% of the main caregivers presented high levels of overload, compared with 29% of the other relatives (p = 0.005). Family functioning evaluated using the APGAR scale showed a total lower response from primary caregivers, but no statistically relevant results were found [25.4 ± 6.7 vs. 26.0 ± 8.2 (p = 0.72)].

CONCLUSION

In this study, we observed that caring for people with PWS can have a significant effect on the mental health, burden and quality of life of caregivers, with a greater impact among primary caregivers compared with the other living relatives.

"Unable to Feed My Hungry Child": Experiences of Mothers Caring for Children With Prader-Willi Syndrome

Mothers' experiences of caring for children with Prader-Willi Syndrome (PWS) is largely unknown. With no treatment for PWS, parents undertake (extra)ordinary care practices to keep children safe from overeating and self harm. Knowledge of these care practices could lead to effective interventions. Narrative inquiry was used to study everyday experience with Canadian mothers. Participants cared for a child 3 to 17 years old who had hyperphagia. Participants were interviewed 8 to 12 times each over the course of a year. Narrative accounts were co-composed through a collaborative process of analysis. Engaging with participants' everyday experiences amplified complex care needs for families and gaps in health and social care systems. Narrative threads focused on engaging in (extra)ordinary care practices, rigid care work to keep children healthy and safe, tension from others while enacting these care practices, and difficulty conforming to social expectations with childrearing and care work. Recommendations for practice and policy include (a) shifting from untenable care practices, (b) reconceptualizing care work, and (c) alternative care models.

AAV-BDNF gene therapy ameliorates a hypothalamic neuroinflammatory signature in the Magel2-null model of Prader-Willi syndrome

Individuals with Prader-Willi syndrome (PWS) exhibit several metabolic and behavioral abnormalities associated with excessive food-seeking activity. PWS is thought to be driven in part by dysfunctional hypothalamic circuitry and blunted responses to peripheral signals of satiety. Previous work described a hypothalamic transcriptomic signature of individuals with PWS. Notably, PWS patients exhibited downregulation of genes involved in neuronal development and an upregulation of neuroinflammatory genes. Deficiencies of brain-derived neurotrophic factor (BDNF) and its receptor were identified as potential drivers of PWS phenotypes. Our group recently applied an adeno-associated viral (AAV)-BDNF gene therapy within a preclinical PWS model, Magel2-null mice, to improve metabolic and behavioral function. While this proof-of-concept project was promising, it remained unclear how AAV-BDNF was influencing the hypothalamic microenvironment and how its therapeutic effect was mediated. To investigate, we hypothalamically injected AAV-BDNF to wild type and Magel2-null mice and performed mRNA sequencing on hypothalamic tissue. Here, we report that (1) Magel2 deficiency is associated with neuroinflammation in the hypothalamus and (2) AAV-BDNF gene therapy reverses this neuroinflammation. These data newly reveal Magel2-null mice as a valid model of PWS-related neuroinflammation and furthermore suggest that AAV-BDNF may modulate obesity-related neuroinflammatory phenotypes through direct or indirect means.

The Utilization of MS-MLPA as the First-Line Test for the Diagnosis of Prader-Willi Syndrome in Thai Patients

Prader-Willi syndrome (PWS) is a genetic disorder caused by the expression disruption of genes on the paternally inherited allele of chromosome 15q11.2-q13. Apart from clinical diagnostic criteria, PWS is confirmed by genetic testing. Methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) is one of the molecular techniques used to analyze this syndrome. This study aimed to evaluate the concordance of the test results of MS-MLPA with conventional techniques in the diagnosis of PWS in Thai patients. Forty leftover specimens from routine genetic testing (MS-PCR and FISH) were tested to obtain MS-MLPA results. By comparison, perfect concordance was shown between the result of MS-MLPA and those of conventional techniques. In conclusion, MS-MLPA is an accurate and cost-effective assay that can be used to confirm PWS diagnosis with explicit deletion of affected genes.

