Circulating Levels of Nesfatin-1 and Spexin in Children with Prader-Willi Syndrome during Growth Hormone Treatment and Dietary Intervention.

BACKGROUND: Despite observable improvement in the treatment outcomes of patients with Prader-Willi syndrome (PWS), adequate weight control is still a clinical problem. Therefore, the aim of this study was to analyze the profiles of neuroendocrine peptides regulating appetite-mainly nesfatin-1 and spexin-in children with PWS undergoing growth hormone treatment and reduced energy intake. METHODS: Twenty-five non-obese children (aged 2-12 years) with PWS and 30 healthy children of the same age following an unrestricted age-appropriate diet were examined. Serum concentrations of nesfatin-1, spexin, leptin, leptin receptor, total adiponectin, high molecular weight adiponectin, proinsulin, insulin-like growth factor-I, and total and functional IGF-binding protein-3 concentrations were determined using immunoenzymatic methods. RESULTS: The daily energy intake in children with PWS was lower by about 30% (p < 0.001) compared with the controls. Daily protein intake was similar in both groups, but carbohydrate and fat intakes were significantly lower in the patient group than the controls (p < 0.001). Similar values for nesfatin-1 in the PWS subgroup with BMI Z-score < -0.5 and the control group, while higher values in the PWS subgroup with BMI Z-score ≥ -0.5 (p < 0.001) were found. Spexin concentrations were significantly lower in both subgroups with PWS than the controls (p < 0.001; p = 0.005). Significant differences in the lipid profile between the PWS subgroups and the controls were also observed. Nesfatin-1 and leptin were positively related with BMI (p = 0.018; p = 0.001, respectively) and BMI Z-score (p = 0.031; p = 0.027, respectively) in the whole group with PWS. Both neuropeptides also correlated positively in these patients (p = 0.042). CONCLUSIONS: Altered profiles of anorexigenic peptides-especially nesfatin-1 and spexin-in non-obese children with Prader-Willi syndrome during growth hormone treatment and reduced energy intake were found. These differences may play a role in the etiology of metabolic disorders in Prader-Willi syndrome despite the applied therapy.

Very young children with Prader-Willi syndrome are refractory to growth hormone-associated decreases in free thyroxine levels.

The earlier initiation of growth hormone (GH) treatment for patients with Prader-Willi syndrome (PWS) who are younger than 2 years has become more prevalent. Because free thyroxine (FT4) levels are low during this period, GH may induce further reductions; however, limited information is currently available on this issue. Therefore, we herein performed age-dependent and time-course analyses of thyroid hormone levels in GH-treated PWS children. This retrospective analysis included genetically diagnosed PWS patients (N = 37, median age of 26 months). An age-dependent analysis was performed by subdividing subjects based on age [a younger group aged between 1 and 24 months (N = 16) and an older group between 25 and 84 months (N = 21)] and was followed by a multiple regression analysis with adjustments for sex and the cumulative GH dose per bodyweight. A time-course analysis of subjects who had not received levothyroxine during the first 18 months of GH treatment (N = 28) was conducted. A one-month treatment with GH decreased FT4 levels in the older group, but not in the younger group, and this was associated with increases in thyroid-stimulating hormone levels. A positive correlation was noted between age and decreases in FT4 levels independent of the cumulative GH dose per bodyweight. The time-course analysis revealed no changes in FT4 levels in the younger group, while transient decreases were observed in the older group. In conclusion, GH treatment causes age-dependent changes in FT4 levels. This result will help clinicians establish a therapeutic strategy to decide the necessity of levothyroxine supplementation in GH-treated children with PWS.

Circulating Irisin in Children and Adolescents With Prader-Willi Syndrome: Relation With Glucose Metabolism.

