A population-based profile of 160 Australians with Prader-Willi syndrome: trends in diagnosis, birth prevalence and birth characteristics

Comparison of perinatal factors in deletion versus uniparental disomy in Prader-Willi syndrome

Prader-Willi syndrome (PWS) is caused by a deficiency of imprinted genes in the 15q11-q13 region and is characterized by prenatal onset of hypotonia, poor feeding, childhood-onset obesity, hyperphagia, short stature, facial dysmorphism, intellectual disability, and behavioral problems. We studied perinatal factors in a cohort of 64 people with PWS resulting from paternal deletion of 15q11-q13 and maternal uniparental disomy (UPD) for chromosome 15. We recruited 34 individuals with deletion and 30 with UPD. We compared the frequency of multiple prenatal and neonatal factors with the general population as well as between the two genetic subtypes. Of the 64 individuals with PWS, fetal movements were decreased in 82.8%, 31.7% were born prematurely, 42.1% by Cesarean section, and 35.9% required oxytocin induction. Apgar scores were low in 34.6%, 96.8% had feeding difficulty, 50% needed tube feeding, and 6.2% subsequently had gastrostomy tube placement. On comparing findings in the deletion versus the UPD groups, we did not find many significant differences. We, however, found a higher maternal age, and also later age at diagnosis in the UPD versus the deletion group. PWS subjects have higher rates of perinatal complications, especially Cesarean section rate, hypotonia, and low Apgar scores compared to the general population. We did not find many differences between the genetic subtypes, except for later age of diagnosis of the UPD 15 group suggesting a milder phenotype. We also found that the mothers in the UPD were older, supporting the hypothesis that UPD results from nondisjunction associated trisomy rescue.

PRADER-WILLI SYNDROME: WHAT IS THE GENERAL PEDIATRICIAN SUPPOSED TO DO? - A REVIEW

OBJECTIVE

To carry out a review about Prader-Willi Syndrome based on the most recent data about the subject and to give recommendation for the general pediatricians for early diagnoses and follow-up.

DATA SOURCES

Scientific articles in the PubMed and SciELO databases. The research was not limited to a specific time period and included all articles in such databases.

DATA SYNTHESIS

The Prader-Willi Syndrome (PWS) is a rare genetic disorder resulting from the loss of imprinted gene expression within the paternal chromosome 15q11-q13. PWS is characterized by endocrine abnormalities, such as growth hormone (GH) deficiency, obesity, central adrenal insufficiency, hypothyroidism, hypogonadism and complex behavioral and intellectual difficulties. PWS individuals also may present other comorbidities, such as sleep disorders, scoliosis, constipation, dental issues and coagulation disorders. The follow-up protocol of the Children's Institute at Universidade de São Paulo is based on four main pillars: diet, exercise, recombinant human growth hormone (rhGH) therapy and behavioral and cognitive issues. The diet must include a caloric restriction of 900 kcal/day, according to the Prader-Willi Eating Pyramid and exercise plan is focused on daily aerobic exercises and postural therapy. The rhGH therapy is highly recommended by the international scientific literature and must be started as soon as the diagnostic is made. The management of behavioral issues is based on strategies to establish routine and rules.

CONCLUSIONS

If the general pediatrician becomes more familiar with PWS, the diagnosis and treatment will start earlier, which is essential to improve the quality of life and care for these individuals.

Newborn screening for Prader-Willi syndrome is feasible: Early diagnosis for better outcomes

Prader-Willi syndrome (PWS), is a complex genetic disease affecting 1/15,000 individuals, characterized by lack of expression of genes on the paternal chromosome 15q11-q13 region. Clinical features include central hypotonia, poor suck, learning and behavior problems, growth hormone deficiency with short stature, hyperphagia, and morbid obesity. Despite significant advances in genetic testing, the mean age for diagnosis in PWS continues to lag behind. Our goal was to perform a pilot feasibility study to confirm the diagnosis utilizing different genetic technologies in a cohort of 34 individuals with genetically confirmed PWS and 16 healthy controls from blood samples spotted and stored on newborn screening (NBS) filter paper cards. DNA was isolated from NBS cards, and PWS testing performed using DNA methylation-specific PCR (mPCR) and the methylation specific-multiplex ligation dependent probe amplification (MS-MLPA) chromosome 15 probe kit followed by DNA fragment analysis for methylation and copy number status. DNA extraction was successful in 30 of 34 PWS patients and 16 controls. PWS methylation testing was able to correctly identify all PWS patients and MS-MLPA was able to differentiate between 15q11-q13 deletion and non-deletion status and correctly identify deletion subtype (i.e., larger Type I or smaller Type II). mPCR can be used to diagnose PWS and MS-MLPA testing to determine both methylation status as well as the type of deletion or non-deletion status from DNA extracted from NBS filter paper. We propose that PWS testing in newborns is possible and could be included in the Recommended Uniform Screening Panel after establishing a validated cost-effective method.

