Respiratory Complications in Children with Prader Willi Syndrome

The outcomes of growth hormone therapy in the obstructive sleep apnea parameters of Prader-Willi syndrome patients: a systematic review

PURPOSE

Prader-Willi syndrome is a serious genetic condition, capable of causing endocrinological imbalance, which has as one of its main treatments the growth hormone therapy. However, this therapy still causes some uncertainty concerning its effects on the respiratory parameters of those patients, especially in cases of obstructive sleep apnea, therefore, presenting a need for the analysis of the relationship between the therapy and the otolaryngologic condition.

METHODS

A systematic review following the PRISMA model was developed, with searches for keywords made in the databases PubMed (MEDLINE), Scopus, and Web of Science and registration in the PROSPERO platform (CRD42023404250).

RESULTS

Three randomized controlled trials were considered eligible for inclusion in the review. None of the studies demonstrated statistically significant modifications in the obstructive sleep apnea parameters of Prader-Willi patients related to the growth hormone administration.

CONCLUSIONS

Growth hormone therapy is safe for Prader-Willi syndrome patients when analyzing their obstructive sleep apnea parameters.

Hypoventilation in patients with Prader-Willi syndrome across the pediatric age

OBJECTIVES

Few data on alveolar hypoventilation in Prader-Willi syndrome (PWS) are available and the respiratory follow-up of these patients is not standardized. The objectives of this study were to evaluate the prevalence of alveolar hypoventilation in children with PWS and identify potential risk factors.

STUDY DESIGN

This retrospective study included children with PWS recorded by polysomnography (PSG) with transcutaneous carbon dioxide pressure (PtcCO2) or end-tidal CO2 (ETCO2) measurements, between 2007 and 2021, in a tertiary hospital center. The primary outcome was the presence of alveolar hypoventilation defined as partial pressure of carbon dioxide (pCO2) ≥ 50 mmHg during ≥2% of total sleep time (TST) or more than five consecutive minutes.

RESULTS

Among the 57 included children (38 boys, median age 4.8 years, range 0.1-15.6, 60% treated with growth hormone [GH], 37% obese), 19 (33%) had moderate-to-severe obstructive sleep apnea syndrome (defined as obstructive apnea-hypopnea index ≥5/h) and 20 (35%) had hypoventilation. The median (range) pCO2 max was 49 mmHg (38-69). Among the children with hypoventilation, 25% were asymptomatic. Median age and GH treatment were significantly higher in children with hypoventilation compared to those without. There was no significant difference in terms of sex, BMI, obstructive or central apnea-hypopnea index between both groups.

CONCLUSION

The frequency of alveolar hypoventilation in children and adolescents with PWS is of concern and may increase with age and GH treatment. A regular screening by oximetry-capnography appears to be indicated whatever the sex, BMI, and rate of obstructive or central apneas.

Prevalence of Sleep-Disordered Breathing in Prader-Willi Syndrome

Introduction

Sleep-disordered breathing (SDB) is common in patients with Prader-Willi Syndrome (PWS). However, the prevalence of SDB varies widely between studies. Early identification of SDB and factors contributing to its incidence is essential, particularly when considering growth hormone (GH) therapy.

Objectives

The aims of the study were to describe the prevalence and phenotypes of sleep-disordered breathing (SDB) in patients with Prader-Willi syndrome (PWS) and to determine the effects of age, gender, symptoms, GH therapy and body mass index on SDB severity.

Methods

This study was a retrospective chart review of all patients with genetically confirmed Prader-Willi syndrome who underwent diagnostic overnight polysomnography (PSG) in the sleep laboratory at Sidra Medicine. Clinical and PSG data of enrolled patients were collected.

