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.

INTRODUCTION:Prader-Willi syndrome (PWS) is a complex genetic condition characterized by hyperphagia, hypotonia, low muscle mass, excess body fat, developmental delays, intellectual disability, behavioral problems, and growth hormone deficiency. This study evaluated the safety and efficacy of orally administered Diazoxide Choline Controlled-Release Tablets (DCCR) in subjects with PWS. METHOD:This was a single-center, Phase II study and included a 10-week Open-Label Treatment Period during which subjects were dose escalated, followed by a 4-week Double-Blind, Placebo-Controlled Treatment Period. RESULTS:Five female and eight male overweight or obese, adolescent and adult subjects with genetically-confirmed PWS with an average age of 15.5±2.9 years were enrolled in the study. There was a statistically significant reduction in hyperphagia at the end of the Open-Label Treatment Period (-4.32, n = 11, p = 0.006). The onset of effect on hyperphagia was rapid and greater reductions in hyperphagia were seen in subjects with moderate to severe Baseline hyperphagia (-5.50, n = 6, p = 0.03), in subjects treated with the highest dose (-6.25, n = 4, p = 0.08), and in subjects with moderate to severe Baseline hyperphagia treated with the highest dose (-7.83, n = 3, p = 0.09). DCCR treatment resulted in a reduction in the number of subjects displaying aggressive behaviors (-57.1%, n = 10, p = 0.01), clinically-relevant reductions in fat mass (-1.58 kg, n = 11, p = 0.02) and increases in lean body mass (2.26 kg, n = 11, p = 0.003). There was a corresponding decrease in waist circumference, and trends for improvements in lipids and insulin resistance. The most common adverse events were peripheral edema and transient increases in glucose. Many of the adverse events were common medical complications of PWS and diazoxide. CONCLUSION:DCCR treatment appears to address various unmet needs associated with PWS, including hyperphagia and aggressive behaviors in this proof-of-concept study. If the results were replicated in a larger scale study, DCCR may be a preferred therapeutic option for patients with PWS.

Background

Prader-Willi syndrome (PWS) is a complex genetic disorder with errors in genomic imprinting, generally due to a paternal deletion of chromosome 15q11-q13 region. Maternal disomy 15 (both 15s from the mother) is the second most common form of PWS resulting from a trisomic zygote followed by trisomy rescue in early pregnancy and loss of the paternal chromosome 15. However, trisomy 15 or mosaicism for trisomy 15 may be present in the placenta possibly leading to placental abnormalities affecting gestational age and delivery.

Methods and subjects

We examined growth and gestational data from 167 PWS infants (93 males and 74 females; 105 infants with 15q11-q13 deletion and 62 infants with maternal disomy 15) to determine if there are differences in gestation between the two genetic subtypes.

Results

No significant differences in growth data (birth weight, length, head circumference) or average gestational ages were found between the two genetic subgroups. However, post-term deliveries (> 42 weeks gestation) were more common in the maternal disomy group (i.e., 12 of 62 infants) compared with the deletion group (i.e., 7 of 105 infants) (chi-square test = 6.22; p < 0.02). The distribution of gestational ages in the 15q11-q13 deletion group was more bell-shaped or normal while the distribution in the maternal disomy group suggested a bimodal pattern.

Conclusions

Maternal disomy 15 in PWS may contribute to disturbances in gestational age and delivery by impacting on placental structure or function secondary to the abnormal chromosomal number in the placental cells or in mechanisms leading to the maternal disomy status in PWS infants.

Craniosynostosis is a defect of the skull caused by early fusion of one or more of the cranial sutures and affects 3 to 5 individuals per 10,000 live births. Craniosynostosis can be divided into two main groups: syndromic and nonsyndromic. Nonsyndromic craniosynostosis is typically an isolated finding that is classified according to the suture(s) involved. Syndromic craniosynostosis is associated with various dysmorphisms involving the face, skeleton, nervous system, and other anomalies and is usually accompanied by developmental delay. More than 180 syndromes exist that contain craniosynostosis. Secondary effects of craniosynostosis may include vision problems and increased intracranial pressure, among others. The molecular basis of many types of syndromic craniosynostosis is known, and diagnostic testing strategies will often lead to a specific diagnosis.