Differences in circulating microRNA signature in Prader-Willi syndrome and non-syndromic obesity

Prader-Willi syndrome (PWS) represents the most common genetic-derived obesity disorder caused by the loss of expression of genes located on the paternal chromosome 15q11.2-q13. The PWS phenotype shows peculiar physical, endocrine and metabolic characteristics compared to those observed in non-syndromic essential obesity. Since miRNAs have now a well-established role in many molecular pathways, including regulatory networks related to obesity, this pilot study was aimed to characterize the expression of circulating miRNAs in PWS compared to essential obesity. The circulating miRNome of 10 PWS and 10 obese subjects, adequately matched for age, BMI and sex, was profiled throughout Genechip miRNA 4.0 microarray analysis. We identified 362 out of 2578 mature miRNAs to be expressed in serum of the studied population. The circulating miRNA signature significantly characterising the two populations include 34 differently expressed RNAs. Among them, miR-24-3p, miR-122 and miR-23a-3p highly differ between the two groups with a FC >10 in obese compared to PWS. In the obese subjects, miR-7107-5p, miR-6880-3p, miR-6793-3p and miR-4258 were associated to the presence of steatosis. A different signature of miRNAs significantly distinguished PWS with steatosis from PWS without steatosis, involving miR-619-5p, miR-4507, miR-4656, miR-7847-3p and miR-6782-5p. The miRNA target GO enrichment analysis showed the different pathway involved in these two different forms of obesity. Although the rarity of PWS actually represents a limitation to the availability of large series, the present study provides novel hints on the molecular pathogenesis of syndromic and non-syndromic obesity.

Children Born Small for Gestational Age: Differential Diagnosis, Molecular Genetic Evaluation, and Implications

Children born small for gestational age (SGA), defined as a birth weight and/or length below -2 SD score (SDS), comprise a heterogeneous group. The causes of SGA are multifactorial and include maternal lifestyle and obstetric factors, placental dysfunction, and numerous fetal (epi)genetic abnormalities. Short-term consequences of SGA include increased risks of hypothermia, polycythemia, and hypoglycemia. Although most SGA infants show catch-up growth by 2 years of age, ∼10% remain short. Short children born SGA are amenable to GH treatment, which increases their adult height by on average 1.25 SD. Add-on treatment with a gonadotropin-releasing hormone agonist may be considered in early pubertal children with an expected adult height below -2.5 SDS. A small birth size increases the risk of later neurodevelopmental problems and cardiometabolic diseases. GH treatment does not pose an additional risk.

Neonatal Features of the Prader-Willi Syndrome; The Case for Making the Diagnosis During the First Week of Life

OBJECTIVE

Early diagnosis is of proven benefit in Prader-Willi syndrome (PWS). We therefore examined key perinatal features to aid early recognition.

METHODS

Data were collected from case records of subjects attending a multi-disciplinary clinic and from a retrospective birth questionnaire.

RESULTS

Ninety patients (54 male-36 female) were seen between 1991-2015, most with paternal deletion (n=56) or maternal isodisomy (n=26). Features included cryptorchidism in 94% males, preterm birth (26%), birthweight <2500 g (24%), polyhydramnios (23%), breech presentation (23%) and need for nasogastric feeding (83%). Reduced fetal movements (FM) were reported in 82.5% patients compared with 4% healthy siblings. Of 35 children born since 1999, 23 were diagnosed clinically within 28 days while diagnosis in 12 was >28 days: 1-12 months in seven; and 3.75-10.5 years in five. Typical PWS features in these 12 infants included hypotonia (100%), feeding difficulties (75%), cryptorchidism (83% males) and reduced FM (66%). Causes other than PWS including neuromuscular disease were considered in nine patients.