Results

We identified 20 patients (nine males, eleven females) with PWS who had overnight sleep polysomnography (PSG) at a median age (IQR) of 5.83 (2.7-12) years. The median apnea-hypopnea index (AHI) was 8.55 (IQR 5.8-16.9) events/hour. The median REM-AHI was 27.8 (IQR 15-50.6) events/hour. The median obstructive apnea-hypopnea index (OAHI) was 7.29 (IQR 1.8-13.5) events/hour. The median central apnea-hypopnea index (CAHI) was 1.77 (IQR 0.6-4.1) events/hour. Nineteen patients (95%) demonstrated SDB by polysomnography (PSG) based on AHI ≥1.5 events/hour. Nine patients (45%) were diagnosed with obstructive sleep apnea (OSA). Three patients (15%) were diagnosed with central sleep apnea (CSA). Seven patients (35%) were diagnosed with mixed sleep apnea. No correlations were observed between AHI and age, gender, BMI, symptoms, or GH therapy. However, REM-AHI was significantly correlated with BMI (P=0.031).

Conclusion

This study shows a high prevalence of SDB among our patients with PWS. Obstructive sleep apnea was the predominant phenotype. BMI was the only predictor for high REM-AHI. Further studies of large cohorts are warranted to define SDB in PWS and design the appropriate treatment.

Quality of Life in Children with Prader-Willi Syndrome and the Impact of the Disease on the Functioning of Families

Objective: Prader−Willi (PWS; OMIM#176270) syndrome is a clinically distinct genetic disorder, caused by an abnormality in the 15q11-q13 region, referred to as the critical region. One of the most popular concepts existing in modern sciences, not only within psychology, but also in the aspect of all sciences that are related to human life and its course, is the quality of life (QoL). Though it is known that health-related quality of life in children with PWS can be reduced, less is understood about the impact on the family. We aimed to identify factors related to the quality of life of children with PWS and the impact of the disease on family functioning. Methods: A cross-sectional questionnaire survey. The subjects were 46 parents of children with PWS. The Computer Assisted Self-Interviewing (CASI) method was used; the Paediatric Quality of Life Inventory and the PedsQL Family Impact Module. Results: The PedsQL mean score was 49.0; (min−max: 5.6−90.8; SD = 16.8), with the highest scores in the Emotional Functioning (EF) (EF; 55.9; min−max: 5.0−100.0; SD = 22.0), and the lowest in the Social Functioning (SF) (SF; 42.7; min−max: 5.0−85.0; SD = 18.7) 56.4 (SD ± 14.7). The child’s age does not affect the quality of life, there were no statistically significant (p > 0.05). families have difficulties in performing daily activities (total score 27.6; SD 16.7), support family functioning (total score 28.9; SD 18.8) and effects physical domain (total score 27.7; SD 15.7). Conclusion: Research on the QoL of patients with PWS and their families is very important in order to assess the QoL, but also to provide the perspective of an active change in the perspective of a better treatment process, rehabilitation and communication in society.

Gastric aspiration in sudden unexpected infant death of Prader-Willi syndrome: immunohistochemical detection of feeding components

Prader–Willi syndrome (PWS) in infants is characterized by hypotonia and poor sucking with feeding difficulties. Two autopsy cases of sudden unexpected death during sleep after tube feeding are described herein. For one, gastric aspiration caused by the possible milk regurgitation was suspected. Immunohistochemical examination of lung sections was performed using three antibodies to human α-lactalbumin, human gross cystic disease fluid protein 15, and cow whey β-lactoglobulin. Five cases of sudden unexpected infant death occurring earlier than at 6 months old were selected as controls. Marked immune-staining for infant formula in one PWS subject was evident within terminal bronchioles and alveoli with granular and amorphous features. However, no positive staining was apparent in the other subject, who exhibited contrasting features in milk distribution. Among control cases, one showed mild staining in the bronchiole, but the others did not. The antibody to β-lactoglobulin reacted specifically with formula, with no nonspecific background. Gastric contents in the airway can be a difficult issue because of the consequent terminal gasping. However, because of an episode of antemortem symptoms of potential regurgitation, and from findings at autopsy such as petechiae, we inferred that fatal regurgitation occurred in this PWS infant after tube feeding. Several clinical reports have described milk aspiration, but this pathological report is the first related to aspiration in PWS during tube feeding.

Factors Associated with Postoperative Respiratory Complications following Posterior Spinal Instrumentation in Children with Early-onset Scoliosis

Objective

To investigate the incidence and risk factors of postoperative respiratory complications (PRCs) in children with early‐onset scoliosis (EOS) following posterior spine deformity surgery (PSDS) based on growth‐friendly techniques, so as to help improve the safety of surgery.