Irisin is a myokine involved in the browning of white adipose tissue and regulation of energy expenditure, glucose homeostasis and insulin sensitivity. Debated evidence exists on the metabolic role played by irisin in children with overweight or obesity, while few information exist in children with Prader Willi Syndrome (PWS), a condition genetically prone to obesity. Here we assessed serum irisin in relation to the metabolic profile and body composition in children and adolescents with and without PWS. In 25 PWS subjects [age 6.6-17.8y; body mass index standard deviation score (BMI SDS) 2.5 ± 0.3] and 25 age, and BMI-matched controls (age 6.8-18.0y; BMI SDS, 2.8 ± 0.1) we assessed irisin levels and metabolic profile inclusive of oral glucose tolerance test (OGTT), and body composition by dual-energy X-ray absorptiometry (DXA). In PWS, we recorded lower levels of fat-free mass (FFM) (p <0.05), fasting (p<0.0001) and 2h post-OGTT insulin (p<0.05) and lower insulin resistance as expressed by homeostatic model of insulin resistance (HOMA-IR) (p<0.0001). Irisin levels were significantly lower in PWS group than in controls with common obesity (p<0.05). In univariate correlation analysis, positive associations linked irisin to insulin OGTT0 (p<0.05), insulin OGTT120 (p<0.005), HOMA-IR (p<0.05) and fasting C-peptide (p<0.05). In stepwise multivariable regression analysis, irisin levels were independently predicted by insulin OGTT120. These results suggest a link between irisin levels and insulin sensitivity in two divergent models of obesity.

Circulating Inhibitory Factor 1 levels in adult patients with Prader-Willi syndrome.

OBJECTIVES: Prader-Willi syndrome (PWS) is a rare genetic syndrome characterized by hyperphagia and early development of morbid obesity. Cardiovascular disease (CVD) and metabolic syndrome (MetS) are major comorbidities in these patients leading to premature death. Inhibitory factor 1 (IF1) works as a regulatory protein, inhibiting the ATP hydrolase activity of mitochondrial ATP synthase and likely playing a role in lipid metabolism. We aimed to assay IF1 in adult patients with PWS evaluating any relationship with clinical, genetic and biochemical parameters. METHODS: We recruited 35 adult patients with genetically confirmed PWS. RESULTS: IF1 serum concentration displayed a normal distribution with an average value of 70.7 ± 22.6 pg/mL, a median value of 66.1 pg/mL. It was above the reference range only in one patient. All parameters were compared from both sides of IF1 median without displaying any significant differences. Patients with normal or low HDL-cholesterol did not present any difference as regards IF1 levels, which were not different between patients with and without MetS. Non-esterified fatty acids (NEFA) serum levels (r=0.623; p<0.001) showed a statistically significant correlation with IF1. Cholesterol and its fractions did not present any correlation with IF1. CONCLUSIONS: In this study we do not confirm that HDL-cholesterol and IF1 are correlated, but we show that in adult PWS patients, NEFA are correlated with serum IF1. This protein could play a role to some extent in determining the complex metabolic alterations in PWS patients.

The genetic background and vitamin D supplementation can affect irisin levels in Prader-Willi syndrome.

BACKGROUND: Prader-Willi syndrome (PWS) is associated to distinctive clinical symptoms, including obesity, cognitive and behavioral disorders, and bone impairment. Irisin is a myokine that acts on several target organs including brain adipose tissue and bone. The present study was finalized to explore circulating levels of irisin in children and adult PWS patients. METHODS: Seventy-eight subjects with PWS, 26 children (15 females, mean age 9.48 ± 3.6 years) and 52 adults (30 females, mean age 30.6 ± 10.7) were enrolled. Irisin serum levels were measured in patients and controls. Its levels were related with anthropometric and metabolic parameters, cognitive performance and bone mineral density either in pediatric or adult PWS. Multiple regression analysis was also performed. RESULTS: Irisin serum levels in PWS patients did not show different compared with controls. A more in-depth analysis showed that both pediatric and adult PWS with DEL15 displayed significantly reduced irisin levels compared to controls. Otherwise, no differences in irisin concentration were found in UPD15 patients with respect to controls. Our study revealed that in pediatric PWS the 25(OH) vitamin-D levels affected irisin serum concentration. Indeed, patients who were not supplemented with vitamin D showed lower irisin levels than controls and patients performing the supplementation. Multiple regression analysis showed that irisin levels in pediatric and adult PWS were predicted by the genetic background and 25(OH)-vitamin D levels, whereas in a group of 29 adult PWS also by intelligent quotient. CONCLUSION: We demonstrated the possible role of genetic background and vitamin-D supplementation on irisin serum levels in PWS patients.

A newborn screening pilot study using methylation-sensitive high resolution melting on dried blood spots to detect Prader-Willi and Angelman syndromes.