CONCLUSION

Neonatal hypotonia, reduced FM, feeding difficulties and cryptorchidism should immediately suggest PWS, yet late diagnosis continues in some cases. Awareness of the typical features of PWS in newborn units is required to allow prompt detection even in the presence of confounding factors such as prematurity.

Intranasal carbetocin reduces hyperphagia in individuals with Prader-Willi syndrome

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.

Analysis of Circulating Mediators of Bone Remodeling in Prader-Willi Syndrome

We tested the hypothesis that the levels of bone remodeling mediators may be altered in Prader-Willi syndrome (PWS). We assessed RANKL, OPG, sclerostin, DKK-1 serum levels, and bone metabolism markers in 12 PWS children (7.8 ± 4.3 years), 14 PWS adults (29.5 ± 7.2 years), and 31 healthy controls matched for sex and age. Instrumental parameters of bone mineral density (BMD) were also evaluated. Lumbar spine BMD Z-scores were reduced in PWS children (P < 0.01), reaching osteopenic levels in PWS adults. PWS patients showed lower 25(OH)-vitamin D serum levels than controls (P < 0.001). Osteocalcin was increased in PWS children but reduced in adults respect to controls (P < 0.005 and P < 0.01, respectively). RANKL levels were higher in both pediatric and PWS adults than controls (P < 0.004), while OPG levels were significantly reduced (P < 0.004 and P < 0.006, respectively). Sclerostin levels were increased in children (P < 0.04) but reduced in adults compared to controls (P < 0.01). DKK-1 levels did not show significant difference between patients and controls. In PWS patients, RANKL, OPG, and sclerostin significantly correlated with metabolic and bone instrumental parameters. Consistently, with adjustment for age, multiple linear regression analysis showed that BMD and osteocalcin were the most important predictors for RANKL, OPG, and sclerostin in children, and GH and sex steroid replacement treatment in PWS adults. We demonstrated the involvement of RANKL, OPG, and sclerostin in the altered bone turnover of PWS subjects suggesting these molecules as markers of bone disease and new potential pharmacological targets to improve bone health in PWS.

Obesity management in Prader-Willi syndrome: current perspectives

Prader-Willi syndrome (PWS) is a complex multisystem disorder due to the absent expression of the paternally active genes in the PWS critical region on chromosome 15 (15q11.2-q13). The syndrome is considered the most common genetic cause of obesity, occurring in 1:10,000-1:30,000 live births. Its main characteristics include neonatal hypotonia, poor feeding, and lack of appetite in infancy, followed by weight gain, lack of satiety, and uncontrolled appetite, frequently after the age of 2-3 years. The clinical picture includes short stature, multiple endocrine abnormalities (hypogonadism, growth hormone/insulin-like growth factor-I axis dysfunction, hypothyroidism, central adrenal insufficiency), dysmorphic features, scoliosis, osteoporosis, mental retardation, and behavioral and psychiatric problems. Subjects with PWS will become severely obese unless their food intake is strictly controlled. Constant and obsessive food seeking behavior can make life very difficult for both the family and caretakers. Prevention of obesity is mandatory in these patients from the first years of life, because once obesity develops it is difficult to maintain the control of food intake. In fact, PWS subjects die prematurely from complications conventionally related to obesity, including diabetes mellitus, metabolic syndrome, sleep apnea, respiratory insufficiency, and cardiovascular disease. The mechanisms underlying hyperphagia in PWS are not completely known, and to date no drugs have proven their efficacy in controlling appetite. Consequently, dietary restriction, physical activity, and behavior management are fundamental in the prevention and management of obesity in PWS. In spite of all available therapeutic tools, however, successful weight loss and maintenance are hardly accomplished. In this context, clinical trials with new drugs have been initiated in order to find new possibilities of a therapy for obesity in these patients. The preliminary results of these studies seem to be encouraging. On the other hand, until well-proven medical treatments are available, bariatric surgery can be taken into consideration, especially in PWS patients with life-threatening comorbidities.