Methods

A retrospective study of children with EOS admitted for PSDS based on growth‐friendly techniques from October 2013 to October 2018 was reviewed at a single center. There were 73 children (30 boys, 43 girls) who fulfilled the criteria in this research. The mean age of the patients was 7 ± 6.2 years. Patients were divided into the groups with and without PRCs. Variables that might affect the PRCs during the perioperative period, including general factors, radiographic factors, laboratory factors and surgical factors, were analyzed using univariate analysis to evaluate the potential risk factors. The variables that were significantly different were further analyzed by binary logistic regression analysis to identify the independent factors of PRCs.

Results

All the 73 children included 42 idiopathic scoliosis (57.5%), 12 congenital scoliosis (16.4%), 10 syndromic scoliosis (13.7%) and nine neuromuscular scoliosis (12.3%). PRCs were detected in 16 children (21.9%) with nine different PRCs. The total frequency of detected PRCs was 54, including pleural effusion (25.9%), postoperative pneumonia (20.4%), hypoxemia (18.5%), atelectasis (14.8%), prolonged intubation with mechanical positive pressure ventilatory support (PIMPPVS) (7.4%), bronchospasm (3.7%), reintubation (3.7%), delayed extubation (3.7%) and pneumothorax (1.9%). Results of univariate testing demonstrated that the following six variables were statistically different (P < 0.05): nonidiopathic scoliosis, combined with pulmonary comorbidities, pretransferrin < 200 mg/dL, prealbumin < 3.5 g/dL, anesthesia time ≥ 300 min and blood loss to total blood volume ratio (BL/TBV) ≥ 15%. Binary logistic regression analysis confirmed that BL/TBV≥15% (odd ratio OR = 29.188, P = 0.010), combined with pulmonary comorbidities (OR = 19.216, P = 0.012), pretransferrin < 200 mg/dL (OR = 11.503, p = 0.024), and nonidiopathic scoliosis (OR = 7.632, P = 0.046) were positively linear correlated with PRCs in children with EOS following PSDS.

Conclusion

PRCs has a higher incidence in children with EOS following PSDS. BL/TBV ≥15%, combined with pulmonary comorbidities, pre‐transferrin < 200 mg/dL, and nonidiopathic scoliosis play an important role for the development of PRCs in this population.

Sleep Disorders in Adults with Prader–Willi Syndrome: Review of the Literature and Clinical Recommendations Based on the Experience of the French Reference Centre

Prader–Willi syndrome (PWS) is a rare, genetic, multisymptomatic, neurodevelopmental disease commonly associated with sleep alterations, including sleep-disordered breathing and central disorders of hypersomnolence. Excessive daytime sleepiness represents the main manifestation that should be addressed by eliciting the detrimental effects on quality of life and neurocognitive function from the patients’ caregivers. Patients with PWS have impaired ventilatory control and altered pulmonary mechanics caused by hypotonia, respiratory muscle weakness, scoliosis and obesity. Consequently, respiratory abnormalities are frequent and, in most cases, severe, particularly during sleep. Adults with PWS frequently suffer from sleep apnoea syndrome, sleep hypoxemia and sleep hypoventilation. When excessive daytime sleepiness persists after adequate control of sleep-disordered breathing, a sleep study on ventilatory treatment, followed by an objective measurement of excessive daytime sleepiness, is recommended. These tests frequently identify central disorders of hypersomnolence, including narcolepsy, central hypersomnia or a borderline hypersomnolent phenotype. The use of wake-enhancing drugs (modafinil, pitolisant) is discussed in multidisciplinary expert centres for these kinds of cases to ensure the right balance between the benefits on quality of life and the risk of psychological and cardiovascular side effects.