Prader-Willi (PWS) and Angelman (AS) syndromes are two clinically distinct imprinted disorders characterized by genetic abnormalities at 15q11-q13. Early diagnosis of both syndromes provides improved treatment and accurate genetic counseling. Whole blood (WB) is the most common DNA source of many methodologies to detect PWS and AS, however, the need of WB makes a massive screening difficult in newborns due to economic and technical limitations. The aim of this study was to adapt a Methylation-sensitive High-Resolution Melting (MS-HRM) approach from dried blood spot (DBS) samples, assessing the different DNA isolation techniques and diagnostic performance. Over a 1-year period, we collected 125 DBS cards, of which 45 had already been diagnosed by MS-HRM (20 PWS, 1 AS, and 24 healthy individuals). We tested three different DBS-DNA extraction techniques assessing the DNA concentration and quality, followed by MS-HRM and statistical comparison. Each DBS-DNA extraction method was capable of accuracy in detecting all PWS and AS individuals. However, the efficiency to detect healthy individuals varied according to methodology. In our experience, DNA extracted from DBS analyzed by the MS-HRM methodology provides an accurate approach for genetic screening of imprinting related disorders in newborns, offering several benefits compared to traditional whole blood methods.

Fat-Free Mass Is Better Related to Serum Uric Acid Than Metabolic Homeostasis in Prader-Willi Syndrome.

Background: Prader-Willi syndrome (PWS) is conventionally regarded as a model of genetic obesity carrying a metabolically healthier profile and fat compartmentalization than subjects with non-syndromic obesity. Serum uric acid (sUA) is a recognized surrogate marker of metabolic derangement. As no information is currently available on sUA levels in adults with PWS, we aimed to analyze sUA in a large cohort of adult patients with PWS in comparison to a control counterpart; secondly, we aimed to investigate the metabolic and non-metabolic determinants of sUA in PWS. Methods: A cross-sectional study was conducted on 89 consecutive adult patients with genetically confirmed PWS spanning a wide BMI range (17.2-56.7 kg/m2). As controls, 180 age-, sex- and BMI-matched healthy controls were included. sUA levels were analyzed in relation to the PWS status, metabolic variables, hormone status, body composition, and resting energy expenditure (REE). Bivariate correlation and multivariable regression studies were used to test for predictors of sUA in PWS. Results: Despite having similar BMI values, patients with PWS presented with higher FM (p < 0.0001), lower FFM (p < 0.0001) and REE values than controls (p < 0.0001). In PWS, sUA levels were non-significantly different between subjects with and without obesity (5.4 ± 1.3 vs. 4.9 ± 1.1 mg/dL, p = 0.09), and did not vary significantly in relation to genotype, sex steroid or GH replacement, as well as psychiatric treatments. Rates of hyperuricaemia (19.1% vs. 33.7%, p < 0.01) and absolute sUA levels were lower in patients with PWS compared to controls owing to significant differences between subgroups with obesity (5.5 ± 1.4 vs. 6.6 ± 1.6 mg/dL, p < 0.0001). In merged populations, sUA increased in parallel with age, BMI, FM, FFM, REE, glucolipid homeostasis, and inflammatory markers. In a separate analysis in PWS, however, sUA correlations with BMI, FM, and inflammatory markers were null. Stepwise multivariable regression analysis in the PWS group adjusted for karyotype, age, sex, FM, FFM, obesity, triglycerides, and HDL cholesterol, showed that sUA levels were independently associated with FFM (ß = 0.35, p < 0.0001) and, albeit less significantly, with triglycerides (ß = 0.23, p < 0.05). The introduction of height-normalized FFM (FFM index) in the regression model, however, abrogated the predictive role of FFM on sUA. Conclusions: FFM mass is a strong predictor of sUA. PWS is associated to lower sUA levels than controls likely due to genetic predisposition to different body composition and healthier metabolic phenotype. Further studies are warranted to assess purine metabolism and the clinical significance of the FFM index in PWS.

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.

Improvement in glycaemic parameters using SGLT-2 inhibitor and GLP-1 agonist in combination in an adolescent with diabetes mellitus and Prader-Willi syndrome: a case report.