Analysis of Hyperphagia Questionnaire for Clinical Trials (HQ-CT) scores in typically developing individuals and those with Prader-Willi syndrome

The Hyperphagia Questionnaire for Clinical Trials (HQ-CT) is an observer-reported outcome measure that has been widely used in interventional studies to assess changes in hyperphagic behaviors in individuals with Prader-Willi syndrome (PWS). However, HQ-CT scores in the wider PWS population and the general population have not been reported. Here we report HQ-CT scores from more than 400 individuals with PWS and 600 typical individuals, aged 5-26. Overall, HQ-CT scores were significantly higher in those with PWS compared to typically developing individuals at all ages evaluated. In addition, while HQ-CT scores in the typically developing population decreased with age, scores increased with age in PWS. To further understand the variability of HQ-CT scores in the PWS population, semi-structured interviews were conducted with caregivers of a small subset of adults with PWS who had unexpectedly low HQ-CT scores. These caregivers reported that strict adherence to a food routine, food security measures and supervised food preparation reduced the frequency and intensity of hyperphagic behaviors measured by HQ-CT. Thus, hyperphagic behaviors are captured by the HQ-CT for most individuals with PWS, but for some individuals residing in settings with highly structured food routines, HQ-CT scores may not fully reflect the extent of PWS-associated hyperphagia.

Longitudinal Changes in Acylated versus Unacylated Ghrelin Levels May Be Involved in the Underlying Mechanisms of the Switch in Nutritional Phases in Prader-Willi Syndrome

INTRODUCTION

Prader-Willi syndrome (PWS) is characterized by a switch from failure to thrive to excessive weight gain and hyperphagia in early childhood. An elevated, more unfavorable ratio between acylated and unacylated ghrelin (AG/UAG ratio) might play a role in the underlying mechanisms of this switch. We aimed to assess the evolution of the appetite-regulating hormones acylated ghrelin (AG) and unacylated ghrelin (UAG) and the AG/UAG ratio and their association with the change in eating behavior in children with PWS, compared to healthy age-matched controls.

METHODS

A longitudinal study was conducted in 134 children with PWS and 157 healthy controls, from the Netherlands, France, and Belgium. Levels of AG and UAG and the AG/UAG ratio were measured and nutritional phases as reported for PWS were scored.

RESULTS

The AG/UAG ratio was lower in the first years of life in PWS than in controls and started to increase from the age of 3 years, resulting in a high-normal AG/UAG ratio compared to controls. The AG levels remained stable during the different nutritional phases (p = 0.114), while the UAG levels decreased from 290 pg/mL in phase 1a to 137 pg/mL in phase 2b (p < 0.001). The AG/UAG ratio increased significantly from 0.81 in phase 2a to 1.24 in phase 2b (p = 0.012).

CONCLUSIONS

The change from failure to thrive to excessive weight gain and hyperphagia in infants and children with PWS coincides with an increase in AG/UAG ratio. The increase in AG/UAG ratio occurred during phase 2a, thus before the onset of hyperphagia.

Food cue reward salience does not explain Hyperphagia in adolescents with Prader-Willi syndrome

Prader-Willi Syndrome (PWS) is characterized by hyperphagia, an extreme and persistent hunger that emerges in early childhood. We used event-related potentials (ERPs) to objectively investigate brain responses to low- and high-calorie foods, animals, and household objects in 20 satiated adolescents with PWS. Late Positive Potential (LPP) responses to food images did not differ from non-food images. Rather, we observed larger ERPs to high-calorie foods relative to animal images (p=.001) in an earlier time window. These responses correlated with greater severity of hyperphagia (p = .01). Thus, hyperphagia associated with PWS may be due to altered satiety regulation rather than increased motivational salience.

Hyperphagia, Growth, and Puberty in Children with Angelman Syndrome

Angelman Syndrome (AS) is a rare genetic disorder caused by lack of maternal UBE3A protein due to a deletion of the chromosome 15q11.2-q13 region, uniparental paternal disomy, imprinting center defect, or pathogenic variant in the UBE3A gene. Characteristics are developmental delay, epilepsy, behavioral, and sleep problems. There is some evidence for hyperphagia, shorter stature, and higher BMI compared to neurotypical children, but longitudinal studies on growth are lacking. In this study, we analyzed prospectively collected data of 145 children with AS, who visited the ENCORE Expertise Center between 2010 and 2021, with a total of 853 visits. Children showed an elevated mean score of 25 on the Dykens Hyperphagia questionnaire (range 11-55) without genotype association. Higher scores were significantly associated with higher body mass index (BMI) standard deviation scores (SDS) (p = 0.004). Mean height was -1.2 SDS (SD 1.3), mean BMI-SDS was 0.6 (SD 1.7); 43% had a BMI-SDS > 1 and 20% had a BMI-SDS > 2. Higher BMI-SDS was significantly associated with non-deletion genotype (p = 0.037) and walking independently (p = 0.023). Height SDS decreased significantly with age (p < 0.001) and BMI-SDS increased significantly with age (p < 0.001. Onset of puberty was normal. In conclusion, children with AS showed moderate hyperphagia, lower height SDS, and higher BMI-SDS compared to norm data, with increasing deviation from the norm with age. It is uncertain how loss of maternal UBE3A function may influence growth. Attention to diet, exercise, and hyperphagia from an early age is recommended to prevent obesity and associated health problems.

