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Prader-Willi syndrome (PWS) is a complex and multisystem neurobehavioral disease, which is caused by the lack of expression of paternally inherited imprinted genes on chromosome15q11.2-q13.1. The clinical manifestations of PWS vary with age. It is characterized by severe hypotonia with poor suck and feeding difficulties in the early infancy, followed by overeating in late infancy or early childhood and progressive development of morbid obesity unless the diet is externally controlled. Compared to Western PWS patients, Chinese patients have a higher ratio of deletion type. Although some rare disease networks, including PWS Cooperation Group of Rare Diseases Branch of Chinese Pediatric Society, Zhejiang Expert Group for PWS, were established recently, misdiagnosis, missed diagnosis and inappropriate intervention were usually noted in China. Therefore, there is an urgent need for an integrated multidisciplinary approach to facilitate early diagnosis and optimize management to improve quality of life, prevent complications, and prolong life expectancy. Our purpose is to evaluate the current literature and evidences on diagnosis and management of PWS in order to provide evidence-based guidelines for this disease, specially from China.

Prader-Willi syndrome (PWS) is an imprinted neurodevelopmental disease characterized by cognitive impairments, developmental delay, hyperphagia, obesity, and sleep abnormalities. It is caused by a lack of expression of the paternally active genes in the PWS imprinting center on chromosome 15 (15q11.2-q13). Owing to the imprinted gene regulation, the same genes in the maternal chromosome, 15q11-q13, are intact in structure but repressed at the transcriptional level because of the epigenetic mechanism. The specific molecular defect underlying PWS provides an opportunity to explore epigenetic therapy to reactivate the expression of repressed PWS genes inherited from the maternal chromosome. The purpose of this review is to summarize the main advances in the molecular study of PWS and discuss current and future perspectives on the development of CRISPR/Cas9- mediated epigenome editing in the epigenetic therapy of PWS. Twelve studies on the molecular mechanism or epigenetic therapy of PWS were included in the review. Although our understanding of the molecular basis of PWS has changed fundamentally, there has been a little progress in the epigenetic therapy of PWS that targets its underlying genetic defects.

Chronic low-grade inflammation plays a major role in the development of insulin resistance. The potential role and underlying mechanism of vitamin C, an antioxidant and anti-inflammatory agent, was investigated in tumor necrosis factor-α (TNF-α)-induced insulin resistance. Gulonolactone oxidase knockout (Gulo-/-) mice genetically unable to synthesize vitamin C were used to induce insulin resistance by continuously pumping small doses of TNF-α for seven days, and human liver hepatocellular carcinoma cells (HepG2 cells) were used to induce insulin resistance by treatment with TNF-α. Vitamin C deficiency aggravated TNF-α-induced insulin resistance in Gulo-/- mice, resulting in worse glucose tolerance test (GTT) results, higher fasting plasma insulin level, and the inactivation of the protein kinase B (AKT)/glycogen synthase kinase-3β (GSK3β) pathway in the liver. Vitamin C deficiency also worsened liver lipid accumulation and inflammation in TNF-α-treated Gulo-/- mice. In HepG2 cells, vitamin C reversed the TNF-α-induced reduction of glucose uptake and glycogen synthesis, which were mediated by increasing GLUT2 levels and the activation of the insulin receptor substrate (IRS-1)/AKT/GSK3β pathway. Furthermore, vitamin C inhibited the TNF-α-induced activation of not only the mitogen-activated protein kinase (MAPKs), but also nuclear factor-kappa B (NF-κB) signaling. Taken together, vitamin C is essential for preventing and improving insulin resistance, and the supplementing with vitamin C may be an effective therapeutic intervention for metabolic disorders.

Prader-Willi syndrome (PWS) is a complex neurobehavioral disorder caused by failure of expression of paternally inherited genes in the PWS region of chromosome 15. Two siblings who both met the inclusion criteria for clinical diagnosis of PWS during neonatal period. Molecular genetic analysis demonstrated a 417-kb microdeletion within the 15q11.2 region inherited from siblings’ paternal grandmother, involving key genes of PWS, except for UBE3A, which may explain why their father and paternal grandmother had a normal phenotype. The findings may be helpful for better understanding of the underlying mechanism of this rare imprinting defect.

Aim This study investigated the relationship between intima-media thickness (IMT) and immune parameters in obese children from five to 16 years of age. Methods We enrolled 185 obese children with a mean age of 10.65 ± 2.10 years and 211 controls with a mean age of 10.32 ± 1.81 years. Glycometabolism, lipid metabolism, sex hormones, immune indices and carotid IMT were measured. Results Serum interleukin (IL)-6, IL-10, tumour necrosis factor (TNF)-alpha, white blood cells and common and internal carotid artery IMTs in the obese group were higher than those in the control group (p < 0.05, respectively). Bivariate correlation analysis showed that the common carotid arterial IMT was positively correlated with alanine aminotransferase, triglyceride, uric acid, apolipoprotein B, IL-6, IL-10, TNF-alpha, follicle-stimulating hormone and testosterone. Internal carotid artery IMT was positively correlated with alanine aminotransferase and follicle-stimulating hormone. Both common and internal carotid artery IMTs were inversely correlated with apolipoprotein A1 (p < 0.05, respectively). Stepwise multiple regression analysis showed that testosterone, alanine aminotransferase and TNF-alpha were the independent determinants of common carotid arterial IMT. Conclusion Tumour necrosis factor-alpha, alanine aminotransferase and testosterone were associated with intima thickening in the early life in obese children and may increase later risks of premature atherogenicity and adult cardio-cerebrovascular diseases.

Background To investigate the clinical and molecular characteristics of Chinese children with maturity onset diabetes of the young (MODY). Methods A total of 42 Chinese patients suspected MODY referred to our unit from 2014 to 2018 were enrolled. Mutational analysis of monogenic diabetes mellitus genes was performed by next-generation sequencing and confirmed by Sanger sequencing. Results There were 28 males (66.7%) and 14 females (33.3%) with a mean age of 9.49 ± 3.46 years (range, 1.4–15.3 years) and a mean birth weight of 3.38 ± 0.49 kg (range, 2.55–4.90 kg). Among these patients, 15 patients had polyuria, polydipsia or weight loss. Two patients (4.8%) were obese and six (14.3%) were overweight. Moreover, 13 patients (30.9%) had a family history of diabetes. Thirty variants were identified in 28 patients. Twenty-six variants in 25 patients were pathogenic or likely pathogenic genes (59.5%, 25/42), including 15 patients (60.0%, 15/25) with GCK mutation, four (16.0%, 4/25) with PAX4 mutation, three (12.0%, 3/25) with HNF4A mutation, one (4.0%, 1/25) with INS mutation, one (4.0%, 1/25) with NEUROD1 mutation and one (4.0%, 1/25) with HNF1A mutation. Nine mutations (36.0%, 9/25) were novel. There was no difference between mutation-suspected patients and MODY-confirmed patients except for a 2-h glucose increment in an oral glucose tolerance test (OGTT), while the GCK-MODY had lower glycated hemoglobin (HbA1c) and a significantly smaller 2-h glucose increment in an OGTT compared with transcription factor MODYs. The GCK-MODY was identified by incidental hyperglycemia without glycosuria. GCK-MODY without drug management and hepatocyte nuclear factor-1 alpha (HNF4A) or HNF1A-MODY with sulfonylurea therapy obtained good glucose controlling. Conclusions Mutation of the GCK gene is the most common in MODY patients in China followed by PAX4. The screening criteria can improve the cost-effectiveness of disease diagnosis and treatment. A precise molecular diagnosis would lead to optimal treatment of the patients.