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Abstract The presence and severity of compulsive behaviours may be evaluated via the Compulsive Behaviour Checklist (CBC) and this instrument has been successfully employed in people with intellectual disability. However, the applicability of the overall CBC scoring system, which entails tallying the number of behavioural categories represented (i.e. five) as well as the number of individual behaviours endorsed (i.e 25), is not known in the population with Prader–Willi syndrome (PWS). The present investigation examined the latent variable structure of the CBC in people with PWS in order to identify possible population-specific scoring and interpretation considerations. The 25 behaviour-specific items of the CBC were analysed for 75 people with PWS (44 females and 31 males) aged between 4 and 41 years (mean ± SD = 11.4 ± 9.4) via factor analysis with principal component extraction and equamax rotation. The most suitable solution was determined on the basis of multiple empirical criteria: (1) the scree test; (2) eigenvalues > 1.00; (3) salient loadings > 0.30; (4) the clarity of item assignment to a single latent dimension; (5) the internal consistency of the latent dimension(s) (coefficient α≥ 0.70); and (6) item-total correlations between 0.20 and 0.79. In addition, solutions were examined with respect to psychological theory and previous research. A ‘general factor’ (i.e. single latent dimension) solution which adhered to all a priori criteria was indicated. Twenty-four out of 25 items achieved salient loadings ranging from 0.46 to 0.80 on the general factor. The single item which failed to achieve salience, ‘deviant grooming-skin picking’, exhibited both substantial unique variance (0.997) and moderate reliability (r = 0.59, P < 0.001). The internal consistency of the general factor was strong (α= 0.93) and all salient items were suitably correlated with the unit-weighted total score... [ABSTRACT FROM AUTHOR]

Background: Information regarding response rate to tigilanol tiglate for mast cell tumors in dogs is limited., Objectives: Report the response rate and durability of tigilanol tiglate intratumoral treatment in dogs with mast cell tumors presented to veterinary oncologists., Animals: One hundred forty-nine dogs; 151 individual tumors., Methods: Multicenter, retrospective survey-based study. Veterinary oncologists subscribed to the American College of Veterinary Internal Medicine (ACVIM) oncology listserv were solicited for information from dogs treated with tigilanol tiglate. An electronic survey was used to collect information at initial treatment, 1 month and 1 year after treatment., Results: Most tumors were cutaneous, occurred on the limbs and were cytologically low grade. Seventy-five percent of dogs achieved a complete response after 1 dose of tigilanol tiglate 1 month after treatment. This response was durable at 1 year in 64% of dogs for which data were available (n = 88). Wound formation, an expectation after treatment, occurred after a median of 7 days (range, 1-91 days), with a median wound area of 4.71 cm 2 (range, 0.09-100 cm 2 ). Wounds took a median of 30 days to heal completely (range, 14-154 days). A moderate association between tumor volume and wound size was confirmed., Conclusions and Clinical Importance: Tigilanol tiglate is an effective local treatment option for mast cell tumors in dogs with a predictable clinical course and response. Because of the unique mode of action and clinical course, client education and careful case selection is necessary before electing tigilanol tiglate for local treatment., (© 2024 The Author(s). Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.)

Background: Prader-Willi syndrome (PWS) is a rare, neurodevelopmental disorder caused by the lack of expression of paternally imprinted genes on chromosome 15q11-13. PWS features a complex behavioral phenotype, including hyperphagia, anxiety, compulsivity, rigidity, repetitive speech, temper outbursts, aggressivity, and skin-picking. Questionnaires exist for measuring hyperphagia, but not for the aggregation of other problems that are distinctive to PWS. A PWS-specific tool is needed for phenotypic research, and to help evaluate treatment efficacy in future clinical trials aimed at attenuating PWS's hyperphagia and related problems. In this 4-phase study, we leveraged our expertise in PWS with feedback from families and specialists to validate the PWS Profile, a novel, informant-based measure of behavioral and emotional problems in this syndrome., Results: The authors developed a bank of 73 items that tapped both common and less frequent but clinically significant problems in PWS (Phase 1). An iterative feedback process with families and stakeholders was used to ensure content and construct validity (Phase 2). After adding, omitting, or revising items, in Phase 3, we pilot tested the measure in 112 participants. Results were reviewed by an international team of PWS specialists and revised again (Phase 3). The final, 57-item Profile was then administered to 761 participants (Phase 4). Principal component factor analyses (n = 873) revealed eight conceptually meaningful factors, accounting for 60.52% of test variance, and were readily interpretated as: Rigidity, Insistence; Aggressive Behaviors; Repetitive Questioning, Speech; Compulsive Behaviors; Depression, Anxiety; Hoarding; Negative Distorted Thinking; and Magical Distorted Thinking. Factors were internally consistent and showed good test-retest reliability and convergent validity with existent measures of behavioral problems. Profile factors were not related to IQ, BMI, or parental SES. Three Profile factors differed across PWS genetic subtypes. Age and gender differences were found in only one Profile factor, Hoarding., Conclusions: The PWS Profile is a valid, psychometrically-sound questionnaire that already has shown responsivity to treatment in a previous clinical trial. The Profile can extend the reach of future clinical trials by evaluating the impact of novel agents not only on hyperphagia, but also on the emotional and behavioral problems that characterize PWS., (© 2024. The Author(s).)

