Prader-Willi Syndrome Patients Research Articles

Expanding deep phenotypic spectrum associated with atypical pathogenic structural variations overlapping 15q11-q13 imprinting region.

The 15q11-q13 region is a genetic locus with genes subject to genomic imprinting, significantly influencing neurodevelopment. Genomic imprinting is an epigenetic phenomenon that causes differential gene expression based on the parent of origin. In most diploid organisms, gene expression typically involves an equal contribution from both maternal and paternal alleles, shaping the phenotype. Nevertheless, in mammals, including humans, mice, and marsupials, the functional equivalence of parental alleles is not universally maintained. Notably, during male and female gametogenesis, parental alleles may undergo differential marking or imprinting, thereby modifying gene expression without altering the underlying DNA sequence. Neurodevelopmental disorders, such as Prader-Willi syndrome (PWS) (resulting from the absence of paternally expressed genes in this region), Angelman syndrome (AS) (associated with the absence of the maternally expressed UBE3A gene), and 15q11-q13 duplication syndrome (resulting from the two common forms of duplications-either an extra isodicentric 15 chromosome or an interstitial 15 duplication), are the outcomes of genetic variations in this imprinting region. Conducted a genomic study to identify the frequency of pathogenic variants impacting the 15q11-q13 region in an ethnically homogenous population from Bangladesh. Screened all known disorders from the DECIPHER database and identified variant enrichment within this cohort. Using the Horizon analysis platform, performed enrichment analysis, requiring at least >60% overlap between a copy number variation and a disorder breakpoint. Deep clinical phenotyping was carried out through multiple examination sessions to evaluate a range of clinical symptoms. This study included eight individuals with clinically suspected PWS/AS, all previously confirmed through chromosomal microarray analysis, which revealed chromosomal breakpoints within the 15q11-q13 region. Among this cohort, six cases (75%) exhibited variable lengths of deletions, whereas two cases (25%) showed duplications. These included one type 2 duplication, one larger atypical duplication, one shorter type 2 deletion, one larger type 1 deletion, and four cases with atypical deletions. Furthermore, thorough clinical assessments led to the diagnosis of four PWS patients, two AS patients, and two individuals with 15q11-q13 duplication syndrome. Our deep phenotypic observations identified a spectrum of clinical features that overlap and are unique to PWS, AS, and Dup15q syndromes. Our findings establish genotype-phenotype correlation for patients impacted by variable structural variations within the 15q11-q13 region.

Cardiovascular Characteristics in Patients with Prader-Willi Syndrome

Abstract The most prevalent type of syndromic obesity is referred to as Prader-Willi Syndrome (PWS), being determined by the lack of expression of paternal genes on chromosome 15q11.2-q13 due to genomic or epigenetic variations, such as DNA and histone methylation or acetylation. The syndrome is frequently associated with behavioral disorders, intellectual deficiencies, short stature, polyphagia, hypogonadism and muscular hypotonia, all stemming from the multiple endocrine dysfunctions characterizing this condition. Cardiovascular (CV) anomalies can manifest even in the early stages of life, and those with PWS have an elevated risk of early onset cardiovascular diseases. The somatic and behavioral aspects of the syndrome interact intricately to cause this increased risk for CV pathologies. Changes in the GH-IGF axis are seen in most Prader-Willi Syndrome (PWS) patients, irrespective of obesity. Specific cardiovascular features of GHD in adult PWS patients include reduced cardiac mass, decreased ejection fraction, and diminished chronotropic response to dobutamine.

HIGH BLOOD PRESSURE IN PATIENTS WITH PRADER WILLI SYNDROME : CASE REPORT AND REVIEW OF THE LITERATURE

Prader-Willi syndrome (PWS), the most common genetic cause of obesity, is characterized by elevated morbi-mortality in all ages. In this context, non-obese PWS patients showed low frequency of metabolic syndrome (MetS), while a high prevalence of hypertension was observed in obese PWS and obese controls. The aim of this report was to estimate the occurrence of high blood pressure and its components in a large group of PWS adults. An association of this syndrome with elevated cardiovascular morbi-mortality was observed, but the underlying mechanisms are not fully known.

