Plasma adiponectin level and sleep structures in children with Prader-Willi syndrome

Sleep and Circadian Disturbances in Children With Neurodevelopmental Disorders

Sleep problems are highly prevalent in those with neurodevelopmental disorders (NDDs). We propose this is secondary to multiple factors that directly and indirectly negatively impact sleep and circadian processes in those with NDDs, which in turn, further perturbs development, resulting in a "developmental and sleep/circadian-related encephalopathy." In this review, we discuss select NDDs with known or suspected sleep and circadian phenotypes. We also highlight important considerations when evaluating and treating sleep and circadian disorders in these populations.

Preserved Sleep for the Same Level of Respiratory Disturbance in Children with Prader-Willi Syndrome

Debate remains as to how to balance the use of recombinant human growth hormone (rhGH) as an important treatment in Prader-Willi syndrome (PWS) with its potential role in obstructive sleep apnea. This single-center, retrospective study assessed differences in overnight polysomnography results between children with and without PWS and changes in respiratory parameters before and after the initiation of rhGH treatment in those with PWS. Compared with age-, sex-, and body-mass-index-matched controls (n = 87), children with PWS (n = 29) had longer total sleep time (434 ± 72 vs. 365 ± 116 min; p < 0.01), higher sleep efficiency (86 ± 7 vs. 78 ± 15%; p < 0.05), and lower arousal events (8.1 ± 4.5 vs. 13.0 ± 8.9 events/h; p < 0.05). Mean oxygen saturation was lower in PWS children (94.3 ± 6.0 vs. 96.0 ± 2.0%; p < 0.05), with no other differences in respiratory parameters between groups. Eleven children with PWS (38%) met the criteria for further analyses of the impact of rhGH; polysomnography parameters did not change with treatment. Compared with other children undergoing polysomnography, children with PWS had more favorable markers of sleep continuity and lower oxygen saturation for the same level of respiratory disturbance. rhGH administration was not associated with changes in respiratory parameters in PWS.

Diagnosis and management of sleep disorders in Prader-Willi syndrome

Clinical experience and a growing body of evidence suggest that sleep disturbances are common in people with Prader-Willi syndrome (PWS). PWS is a rare neuroendocrine disorder characterized by early hypotonia and feeding difficulties; developmental delays; endocrinopathies; and behavioral concerns, especially rigidity, anxiety, and behavioral outbursts. PWS is also characterized by decreased resting energy expenditure and transition to hyperphagia and obesity. We propose that, for many people with PWS, clinical diagnosis and management of sleep disorders is an unmet need. We present current information to suggest disordered sleep is a significant burden for individuals with PWS and often overlooked. While central and obstructive sleep apnea are more widely recognized in PWS, other sleep disorders have increasingly gained recognition, including hypersomnia, narcolepsy-like phenotypes, and insomnia. Sleep disorders can impact behavior, cognition, and quality of life and health for individuals with PWS. Our goal is to bring sleep disorders to the forefront of therapeutic intervention for patients with PWS. This paper presents a review of the literature and recommendations for clinical practice based on published research and our clinical experience as sleep specialists, geneticists, psychiatrists, pediatricians, otolaryngologists, and pulmonologists with extensive experience with this patient population. We recommend that management of sleep be considered an integral part of successful medical management of PWS. Further research concerning sleep problems in PWS is urgently needed to develop best practices and work toward a consensus statement for medical management to meet the needs of people with PWS.

CITATION

Duis J, Pullen LC, Picone M, et al. Diagnosis and management of sleep disorders in Prader-Willi syndrome. J Clin Sleep Med. 2022;18(6):1687-1696.