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.

Context: Prader-Willi syndrome (PWS) is a rare genetic disorder characterized by endocrine and neuropsychiatric problems including hyperphagia, anxiousness, and distress. Intranasal carbetocin, an oxytocin analog, was investigated as a selective oxytocin replacement therapy., Objective: To evaluate safety and efficacy of intranasal carbetocin in PWS., Design: Randomized, double-blind, placebo-controlled phase 3 trial with long-term follow-up., Setting: Twenty-four ambulatory clinics at academic medical centers., Participants: A total of 130 participants with PWS aged 7 to 18 years., Interventions: Participants were randomized to 9.6 mg/dose carbetocin, 3.2 mg/dose carbetocin, or placebo 3 times daily during an 8-week placebo-controlled period (PCP). During a subsequent 56-week long-term follow-up period, placebo participants were randomly assigned to 9.6 mg or 3.2 mg carbetocin, with carbetocin participants continuing at their previous dose., Main Outcome Measures: Primary endpoints assessed change in hyperphagia (Hyperphagia Questionnaire for Clinical Trials [HQ-CT]) and obsessive-compulsive symptoms (Children's Yale-Brown Obsessive-Compulsive Scale [CY-BOCS]) during the PCP for 9.6 mg vs placebo, and the first secondary endpoints assessed these same outcomes for 3.2 mg vs placebo. Additional secondary endpoints included assessments of anxiousness and distress behaviors (PWS Anxiousness and Distress Behaviors Questionnaire [PADQ]) and clinical global impression of change (CGI-C)., Results: Because of onset of the COVID-19 pandemic, enrollment was stopped prematurely. The primary endpoints showed numeric improvements in both HQ-CT and CY-BOCS which were not statistically significant; however, the 3.2-mg arm showed nominally significant improvements in HQ-CT, PADQ, and CGI-C scores vs placebo. Improvements were sustained in the long-term follow-up period. The most common adverse event during the PCP was mild to moderate flushing., Conclusions: Carbetocin was well tolerated, and the 3.2-mg dose was associated with clinically meaningful improvements in hyperphagia and anxiousness and distress behaviors in participants with PWS., Clinical Trials Registration Number: NCT03649477., (© The Author(s) 2023. Published by Oxford University Press on behalf of the Endocrine Society.)

Introduction: People with neurodevelopmental disabilities, including Prader-Willi syndrome (PWS), are at heightened risk for the negative sequalae of loneliness, including depression and anxiety. While societal factors such as stigma or limited social opportunities contribute to loneliness, so too do deficits in social cognition and social skills. People with PWS have specific difficulties recognizing affect in others, accurately interpreting social interactions, and taking the perspectives of others. These features, combined with hyperphagia, rigidity, and insistence on sameness conspire to impede the abilities of people with PWS to make and sustain friendships and reduce feelings of loneliness., Methods: We developed and administered an intervention, Building Our Social Skills (BOSS), that aimed to improve social skill deficits in PWS. The 10-week intervention was administered on-line via Zoom to 51 young people with PWS in the U.S. (M age = 20.8, SD = 6.42). Two clinicians co-led groups of 6-8 participants in 30-min sessions, 3 times per week, and also trained 4 graduate students to co-lead groups with high fidelity. We used a pre-post intervention and 3-month follow-up design, with no control group, and mitigated this design limitation by triangulating across informants and methodologies. Specifically, parents completed the widely used Social Responsiveness Scale (SRS) and Child Behavior Checklist (CBCL), and participants were individually interviewed about their friendships and loneliness. Interview responses were reliably coded by independent raters., Results: Repeated measure multivariate analyses, with baseline values entered as covariates, revealed significant pre-to post-test improvements in the SRS's social cognition, motivation and communication subscales ( p 's < 0.001), with large effect sizes ( n p 2 = 0.920, 0.270, and 0.204, respectively). Participant and parental reports of loneliness were correlated with the CBCL's Internalizing domain, specifically the Anxiety/Depressed subdomain. Over time, parents reported getting along better with peers, increased contact with friends, more friends and less loneliness. Participants also reported significantly less loneliness and more friends., Conclusions: This mixed method, proof-of-concept study demonstrated the feasibility of delivering an on-line social skills intervention to young people with PWS. As no differences were found between clinician vs. graduate student outcomes, the BOSS curriculum holds considerable promise for wider dissemination and implementation in the PWS community., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Dykens, Roof, Hunt-Hawkins and McDonald.)

