Obstructive sleep apnea syndrome (OSAS) is one of the most common comorbidities in patients with Prader–Willi syndrome (PWS) and causes significant consequences. This observational study was conducted to investigate the progression of OSAS in pediatric patients with PWS, who had not undergone upper airway surgery, through a longitudinal follow-up of their annual polysomnography results. Annual body mass index (BMI), BMI z-score, sleep efficiency and stages, central apnea index (CAI), obstructive apnea–hypopnea index (OAHI), and oxygen saturation nadir values were longitudinally analyzed. At enrollment, of 22 patients (10 boys and 12 girls) aged 11.7 ± 3.9 years, 20 had OSAS. During the 4-year follow-up, only two patients had a spontaneous resolution of OSAS. The average BMI and BMI z-score increased gradually, but CAI and OAHI showed no significant differences. After statistical adjustment for sex, age, genotype, growth hormone use, and BMI z-score, OAHI was associated with the BMI z-score and deletion genotype. In conclusion, OSAS is common in patients with PWS, and rarely resolved spontaneously. Watchful waiting may not be the best OSAS management strategy. Weight maintenance and careful selection of surgical candidates are important for OSAS treatment in patients with PWS.

Background: Silver–Russell syndrome (SRS) is a clinically and genetically heterogeneous disorder characterized by severe intrauterine growth retardation, poor postnatal growth, characteristic facial features, and body asymmetry. Hypomethylation of the imprinted genes of the chromosome 11p15.5 imprinting gene cluster and maternal uniparental disomy of chromosome 7 (mUPD7) are the major epigenetic disturbances. The aim of this study was to characterize the epigenotype, genotype, and phenotype of these patients in Taiwan. Methods: Two hundred and six subjects with clinically suspected SRS were referred for diagnostic testing, which was performed by profiling the methylation of H19-associated imprinting center (IC) 1 and the imprinted PEG1/MEST region using methylation-specific multiplex ligation-dependent probe amplification and high-resolution melting analysis with a methylation-specific polymerase chain reaction assay. We also applied a whole genome strategy to detect copy number changes and loss of heterozygosity. Clinical manifestations were recorded and analyzed according to the SRS scoring system proposed by Bartholdi et al. Results: Among the 206 referred subjects, 100 were classified as having a clinical diagnosis of SRS (score ≥ 8, maximum = 15) and 106 had an SRS score ≤ 7. Molecular lesions were detected in 45% (45/100) of the subjects with a clinical diagnosis of SRS, compared to 5% (5/106) of those with an SRS score ≤ 7. Thirty-seven subjects had IC1 hypomethylation, ten subjects had mUPD7, and three subjects had microdeletions. Several clinical features were found to be statistically different (p < 0.05) between the “IC1 hypomethylation” and “mUPD7” groups, including relative macrocephaly at birth (89% vs. 50%), triangular shaped face (89% vs. 50%), clinodactyly of the fifth finger (68% vs. 20%), and SRS score (11.4 ± 2.2 vs. 8.3 ± 2.5). Conclusions: The SRS score was positively correlated with the molecular diagnosis rate (p < 0.001). The SRS subjects with mUPD7 seemed to have fewer typical features and lower SRS scores than those with IC1 hypomethylation. Careful clinical observation and timely molecular confirmation are important to allow for an early diagnosis and multidisciplinary management of these patients.

Objective: Prone sleep is an identified risk factor for sudden infant death syndrome, possibly due to reduced blood pressure, cerebral oxygenation, and impaired cerebral vascular control. Cardiac and respiratory responses in neonates during supine and prone sleep have not been reported. Materials and Methods: In this study, daytime polysomnography (PSG) data from 17 neonates aged 2–3 days during supine and prone sleep were reported and the NDN gene, an important gene for neonatal respiratory control, was sequenced for correlation with neonatal respiratory parameters. Heart rate (HR), oxygen saturation, carbon dioxide concentration, sleep stages, central apnea index (CAI), obstructive apnea/hypopnea index (OAHI), and oxygen nadir were compared between supine and prone sleep and between participants with different single-nucleotide polymorphisms (SNPs) in the NDN gene. Results: During prone sleep, neonates had a faster HR, decreased oxygen saturation, and a longer duration of oxygen saturation <90% than during supine sleep, suggesting that cardiopulmonary responsiveness was impaired. Sleep efficiency, sleep stages, oxygen nadir, and carbon dioxide tension were not different during supine and prone sleep. Central apnea occurred more significantly than obstructive apnea. During supine and prone sleep, the CAI was 3.3 ± 2.9/h and 2.3 ± 2.6/h and the OAHI was 0.6 ± 0.7/h and 0.6 ± 0.8/h, respectively. We found one SNP rs3743340 in the NDN gene that had no effect on the sleep and respiratory parameters of PSG. Conclusion: Tachycardia and respiratory instability were recorded in neonates during prone sleep, suggesting that neonates are vulnerable to cardiopulmonary events during prone sleep. Therefore, young neonates should be kept in the supine sleep position unless there are contraindications.

This cross-sectional study aimed to compare the accelerometer-assessed physical activity (PA) and sedentary behavior (SB) of adults with Prader-Willi syndrome (PWS) attending or not attending a small-scale community workshop (SSCW). A total of 18 adults with PWS were recruited in this study. Of these participants, 10 regularly attended an SSCW and 8 did not. All of the participants were asked to wear accelerometers for eight continuous days for measuring their PA and SB. The independent sample t-test was used. The results showed that the adults with PWS who attended the SSCW engaged in more moderate-to-vigorous PA (MVPA) and daily steps than those who did not. By stratifying between daytime/nighttime on weekdays, we found the participants who attended the SSCW had higher total PA, MVPA, daily steps, as well as lower total sedentary time, during the daytime on weekdays than those who did not. Policies or programs promoting PA and reducing SB among adults with PWS should thus consider providing structured programs or courses in a community center.