Objectives Prader-Willi Syndrome (PWS) is characterised by hyperphagia often leading to obesity; a known risk factor for insulin resistance and type 2 (T2) diabetes. We present a prepubertal girl with PWS who developed diabetes. Case presentation Our case was diagnosed with PWS in infancy following investigation for profound central hypotonia and feeding difficulties. She commenced growth hormone (GH) aged 8 years for short stature and treatment improved linear growth. At age 12 years, she presented with polydipsia, polyuria and vulvovaginitis. She was overweight (BMI SDS +1.43). Diabetes was diagnosed (Blood glucose = 24.2 mmol/L, HbA1c = 121 mmol/mol or 13.2%). She was not acidotic and had negative blood ketones. Autoantibodies typical of type 1 diabetes were negative. She was initially treated with basal bolus insulin regime. GH was discontinued 3 months later due to concerns regarding GH-induced insulin resistance. Off GH, insulin requirements reduced to zero, allowing Metformin monotherapy. However off GH, she reported significant lethargy with static growth and increased weight. Combinations of Metformin with differing insulin regimes did not improve glucose levels. Liraglutide (GLP-1 agonist) and Metformin did not improve glucose levels nor her weight. Liraglutide and Empaglifozin (SGLT-2 inhibitor) therapy used in combination were well tolerated and demonstrated rapid normalisation of blood glucose and improvement in her HbA1c to within target (48 mmol/mol) which was sustained after 6 months of treatment. Conclusions Newer treatments for type 2 diabetes (e. g. GLP-1 agonists or SGLT-2 inhibitors) offer potential treatment options for those with diabetes and PWS when conventional treatments are ineffective.

The Sun's Vitamin in Adult Patients Affected by Prader-Willi Syndrome.

Prader-Willi syndrome (PWS) is a genetic disorder characterized by hyperphagia with progressive, severe obesity, and an increased risk of obesity-related comorbidities in adult life. Although low dietary vitamin D intake and low 25-hydroxy vitamin D (25OHD) levels are commonly reported in PWS in the context of bone metabolism, the association of low 25OHD levels with fat mass has not been extensively evaluated in PWS adults. The aims of this study were to investigate the following in PWS adults: (1) 25OHD levels and the dietary vitamin D intake; (2) associations among 25OHD levels with anthropometric measurements and fat mass; (3) specific cut-off values for body mass index (BMI) and fat mass predictive of the 25OHD levels. In this cross-sectional, single-center study we enrolled 30 participants, 15 PWS adults (age 19-41 years and 40% males) and 15 control subjects matched by age, sex, and BMI from the same geographical area (latitude 40° 49' N; elevation 17 m). Fat mass was assessed using a bioelectrical impedance analysis (BIA) phase-sensitive system. The 25OHD levels were determined by a direct competitive chemiluminescence immunoassay. Dietary vitamin D intake data was collected by three-day food records. The 25OHD levels in the PWS adults were constantly lower across all categories of BMI and fat mass compared with their obese counterpart. The 25OHD levels were negatively associated with BMI (p = 0.04), waist circumference (p = 0.03), fat mass (p = 0.04), and dietary vitamin D intake (p < 0.001). During multiple regression analysis, dietary vitamin D intake was entered at the first step (p < 0.001), thus explaining 84% of 25OHD level variability. The threshold values of BMI and fat mass predicting the lowest decrease in the 25OHD levels were found at BMI ≥ 42 kg/m2 (p = 0.01) and fat mass ≥ 42 Kg (p = 0.003). In conclusion, our data indicate that: (i) 25OHD levels and dietary vitamin D intake were lower in PWS adults than in the control, independent of body fat differences; (ii) 25OHD levels were inversely associated with BMI, waist circumference, and fat mass, but low dietary vitamin D intake was the major determinant of low vitamin D status in these patients; (iii) sample-specific cut-off values of BMI and fat mass might help to predict risks of the lowest 25OHD level decreases in PWS adults. The presence of trained nutritionists in the integrated care teams of PWS adults is strongly suggested in order to provide an accurate nutritional assessment and tailored vitamin D supplementations.

Irisin levels in genetic and essential obesity: clues for a potential dual role.