High Prevalence of Scoliosis in a Large Cohort of Patients with Prader-Willi Syndrome

The characteristics of scoliosis were investigated in a large cohort of children and adults with Prader–Willi syndrome (PWS), analysing the role of age, gender, puberty, body mass index (BMI), genotype and growth hormone therapy (GHT) on its onset and severity. A retrospective cross-sectional study was performed in 180 patients with genetically confirmed PWS (96 females), aged 17.6 ± 12 years. Eighty-five subjects (47%) were obese. One hundred and fifty subjects (83.3%) were on GHT, while 30 patients had never been treated. Overall, 150 subjects (83.3%) were affected by scoliosis, 80.2% of children and adolescents and 87.8% of adults. A mild degree of scoliosis was observed in 58 patients (38.7%), moderate in 43 (28.7%) and severe in 49 (32.6%). Median age at diagnosis of scoliosis was 6.3 years, while the severe forms were diagnosed earlier (median age: 3.8 years). The cumulative probability at 5 years of age was equal to 0.403 and almost doubled at 15 years. No significant associations were found between scoliosis and genotype, gender, pubertal stage, GHT and BMI. A corset was prescribed to 75 subjects (50%) at a median age of 7.5 years, while 26 subjects (17.3%) underwent surgery at a median age of 13.1 years. Our data indicate that scoliosis is one of the major concerns for PWS patients that increases with age, and therefore suggest the need for regular systematic monitoring of spinal deformity from paediatric age.

Establishing the content validity of the Epworth Sleepiness Scale for Children and Adolescents in Prader-Willi syndrome

STUDY OBJECTIVES

Excessive daytime sleepiness is common in Prader-Willi syndrome (PWS), with prevalence ranging from 52% to 100%. The goal of this study was to establish the content validity (ie, evidence that an instrument measures an intended concept of interest) of the parent/caregiver version of the Epworth Sleepiness Scale for Children and Adolescents (ESS-CHAD), a measure of daytime sleepiness, in PWS.

METHODS

Qualitative, dyadic semistructured video interviews were conducted with 18 caregivers and their children with PWS from April to June 2020. Concept elicitation and cognitive interview techniques were implemented. Thematic analyses allowed for examination of themes and data patterns.

RESULTS

All caregivers (mean age 49 years) were mothers of individuals with PWS who experienced troublesome daytime sleepiness (mean age 14 years). The most prevalent observable signs/symptoms of daytime sleepiness were sleepy/sleepiness (n = 17; 94.4%), tired/tiredness (n = 16; 88.9%), exhaustion/exhausted (n = 5; 27.8%), anxious/stressed (n = 5; 27.8%), irritable/frustrated (n = 5; 27.8%), having tantrums/outbursts (n = 5; 27.8%), and lethargy (n = 4; 22.2%). Daytime sleepiness impacted various aspects of health including mental, emotional, physical, and social well-being. When caregivers were asked about the activities associated with daytime sleepiness, all salient concepts elicited mapped to the ESS-CHAD; saturation was met after the first 4 interviews. Only 2 concepts, after physical exertion and while inactive/bored, did not map. Caregiver statements indicated that these concepts, although related to daytime activities, were atypical of daily routines. The ESS-CHAD was well understood and relevant to caregivers.

CONCLUSIONS

This study supports the content validity of the ESS-CHAD and its appropriateness for evaluating treatment efficacy of daytime sleepiness in PWS.

CITATION

Patel VP, Patroneva A, Glaze DG, Davis K, Merikle E, Revana A. Establishing the content validity of the Epworth Sleepiness Scale for Children and Adolescents in Prader-Willi syndrome. J Clin Sleep Med. 2022;18(2):485-496.

Sleep-disordered breathing in school-aged children with Prader-Willi Syndrome

STUDY OBJECTIVES

Studies of sleep-disordered breathing (SDB) in children with Prader-Willi syndrome (PWS) have focused on early childhood and growth hormone (GH)-naïve children, but little is known about older children, including those on long term GH therapy. This study aimed to describe the nature and prevalence of SDB in school-aged children with PWS in the growth hormone era.

METHODS

This retrospective single-center chart review included children aged 6-18 years with PWS who had overnight polysomnography not involving respiratory support over five years (2012-2017). The main outcome measures were the presence of obstructive sleep apnea, central sleep apnea or hypoventilation defined by an elevated PCO₂ as per standard pediatric criteria.