Prader-Willi syndrome (PWS) is a complex genetic disorder with three genetic classes. Patients with PWS are characterized by severe hypotonia, developmental delay, behavioral problems, learning disabilities and morbid obesity in early childhood if untreated. Data were collected through Rare Disease Clinical Research Network (RDCRN) from four study centers which evaluated patients with PWS. The Behavior Assessment System for Children 2nd edition (BASC-2) was chosen to provide behavioral assessment. Data from 330 participants ((64% 15q11-q13 deletion (DEL), 36% maternal disomy 15 (UPD)) were separated into three age groups and analyzed, 68% of whom were still actively receiving recombinant human growth hormone (rhGH) treatment. When comparing the BASC results by molecular subtype, parent-reported aggression was higher for the deletion than for the UPD cohort ( p = 0.007). Participants who were on rhGH treatment showed lower scores for parent-reported hyperactivity and aggression ( p = 0.04, 0.04, respectively), and a trend for anger control ( p = 0.06) and teacher-reported attention problems and aggression ( p = 0.01, 0.004, respectively). Additional adjusted analyses were undertaken and significant differences were noted in the GH versus non-GH treated groups for only teacher-reported aggression, which increased in the No GH treated patient group ( p = 0.03). This study showed documented differences in PWS behavior by molecular class and rhGH treatment. RhGH therapy may be beneficial for certain behaviors in patients with PWS; however, observed differences need more studies for confirmation in the future.

Background: Prader Willi Syndrome (PWS) is a genetic disorder caused by the absence of expression of the paternal copies of maternally imprinted gene(s) located at 15q11-q13. While the physical and medical characteristics of PWS, including short stature, hyperphagia and endocrine dysfunction are well-characterized, systematic investigation of the long-recognized psychiatric manifestations has been recent., Methods: Here, we report on the first remote (web-based) assessment of neurobehavioral traits, including psychosis-risk symptoms (Prodromal Questionnaire-Brief Version; PQ-B) and sleep behaviors (Pittsburgh Sleep Quality Index), in a cohort of 128 participants with PWS, of whom 48% had a paternal deletion, 36% uniparental disomy, 2.4% an imprinting mutation and 13% unknown mutation (mean age 19.3 years ± 8.4; 53.9% female). We aimed to identify the most informative variables that contribute to psychosis-risk symptoms. Multiple domains of cognition (accuracy and speed) were also assessed in a subset of PWS participants ( n = 39) using the Penn Computerized Neurocognitive Battery (Penn-CNB)., Results: Individuals with PWS reported a range of psychosis-risk symptoms, with over half reporting cognitive disorganization (63.1%) and about one third reporting unusual beliefs (38.6%) and/or suspiciousness (33.3%). Subjectively-reported sleep quality, nap frequency, sleep duration, sleep disturbance, and daytime dysfunction were significant predictors of psychosis-risk symptom frequency and severity (all p's < 0.029). Sleep disturbance ratings were the strongest predictors of psychosis-risk symptoms. Regarding cognition, individuals with PWS showed the most prominent deficits in accuracy on measures of social cognition involving faces, namely Face Memory, Age Differentiation and Emotion Recognition, and greatest slowing on measures of Attention and Emotion Recognition. However, there were no significant differences in psychosis-risk symptoms or cognitive performance as a function of PWS genetic subtype., Conclusions: PWS is associated with a high prevalence of distressing psychosis-risk symptoms, which are associated with sleep disturbance. Findings indicate that self/parent-reported neurobehavioral symptoms and cognition can be assessed remotely in individuals with PWS, which has implications for future large-scale investigations of rare neurogenetic disorders., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 O'Hora, Zhang, Vajdi, Kushan-Wells, Huang, Pacheco-Hansen, Roof, Holland, Gur and Bearden.)

Background: Despite work on the self-identities of people with intellectual disabilities, research has yet to describe the self-perceptions of people with Prader-Willi syndrome (PWS). The perspectives of those with PWS are also important for rapidly evolving clinical trials aimed at treating symptoms of PWS., Method: Twenty-one young people with PWS were administered a semi-structured interview that assessed how they perceive their syndrome and clinical trials. Transcribed interviews were reliably coded using content-driven, applied thematic analyses., Results: Five themes emerged: struggles with chronic hunger and food-seeking that impede goals and relationships; struggles with anxiety and outbursts, schedule changes and school; distancing from PWS; needs for clinical trials that cure PWS, reduce hunger or anxiety, and lead to improved outcomes; and needs for advocacy and awareness of PWS., Conclusions: Findings shed new light on the self-perceptions of those with PWS and have important implications for current interventions and future clinical trials., (© 2021 John Wiley & Sons Ltd.)