Baby food and bedtime: Evidence for opposite phenotypes from different genetic and epigenetic alterations in Prader-Willi and Angelman syndromes

Prader–Willi and Angelman syndromes are often referred to as a sister pair of neurodevelopmental disorders, resulting from different genetic and epigenetic alterations to the same chromosomal region, 15q11-q13. Some of the primary phenotypes of the two syndromes have been suggested to be opposite to one another, but this hypothesis has yet to be tested comprehensively, and it remains unclear how opposite effects could be produced by changes to different genes in one syndrome compared to the other. We evaluated the evidence for opposite effects on sleep and eating phenotypes in Prader–Willi syndrome and Angelman syndrome, and developed physiological–genetic models that represent hypothesized causes of these differences. Sleep latency shows opposite deviations from controls in Prader–Willi and Angelman syndromes, with shorter latency in Prader–Willi syndrome by meta-analysis and longer latency in Angelman syndrome from previous studies. These differences can be accounted for by the effects of variable gene dosages of UBE3A and MAGEL2, interacting with clock genes, and leading to acceleration (in Prader–Willi syndrome) or deceleration (in Angelman syndrome) of circadian rhythms. Prader–Willi and Angelman syndromes also show evidence of opposite alterations in hyperphagic food selectivity, with more paternally biased subtypes of Angelman syndrome apparently involving increased preference for complementary foods (“baby foods”); hedonic reward from eating may also be increased in Angelman syndrome and decreased in Prader–Willi syndrome. These differences can be explained in part under a model whereby hyperphagia and food selectivity are mediated by the effects of the genes SNORD-116, UBE3A and MAGEL2, with outcomes depending upon the genotypic cause of Angelman syndrome. The diametric variation observed in sleep and eating phenotypes in Prader–Willi and Angelman syndromes is consistent with predictions from the kinship theory of imprinting, reflecting extremes of higher resource demand in Angelman syndrome and lower demand in Prader–Willi syndrome, with a special emphasis on social–attentional demands and attachment associated with bedtime, and feeding demands associated with mother-provided complementary foods compared to offspring-foraged family-type foods.

Sleep in Neurodevelopmental Disorders

Individuals with intellectual and developmental disabilities (IDD) experience sleep problems at higher rates than the general population. Although individuals with IDD are a heterogeneous group, several sleep problems cluster within genetic syndromes or disorders. This review summarizes the prevalence of sleep problems experienced by individuals with Angelman syndrome, Cornelia de Lange syndrome, Cri du Chat syndrome, Down syndrome, fragile X syndrome, Prader-Willi syndrome, Smith-Magenis syndrome, Williams syndrome, autism spectrum disorder, and idiopathic IDD. Factors associated with sleep problems and the evidence for sleep treatments are reviewed for each neurodevelopmental disorder. Sleep research advancements in neurodevelopmental disorders are reviewed, including the need for consistency in defining and measuring sleep problems, considerations for research design and reporting of results, and considerations when evaluating sleep treatments.

Sleep, plasticity and the pathophysiology of neurodevelopmental disorders: the potential roles of protein synthesis and other cellular processes

Sleep is important for neural plasticity, and plasticity underlies sleep-dependent memory consolidation. It is widely appreciated that protein synthesis plays an essential role in neural plasticity. Studies of sleep-dependent memory and sleep-dependent plasticity have begun to examine alterations in these functions in populations with neurological and psychiatric disorders. Such an approach acknowledges that disordered sleep may have functional consequences during wakefulness. Although neurodevelopmental disorders are not considered to be sleep disorders per se, recent data has revealed that sleep abnormalities are among the most prevalent and common symptoms and may contribute to the progression of these disorders. The main goal of this review is to highlight the role of disordered sleep in the pathology of neurodevelopmental disorders and to examine some potential mechanisms by which sleep-dependent plasticity may be altered. We will also briefly attempt to extend the same logic to the other end of the developmental spectrum and describe a potential role of disordered sleep in the pathology of neurodegenerative diseases. We conclude by discussing ongoing studies that might provide a more integrative approach to the study of sleep, plasticity, and neurodevelopmental disorders.

Serum omentin levels in patients with obstructive sleep apnea

BACKGROUND

Obstructive sleep apnea syndrome (OSAS) is associated with increased rates of cardiovascular diseases (CVD). The basic mechanisms involved in the increased cardiovascular risk of OSAS remain unclear. Recent discoveries of fat-secreted substances which serve endocrine roles improve our understanding of the relationship between OSAS, CVD, and the metabolic syndrome. In this study, we aimed to examine associations between omentin levels and OSA.

METHODS

Forty-six newly diagnosed OSA patients and 35 non-apneic controls were enrolled in this study. Demographical data, cigarette smoking status, previous history of chronic diseases including CVD and metabolic diseases and drugs, and habits were obtained using a standardized questionnaire. All patients underwent polysomnographic evaluation. Omentin was measured the following morning.

