This study aimed to increase our understanding of cardiac activity abnormalities in Prader-Willi Syndrome (PWS) and the relationship between cardiac activity, PWS behaviours thought to be associated with cardiac vagal tone and endogenous oxytocin and vasopressin levels. We compared cardiac activity (respiratory sinus arrhythmia (RSA), low-frequency heart rate variability (LF-HRV), heart period) in 30 adolescents and adults with PWS to 30 typically developing age-matched controls. RSA, LF-HRV, and heart period were lower in individuals with PWS than in the control group. In the control group, RSA was higher for females than males. However, for those with PWS, there was no difference between the sexes. Individuals with the mUPD genetic subtype had lower RSA and LF-HRV than participants with the PWS deletion subtype and compared to typically developing controls, no difference was found between the latter two groups. Heart period was also lower for those with mUPD compared to controls. Higher RSA reduced the odds of having temper outbursts and skin-picking. RSA was lower in those with PWS and psychosis compared to those with PWS without psychosis. Finally, we found RSA correlated with vasopressin for those with mUPD but not deletion. There was no relationship between RSA and oxytocin plasma or saliva levels. Our findings suggest autonomic dysfunction in PWS that is more marked in mUPD than deletion and potentially due to greater loss of parasympathetic activity in mUPD.

Genomic imprinting involves differential DNA methylation and gene expression between homologous paternal and maternal loci. It remains unclear, however, whether DNA replication also shows parent-of-origin-specific patterns at imprinted or other genomic regions. Here, we investigate genome-wide asynchronous DNA replication utilizing uniparental human embryonic stem cells containing either maternal-only (parthenogenetic) or paternal-only (androgenetic) DNA. Four clusters of imprinted genes exhibited differential replication timing based on parent of origin, while the remainder of the genome, 99.82%, showed no significant replication asynchrony between parental origins. Active alleles in imprinted gene clusters replicated earlier than their inactive counterparts. At the Prader-Willi syndrome locus, replication asynchrony spanned virtually the entirety of S phase. Replication asynchrony was carried through differentiation to neuronal precursor cells in a manner consistent with gene expression. This study establishes asynchronous DNA replication as a hallmark of large imprinted gene clusters.

This study aims to explore the food management strategies among caregivers/family members of children with Prader-Willi Syndrome (PWS) using the lens of \'familialisation\' of a health problem and the sociology of food socialization. Food intake among individuals with PWS is a main concern for parents, caregivers, and medical practitioners as it affects their physical, mental, and social well-being throughout their lives. Earlier studies on PWS and food intake centered around dietary management, dietary intake and growth, nutritional treatment and pharmacological approaches, nutritional phases, and weight gain. However, little has been done to understand the challenges of managing children with PWS from the sociological lens of food management strategies and socialization among families in Malaysia. This study is based on an investigation involving eight children with PWS and 46 family members and caregivers through lab observations and reflexive interviews. Ten food management strategies were identified that were adopted by the caregivers and families, which were influenced by cultural factors, family norms, and formal and informal support systems. The findings will influence future behavioral interventions to ensure the empowerment and well-being of individuals with PWS and their families.