Hyperphagia and the associated interest in food is a characteristic feature of Prader-Willi syndrome (PWS) that emerges during childhood and remains a life-long concern. This study examined neural responses reflecting food cue salience in children with PWS and typical controls, age 3-12 years. Visual event-related potentials were recorded while participants in satiated state passively viewed photographs of high- and low-calorie foods, animals, and neutral objects. Contrary to the prediction, children with PWS did not demonstrate greater than typical neural responses to food, suggesting that it is not an exceptionally motivationally salient stimulus in PWS. Caregiver reports of greater hyperphagia were associated with neural responses to low-calorie foods suggesting accelerated and more fine-grained visual stimulus categorization in terms of edibility and caloric content. Overall, the findings align more closely with the altered satiety rather than increased food reward models of hyperphagia in PWS., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Prader-Willi syndrome (PWS) is a complex genetic disorder with three molecular classes but clinical ascertainment is based on distinctive features. The prevalence of dysmorphic features was studied in 355 PWS participants (61% deletion, 36% maternal disomy [UPD], and 3% imprinting defects) from the National Institute of Health PWS Rare Diseases Clinical Research Network. The effect of growth hormone (GH) treatment on growth and dysmorphic features was compared. Among participants, upslanting palpebral fissures were seen in 23%; strabismus in 42%; abnormal dentition in 32%; small hands in 63% and small feet in 70%; hypopigmentation in 30%; striae in 32% and skin picking in 26%. Compared to those with UPD, participants with deletions were found to be heavier (p = 0.002), had smaller head circumference (HC) (p = 0.009), higher incidence of a flat occiput (p = 0.005); low-anterior hairline (p = 0.04); abnormal dentition (p = 0.009); abdominal striae (p = 0.045), nail abnormalities (p = 0.050), and fair-haired (p < 0.001). Participants in both genetic groups receiving GH were taller (p = 0.005), had larger HCs (p = 0.005), and longer hands (p = 0.049). This study suggested that PWS genetic subtypes and GH treatment can influence growth and dysmorphic features that may impact clinical diagnosis of PWS, such as stature, head shape and appearance of the eyes, nose, and genitalia., (© 2021 John Wiley & Sons A/S . Published by John Wiley & Sons Ltd.)

Prader-Willi syndrome (PWS) is a rare neurodevelopmental genetic disorder associated with a characteristic behavioral phenotype that includes severe hyperphagia and a variety of other behavioral challenges such as temper outbursts and anxiety. These behaviors have a significant and dramatic impact on the daily functioning and quality of life for the person with PWS and their families. To date, effective therapies addressing these behavioral challenges have proven elusive, but several potential treatments are on the horizon. However, a limiting factor for treatment studies in PWS is the lack of consensus in the field regarding how to best define and measure the complex and interrelated behavioral features of this syndrome. The International PWS Clinical Trials Consortium (PWS-CTC, www.pwsctc.org ) includes expert PWS scientists, clinicians, and patient advocacy organization representatives focused on facilitating clinical trials in this rare disease. To address the above gap in the field, members of the PWS-CTC "Behavior Outcomes Working Group" sought to develop a unified understanding of the key behavioral features in PWS and build a consensus regarding their definition and description. The primary focus of this paper is to present consensus definitions and descriptions of key phenotypic PWS behaviors including hyperphagia, temper outbursts, anxiety, obsessive-compulsive behaviors, rigidity, and social cognition deficits. Patient vignettes are provided to illustrate the interrelatedness and impact of these behaviors. We also review some available assessment tools as well as new instruments in development which may be useful in measuring these behavioral features in PWS.

Prader-Willi syndrome (PWS) is an imprinting genetic disorder characterized by lack of expression of genes on the paternal chromosome 15q11-q13 region. Growth hormone (GH) replacement positively influences stature and body composition in PWS. Our hypothesis was that early diagnosis delays onset of obesity in PWS. We studied 352 subjects with PWS, recruited from the NIH Rare Disease Clinical Research Network, to determine if age at diagnosis, ethnicity, gender, and PWS molecular class influenced the age they first become heavy, as determined by their primary care providers, and the age they first developed an increased appetite and began seeking food. The median ages that children with PWS became heavy were 10 years, 6 years and 4 years for age at diagnosis < 1 year, between 1 and 3 years, and greater than 3 years of age, respectively. The age of diagnosis and ethnicity were significant factors influencing when PWS children first became heavy ( p < 0.01), however gender and the PWS molecular class had no influence. Early diagnosis delayed the onset of becoming heavy in individuals with PWS, permitting early GH and other treatment, thus reducing the risk of obesity-associated co-morbidities. Non-white individuals had an earlier onset of becoming heavy.