Ethnic and population differences in the genetic predisposition to human obesity

Obesity rates have escalated to the point of a global pandemic with varying prevalence across ethnic groups. These differences are partially explained by lifestyle factors in addition to genetic predisposition to obesity. This review provides a comprehensive examination of the ethnic differences in the genetic architecture of obesity. Using examples from evolution, heritability, admixture, monogenic and polygenic studies of obesity, we provide explanations for ethnic differences in the prevalence of obesity. The debate over definitions of race and ethnicity, the advantages and limitations of multi-ethnic studies and future directions of research are also discussed. Multi-ethnic studies have great potential to provide a better understanding of ethnic differences in the prevalence of obesity that may result in more targeted and personalized obesity treatments.

[Neonatal presentation of Prader-Willi syndrome: A report of five cases]

Prader-Willi syndrome (PWS) is a fingerprint disease caused by the loss of paternally inherited chromosome 15q11.2-q13. In several populations studied, prevalence is estimated to be from 1/10,000 to 1/25,000 births. The disease initially manifests by neonatal hypotonia associated with orality disorders. Secondly, hyperphagia appears with significant obesity and hypogonadism. Motor milestones and language development are delayed, and all individuals have variable degrees of cognitive disability during childhood. Frequently, the most prominent features do not become evident until the later childhood stage, which can lead to underdiagnosis or late diagnosis in early childhood. Because of the long-term implications of this syndrome, it is important to recognize its features as soon as possible so that early counseling of parents and the affected child is possible. The diagnosis is suspected on clinical grounds and confirmed by genetic analysis. Prenatal diagnosis is possible and can be considered in polyhydramnios, decreased fetal active movements, malpresentation, oddly positioned hands and feet, and abnormal fetal heart rhythm. Since PWS can also lead to complications in both pregnancy and labor, proper prenatal diagnosis can also help optimize perinatal care for affected children. We report a series of five newborns for whom PWS was diagnosed in the neonatal period over 6 years. During this period, no prenatal signs of PWS were detected. The incidence in our population was 1/7937 births. The disease was diagnosed on clinical criteria: severe hypotonia, failure to thrive with poor sucking, and dysmorphic and abnormalities of the genitalia. Polyhydramnios was observed in only one case. The delivery was normal for only one patient. All except one were term newborns. There were three males and two females. We noted abnormal fetal heart rate for 80 % of the patients. The birth weight was close to the 10th percentile for two patients, less than the 3rd percentile for two others. All individuals had eutrophic cranial perimeter and four presented peculiar position of fingers. Genetic analyses found a deletion of the paternal chromosome 15 in three patients (60 %) and maternal uniparental disomy for the two others (40 %). The distribution by sex, weight, cranial perimeter, and mutations are those reported in the literature. PWS should be sought in cases of severe neonatal hypotonia, most particularly if it combines dysmorphism, hypogonadism, malposition of the fingers, and suggestive prenatal history. An early diagnosis provides better multidisciplinary care for the patient and family. We have no explanation for the higher incidence of the disease than in the general population. It is possible that this incidence is only fortuitous, but further studies would help to identify potential risk factors for the disease.

Congenital hypothyroidism due to ectopic sublingual thyroid gland in Prader-Willi Syndrome: a case report

Background

Thyroid gland disorders are variably associated with Prader-Willi syndrome (PWS).

Many of the clinical features in newborns with PWS are similar to those found in congenital hypothyroidism (CH).

Case presentation

We report a case of a girl with CH and PWS. At the age of 9 months CH caused by an ectopic sublingual thyroid was diagnosed, and hormone replacement therapy was started. In spite of this treatment a decrease in growth velocity, weight excess and delayed development were observed. At the age of 9 years PWS was suspected on the basis of phenotype and genetic tests confirmed a maternal uniparental disomy of chromosome 15. This is the second reported case of hypothyroidism due to an ectopic sublingual thyroid gland in PWS suggesting that, although rare, an association between CH and PWS may exist. In our case diagnosis of PWS was delayed because mental retardation, hypotonia, obesity and short stature were initially attributed to hypothyroidism.

Conclusions

In this context PWS should be considered in obese children with CH who do not improve adequately with l-thyroxine therapy. Also, thyroid function in all PWS children should be assessed regularly in order to avoid delayed diagnosis of hypothyroidism.

Syndrome specific modules to enhance the Stepping Stones Triple P public health intervention

BACKGROUND

Service responses to behaviour phenotypes include care by expert clinicians, syndrome-specific clinics, disability-specific mental health services and generic mental health services. While these services contribute to care, they are often of limited accessibility.