Intranasal oxytocin as a treatment for obesity: safety and efficacy

INTRODUCTION

Known for its effect on labor and lactation and on emotional and social functions, oxytocin has recently emerged as a key modulator of feeding behavior and indeed suggested as a potential treatment for obesity. The potential positive effect of oxytocin on both metabolic and psychological-behavioral complications of hypothalamic lesions makes it a promising tool in the management of these conditions.

AREAS COVERED

The aim of the present review article is to provide an overview of the mechanism of action and clinical experience of the use of oxytocin in different forms of obesity.

EXPERT OPINION

Current evidence suggests a potential role of oxytocin in the treatment of obesity with different causes. Several challenges remain: an improved understanding of the physiological regulation, mechanisms of action of oxytocin, and interplay with other endocrine axes is fundamental to clarify its role. Further clinical trials are needed to determine the safety and efficacy of oxytocin for the treatment of different forms of obesity. Understanding the mechanism(s) of action of oxytocin on body weight regulation might also improve our understanding of obesity and reveal possible new therapeutic targets - as well as promoting advances in other fields in which oxytocin might be used.

Analysis of the Diet Quality and Nutritional State of Children, Youth, and Young Adults with Prader-Willi Syndrome: A Polish Multiple Case Study

Given the lack of data on dietary quality in young individuals with Prader-Willi syndrome (PWS) in Poland, a multiple case study was conducted in which anthropometric measurements and 7-day dietary records were collected from 20 subjects with PWS. The study group consisted of 8 females and 12 males with a mean age of 14.8 years and a mean BMI of 21.6. Based on BMI analysis, five subjects were overweight, including two subjects who were obese. The study showed that 35% of the subjects had energy intakes above the recommended levels. Protein deficiency was found in one subject in the analyzed diets. However, fat intake was excessive in four subjects, and the majority exceeded the recommended intake of saturated fatty acids. Vitamin E and B12 deficiencies were found in 40% and 85% of the subjects, respectively. All subjects had inadequate intakes of vitamin D and iodine, while the majority had deficiencies in sodium and copper intakes. Calcium intake was deficient in 35% of the subjects. However, most subjects met recommendations for the intakes of other minerals, vitamins, and fiber. These findings confirm the suboptimal dietary patterns of Polish individuals with PWS, with deficits observed in the intake of certain vitamins and minerals.

Hormonal Imbalances in Prader-Willi and Schaaf-Yang Syndromes Imply the Evolution of Specific Regulation of Hypothalamic Neuroendocrine Function in Mammals

The hypothalamus regulates fundamental aspects of physiological homeostasis and behavior, including stress response, reproduction, growth, sleep, and feeding, several of which are affected in patients with Prader-Willi (PWS) and Schaaf-Yang syndrome (SYS). PWS is caused by paternal deletion, maternal uniparental disomy, or imprinting defects that lead to loss of expression of a maternally imprinted region of chromosome 15 encompassing non-coding RNAs and five protein-coding genes; SYS patients have a mutation in one of them, MAGEL2. Throughout life, PWS and SYS patients suffer from musculoskeletal deficiencies, intellectual disabilities, and hormonal abnormalities, which lead to compulsive behaviors like hyperphagia and temper outbursts. Management of PWS and SYS is mostly symptomatic and cures for these debilitating disorders do not exist, highlighting a clear, unmet medical need. Research over several decades into the molecular and cellular roles of PWS genes has uncovered that several impinge on the neuroendocrine system. In this review, we will discuss the expression and molecular functions of PWS genes, connecting them with hormonal imbalances in patients and animal models. Besides the observed hormonal imbalances, we will describe the recent findings about how the loss of individual genes, particularly MAGEL2, affects the molecular mechanisms of hormone secretion. These results suggest that MAGEL2 evolved as a mammalian-specific regulator of hypothalamic neuroendocrine function.