Introduction: People with Prader-Willi syndrome (PWS) have a distinctive behavioral phenotype that includes intellectual disability, compulsivity, inattention, inflexibility and insistence on sameness. Inflexibility and inattention are at odds with the cognitive flexibility and attention to social cues needed to accurately perceive the social world, and implicate problems in social cognition. This study assessed two social cognition domains in people with PWS; emotion recognition and social perception. We identified changes in social cognition over an approximate two-year time period (M = 2.23 years), relative strengths and weakness in social cognition, and correlates and predictors of social cognition., Methods: Emotion recognition and social perception were examined at two time points in 94 individuals with PWS aged 5 to 62 years (M = 13.81, SD = 10.69). Tasks administered included: standardized IQ testing; parent-completed measures of inattention and inflexibility; standard emotion recognition photos (fear, sadness, anger, happy); and videotaped social perception vignettes depicting negative events with either sincere/benign or insincere/hostile interactions between peers., Results: An atypical trajectory of negative emotion recognition emerged, marked by similar levels of poor performances across age, and confusion between sad and anger that is typically resolved in early childhood. Recognition of sad and fear were positively correlated with IQ. Participants made gains over time detecting social cues, but not in forming correct conclusions about the intentions of others. Accurately judging sincere intentions remained a significant weakness over time. Relative to sincere intentions, participant's performed significantly better in detecting negative social cues, and correctly judging trickery, deceit and lying. Age, IQ, inattention, and recognition of happy and sad accounted for 29% of variance in social perception., Conclusion: Many people with PWS have deficits in recognizing sad, anger and fear, and accurately perceiving the sincere intentions of other people. The impact of these deficits on social behavior and relationships need to be better understood., Competing Interests: The authors have declared that no competing interests exist.

Introduction: Prader-Willi syndrome (PWS) is a complex genetic disorder associated with three different genetic subtypes: deletion of the paternal copy of 15q11-q13, maternal UPD for chromosome 15 and imprinting defect. Patients are typically diagnosed because of neonatal hypotonia, dysmorphism and feeding difficulties; however, data on the prenatal features of PWS are limited., Objective: The aim of the study was to identify and compare frequencies of prenatal and neonatal clinical features of PWS among the three genetic subtypes., Methods: Data from 355 patients with PWS from the Rare Diseases Clinical Research Network PWS registry were used to analyse multiple maternal and neonatal factors collected during an 8-year multisite study., Results: Among our cohort of 355 patients with PWS (61% deletion, 36% UPD and 3% imprinting defect) 54% were born by caesarean section, 26% were born prematurely and 34% with a low birth weight (frequencies 32%, 9.6% and 8.1%, respectively, in the general population). Fetal movements were reported as decreased in 72%. All babies were hypotonic, and 99% had feeding difficulties. Low Apgar scores (<7) were noted in 17.7% and 5.6% of patients, respectively, compared with 1% and 1.4%, respectively, in the general population. Maternal age and pre-pregnancy weight were significantly higher in the UPD group (p=0.01 and <0.001, respectively)., Conclusion: We found a higher rate of perinatal complications in PWS syndrome compared with the general population. No significant differences in the genetic subtypes were noted except for a higher maternal age and pre-pregnancy weight in the UPD subgroup., Competing Interests: Competing interests: None declared., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Background: Prader-Willi syndrome (PWS) is a genetic neurodevelopmental disorder of life-threatening hyperphagia, obesity, intellectual deficits, compulsivity, and other behavioral problems. The efficacy and safety of i.n. carbetocin, an oxytocin analog, was evaluated in a prospective, randomized, double-blinded trial in adolescents with PWS., Methods: Eligible patients aged 10-18 years with genetically confirmed PWS were randomized (1:1) to i.n. carbetocin or placebo 3 times daily for 14 days. The primary efficacy endpoint was change in parent/caregiver-rated Hyperphagia in PWS Questionnaire-Responsiveness (HPWSQ-R) total score. Secondary efficacy endpoints included HPWSQ-R behavior, drive, and severity domains; clinician-rated HPWSQ; Children's Yale-Brown Obsessive-Compulsive Severity Scale; food domain of the Reiss Profile; and Clinical Global Impression-Improvement scale. Endpoints were assessed using analysis of covariance. Relationship between primary and secondary endpoints was assessed using Pearson correlation coefficients. Safety was assessed throughout the study., Results: Demographics and clinical characteristics were similar between treatment groups (carbetocin, n = 17; placebo, n = 20). Patients receiving carbetocin had statistically significant reductions in HPWSQ-R total score at study end (-15.6) versus patients receiving placebo (-8.9; P = 0.029); several secondary efficacy endpoints also demonstrated significant differences (P < 0.05). Treatment effects for the primary and secondary endpoints were highly correlated (P ≤ 0.0001). Incidence of adverse events (AEs) was similar between treatment groups., Conclusion: I.n. carbetocin was well tolerated and improved hyperphagia and behavioral symptoms of PWS., Trial Registration: ClinicalTrials.gov: NCT01968187FUNDING. The study was funded by Ferring Pharmaceuticals. Recruitment was aided by ongoing work in PWS performed through Eunice Kennedy Shriver National Institute of Child Health and Human Development grant U54 HD083211.