RESULTS

Seventeen children (8 male, median age 11.6y, range 6.6-16.1y) were included. Fifteen demonstrated SDB of different types: central sleep apnea (18%), obstructive sleep apnea (24%), both obstructive and central sleep apnea (29%), or hypoventilation without obstructive or central sleep apnea (18%). Twelve (71%) children had evidence of hypoventilation. Those with hypoventilation had a higher central apnea-hypopnea index (AHI) but no difference in the obstructive AHI, age, sex, growth parameters, or the presence of scoliosis or sleep-related symptoms compared to those without hypoventilation.

CONCLUSIONS

Sleep-related hypoventilation is common in school-aged children with PWS. The presence of central sleep apnea, including the quantification of central hypopneas, but not obstructive sleep apnea or clinical factors predicted the presence of hypoventilation. Long-term polysomnography surveillance in children with PWS should include identification of central hypopneas and measurement of continuous pCO₂.

Respiratory failure after scoliosis correction surgery in patients with Prader-Willi syndrome: Two case reports

BACKGROUND

Sleep-disordered breathing, including hypoventilation and obstructive sleep apnea, is often observed in Prader-Willi syndrome (PWS). Particularly in adolescence, scoliosis causes a progressive restrictive pulmonary pattern, leading to hypoventilation, so timely corrective surgery is required. However, the effect is controversial. In addition, since mental retardation of PWS, patient effort-based respiratory tests may be less reliable. So far, no studies have accurately reported on the comparison of respiratory function before and after corrective surgery, and appropriate respiratory function measurement method in PWS.

CASE SUMMARY

We present two cases of adolescent PWS with typical characteristics, including obesity, mental retardation, and scoliosis. Two boys, aged 12 and 13, diagnosed with PWS, both underwent scoliosis correction surgery. Before and immediately after surgery, arterial blood tests showed no abnormalities and no respiratory symptoms occurred. However, after 6-7 mo, both patients complained of daytime sleepiness, difficulty sleeping at night, dyspnea on exertion, and showed cyanosis. Hypercapnia and hypoxia were confirmed by polysomnography and transcutaneous CO₂ monitoring during sleep and were diagnosed with obstructive sleep apnea and alveolar hypoventilation. It was corrected by nighttime noninvasive ventilation application and normal findings of arterial blood gas were maintained after 6-8 mo follow-up.

CONCLUSION

Even after scoliosis surgery, “periodic” monitoring of respiratory failure with an “objective” test method is needed for timely respiratory support.

Effects of Growth Hormone Treatment on Sleep-Related Parameters in Adults With Prader-Willi Syndrome

CONTEXT

Prader-Willi syndrome (PWS) is a rare, genetic, multisymptom, neurodevelopmental disease due to lack of the expression of the paternal genes in the q11 to q13 region of chromosome 15. The main characteristics of PWS are muscular hypotonia, hyperphagia, obesity, behavioral problems, cognitive disabilities, and endocrine deficiencies, including growth hormone (GH) deficiency. Sleep apnea and abnormal sleep patterns are common in PWS. GH treatment might theoretically have a negative impact on respiration.

OBJECTIVE

Here we present the effect of GH treatment on polysomnographic measurements.

METHODS

Thirty-seven adults, 15 men and 22 women, with confirmed PWS were randomly assigned to 1 year of GH treatment (n = 19) or placebo (n = 18) followed by 2 years of GH treatment to all. Polysomnographic measurements were performed every 6 months. A mixed-effect regression model was used for comparison over time in the subgroup that received GH for 3 years.

RESULTS

At baseline median age was 29.5 years, body mass index 27.1, insulin-like growth factor 115 µg/L, apnea-hypopnea index (AHI) 1.4 (range, 0.0-13.9), and sleep efficiency (SE) 89.0% (range, 41.0%-99.0%). No differences in sleep or respiratory parameters were seen between GH- and placebo-treated patients. SE continuously improved throughout the study, also after adjustment for BMI, and the length of the longest apnea increased. AHI inconsistently increased within normal range.

CONCLUSION

SE improved during GH treatment and no clinical, significantly negative impact on respiration was seen. The etiology of breathing disorders is multifactorial and awareness of them should always be present in adults with PWS with or without GH treatment.