Evaluating the effect of recombinant human growth hormone treatment on sleep-related breathing disorders in toddlers with Prader–Willi syndrome: a one-year retrospective cohort study

BackgroundRecombinant human growth hormone (rhGH) therapy is beneficial for children with Prader–Willi syndrome (PWS) in improving short stature and metabolism, but the effect of early rhGH treatment on respiratory and sleep parameters for PWS children under three years old remains elusive. Thus, this study aimed to investigate the impact of rhGH treatment on sleep-related breathing disorders (SRBDs) for toddlers with PWS.MethodsA total of 17 age-matched PWS patients receiving rhGH treatment (rhGH group) and 17 control individuals not receiving rhGH treatment (non-rhGH group) were recruited for this study between October 2018 and January 2023. Data related to polysomnography-polygraphy (PSG) and serum levels of insulin-like growth factor (IGF-1) and insulin-like growth factor binding protein 3 (IGFBP-3) were collected.ResultsThe mean age in the rhGH group was 20.76 ± 9.22 months, which was comparable to that of the non-rhGH group (25.23 ± 13.81 months). The demographic and anthropometric parameters were similar across the two groups after 52 weeks of treatment. Administration of rhGH to toddlers did not exert adverse effects on the obstructive apnea–hypopnea index (OAHI), central apnea index (CAI), oxygen desaturation index (ODI), mean percutaneous oxygen saturation (SpO2), lowest SpO2, duration when SpO2 is lower than 90%, or proportion of the patients with SpO2 lower than 90%. Furthermore, the increased IGF-1 z-score and IGFBP-3 level did not worsen SRBDs.ConclusionTreatment with rhGH for 52 weeks on young toddlers with PWS showed no deleterious effects on SRBDs. This shed more light on the importance of initiating rhGH therapy early in PWS patients.

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

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

Gut microbiota, a potential cause of higher insulin sensitivity in children with Prader-Willi syndrome.

Obesity is the main driving factor for comorbidities in Prader-Willi syndrome (PWS) patients due to overeating behaviors. The gut microbiota has been implicated in the etiology of obesity and associated comorbidities. The purpose of the present study was to characterize the fecal microbiota in Chinese patients with PWS and compare it to that of patients with obesity as well as healthy controls. We conducted a cross-sectional study with 35 PWS patients (PWS), 35 patients with obesity (OB), and 35 healthy controls (HC). Metagenomic sequencing was performed in stool samples. The composition of the fecal microbiota in PWS patients differed from that of participants in the OB and HC groups. It was characterized by increased Akkermansia Eubacterium, Eubacterium rectale, and Roseburia intestinalis and decreased Parabacteroides and Phascolarctobacterium. Additionally, the homeostatic model assessment of insulin resistance (HOMA-IR) was lower in PWS patients than in patients with obesity. Spearman rank correlation analysis showed that Achromobacter, Acidiphilium, Xylophilus, and Frisingicoccus were significantly negatively correlated with HOMA-IR. The composition of the gut microbiota in Chinese PWS patients differed from that in patients with obesity, which might contribute to higher insulin sensitivity in PWS patients.

AAV-BDNF gene therapy ameliorates a hypothalamic neuroinflammatory signature in the Magel2-null model of Prader-Willi syndrome

Individuals with Prader-Willi syndrome (PWS) exhibit several metabolic and behavioral abnormalities associated with excessive food-seeking activity. PWS is thought to be driven in part by dysfunctional hypothalamic circuitry and blunted responses to peripheral signals of satiety. Previous work described a hypothalamic transcriptomic signature of individuals with PWS. Notably, PWS patients exhibited downregulation of genes involved in neuronal development and an upregulation of neuroinflammatory genes. Deficiencies of brain-derived neurotrophic factor (BDNF) and its receptor were identified as potential drivers of PWS phenotypes. Our group recently applied an adeno-associated viral (AAV)-BDNF gene therapy within a preclinical PWS model, Magel2-null mice, to improve metabolic and behavioral function. While this proof-of-concept project was promising, it remained unclear how AAV-BDNF was influencing the hypothalamic microenvironment and how its therapeutic effect was mediated. To investigate, we hypothalamically injected AAV-BDNF to wild type and Magel2-null mice and performed mRNA sequencing on hypothalamic tissue. Here, we report that (1) Magel2 deficiency is associated with neuroinflammation in the hypothalamus and (2) AAV-BDNF gene therapy reverses this neuroinflammation. These data newly reveal Magel2-null mice as a valid model of PWS-related neuroinflammation and furthermore suggest that AAV-BDNF may modulate obesity-related neuroinflammatory phenotypes through direct or indirect means.