Aims: There are no treatments for the extreme hyperphagia and obesity in Prader-Willi syndrome (PWS). The bestPWS clinical trial assessed the efficacy, safety and tolerability of the methionine aminopeptidase 2 (MetAP2) inhibitor, beloranib., Materials and Methods: Participants with PWS (12-65 years old) were randomly assigned (1:1:1) to biweekly placebo, 1.8 mg beloranib or 2.4 mg beloranib injection for 26 weeks at 15 US sites. Co-primary endpoints were the changes in hyperphagia [measured by Hyperphagia Questionnaire for Clinical Trials (HQ-CT); possible score 0-36] and weight by intention-to-treat. ClinicalTrials.gov registration: NCT02179151., Results: One-hundred and seven participants were included in the intention-to-treat analysis: placebo (n = 34); 1.8 mg beloranib (n = 36); or 2.4 mg beloranib (n = 37). Improvement (reduction) in HQ-CT total score was greater in the 1.8 mg (mean difference -6.3, 95% CI -9.6 to -3.0; P = .0003) and 2.4 mg beloranib groups (-7.0, 95% CI -10.5 to -3.6; P = .0001) vs placebo. Compared with placebo, weight change was greater with 1.8 mg (mean difference - 8.2%, 95% CI -10.8 to -5.6; P < .0001) and 2.4 mg beloranib (-9.5%, 95% CI -12.1 to -6.8; P < .0001). Injection site bruising was the most frequent adverse event with beloranib. Dosing was stopped early due to an imbalance in venous thrombotic events in beloranib-treated participants (2 fatal events of pulmonary embolism and 2 events of deep vein thrombosis) compared with placebo., Conclusions: MetAP2 inhibition with beloranib produced statistically significant and clinically meaningful improvements in hyperphagia-related behaviours and weight loss in participants with PWS. Although investigation of beloranib has ceased, inhibition of MetAP2 is a novel mechanism for treating hyperphagia and obesity., (© 2017 John Wiley & Sons Ltd.)

Background: A small percentage of people with autism spectrum disorders (ASD) have alterations in chromosome 15q11.2-q3, the critical region for Prader-Willi syndrome (PWS). Data are limited, however, on the rates and characteristics of ASD in PWS. Previous estimates of ASD in PWS (25 to 41%) are questionable as they are based solely on autism screeners given to parents. Inaccurate diagnoses of ASD in PWS can mislead intervention and future research., Methods: One hundred forty-six children and youth with PWS aged 4 to 21 years ( M  = 11) were assessed with the Autism Diagnostic Observation Schedule-2 (ADOS-2). An expert clinical team-made best-estimate ASD diagnoses based on ADOS-2 videotapes, calibrated severity scores, and children's developmental histories and indices of current functioning. Children were also administered the Kaufman Brief Intelligence Test-2, and parents completed the Repetitive Behavior Scale-Revised and Vineland Adaptive Behavior Scales. Scores were compared across children with PWS + ASD versus PWS only. The performance of an ASD screener, the Social Communication Questionnaire (SCQ) and the ADOS-2 were evaluated in relation to best-estimate diagnoses., Results: Best-estimate diagnoses of ASD were made in 18 children, or 12.3% of the sample, and the majority of them had the maternal uniparental disomy (mUPD) PWS genetic subtype. Compared to the PWS-only group, children with PWS + ASD had lower verbal and composite IQ's and adaptive daily living and socialization skills, as well as elevated stereotypies and restricted interests. Regardless of ASD status, compulsivity and insistence on sameness in routines or events were seen in 76-100% of children and were robustly correlated with lower adaptive functioning. The SCQ yielded a 29-49% chance that screen-positive cases will indeed have ASD. The ADOS-2 had higher sensitivity, specificity and predictive values. Communication problems were seen in children who were ADOS-2 positive but deemed not to have ASD by the clinical team., Conclusions: Autism screeners should not be the sole index of probable ASD in PWS; children need to be directly observed and evaluated. Compulsivity and insistence on sameness are salient in PWS and likely impede adaptive functioning. Most children with PWS only evidenced sub-threshold problems in social interactions that could signal risks for other psychopathologies.

Background: People with Prader-Willi syndrome (PWS) typically have mild to moderate intellectual deficits, compulsivity, hyperphagia, obesity, and growth hormone deficiencies. Growth hormone treatment (GHT) in PWS has well-established salutatory effects on linear growth and body composition, yet cognitive benefits of GHT, seen in other patient groups, have not been well studied in PWS., Methods: Study 1 included 96 children and youth with PWS aged 4-21 years who naturalistically varied in their exposures to GHT. Controlling for socioeconomic status, analyses compared cognitive and adaptive behavior test scores across age-matched treatment naïve versus growth hormone treated children. Study II assessed if age of treatment initiation or treatment duration was associated with subsequent cognition or adaptive behavior in 127, 4- to 21-year olds with PWS. Study III longitudinally examined cognitive and adaptive behavior in 168 participants who were either consistently on versus off GHT for up to 4-5 years., Results: Compared to the treatment naïve group, children receiving GHT had significantly higher Verbal and Composite IQs, and adaptive communication and daily living skills. Children who began treatment before 12 months of age had higher Nonverbal and Composite IQs than children who began treatment between 1 and 5 years of age. Longitudinally, the groups differed in their intercepts, but not slopes, with each group showing stable IQ and adaptive behavior scores over time., Conclusions: Cognitive and adaptive advantages should be considered an ancillary benefit and additional justification for GHT in people with PWS. Future efforts need to target apparent socioeconomic inequities in accessing GHT in the PWS population., Competing Interests: No conflicts declared., (© 2016 Association for Child and Adolescent Mental Health.)