Prader-Willi syndrome (PWS) is a rare, complex multisystem genetic disorder which includes hypothalamic dysfunction, hyperphagia, cognitive and behavioral problems, increased anxiety, and compulsive behaviors. Individuals with PWS have a deficit of oxytocin producing neurons in the paraventricular nucleus of the hypothalamus. Oxytocin plays a role in regulation of feeding behaviors, social interactions, and emotional reactivity, which are all issues that significantly affect the quality of life for individuals with this syndrome. We performed a double-blind, placebo-controlled, crossover study in 24 children with PWS at three academic institutions using 5 days of intranasal oxytocin (IN-OT) or 5 days of intranasal placebo spray, followed by a 4 week washout period, and then patients returned for 5 days of treatment with the alternate source. Questionnaires, including the Aberrant Behavior Checklist, Social Responsiveness Scale, Repetitive Behavior Scale - Revised, and the Hyperphagia Questionnaire, as well as Clinical Global Impression scales were administered. Blood testing for sodium, potassium, and glucose levels on days 2, 4, and 6, and a 24 hr diet recall. All scales factor improvement from Day 3 to Day 6 favored oxytocin over placebo. No single factor showed a statistically significant difference (P < 0.05) between groups at Day 6. The drug effect appeared to be diminished at Day 14. There was no evidence of a difference between oxytocin and placebo in safety lab parameters, 60 min post dose vital signs, weight, or diet parameters. The results from this study suggest that low dose intranasal oxytocin is safe for individuals with PWS and may result in reduction in appetite drive, and improvements in socialization, anxiety, and repetitive behaviors. Further, long-term studies with a larger population of participants are necessary to confirm these findings. The results of this study are encouraging that oxytocin may be a safe and effective treatment for many of the issues that negatively impact individuals with PWS.

Prader-Willi syndrome (PWS) affects 1/15,000-1/30,000 live births and is characterized by lack of expression of paternally inherited genes on 15q11.2-15q13 caused by paternal deletions, maternal uniparental disomy (UPD), or imprinting defects. Affected individuals have distinct physical features, and growth hormone (GH) deficiency occurs in some individuals with PWS. The aim of this study is to test the hypotheses that (a) individuals with deletions and UPD have different physical and dysmorphic features, (b) individuals treated with GH have different physical and dysmorphic features than those not treated, and (c) GH treatment effects are different for individuals with UPD in comparison to those with deletions. Study participants included 30 individuals with deletions or UPD, who did or did not have GH treatment. Participants' molecular abnormalities were determined by molecular and cytogenetic analysis. Clinical data were obtained by a single dysmorphologist. Individuals with deletions were found to be heavier (p = .001), taller (p = .031), with smaller head circumferences (p = .042) and were more likely to have fair skin and hair than their family members (p = .031, .049, respectively) compared to UPD patients. Females with deletions more commonly had hypoplastic labia minora (p = .009) and clitoris (.030) in comparison to those with UPD. Individuals who received GH in both deletion and UPD groups were taller (p = .004), had larger hands (p = .011) and feet (p = .006) and a trend for a larger head circumference (p = .103). Interestingly, the GH-treated group also had a lower rate of strabismus (esotropia [p = .017] and exotropia [p = .039]). This study showed statistically significant correlations between phenotype and molecular subtypes and also between phenotype and GH treatment.

Prader-Willi syndrome (PWS) is a multi-system disorder resulting from a lack of paternal gene expression in the 15q11.2-q13 region. Using databases compiled through response questionnaires completed by families known to the Prader-Willi Syndrome Association (USA), this study tested the hypothesis that PWS genetic subtype, BMI, age of diagnosis, clinical symptoms, and growth hormone treatment differ among deceased and living individuals with PWS. Categorical and continuous variables were compared using chi-square and two-group t tests, respectively. Deceased individuals had higher rates of clinical features, including increased weight concerns, heart problems, sleep apnea, other respiratory complications, diabetes, osteoporosis, high pain tolerance, and severe skin picking, when compared to living individuals. Meanwhile, living individuals had higher rates of growth hormone use and early puberty. Obesity and subsequent consequences are the primary contributors to increased mortality in PWS. Additional emphasis on areas to decrease mortality is needed.

Objective

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

Methods

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

Results

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

Conclusions

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

Prader-Willi syndrome (PWS) is a genomic imprinting disorder characterized by infantile hypotonia with a poor suck and failure to thrive, hypogenitalism/hypogonadism, behavior and cognitive problems, hormone deficiencies, hyperphagia, and obesity. The Stanford Binet and Wechsler (WAIS-R; WISC-III) intelligence (IQ) tests were administered on 103 individuals with PWS from two separate cohorts [University of California, Irvine (UCI) (N = 56) and Vanderbilt University (N = 47)] and clinical information obtained including growth hormone (GH) treatment, PWS molecular classes, weight and height. Significantly higher IQ scores (p < .02) were found representing the vocabulary section of the Stanford Binet test in the growth hormone (GH) treated group when compared with non-GH treatment in the pediatric-based UCI PWS cohort with a trend for stabilization of vocabulary IQ scores with age in the GH treated maternal disomy (UPD) 15 subject group. Significant differences (p = .05) were also found in the adult-based Vanderbilt PWS cohort with 15q11-q13 deletion subjects having lower Verbal IQ scores compared with UPD 15. No difference in body mass index was identified based on the PWS molecular class or genetic subtype. Medical care and response to treatment with growth hormone may influence intelligence impacted by PWS genetic subtypes and possibly age, but more studies are needed.