BACKGROUND: Prader-Willi syndrome (PWS, MIM 176,270) and Angelman syndrome (AS, MIM 105,830) are caused by imprinting defects of chromosome 15q11-13, with loss of maternal gene expression causing AS and paternal gene expression causing PWS. The diagnosis, once established in most cases by using a methylation-specific PCR test, enables appropriate therapeutic interventions and avoids the need for further investigations. Genetic testing for PWS/AS is limited in Sri Lanka (and in other low- and middle-income countries), mainly because parents are unable to pay for testing as these are not funded by the health service.
METHODS: Ninety cases (46 female) with clinical features suggesting PWS (n = 37) and AS (n = 53), referred by a pediatric endocrinologist and a pediatric neurologist, were recruited. Clinical information and blood samples were obtained following informed consent. DNA was extracted and methylation-specific PCR (MS-PCR) was performed following bisulfite modification of DNA by using an in-house method and a kit. Results were validated using known positive controls. Parent-child trio DNA samples were used in cases with confirmed PWS and AS to determine if the disease was due to a deletion or uniparental disomy. The cost of the MS-PCR testing of the two modification methods and the microsatellite analysis was determined.
RESULTS: Among the suspected PWS cases, 19/37 were positive, while 5/53 of the suspected AS cases were positive. The lower identification rate of AS is probably related to the overlap of clinical features of this condition with other disorders. The kit-based modification method was more reliable, less time-consuming, and cost-effective in our laboratory.
CONCLUSIONS: The kit-based modification followed by MS-PCR described in this study enables more affordable genetic testing of suspected PWS/AS cases, and this is likely to improve patient care by targeting appropriate therapy for the affected cases. Parental genetic counselling is made possible regarding the low recurrence risk, especially where a deletion or uniparental disomy is confirmed. In MS-PCR, negative cases with a strong clinical suspicion of AS, UBE3A mutation testing is required. In addition, imprinting center mutation/deletion testing may also be needed in strongly clinically suspected, MS-PCR negative PWS and AS cases.

Prader-Willi syndrome (PWS) is a multisystemic disorder. Notably, many characteristic symptoms of PWS are correlated with locus coeruleus norepinephrine system (LC-NE) dysfunction, including impairment in arousal, learning, pain modulation, and stress-induced negative affective states. Although electrophysiological experiments in necdin-deficient mice, an established PWS animal model, have revealed decreased spontaneous neuronal firing activity in the LC and impaired excitability, the behavioral phenotypes related to LC-NE dysfunction remain unexplored. In this study, heterozygous necdin-deficient mice (B6.Cg-Ndntm1ky) were bred from wild-type (WT) females to generate WT (+m/+p) and heterozygous (+m/-p) animals. Compared to WT mice, Ndn + m/-p mice demonstrated impaired visual-spatial memory in the Y-maze test, reduced social interaction, impaired sexual recognition, and shorter falling latency on the Rotarod. Using the open field test (OFT) and elevated plus maze (EPM), we observed similar locomotion activity of Ndn + m/-p and WT mice, but Ndn + m/-p mice were less anxious. After acute restraint, Ndn + m/-p mice exhibited significant impairment in stress-induced anxiety. Additionally, the plasma norepinephrine surge following exposure to acute restraint stress was also impaired. Pretreatment with atomoxetine, a norepinephrine reuptake inhibitor aimed to enhance LC function, restored Ndn + m/-p mice to exhibit a normal response to acute restraint stress. Furthermore, by employing chemogenetic approaches to facilitate LC neuronal firing, post-stress anxious responses were also partially rescued in Ndn + m/-p mice. These data strongly suggest that LC dysfunction is implicated in the pathogenesis of stress-related neuropsychiatric symptoms in PWS. Manipulation of LC activity may hold therapeutic potential for patients with PWS.

Obesity among adolescents poses a significant global health concern with profound short- and long-term impact on physical and mental well-being. The intricate relationship between obesity and the onset of diabetes remains ambiguous, particularly in cases where the manifestation may differ from that observed in individuals with uncomplicated obesity. Herein, we present the case of a 14-year-old male adolescent with Prader-Willi phenotype and subsequent obesity, exhibiting symptoms of polyuria and polydipsia over a 10-day period, indicative of potential diabetes mellitus (DM). Laboratory assessments revealed a hemoglobin A1c level of 10%, confirming the suspected diagnosis. Notably, despite the absence of ketosis, elevated C-peptide levels and the presence of slightly positive islet-cell antibodies warranted further investigation. While the presence of antibodies typically aligns with a diagnosis of type 1 DM, recent research has highlighted the occurrence of anti-insulin pancreatic cell antibodies in type 2 DM cases. This article aims to delve into the multifaceted issues surrounding adolescent obesity, atypical presentations of DM with positive antibodies, and the long-term management of patients with genetic syndromes.