RESULTS

The mean age was 48.1 ± 12.5 (24-74) years in the OSA group and 42.8 ± 14.1 (21-69) years in the control group. Of the 81 patients, 46 (34 males and 12 females) were classified as having OSA and 35 patients (20 males and 15 females) as control. Plasma levels of omentin were found to be markedly higher in OSA patients (570.8 ng/ml) than in the control group (432.0 ng/ml; p < 0.001). In addition, plasma levels of omentin were found to be high in all OSA subgroups than in controls. The plasma omentin levels were significantly correlated only with age in patients with OSA.

CONCLUSIONS

We conclude that circulating omentin levels are elevated in OSA patients. To the best of our knowledge, this is the first clinical study that demonstrated the association between omentin and OSA.

Nocturnal sleep measured by actigraphy in children with Prader-Willi syndrome

OBJECTIVE

To assess nocturnal sleep duration by actigraphy in children with Prader-Willi syndrome (PWS).

STUDY DESIGN

Baseline measurements including height, weight, and body mass index (BMI) were collected on 8 children with PWS (6 boys) with each subject age- and sex-matched to 2 control children. From 7 consecutive nights of actigraphy data, values for total sleep time (TST), sleep efficiency, sleep latency (SL), number of awakenings after sleep onset, and duration of awakenings after sleep onset (WASO) were extracted. Parents also completed a sleep diary and questionnaire during this period.

RESULTS

Subjects with PWS ranged from 4.2 to 15.4 years, and they had a lower height z score and higher BMI z score compared with controls. The PWS group had a shorter SL (P = .0007), longer WASO (P = .009), and higher daytime sleepiness score. TST, sleep efficiency, and number of awakenings after sleep onset were not significantly different between the groups, and subjects with PWS did not wake earlier than controls. There was no correlation between WASO and BMI or between WASO and sleepiness score.

CONCLUSION

Children with PWS appear to have a shorter SL but more time awake in the night than normal children and have similar TST and morning wake time compared with controls.

Hypothalamic obesity in children

Hypothalamic obesity is an intractable form of obesity syndrome that was initially described in patients with hypothalamic tumours and surgical damage. However, this definition is now expanded to include obesity developing after a variety of insults, including intracranial infections, infiltrations, trauma, vascular problems and hydrocephalus, in addition to acquired or congenital functional defects in central energy homeostasis in children with the so-called common obesity. The pathogenetic mechanisms underlying hypothalamic obesity are complex and multifactorial. Weight gain results from damage to the ventromedial hypothalamus, which leads, variously, to hyperphagia, a low-resting metabolic rate; autonomic imbalance; growth hormone-, gonadotropins and thyroid-stimulating hormone deficiency; hypomobility; and insomnia. Hypothalamic obesity did not receive enough attention, as evidenced by rarity of studies in this group of patients. A satellite symposium was held during the European Congress of Obesity in May 2011, in Istanbul, Turkey, to discuss recent developments and concepts regarding pathophysiology and management of hypothalamic obesity in children. An international group of leading researchers presented certain aspects of the problem. This paper summarizes the highlights of this symposium. Understanding the central role of the hypothalamus in the regulation of feeding and energy metabolism will help us gain insights into the pathogenesis and management of common obesity.

Sleep and daytime functioning: a short-term longitudinal study of three preschool-age comparison groups

This study examined sleep, sleepiness, and daytime performance in 68 children with autism, 57 children with intellectual disability (ID), and 69 typically developing preschool children. Children in the autism and ID groups had poorer daytime performance and behaviors than the typically developing children. Children in the ID group also were significantly sleepier than children in both the autism and typically developing groups. These significant differences persisted over 6 months. Actigraph-defined sleep behaviors and problems did not relate to daytime sleepiness or daytime performance and behaviors for the children with autism or the typically developing group. For the ID group, longer night awakenings and lower sleep efficiency predicted more daytime sleepiness. For each group, parent-report sleep problems were associated with more daytime sleepiness and more behavior problems.