METHODS

We describe a population-wide public health intervention aimed at increasing the accessibility of services to the target population. Stepping Stones Triple P (SSTP) is a public health intervention of known efficacy in reducing behaviour problems when delivered to parents of children aged 0-12 with mixed developmental disabilities.

RESULTS

The strategy we discuss involves enhancing SSTP with modules for specific causes of developmental disabilities including Down, Fetal Alcohol, Fragile X, Prader-Willi and Williams syndromes.

CONCLUSIONS

We propose that enhancing SSTP with syndrome specific modules will increase the accessibility of support to families who have a child with a specific behaviour phenotype. We suggest that future research should confirm the public health impact of the modified SSTP programme using the RE-AIM framework.

Early diagnosis and care is achieved but should be improved in infants with Prader-Willi syndrome

Background

PWS is a severe neurodevelopmental genetic disorder now usually diagnosed in the neonatal period from hypotonia and feeding difficulties. Our study analyzed the birth incidence and care of infants with early diagnosis.

Methods

Data were collected on 61 infants with a molecular diagnosis of PWS born in 2012 and 2013 in France.

Results

Thirty-eight infants with PWS were born in 2013. The median age at diagnosis was 18 days. Birth incidence calculated for 2013 was 1/21,000 births. No case was diagnosed prenatally, despite 9 amniocenteses, including 4 for polyhydramnios. Five infants had delayed diagnosis, after 3 months of life. For 2 of them, the diagnosis was not suspected at birth and for 3, FISH analysis in the neonatal period was normal, with no further molecular studies. Ninety-three percent of the neonates were hospitalized, and 84% needed nasogastric tube feeding for a median of 38 days. Swallowing assessment was performed for 45%, at a median age of 10 days. Physiotherapy was started for 76% during hospitalization. Eighty percent of those diagnosed within the first 3 months were seen by a pediatric endocrinologist within the first week of life.

Conclusion

Our study is the first to assess the birth incidence of PWS in France, at 1/21,000 births. Some prenatal or neonatal cases remain undiagnosed because of unrecognized clinical signs and the inappropriate choice of the initial molecular test. We also underscore the need to optimize neonatal care of infants with PWS.

Effects of exenatide on weight and appetite in overweight adolescents and young adults with Prader-Willi syndrome

BACKGROUND

Prader-Willi syndrome (PWS) is associated with hyperphagia and hyperghrelinemia with major morbidity because of obesity without effective medical treatment targeting hyperphagia. Exenatide (Byetta [synthetic Exendin-4]; AstraZeneca, Wilmington DE) is a GLP-1 receptor agonist which reduces appetite and weight and may be an effective treatment in PWS.

OBJECTIVE

The objective of this study is to determine the effect of a 6-month trial of exenatide on appetite, weight and gut hormones in youth with PWS.

METHODS

Ten overweight and obese subjects with PWS (13-25 years) were recruited for a 6-month open-label, non-randomized, longitudinal study conducted at Children's Hospital Los Angeles. Exenatide was given using standard diabetes dosing without dietary modifications. Weight, body mass index (BMI), truncal fat, appetite and plasma acylated ghrelin were measured over 6 months. Mixed meal tolerance tests were performed at 0 and 6 months.

RESULTS

Appetite scores significantly decreased from baseline (32.2 ± 8.7) after 1, 3 and 6 moths of treatment (27.5 ± 8.8, 25.4 ± 9.3, and 25.4 ± 7.2 respectively; p = 0.004). Hemoglobin A1c decreased significantly after treatment, but weight, BMI z-score and adiposity did not. There was no significant change in ghrelin.

CONCLUSIONS

This is the first longitudinal investigation of the effects of exenatide in subjects with PWS. It was effective in decreasing appetite, without change in weight or BMI in the short term. Larger, controlled, longer-term trials in patients with PWS are needed to confirm the efficacy and safety of exenatide and to evaluate whether its use might induce weight loss when given in conjunction with behavioural modification.