First results of the growth disorders related twinning programme Partners4Growth implemented at the tertiary university pediatric endocrinology clinics in Bulgaria.

Early diagnosis of childhood growth disorders, their timely and proper treatment are important for better outcomes.The aim of the present study was to assess the results of the first 18months of the growth disorders related twinning programme "Partners4Growth" implemented at all tertiary university pediatric endocrinology clinics in Bulgaria. In 2019, Partners4Growth started operation at 7 centres (4 experienced and 3 twin centres) with the main aim of aligning their practices in the shortest possible time. Education of twin centres' personnel was organized, equipment and methods for growth evaluation and follow-up were standardized. The approach was tested initially at one centre. At baseline and at the 18th month a questionnaire concerning diagnosis and management of recombinant human growth hormone (rhGH) requiring disorders was applied. A total of 104 new patients were diagnosed compared to 30 in the previous year. Of those, 91 started rhGH treatment- 65 (64 %) GH deficient, 12 (12 %) Turner syndrome, 7 (7 %) Prader-Willi syndrome patients, and 7 (7 %) born small for gestational age without postnatal catch-up, representing 35.8 % of all currently rhGH treated Bulgarian children. A better geographical coverage and more advanced diagnostic and management practices were achieved. Partners4Growth facilitated the alignment of the tertiary pediatric endocrinology centres competences thus leading to an improved diagnosis and treatment of growth disorders as well as better patients' access. For its short existence, the Programme increased significantly the number of new patients in the difficult times of COVID-19 pandemic thus justifying its continuation.

Defects in early synaptic formation and neuronal function in Prader-Willi syndrome

Prader-Willi syndrome (PWS), which is a complex epigenetic disorder caused by the deficiency of paternally expressed genes in chromosome 15q11-q13, is associated with several psychiatric dimensions, including autism spectrum disorder. We have previously reported that iPS cells derived from PWS patients exhibited aberrant differentiation and transcriptomic dysregulation in differentiated neural stem cells (NSCs) and neurons. Here, we identified SLITRK1 as a downregulated gene in NSCs differentiated from PWS patient iPS cells by RNA sequencing analysis. Because SLITRK1 is involved in synaptogenesis, we focused on the synaptic formation and function of neurons differentiated from PWS patient iPS cells and NDN or MAGEL2 single gene defect mutant iPS cells. Although βIII tubulin expression levels in all the neurons were comparable to the level of differentiation in the control, pre- and postsynaptic markers were significantly lower in PWS and mutant neurons than in control neurons. PSD-95 puncta along βIII tubulin neurites were also decreased. Membrane potential responses were measured while exposed to high K+ stimulation. The neuronal excitabilities in PWS and mutant neurons showed significantly lower intensity than that of control neurons. These functional defects in PWS neurons may reflect phenotypes of neurodevelopmental disorders in PWS.

Generation of an induced pluripotent stem cell line, ZIPi021-A, from fibroblasts of a Prader-Willi syndrome patient with maternal uniparental disomy (mUPD)

Prader-Willi syndrome (PWS) is a neurodevelopmental disorder caused by loss of paternal expression of imprinted genes on chromosome 15q11-q13. We established a human induced pluripotent stem cell line (hiPSC), ZIPi021-A, from fibroblasts of a 4-year-old female PWS patient with the subtype of maternal uniparental disomy (mUPD). The generated hiPSC line was transgene-free, expressed pluripotency markers and showed the ability to differentiate into all three germ layers in vitro. The ZIPi021-A hiPSC line could be used as a cellular model for PWS in humans.