Phenotypic variance in pediatric obstructive sleep apnea

It is crucial that clinicians understand what underpins the considerable phenotypic variance in pediatric obstructive sleep apnea syndrome (OSAS), if they are to implement individually tailored phenotype-based approaches to diagnosis and management. This review summarizes the current literature on how disease severity, comorbidities, genetic and environmental/lifestyle factors interact to determine the overall OSAS phenotype. The first part discusses the impact of these factors on OSAS-related morbidity in the context of otherwise healthy children, whilst the second half details children with complex conditions, particularly focusing on the anatomical and functional abnormalities predisposing to upper airway obstruction unique to each condition. One can then understand the need for a multidimensional assessment strategy for pediatric OSAS; one that incorporates the history, physical examination, sleep study results, and biomarkers to enable precise stratification, so vital for effective determination of the timing and the nature of the therapeutic interventions required.

Measures of nocturnal oxyhemoglobin desaturation in children with neuromuscular disease or Prader-Willi syndrome

OBJECTIVES

Evidence for nocturnal oximetry interpretation in patients with abnormal neuromuscular function is limited. We aimed to compare children with neuromuscular disease (NMD) or Prader-Willi syndrome (PWS) to otherwise healthy subjects with obstructive sleep-disordered breathing (SDB) or without respiratory disorder (controls) regarding nocturnal oximetry parameters.

METHODS

We analyzed recordings from children with: (a) NMD; (b) PWS; (c) snoring and adenotonsillar hypertrophy and/or obesity (SDB); and (d) controls. Outcomes included: (a) basal SpO₂ ; (b) proportions of subjects with McGill oximetry score (MOS) >1 (clusters of desaturations); and (c) desaturation index (SpO₂ drops ≥3%/h-ODI3).

RESULTS

Data of 12 subjects with NMD (median age, 5.2 years; IQR, 2.7, 8.2), 14 children with PWS (5 years; 2.3, 6.9), 21 children with SDB (5.8 years; 4.6, 9.6), and 20 controls (6.2 years; 5.4, 11.2) were analyzed. Children with NMD, PWS, and SDB had lower basal SpO₂ than controls (95.6% [94.5%, 96.9%], 96.2% [95.1%, 97.4%], 96.1% [95.8%, 97.5%] vs 97.8% [97.2%, 97.9%], respectively; (P < .01). NMD and PWS showed the greatest negative effect on basal SpO₂ (P < .05). Children with SDB or PWS had a higher risk of MOS >1 than patients with NMD (OR, 25.9 [95% CI, 3.4-200.4] and 9.5 [1.5-62.6]). NMD, PWS, and SDB were similar regarding ODI3, which was elevated compared to ODI3 in controls (P < .05). Frequent desaturations predominated in NMD, while periods of sustained desaturation were noted in NMD and PWS.

CONCLUSION

PWS and NMD have a negative effect on basal SpO₂ , while clusters of desaturations are prevalent in patients with PWS or obstructive SDB.

Clinical Observations and Treatment Approaches for Scoliosis in Prader-Willi Syndrome

Prader–Willi syndrome (PWS) is recognized as the first example of genomic imprinting, generally due to a de novo paternal 15q11-q13 deletion. PWS is considered the most common genetic cause of marked obesity in humans. Scoliosis, kyphosis, and kyphoscoliosis are commonly seen in children and adolescents with PWS with a prevalence of spinal deformities cited between 15% to 86%. Childhood risk is 70% or higher, until skeletal maturity, with a bimodal age distribution with one peak before 4 years of age and the other nearing adolescence. As few reports are available on treating scoliosis in PWS, we described clinical observations, risk factors, therapeutic approaches and opinions regarding orthopedic care based on 20 years of clinical experience. Treatments include diligent radiographic screening, starting once a child can sit independently, ongoing physical therapy, and options for spine casting, bracing and surgery, depending on the size of the curve, and the child’s age. Similarly, there are different surgical choices including a spinal fusion at or near skeletal maturity, versus a construct that allows continued growth while controlling the curve for younger patients. A clear understanding of the risks involved in surgically treating children with PWS is important and will be discussed.

Adenotonsillectomy for the Treatment of Obstructive Sleep Apnea in Children with Prader-Willi Syndrome: A Meta-analysis

Objective

Adenotonsillectomy outcomes in obstructive sleep apnea (OSA) treatment among children with Prader-Willi syndrome (PWS) remain unclear. This study aimed to elucidate the effectiveness of adenotonsillectomy in OSA treatment among children with PWS.