Applying Precision Public Health to Prevent Preterm Birth

Preterm birth (PTB) is one of the major health-care challenges of our time. Being born too early is associated with major risks to the child with potential for serious consequences in terms of life-long disability and health-care costs. Discovering how to prevent PTB needs to be one of our greatest priorities. Recent advances have provided hope that a percentage of cases known to be related to risk factors may be amenable to prevention; but the majority of cases remain of unknown cause, and there is little chance of prevention. Applying the principle of precision public health may offer opportunities previously unavailable. Presented in this article are ideas that may improve our abilities in the fields of studying the effects of migration and of populations in transition, public health programs, tobacco control, routine measurement of length of the cervix in mid-pregnancy by ultrasound imaging, prevention of non-medically indicated late PTB, identification of pregnant women for whom treatment of vaginal infection may be of benefit, and screening by genetics and other “omics.” Opening new research in these fields, and viewing these clinical problems through a prism of precision public health, may produce benefits that will affect the lives of large numbers of people.

Diagnosis and treatment of GH deficiency in Prader-Willi syndrome

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

Subclinical dysphagia in persons with Prader-Willi syndrome

Prader-Willi Syndrome (PWS) is caused by a genetic imprinting abnormality resulting from the lack of expression of the paternal genes at 15q11-q13. Intellectual disability, low muscle tone, and life-threatening hyperphagia are hallmarks of the phenotype. The need for the Heimlich maneuver, death from choking, and pulmonary infection occur in a disproportionally high number of persons with PWS. The widely held belief is that eating behaviors are responsible for choking and aspiration; yet, no investigation had sought to determine if swallowing impairments were present in persons with PWS. To address this research and clinical gap, simultaneous videofluoroscopy and nasal respiratory signals were used to record swallowing function and breathing/swallowing coordination in 30 participants with PWS. Subjects consumed thin liquid and barium cookies under two randomized conditions as follows: (i) controlled (cues to swallow and standardized bolus sizes); (ii) spontaneous (no cues or bolus size control). Under videofluoroscopy, the cohort showed disordered pharyngeal and esophageal swallowing in both conditions with disturbances in timing, clearance, and coordination of swallowing with the respiratory cycle. No participant showed a sensory response such as attempting to clear residue or coughing; thereby supporting the lack of overt symptoms. We conclude that the high death rate from choking and pulmonary infection in children and adults with PWS may be related, in part, to underlying, asymptomatic dysphagia. The combination of rapid eating and dysphagia would increase the risk of aspiration-related morbidity and mortality. © 2016 Wiley Periodicals, Inc.

Beneficial Effect of Growth Hormone Treatment on Health-Related Quality of Life in Children with Prader-Willi Syndrome: A Randomized Controlled Trial and Longitudinal Study

BACKGROUND/AIMS

Growth hormone (GH) treatment is beneficial for children with Prader-Willi syndrome (PWS), but data about health-related quality of life (HRQOL) and effects of GH treatment are scarce. We, therefore, investigated the effects of GH treatment on HRQOL in PWS children.

METHODS

In a randomized controlled GH trial including 26 PWS children and during an 11-year longitudinal GH study in 76 children, we annually assessed HRQOL recorded by patients and parents, using a generic questionnaire (DUX25), containing 4 subdomains (Physical, Home, Social, and Emotional) and a PWS-specific questionnaire (DUXPW).

RESULTS

At baseline, PWS children rated HRQOL similar to or higher than healthy and obese children. GH-treated children reported an increase in HRQOL in the Physical and Social subdomains and the DUXPW compared to untreated children. Parents reported an increase in the Physical and Emotional subdomains and borderline in the total DUX25 compared to parents of untreated children. During the 11 years of GH treatment, the Physical subdomain continued to improve, according to parents, whereas the Home, Social and Emotional subdomains, the total DUX25, and the DUXPW remained similar, according to children and parents.

CONCLUSIONS

PWS children rated HRQOL equally to or better than healthy and obese children. HRQOL increased during GH treatment, in contrast to HRQOL of untreated children. This effect was sustained during long-term GH treatment. PWS children consider themselves quite happy, despite some difficulties related to the syndrome.

Understanding the causes of obesity in children with trisomy 21: hyperphagia vs physical inactivity

BACKGROUND

Individuals with intellectual disabilities are at increased risk of becoming overweight or obese. This is particularly evident in people with trisomy 21 and Prader-Willi syndrome (PWS). Although metabolic factors are known to contribute to obesity in trisomy 21 and hyperphagia plays a primary role in PWS, hyperphagia has not yet been investigated as a possible contributing factor to obesity in trisomy 21.