CD16+ monocytes are involved in the hyper-inflammatory state of Prader-Willi Syndrome by single-cell transcriptomic analysis.

Patients with Prader-Willi syndrome (PWS) have a reduced life expectancy due to inflammation-related disease including cardiovascular disease and diabetes. Abnormal activation of peripheral immune system is postulated as a contributor. However, detailed features of the peripheral immune cells in PWS have not been fully elucidated. Serum inflammatory cytokines were measured in healthy controls (n=13) and PWS patients (n=10) using a 65- multiplex cytokine assays. Changes of the peripheral immune cells in PWS was assessed by single-cell RNA sequencing (scRNA-seq) and high-dimensional mass cytometry (CyTOF) using peripheral blood mononuclear cells (PBMCs) from PWS patients (n=6) and healthy controls (n=12). PWS patients exhibited hyper-inflammatory signatures in PBMCs and monocytes were the most pronounced. Most inflammatory serum cytokines were increased in PWS, including IL-1β, IL-2R, IL-12p70, and TNF-α. The characteristics of monocytes evaluated by scRNA-seq and CyTOF showed that CD16+ monocytes were significantly increased in PWS patients. Functional pathway analysis revealed that CD16+ monocytes upregulated pathways in PWS were closely associated with TNF/IL-1β- driven inflammation signaling. The CellChat analysis identified CD16+ monocytes transmitted chemokine and cytokine signaling to drive inflammatory process in other cell types. Finally, we explored the PWS deletion region 15q11-q13 might be responsible for elevated levels of inflammation in the peripheral immune system. The study highlights that CD16+ monocytes contributor to the hyper-inflammatory state of PWS which provides potential targets for immunotherapy in the future and expands our knowledge of peripheral immune cells in PWS at the single cell level for the first time.

A potential role for GPR160 and its ligand, CART, in the modulation of feeding behavior in Prader-Willi Syndrome

Hyperphagia is a hallmark of Prader-Willi syndrome (PWS). Managing the extreme hunger and insatiability associated with PWS remains a considerable challenge to PWS patients and their caregivers. Appetite and feeding behavior are governed by numerous neural circuits, several of which are potentially disrupted when some or all of the Prader-Willi critical region on chromosome 15 is lost. Previous research has focused on well-established feeding circuits in an effort to uncover the physiology underlying PWS hyperphagic behavior; however, due to the complex interplay between these circuits, much is left to be explored. We have previously demonstrated that interactions between GPR160 and its ligand cocaine and amphetamine regulated transcript (CART) are important in the control of feeding behavior. Several groups have reported that CART exerts anorexigenic properties when injected into areas of the brain that are important to feeding behavior, including regions of the brainstem and hypothalamus. The prohormone convertase PSCK1, which is responsible for post-translational processing of the CART prohormone, appears to be reduced in PWS patients, suggesting that CART could play a role in the pathophysiology of PWS. Using a rat model of PWS supplied by the Foundation for Prader-Willi Research (Magel2- deficient), we seek to investigate this potential role of CART and GPR160 in PWS-associated hyperphagia. Through the use of continuous monitoring of food and water intake, we were able to define meal patterning differences between wild type and paternally Magel2-deficient rats. In addition to evaluating baseline meal patterning, we also administered CART centrally and recorded CART-induced changes in feeding behavior. Lastly, we determined physiologic changes in levels of GPR160, CART, and PSCK1 in the pituitary, hypothalamus, amygdala, and brainstem from WT and paternally-deficient Magel2 rats in the setting of metabolic stress (fasting). Although additional studies must be performed to better define the role of CART and GPR160 in the feeding behavior of PWS patients, we anticipate that this ligand-receptor pair has the potential to serve as a novel therapeutic target for the treatment of PWS-associated hyperphagia. Foundation for Prader-Willi Research This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Effectiveness of a transdisciplinary approach on hyperphagia management among patients with Prader Willi syndrome