Data Source

PubMed, MEDLINE, Embase, and Cochrane Review up to February 2019.

Review Methods

The registry number of the protocol published on PROSPERO was CRD42015027053. Two authors independently searched the relevant database. Polysomnography outcomes in these children were examined, including net postoperative changes in the apnea-hypopnea index (AHI), net postoperative changes in the minimum and mean oxygen saturation, the overall success rate for a postoperative AHI <1, and the overall success rate for a postoperative AHI <5.

Results

Six studies with 41 patients were analyzed (mean age, 5.0 years; 55% boys; mean sample size, 6.8 patients). All children had PWS and received adenotonsillectomy for the treatment of OSA. The AHI was 13.1 events per hour (95% CI, 11.0-15.1) before surgery and 4.6 events per hour (95% CI, 4.1-5.1) after surgery. The mean change in the AHI was a significant reduction of 8.0 events per hour (95% CI, −10.8 to −5.1). The overall success rate was 21% (95% CI, 11%-38%) for a postoperative AHI <1 and 71% (95% CI, 54%-83%) for a postoperative AHI <5. Some patients developed velopharyngeal insufficiency postoperatively.

Conclusion

Adenotonsillectomy was associated with OSA improvement among children with PWS. However, residual OSA was frequently observed postoperatively in these patients.

Causes of death in Prader-Willi syndrome: lessons from 11 years' experience of a national reference center

Background

In the last 20 years, substantial improvements have been made in the diagnosis, treatment and management of patients with Prader-Willi syndrome (PWS). Few data on causes of death are available since those improvements were made. Our study assessed the causes of death among French patients with PWS over the first 11 years of experience of the nationwide French Reference Center for PWS (FRC-PWS).

Methods

Our study relied on two sources of mortality information at national level between 2004 and 2014: The French Epidemiological Centre for the Medical Causes of Death (CépiDc) Registry and the FRC-PWS database. Causes of death were classified into seven categories: respiratory, cardiovascular, gastrointestinal, severe infection, sudden death, other causes, and unknown. Descriptive statistics were calculated separately for children (< 18 years-old) and adults (≥18 years-old).

Results

One hundred and four deaths were identified in France from 2004 to 2014. The median age at death was 30 years, ranging from less than 1 month to 58 years. Seventeen deaths occurred in patients under 18 years, with 70% of them in children under 2 years. Respiratory causes accounted for more than 50% of the deaths in patients with PWS in both children and adults. Both cause and age of death did not significantly differ according to gender or genetic subtype.

Conclusions

Patients with PWS die prematurely due to a respiratory cause in most cases at all ages. In those adult patients with data on obesity, 98% were reported to be obese.

Requirements for improving health and well-being of children with Prader-Willi syndrome and their families

Prader-Willi syndrome (PWS) is a rare genetic condition with multi-system involvement. The literature was reviewed to describe neurodevelopment and the behavioural phenotype, endocrine and metabolic disorders and respiratory and sleep functioning. Implications for child and family quality of life were explored. Challenging behaviours contribute to poorer well-being and quality of life for both the child and caregiver. Recent evidence indicates healthy outcomes of weight and height can be achieved with growth hormone therapy and dietary restriction and should be the current target for all individuals with PWS. Gaps in the literature included therapies to manage challenging behaviours, as well as understanding the effects of growth hormone on respiratory and sleep function. New knowledge regarding the transition of children and families from schooling and paediatric health services to employment, accommodation and adult health services is also needed. Developing a national population-based registry could address these knowledge gaps and inform advocacy for support services that improve the well-being of individuals with PWS and their families.

Obstructive Sleep Apnea and Otolaryngologic Manifestations in Children with Pseudohypoparathyroidism

BACKGROUND/AIMS

Pseudohypoparathyroidism (PHP) is a rare, genetic disorder. Patients with PHP may have increased prevalence of obstructive sleep apnea (OSA) but this has not been prospectively studied.

METHODS

We enrolled children aged 6-18 years with PHP and matched controls. Evaluation included physical examination, medical history, and polysomnography.