Rare neurological diseases include a vast group of heterogenous syndromes with primary impairment(s) in the peripheral and/or central nervous systems. Such rare disorders may have overlapping phenotypes, despite their distinct genetic etiology. One unique aspect of rare neurological diseases is their potential common association with altered epigenetic mechanisms. Epigenetic mechanisms include regulatory processes that control gene expression and cellular phenotype without changing the composition of the corresponding DNA sequences. Epigenetic factors include three types of proteins, the \"readers, writers, and erasers\" of DNA and DNA-bound proteins. Thus, epigenetic impairments of many neurological diseases may contribute to their pathology and manifested phenotypes. Here, we aim to provide a comprehensive review on the general etiology of selected rare neurological diseases, that include Rett Syndrome, Prader-Willi Syndrome, Rubinstein-Taybi Syndrome, Huntington\'s disease, and Angelman syndrome, with respect to their associated aberrant epigenetic mechanisms.

OBJECTIVE: Clinical benefits of growth hormone (GH) in Prader-Willi syndrome (PWS) are proven and scoliosis is a known association of both PWS and GH therapy. The aims of this study were to assess GH prescribing practices and growth outcomes over time, the prevalence and predictors of scoliosis in GH-treated PWS children, and the near-final height of GH-treated PWS patients.
METHODS: This is a retrospective, descriptive study evaluating data from all clinic visits of patients aged 0-18 years with PWS, seen through the Children\'s Hospital at Westmead between March 1992 and May 2022 (n=75).
RESULTS: A total of 64 patients were treated with GH (visits = 1,414). In the recent decade, the diagnosis of PWS and GH commencement were made significantly earlier in life. The prevalence of scoliosis was 41 %, in which age was the only significant predictor for scoliosis (odds ratio 1.19: 95 % CI [1.08-1.31; p=0.001]) adjusted for other predictors. In patients with data available at the age 16 years (23/28 treated with GH), those who were GH treated had significantly higher height SDS vs. nontreated group (SDS -0.67 vs. -2.58; p=0.0001) and lower BMI SDS (1.18 vs. 2.37; p<0.001).
CONCLUSIONS: Significant improvements in growth and body composition were seen in the GH-treated group vs. non-treated group of children with PWS. There were no significant modifiable clinical predictors of scoliosis in children with PWS, but our findings confirm the high prevalence of scoliosis in GH-treated children with PWS reinforcing the need for close surveillance.

Congenital disorders of ventilatory control typically manifest as central apneas, periodic breathing, and hypoventilation in the neonatal period, but some may present at a later age. Obstructive apneas may be the initial presentation, and some may have associated autonomic nervous system dysfunction. Individuals with these disorders can have absent or impaired ventilatory and arousal responses to hypoxemia and hypercapnia. This article discusses the presentation, pathophysiology, evaluation, and management of congenital central hypoventilation syndrome, rapid-onset obesity with hypothalamic dysfunction, hypoventilation, and autonomic dysregulation (ROHHAD) syndrome, Prader-Willi syndrome, and myelomeningocele.

OBJECTIVE: An investigation for the co-occurrence of two unrelated genetic disorders of muscular dystrophy and Prader-Willi syndrome (PWS) (OMIM#176270) using joint whole genome sequencing (WGS).
METHODS: Trio WGS joint analysis was performed to investigate the genetic etiology in a proband with PWS, prolonged muscular hypotonia associated hyperCKemia, and early-onset obesity. The parents were unaffected.
RESULTS: Results showed maternal isodisomy uniparental disomy (UPD) in chromosome 15, expanding from 15q11.2 to 15q22.2, including PWS regions at 15q11.2-15q13. Maternal heterodisomy was detected from 15q22.2 to 15q26.3. A pathogenic variant, NM_000070.3(CAPN3):c.550del (p.Thr184fs), was identified at 15q15.1 in a heterozygous state in the mother that was homozygous in the proband due to maternal isodisomy.
CONCLUSIONS: This is the first study of the concurrent molecular etiology of PWS and calpainopathy (OMIM#253600) in the same patient. This report highlights the utility of joint analysis and the need for the assessment of autosomal recessive disease in regions of isodisomy in patients with complex and unexplained phenotypes.