BackgroundOne of the main characteristics of Prader Willi syndrome (PWS) is hyperphagia and obesity. This study sought to evaluate behaviours related to hyperphagia in individuals with PWS under a non-pharmacological transdisciplinary approach. MethodsThis observational study included PWS patients under a traditional non-pharmacological nutritional approach immersed within a regular transdisciplinary treatment (RTT) and a control group of PWS individuals without RTT. All individuals were evaluated using the Hyperphagia Questionnaire for Clinical Trials (HQ-CT). ResultsForty-three individuals were evaluated. The mean age at baseline (treatment onset) was 18.4±8.3 years in the RTT group and 19.1±6.9 years in the control group (p=0.74). Hyperphagia-related behaviours were significantly lower among those under RTT (RTT 5.7±3.7 vs control 13.1±7.5, p<0.0001). This was also identified within the three categories: arguing or manipulating to obtain food (2.71±2.1 vs 5.41±3.2, p=0.003), sneaking food (1.33±1.5 vs 3.55±3.3, p=0.007), and anger or tantrums related to food (1.67±1.8 vs 4.09±2.7, p=0.001). After a mean treatment duration of 41.0 months, the RTT group had a reduction in body mass index (baseline 38.7±17.1kg/m2 vs follow-up 29.2±9.2kg/m2; p<0.0001). A significant association between RTT duration and BMI reduction (p=0.037) was identified. ConclusionWe observed a positive impact on behaviours related to hyperphagia and a BMI reduction in PWS individuals in a context of a non-pharmacological nutritional approach as part of an RTT.

Progress in Brain Magnetic Resonance Imaging of Individuals with Prader-Willi Syndrome.

Prader-Willi syndrome (PWS), a rare epigenetic disease mapping the imprinted chromosomal domain of 15q11.2-q13.3, manifests a regular neurodevelopmental trajectory in different phases. The current multimodal magnetic resonance imaging (MRI) approach for PWS focues on morphological MRI (mMRI), diffusion MRI (dMRI) and functional MRI (fMRI) to uncover brain alterations. This technique offers another perspective to understand potential neurodevelopmental and neuropathological processes of PWS, in addition to specific molecular gene expression patterns, various clinical manifestations and metabolic phenotypes. Multimodal MRI studies of PWS patients demonstrated common brain changes in the volume of gray matter, the integrity of the fiber tracts and the activation and connectivity of some networks. These findings mainly showed that brain alterations in the frontal reward circuit and limbic system were related to molecular genetics and clinical manifestations (e.g., overwhelming eating, obsessive compulsive behaviors and skin picking). Further exploration using a large sample size and advanced MRI technologies, combined with artificial intelligence algorithms, will be the main research direction to study the structural and functional changes and potential pathogenesis of PWS.

Diagnosis of Prader-Willi syndrome and Angelman syndrome by targeted nanopore long-read sequencing

The CpG island flanking the promoter region of SNRPN on chromosome 15q11.2 contains CpG sites that are completely methylated in the maternally derived allele and unmethylated in the paternally derived allele. Both unmethylated and methylated alleles are observed in normal individuals. Only the methylated allele is observed in patients with Prader-Willi syndrome, whereas only the unmethylated allele is observed in those with Angelman syndrome. Hence, detection of aberrant methylation at the differentially methylated region is fundamental to the molecular diagnosis of Prader-Willi syndrome and Angelman syndromes. Traditionally, bisulfite treatment and methylation-sensitive restriction enzyme treatment or methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) have been used. We here developed a long-read sequencing assay that can distinguish methylated and unmethylated CpG sites at 15q11.2 by the difference in current intensity generated from nanopore reads. We successfully diagnosed 4 Prader-Willi syndrome patients and 3 Angelman syndrome patients by targeting differentially methylated regions. Concurrent copy number analysis, homozygosity analysis, and structural variant analysis also allowed us to precisely delineate the underlying pathogenic mechanisms, including gross deletion, uniparental heterodisomy, uniparental isodisomy, or imprinting defect. Furthermore, we showed allele-specific methylation in imprinting-related differentially methylated regions on chromosomes 6, 7, 11, 14, and 20 in a normal individual together with 4 Prader-Willi patients and 3 Angelman syndrome patients. Hence, presently reported method is likely to be applicable to the diagnosis of imprinting disorders other than Prader-Willi syndrome and Angelman syndrome as well.