RESULTS

Fifteen children with PHP type 1A (PHP1A) and 15 controls completed the study. Both groups were obese (BMI 32.2 ± 8.7 vs. 31.7± 6.5). The majority of PHP1A patients required tympanostomy tubes (86.7%) and adenotonsillectomy (73.3%). The primary outcome, i.e., the obstructive disturbance index, was significantly higher in PHP1A children versus controls (1.8 ± 2.3 vs. 0.6 ± 0.5, p = 0.045). Children with PHP1A were more likely to have OSA compared with controls (60.0 vs. 13.3%, p = 0.008). Three siblings with PHP type 1B (PHP1B) were also studied (BMI 25.9 ± 9.0). None had a history of adenotonsillectomy, one had tympanostomy tubes. The obstructive disturbance index (2.0 ± 2.3) was similar to that of children with PHP1A. Two (66.7%) PHP1B participants had OSA.

CONCLUSION

Children with PHP1A are at an increased risk for OSA compared with similarly obese peers. They also have higher rates of otitis media and adenotonsillar hypertrophy. Screening for OSA should be considered in all patients with PHP1A and possibly PHP1B though more research is needed.

Necdin shapes serotonergic development and SERT activity modulating breathing in a mouse model for Prader-Willi syndrome

Prader-Willi syndrome (PWS) is a genetic neurodevelopmental disorder that presents with hypotonia and respiratory distress in neonates. The Necdin-deficient mouse is the only model that reproduces the respiratory phenotype of PWS (central apnea and blunted response to respiratory challenges). Here, we report that Necdin deletion disturbs the migration of serotonin (5-HT) neuronal precursors, leading to altered global serotonergic neuroarchitecture and increased spontaneous firing of 5-HT neurons. We show an increased expression and activity of 5-HT Transporter (SERT/Slc6a4) in 5-HT neurons leading to an increase of 5-HT uptake. In Necdin-KO pups, the genetic deletion of Slc6a4 or treatment with Fluoxetine, a 5-HT reuptake inhibitor, restored normal breathing. Unexpectedly, Fluoxetine administration was associated with respiratory side effects in wild-type animals. Overall, our results demonstrate that an increase of SERT activity is sufficient to cause the apneas in Necdin-KO pups, and that fluoxetine may offer therapeutic benefits to PWS patients with respiratory complications.

Prader-Willi syndrome results from the disruption of a cluster of neighboring genes, including one called Necdin. Symptoms begin in early infancy and worsen with age. Affected children tend to develop an insatiable appetite, which often leads to obesity. They also experience serious problems with their breathing. Chest infections, high altitude and intense physical activity can be dangerous for children with Prader-Willi syndrome. This is because a slight shortage of oxygen may trigger breathing difficulties that could prove fatal.

The brain cells that produce a chemical messenger called serotonin help to control breathing. Several lines of evidence suggest that loss of Necdin may trigger breathing difficulties in Prader-Willi syndrome via effects on the serotonin system. First, serotonin neurons produce the Necdin protein. Second, laboratory mice that lack the gene for Necdin have abnormally shaped serotonin neurons. Third, these mice show breathing difficulties like those of individuals with Prader-Willi syndrome. But while this implies a connection between serotonin, Necdin and breathing difficulties, it falls short of establishing a causal link.

Matarazzo et al. now reveal an increase in the quantity and activity of a protein called the serotonin transporter in mutant mice that lacked the gene for Necdin compared to normal mice. Serotonin transporter proteins mop up the serotonin that neurons release when they signal to one another. Neurons in the mutant mice take up more serotonin than their counterparts in normal mice; this means they have less serotonin available for signaling. This may make it harder for the mutant mice to regulate their breathing.

Drugs called selective serotonin-reuptake inhibitors (or SSRIs for short) can block the serotonin transporter. These drugs, which include Fluoxetine (also called Prozac), are antidepressants. Matarazzo et al. show that SSRIs temporarily restore normal breathing in young mice that lack the gene for Necdin. However, these drugs have harmful long-term effects on breathing in non-mutant mice. Further studies should test whether short-term use of SSRIs could offer immediate relief for breathing difficulties in infants and children with Prader-Willi syndrome.