This paper reports on the 'Prader-Willi Syndrome (PWS) Mental Health Research Strategy Workshop' that took place in March 2015. PWS is characterized by a complex phenotype affecting multiple systems with a high prevalence of maladaptive behaviours, and neuropsychiatric illness. Prader Willi syndrome results from the absence of paternally derived alleles located at the imprinted chromosomal locus, 15q11-13. The goal of the workshop was to highlight the state of the science of the mental health of people with this rare neurodevelopmental disorder. Mental ill health and maladaptive behaviors significantly impact quality of life for persons with PWS and their caregivers. Effective treatments and further research into this area are critically needed., Methods: A multidisciplinary group of scientists and health care professionals were brought together to discuss the mental health and behavioral needs of people with PWS. The workshop strategy was to integrate established work on PWS with other relevant areas of study. The meeting also focused on two neurobiological systems that research had suggested were relevant to understanding the broader mental health aspects of PWS: the autonomic nervous system and oxytocin/vasopressin pathways. Other relevant topics were considered and recommendations made., Results: The workshop presentations and working group discussions revealed that no one approach was sufficient to fully conceptualize the mental health challenges in PWS. Workshop discussions pointed to the need for theoretically informed studies focused on clinical characterization, measurement, and the probing of specific neurobiological systems through pharmaceutical or other interventions. Future studies in this area should explore the use of advanced neuroimaging protocols, as well as molecular studies using iPS cells in order to create more informed theories., Conclusions: Within this framework, workshop participants identified and prioritized key research questions, and highlighted current opportunities. Recommendations were made with respect to the development of specific resources and tools for furthering mental health research such as The Global PWS Registry, the development of effective endpoints, the use of animal models and iPS cells to aid understanding of the neurobiological underpinnings. Additionally, collaborative opportunities across disciplines and syndromes were highlighted and targeted research initiatives focused on psychological/behavioral interventions modified for use in PWS were recommended.

The purpose of the current study was to develop syndrome-specific standardized growth curves for growth hormone-treated Prader-Willi syndrome (PWS) individuals aged 0 to 18 years. Anthropometric growth-related measures were obtained on 171 subjects with PWS who were treated with growth hormone for at least 40% of their lifespan. They had no history of scoliosis. PWS standardized growth curves were developed for 7 percentile ranges using the LMS method for weight, height, head circumference, weight/length, and BMI along with normative 3rd, 50th, and 97th percentiles plotted using control data from the literature and growth databases. Percentiles were plotted on growth charts for comparison purposes. Growth hormone treatment appears to normalize stature and markedly improves weight in PWS compared with standardized curves for non-growth hormone-treated PWS individuals. Growth chart implications and recommended usage are discussed., (© The Author(s) 2016.)

Purpose: Prader-Willi syndrome is an imprinting disorder characterized by typical facial, physical, and cognitive/behavioral features, resulting from lack of paternally expressed genes on chromosome 15q11.2-q13. Studies have suggested an increased risk of other imprinting disorders in children conceived by assisted reproductive techniques. This study was designed to determine the association between assisted reproductive technology and Prader-Willi syndrome., Methods: Data on individuals with Prader-Willi syndrome were collected from three distinct sources and the proportion of assisted reproductive technology births analyzed., Results: The proportions of assisted reproductive technology births in the Prader-Willi Syndrome Association (USA), Rare Diseases Clinical Research Network, and University of California, Irvine Medical Center populations were 1.0% (18/1,736), 1.0% (1/98), and 2.0% (1/50), respectively (overall 1.1%; population frequency for the United States was 1.0%). Of note, 2.4% (45/1,898) of participants were co-twins (11 born after assisted reproductive technology procedures); US twin frequency is 1.6% (P = 0.007). The proportion of individuals with maternal disomy 15/imprinting defects born after assisted reproductive technology was higher than that in the total sample, 55.6% (10/18) and 34.5% (431/1,250), respectively., Conclusion: This study found no association between assisted reproductive technology and Prader-Willi syndrome. There was an increased frequency of twinning. The number of individuals with maternal disomy 15/imprinting defect was nearly double in the assisted reproductive technology group as compared with the total Prader-Willi syndrome participants.

Prader-Willi syndrome (PWS) is well-known for its genetic and phenotypic complexities. Caused by a lack of paternally derived imprinted material on chromosome 15q11-q13, individuals with PWS have mild to moderate intellectual disabilities, repetitive and compulsive behaviors, skin picking, tantrums, irritability, hyperphagia, and increased risks of obesity. Many individuals also have co-occurring autism spectrum disorders (ASDs), psychosis, and mood disorders. Although the PWS 15q11-q13 region confers risks for autism, relatively few studies have assessed autism symptoms in PWS or directly compared social, behavioral, and cognitive functioning across groups with autism or PWS. This article identifies areas of phenotypic overlap and difference between PWS and ASD in core autism symptoms and in such comorbidities as psychiatric disorders, and dysregulated sleep and eating. Though future studies are needed, PWS provides a promising alternative lens into specific symptoms and comorbidities of autism.