Prader-Willi syndrome patient with atypical phenotypes caused by mosaic deletion in the paternal 15q11-q13 region: a case report

BackgroundPrader-Willi syndrome (PWS) is a multisystemic complex genetic disorder caused by the loss of paternally expressed genes in the human chromosome region 15q11.2-q13. It is characterized by severe hypotonia and feeding difficulties in early infancy, followed in later infancy or early childhood by excessive eating and gradual development of morbid obesity. Motor milestones and language development are delayed and most patients have intellectual disability.Case presentationHere we describe a rare PWS case caused by mosaic imprinting defect in the region 15q11.2-q13 of paternal origin. The proband was a male child with a clinical presentation of global developmental delay and hypotonia with specific facial features. Karyotype of the child was noted as mosaic: 45XY,der(15)?t(15;21),-21[26]/46,XY[24]. Whole-exome sequencing (WES) identified a deletion of 22.7 Mb in size at chr15q11.2q21.1 region and a deletion of 2.1 Mb in size at chr21q22.3 region. The Methylation-specific multiplex ligation-dependent probe amplification(MS-MLPA) of the 15q11.2-q13 region showed that the loading ratio of methylated alleles was 70% and that of unmethylated alleles was 30%(50% normal), which confirmed that the loss of mosaic imprinted defects in the paternal allele led to the diagnosis of PWS.ConclusionsWe propose that complete clinical criteria for PWS should not be considered sensitive in diagnosing partial atypical PWS due to mosaic imprinting defects. In contrast, clinical suspicion based on less restrictive criteria followed by multiple techniques is a more powerful approach.

Alteration of brain nuclei in obese children with and without Prader-Willi syndrome.

Introduction: Prader-Willi syndrome (PWS) is a multisystem genetic imprinting disorder mainly characterized by hyperphagia and childhood obesity. Extensive structural alterations are expected in PWS patients, and their influence on brain nuclei should be early and profound. To date, few studies have investigated brain nuclei in children with PWS, although functional and structural alterations of the cortex have been reported widely. Methods: In the current study, we used T1-weighted magnetic resonance imaging to investigate alterations in brain nuclei by three automated analysis methods: shape analysis to evaluate the shape of 14 cerebral nuclei (bilateral thalamus, caudate, putamen, globus pallidus, hippocampus, amygdala, and nucleus accumbens), automated segmentation methods integrated in Freesurfer 7.2.0 to investigate the volume of hypothalamic subregions, and region of interest-based analysis to investigate the volume of deep cerebellar nuclei (DCN). Twelve age- and sex-matched children with PWS, 18 obese children without PWS (OB) and 18 healthy controls participated in this study. Results: Compared with control and OB individuals, the PWS group exhibited significant atrophy in the bilateral thalamus, pallidum, hippocampus, amygdala, nucleus accumbens, right caudate, bilateral hypothalamus (left anterior-inferior, bilateral posterior, and bilateral tubular inferior subunits) and bilateral DCN (dentate, interposed, and fastigial nuclei), whereas no significant difference was found between the OB and control groups. Discussion: Based on our evidence, we suggested that alterations in brain nuclei influenced by imprinted genes were associated with clinical manifestations of PWS, such as eating disorders, cognitive disability and endocrine abnormalities, which were distinct from the neural mechanisms of obese children.

Facile discovery of red blood cell deformation and compromised membrane/skeleton assembly in Prader-Willi syndrome.