METHODS

Participants comprised three diagnostic groups: trisomy 21 (T21 group), PWS (PWS group) and lifestyle-related obesity (LRO group). They were required to be aged 6-18 years and have a body mass index over the 85th percentile for age and gender. A parent of each participant completed the Hyperphagia Questionnaire and the Children's Leisure Activity Study Survey. Mean scores for each domain and across all domains of the Hyperphagia Questionnaire and the Children's Leisure Activity Study Survey were compared between diagnostic groups using linear regression analysis.

RESULTS

The study group consisted of 52 young people (23 men and 29 women) aged 6-18 years (mean 12.5 years; T21 group n = 17, PWS group n = 16 and LRO group n = 19). As hypothesised, the PWS group had the highest mean scores across all domains of the Hyperphagia Questionnaire, and the LRO group had the lowest. Food-seeking behaviour was more pronounced in the PWS group than the T21 group (mean score 13.2 vs. 8.6, p = 0.008). The LRO group spent more hours per week engaged in physical activity (14.7) in comparison with the other groups (9.6 and 9.7), whereas between the groups, differences in time spent in sedentary activities were less pronounced.

CONCLUSIONS

Preoccupation with food and low levels of physical activity may contribute to the development of overweight and obesity in some individuals with trisomy 21. These factors warrant consideration in the clinical context.

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

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

Unaltered ratio of circulating levels of growth hormone/GH isoforms in adults with Prader-Willi syndrome after GHRH plus arginine administration

Human growth hormone (GH) is a heterogeneous protein hormone consisting of several isoforms, the most abundant being 22 kDa- and 20 kDa-GH. The availability of analytical methods to measure these GH isoforms might represent a valuable diagnostic tool to investigate GH hyposecretory states, including Prader-Willi syndrome (PWS), one of the most common causes of syndromic obesity. The aim of the present study was to measure circulating levels of 22 kDa- and 20 kDa-GH in PWS adults (n=14; M/F: 5/9; genotype DEL15/UPD15: 12/2; age: 19.0±3.7 years; BMI: 29.9±8.7 kg/m2) after combined GH releasing hormone (GHRH) plus arginine (ARG) administration. The results were analysed subdividing the study population in obese vs. nonobese (6/8) and GH deficient vs. nonGH deficient (GHD) (6/8) subjects, according to appropriate BMI-related diagnostic cut-off limits of GH peak response to the provocative test. Circulating levels of 22 kDa-GH were measured by a chemiluminescent method based on a detection monoclonal antibody targeting an epitope in the loop connecting helix 1 and 2 of GH, which is missing in 20 kDa-GH; the 20 kDa-GH was measured using a time resolved fluorescence assay based on two monoclonal antibodies with no cross-reactivity to 22-kDa GH. GHRH plus ARG significantly stimulated the secretions of 22 kDa- and 20 kDa-GH in nonobese (at 30, 45, 60 and 90 min and at 45, 60, 90 and 120 min vs. 0 min, p<0.05, with GH peaks of 15.8±10.3 ng/ml and 2.7±1.2 ng/ml, respectively) and in nonGHD PWS (at 30, 45 and 60 min and at 45, 60 and 90 min vs 0 min, p<0.05, with GH peaks of 12.5±9.0 ng/ml and 2.0±1.8 ng/ml, respectively). No significant GHRH plus ARG-induced changes in 22 kDa- and 20 kDa-GH were observed in obese or GHD PWS patients, the only exception being the increase of 22 kDa-GH (p<0.05) 60 min after the stimulus administration in GHD group (with GH peaks of 6.9±4.7 ng/ml and 0.8±0.6 ng/ml in obese subjects and 8.5±6.0 ng/ml and 1.2±1.0 ng/ml in GHD subjects for 22 kDa- and 20 kDa-GH, respectively). The GH responses for both isoforms were significantly higher in nonobese than in obese PWS patients (at 45 and 60 min for 22 kDa-GH and at 45, 60, 90 and 120 min for 20 kDa-GH, p<0.05), while no differences were detected between GHD vs. nonGHD groups. As previously reported in healthy subjects, the ratios of circulating levels of 22 kDa- to 20 kDa-GH remained constant after GHRH plus ARG both in obese/non-obese and GHD/non-GHD groups, thus suggesting the preservation of a normal balance in GH isoforms in PWS.