Co-morbidity of complex genetic disorders and hypersomnias of central origin: lessons from the underlying neurobiology of wake and sleep

Appropriate wake and sleep cycles are important to physical well-being, and are modulated by neuronal networks in the brain. A variety of medical conditions can disrupt sleep or cause excessive daytime sleepiness. Clinical diagnostic classification schemes have historically lumped genetic disorders together into a category that considers the sleep dysfunction to be secondary to a medical condition. The unique nature of sleep endophenotypes that occur more frequently in particular genetic disorders has been underappreciated. Increased understanding of the pathophysiology of wake/sleep dysfunction in rare genetic disorders could inform studies of the neurological mechanisms that underlie more common forms of wake and sleep dysfunction. In this review, we highlight genetic developmental disorders in which sleep endophenotypes have been described, and then consider genetic neurodegenerative disorders with sleep characteristics that set them apart from the disruptions to sleep that are typically associated with aging and dementia.

Sleep duration and circulating adipokine levels

INTRODUCTION

Short sleep duration is associated with systemic inflammation and diabetes; however the mechanisms by which reduced sleep leads to these complications are unclear. One possibility is sleep may impact secretion of adipocyte derived hormones that regulate inflammation and insulin resistance. In this study we assessed the association between sleep duration and 3 adipokine levels.

METHODS

A total of 561 adults from the Cleveland Family Study underwent standardized laboratory polysomnography followed by a morning fasting blood draw assayed for leptin, visfatin, and retinol binding protein-4 (RBP4) levels.

RESULTS

The cohort had an age of 44.5 (16.1) years and total sleep time (TST) of 6.2 (1.3) hours (mean [SD]). Each hour reduction in TST was associated with a 10% increase in leptin (P = 0.01) and a 14% increase in visfatin levels (P = 0.03) in analyses adjusted for age, gender, and race. After additional adjustment for obesity, sleep apnea severity, hypertension, and diabetes, each hour reduction in TST was associated with a 6% increase in leptin (P = 0.01) and a 14% increase in visfatin levels (P = 0.02). Leptin increased by 15% (P = 0.01) and visfatin increased by 31% (P = 0.05) for every 1-h decrease in REM sleep. In contrast, no association between sleep duration and RBP4 was found.

CONCLUSIONS

Reduced sleep and reduced REM sleep are associated with elevations in leptin and visfatin, 2 adipokines associated with inflammation and insulin resistance. Further investigation of the effect of sleep on adipose tissue function should be pursued.

The metabolic phenotype of Prader-Willi syndrome (PWS) in childhood: heightened insulin sensitivity relative to body mass index

CONTEXT

Insulin sensitivity is higher in patients with Prader-Willi syndrome (PWS) than in body mass index-matched obese controls (OCs). Factors contributing to the heightened insulin sensitivity of PWS remain obscure. We compared the fasting levels of various hormones, cytokines, lipids, and liver function tests in 14 PWS patients and 14 OCs with those in 14 age- and gender-matched lean children (LC). We hypothesized that metabolic profiles of children with PWS are comparable with those of LC, but different from those of OCs.

RESULTS

Leptin levels were comparable in PWS patients and OCs, suggesting comparable degrees of adiposity. Glucose levels were comparable among groups. However, fasting insulin concentrations and homeostasis model assessment insulin resistance index were lower in PWS patients than in OCs (P < 0.05) and similar to LC. Moreover, high-density lipoprotein levels were lower and triglycerides higher in OCs (P < 0.05) but not PWS patients. Total adiponectin, high-molecular-weight (HMW) adiponectin and the HMW to total adiponectin ratio were higher in PWS patients (P < 0.05) than in OCs and similar to LC. High-sensitivity C-reactive protein and IL-6 levels were higher in OCs than in PWS patients or LC (P < 0.05). Nevertheless, PAI-1 levels were elevated in both OC and PWS patients. There were no group differences in glucagon-like peptide-1, macrophage chemoattractant protein-1, TNFα, IL-2, IL-8, IL-10, IL-12p40, IL-18, resistin, total or low-density lipoprotein cholesterol, aspartate aminotransferase, or alanine aminotransferase.

CONCLUSIONS

The heightened insulin sensitivity of PWS patients relative to OCs is associated with higher levels of adiponectin and lower levels of high-sensitivity C-reactive protein and IL-6. Future studies will determine whether PWS children are protected from obesity comorbidities such as type 2 diabetes, hyperlipidemia, and nonalcoholic fatty liver disease.