Prader-Willi syndrome (PWS) is a rare congenital disease with genetic alterations in chromosome 15. Although genetic disorders and DNA methylation abnormalities involved in PWS have been investigated to a significant degree, other anomalies such as those in erythrocytes may occur and these have not been clearly elucidated. In the present study, we uncovered slight anemia in children with PWS that was associated with increased red blood cell (RBC) distribution width (RDW) and contrarily reduced hematocrit (HCT) values. Intriguingly, the increased ratio in RDW to HCT allowed sufficient differentiation between the PWS patients from the healthy controls and, importantly, with individuals exhibiting conventional obesity. Further morphologic examinations revealed a significant deformity in erythrocytes and mild hemolysis in PWS patients. Comprehensive mechanistic investigations unveiled compromised membrane skeletal assembly and membrane lipid composition, and revealed a reduced F-actin/G-actin ratio in PWS patients. We ascribed these phenotypic changes in erythrocytes to the observed genetic defects, including DNA methylation abnormalities. Our collective data allowed us to uncover RBC deformation in children with PWS, and this may constitute an auxiliary indicator of PWS in early childhood.

A Case Series Study on Growth Hormone Therapy in Children with Prader-Willi Syndrome in Portugal.

Prader-Willi syndrome is a multisystemic genetic disorder associated with shorter adult height. Nowadays, all paediatric Prader-Willi syndrome patients are considered for growth hormone treatment. We present the experience of this treatment at a Portuguese paediatric endocrinology unit and intend to emphasise the importance of creating a follow-up national network of these patients. Longitudinal, retrospective, analytical study of Prader-Willis syndrome patients using data between 1989 and 2021. Growth hormone therapy was offered to eligible patients. The analysis included all Prader-Willis syndrome patients, with a comparison between treated and untreated patients; a longitudinal analysis of patients receiving growth hormone therapy (baseline, 12 and 36 months of follow-up) was also carried out. The statistical analysis was carried out using STATA® v13.0. Out of 38 patients with Prader-William syndrome, 61% were male. The median age at diagnosis was four months and 61% received growth hormone therapy. The patients who reached adulthood, or 18 years old, had a median near-adult height, Z-score of -2.71, and their median body mass index indicated class 2 obesity, regardless of growth hormone therapy. Patients had a lower body mass index in the growth hormone group (35 vs 51 kg/m2, p < 0.042) near-adult height. This case series represents the first national study that included patients on growth hormone therapy after the National Health Service started supporting the treatment for Prader-Willi syndrome patients and supports its use, reinforcing the positive effects on growth and body mass index. Longer follow-up studies are needed to analyse the effect of growth hormone on patient metabolic profiling, body composition and cognitive level.

MKRN3 circulating levels in Prader-Willi syndrome: a pilot study.

Hypogonadism in Prader-Willi syndrome (PWS) is generally attributed to hypothalamic dysfunction or to primary gonadal defect. MKRN3, a maternal imprinted gene located on 15q11.2-q13 region, encodes makorin ring finger protein 3, whose deficiency causes precocious puberty, an extremely rare symptom in PWS. This study aimed to evaluate MKRN3 levels in patients with PWS and to analyze its correlation with sexual hormone levels, insulin resistance and Body Mass Index (BMI). We performed an observational cross-sectional study and enrolled 80 patients with genetically confirmed diagnosis of PWS with median age of 9.6years. MKRN3 levels were measurable in 49 PWS patients with a geometric mean of 34.9 ± 22pg/ml (median: 28.4). Unmeasurable levels of MKRN3 were found in 31 patients. No statistically significant differences were found between patients with and without measurable MKRN3 levels for any clinical, biochemical, or genetic characteristics. However, MKRN3 levels were inversely correlated with HOMA-IR index (p: 0.005) and HbA1c (p: 0.046) values. No statistically significant correlations were found between MKRN3 and LH, estradiol and testosterone concentrations, pubertal development and genetic defect, whereas a direct correlation with FSH was found (p: 0.007). The typical genetic defect of PWS should lead to unmeasurable levels of the MKRN3 protein due to the inactivation of the paternal allele. Measurable circulating MKRN3 could suggest the possible involvement of tissue-specific imprinting mechanisms and other regulatory factors in gene expression. Correlations with HOMA-IR index, HbA1c, and FSH suggest peripheral actions of MKRN3, but future studies are warranted to investigate this topic.