Background: Prader-Willi syndrome (PWS) is a genetic, neurodevelopmental disorder characterized by intellectual disabilities, growth hormone dysregulation, hyperphagia, increased risks of morbid obesity, compulsive behaviors, and irritability. As aberrant serotonergic functioning is strongly implicated in PWS, we examined associations between the PWS phenotype and polymorphisms in tryptophan hydroxylase 2 (TPH2), the rate-limiting enzyme in the biosynthesis of serotonin in the brain., Methods: Ninety-two individuals with PWS aged 4 to 50 years (M = 21.97) were genotyped for the TPH2 G703-T polymorphism. IQ testing was conducted in offspring, and parents completed questionnaires that tapped their child's compulsivity, hyperphagia, and other behavior problems., Results: As expected, the frequency of G/T or T/T polymorphisms in participants with PWS (39%) was similar to rates found in the general population (38%). Compared to those with a homozygous (G/G) genotype, individuals with a T allele had significantly higher hyperphagic behavior, drive, and severity scores, and they also had a younger age of onset of hyperphagia. Those with a T allele also had higher IQ scores than their counterparts. Females with a T allele had significantly higher internalizing symptoms, primarily anxiety and depression, than all others., Conclusions: TPH2 G/T polymorphisms, and presumed loss of enzyme function, were associated with specific aspects of the PWS phenotype. Aberrant serotonergic functioning is strongly implicated in hyperphagia in PWS, and females with TPH2 T alleles may be at higher risk for affective or mood disorders. Findings hold promise for examining other serotonin-altering genes in PWS, and for future serotonin-altering treatment trials., (© 2011 The Authors. Journal of Child Psychology and Psychiatry © 2011 Association for Child and Adolescent Mental Health.)

Background: Some behavioral features of Prader-Willi syndrome (PWS) are associated with the major genetic subtypes of this disorder. While most agree that those with maternal uniparental disomy (UPD) have a distinctive cognitive and psychiatric profile, findings are more controversial regarding possible differences among persons who vary in paternal deletion size., Methods: Caregivers of 88 persons with PWS aged 5 to 51 years (M = 22 years) were administered measures of problem behavior, compulsivity, hyperphagia, and adaptive skills. The sample was well characterized as having relatively large, Type I (n = 26) or smaller, Type II (n = 29) deletions, or UPD (n = 33)., Results: No significant behavioral differences were found between the Type I versus Type II deletion groups. Within each genetic subtype, however, differences emerged in how advancing age related to behavior. Although age did not emerge as a significant correlate of behavior in the Type II or UPD groups, in the Type I group age was consistently associated with lower problem behaviors, adaptive skills, and externalizing symptoms., Conclusion: Although differences between deletion subtypes were not found, significant within-subtype differences emerged in relationships between age and behavior. Negative associations between age and behavior in the Type I group only may relate to non-imprinted genes that are deleted in Type I but not Type II cases, including CYFIP1. Altered expression of CYFIP1 is seen in other developmental disabilities, including 15q disorders, and haploinsufficiency of CYFIP1 in Type I PWS cases may be associated with age-related phenotypic effects. Findings underscore the importance of a life-span perspective in phenotypic research.

Objective: Prader-Willi syndrome (PWS), the leading known genetic cause of obesity, is characterized by intellectual disabilities, maladaptive and compulsive behaviors, and hyperphagia. Although complications of obesity resulting from hyperphagia are the leading cause of death in PWS, quantifying this drive for food has long been an unmet research need. This study provides factor-analytic and within-syndrome analyses of a new measure of hyperphagia in PWS., Research Methods and Procedure: A 13-item informant measure, the Hyperphagia Questionnaire, was developed and administered to the parents of 153 persons with PWS, 4 to 51 years of age. The intelligence quotients, genetic subtypes of PWS, and BMIs of offspring were obtained, as were measures of their non-food problem behaviors., Results: Factor analyses with varimax rotation produced three statistically and conceptually robust factors that accounted for 59% of the variance: Hyperphagic Behaviors, Drive, and Severity. Hyperphagic Behavior increased with age, whereas Drive remained stable, and Severity dipped in older adults. Hyperphagic Drive and Severity were positively correlated with non-food behavior problems, and Hyperphagic Drive differentiated the 36% of participants with extreme obesity from those who had overweight/obese (48%) or healthy (16%) BMI classifications., Discussion: The Hyperphagia Questionnaire is a robust tool for relating breakthroughs in the neurobiology of hyperphagia to in vivo food-seeking behavior and for examining the psychological and developmental correlates of hyperphagia in PWS. The Hyperphagia Questionnaire also offers a nuanced, real-life outcome measure for future clinical trials aimed at curbing the life-threatening drive for food in PWS.