Report of two cases of Schaaf-Yang syndrome: Same genotype and different phenotype

We report two, genotypically identical but phenotypically distinct cases of Schaaf-Yang syndrome and propose the early use of Genome Sequencing in patients with nonspecific presentations to facilitate the early diagnosis of children with rare genetic diseases and improve overall health care outcomes.

Hyperinsulinemia is a probable trigger for weight gain and hyperphagia in individuals with Prader-Willi syndrome

Objective

Prader-Willi syndrome (PWS) is the most frequently diagnosed genetic cause of early childhood obesity. Individuals with PWS typically progress through 7 different nutritional phases during their lifetime. The main objective of this study was to assess potential factors, particularly insulin, that may be responsible for the weight gains in sub-phase 2a and their role in the subsequent increase in fat mass and obesity in sub-phase 2b and insatiable appetite in phase 3.

Methods

Fasting plasma insulin levels were measured in children with PWS between the ages of 0-12 years and in age-matched non-PWS participants with early-onset major (clinically severe) obesity (EMO) and in healthy-weight sibling controls (SC).

Results

Participants with PWS in nutritional phases 1a and 1b had plasma insulin levels comparable to SC. However, the transition from phase 1b up to phase 3 in the PWS group was accompanied by significant increases in insulin, coinciding in weight gains, obesity, and hyperphagia. Only individuals with PWS in phase 3 had comparable insulin levels to the EMO group who were higher than the SC group at any age.

Conclusions

Elevated insulin signaling is a probable trigger for weight gain and onset of hyperphagia in children with Prader-Willi syndrome. Regulating insulin levels early in childhood before the onset of the early weight gain may be key in modulating the onset and severity of obesity and hyperphagia in individuals with PWS, as well as in other young children with non-PWS early-onset obesity. Preventing or reversing elevated insulin levels in PWS with pharmacological agents and/or through diet restrictions such as a combined low carbohydrate, low glycemic-load diet may be a viable therapeutic strategy in combating obesity in children with PWS and others with early childhood obesity.

Diazoxide Choline Extended-Release Tablet in People With Prader-Willi Syndrome: A Double-Blind, Placebo-Controlled Trial

CONTEXT

Prader-Willi syndrome (PWS) is a rare neurobehavioral-metabolic disease caused by the lack of paternally expressed genes in the chromosome 15q11-q13 region, characterized by hypotonia, neurocognitive problems, behavioral difficulties, endocrinopathies, and hyperphagia resulting in severe obesity if not controlled.

OBJECTIVE

The primary end point was change from baseline in hyperphagia using the Hyperphagia Questionnaire for Clinical Trials (HQ-CT). Other end points included Global Impression Scores, and changes in body composition, behaviors, and hormones.

METHODS

In DESTINY PWS, a 13-week, randomized, double-blind, placebo-controlled, phase 3 trial, 127 participants with PWS aged 4 years and older with hyperphagia were randomly assigned 2:1 to diazoxide choline extended-release tablet (DCCR) or placebo.

RESULTS

DCCR did not significantly improve hyperphagia (HQ-CT least-square mean (LSmean) [SE] -5.94 [0.879] vs -4.27 [1.145]; P = .198), but did so in participants with severe hyperphagia (LSmean [SE] -9.67 [1.429] vs -4.26 [1.896]; P = .012). Two of 3 secondary end points were improved (Clinical Global Impression of Improvement [CGI-I]; P = .029; fat mass; P = .023). In an analysis of results generated pre-COVID, the primary (HQ-CT; P = .037) and secondary end points were all improved (CGI-I; P = .015; Caregiver Global Impression of Change; P = .031; fat mass; P = .003). In general, DCCR was well tolerated with 83.3% in the DCCR group experiencing a treatment-emergent adverse event and 73.8% in the placebo group (not significant).

CONCLUSION

DCCR did not significantly improve hyperphagia in the primary analysis but did in participants with severe baseline hyperphagia and in the pre-COVID analysis. DCCR treatment was associated with significant improvements in body composition and clinician-reported outcomes.