Irisin is conventionally regarded as a myokine involved in the browning of white adipose tissue, energy expenditure and glucose tolerance. Its potential link to fat accumulation and metabolic dysfunction is debated. We sought to explore the relationship between circulating irisin and components of body composition in two different phenotypes of severe obesity. For this purpose, 30 obese adults with Prader-Will syndrome (PWS) (age 35.7 ± 1.5 y, BMI 45.5 ± 1.5 kg/m2) and 30 adult controls with common obesity (age 34.9 ± 1.7 y, BMI 46.8 ± 1.4 kg/m2) underwent analysis of irisin levels, metabolic profile, body composition and resting energy expenditure (REE). Normal irisin levels were obtained from a group of 20 lean donors (age 32.4 ± 1.5 y, BMI 23.8 ± 0.8 kg/m2). Expected differences in body composition and metabolic profile existed between study groups. PWS exhibited lower muscle mass (p < 0.001), FFM (p < 0.001), REE (p < 0.001), as well as insulin (p < 0.05), HOMA-IR (p < 0.05) and triglycerides levels (p < 0.05) than controls with common obesity. In PWS, irisin levels were significantly lower and overall less dispersed than in controls with common obesity (p < 0.05), while being similar to values recorded in lean subjects. To explore the relation between irisin and body composition in obesity, univariate correlation analysis in the obese populations as a whole showed positive associations between irisin and muscle mass (p = 0.03) as well as REE (p = 0.01), which disappeared when controlled for the PWS status. Noticeably, a positive association became evident between irisin and %FM after controlling for the PWS status (p = 0.02). Also positive were associations between irisin and insulin (p = 0.02), HOMA-IR (p = 0.02) and triglycerides (p = 0.04). In stepwise multivariable regression analysis, irisin levels were independently predicted by the PWS status (p = 0.001), %FM (p = 0.004) and triglycerides (p = 0.008). Current results suggest that obese adults with PWS harbor lower irisin levels than individuals with common obesity. The divergent models of obesity herein studied suggest a potential link between circulating irisin and muscle mass and metabolic dysfunction relating to adiposity.

Myokine levels after resistance exercise in young adults with Prader-Willi syndrome (PWS).

Individuals with PWS require marked caloric restriction and daily exercise to prevent morbid obesity. Lower energy expenditure, hypotonia, decreased muscle mass, and cognitive impairment make exercise challenging for this population. Exercise guidelines include resistance training as an important component. Myokine responses to resistance exercise may mediate beneficial metabolic effects. We aimed to determine if young PWS adults can perform a resistance exercise program and to measure myokine responses in PWS versus age- and BMI-matched controls. Each group included 11 participants (7M/4F). Ages and BMI for PWS and controls were 30.7 ± 4.6 versus 30.1 ± 4.3 years and 28.3 ± 4.3 versus 28.2 ± 4.2 kg/m2 , respectively. Glucose, creatine kinase (CK), lactate, and myokines were measured before, after, 30, and 60 min after completing eight resistance exercises. Myokines were assayed using a multiplex myokine panel (Merck Millipore). CK was lower in PWS versus controls (62 ± 16 vs.322 ± 100 U/L, p < .04). Peak lactate was 3.7 ± 0.7 in PWS versus 7.3 ± 0.7 mmol/Lin controls (p < .001). The increase in interleukin-6 was similar in PWS and controls (41 ± 16% and 35 ± 10%, respectively). Pre- and post-exercise levels of the six myokines assayed showed no consistent differences between the PWS and control participants. PWS young adults are capable of performing resistance/strength-building exercise. The lower CK and peak lactate levels in PWS may reflect decreased muscle mass in this population. Further studies are needed to determine optimal exercise regimens and assess the role of myokines incontributing to the metabolic phenotype of PWS.

Single-Case Study of Appetite Control in Prader-Willi Syndrome, Over 12-Years by the Indian Extract Caralluma fimbriata.

This paper reports on the successful management of hyperphagia (exaggerated hunger) in a 14yr-old female with Prader-Willi syndrome (PWS). This child was diagnosed with PWS, (maternal uniparental disomy) at 18 months due to developmental delay, hypertonia, weight gain and extreme eating behaviour. Treatment of a supplement for appetite suppression commenced at 2 years of age. This single-case records ingestion of an Indian cactus succulent Caralluma fimbriata extract (CFE) over 12 years, resulting in anecdotal satiety, free access to food and management of weight within normal range. CFE was administered in a drink daily and dose was slowly escalated by observation for appetite suppression. Rigorous testing determined blood count, vitamins, key minerals, HbA1c, IGF-1 and function of the liver and thyroid all within normal range. The report suggests a strategy for early intervention against hyperphagia and obesity in PWS. This case was the instigator of the successful Australian PWS/CFE pilot and though anecdotal, the adolescent continues to ingest CFE followed by paediatricians at the Royal Children's Hospital Melbourne, Victoria, Australia. Future clinical trials are worth considering, to determine an appropriate dose for individuals with PWS.

Prevalence of growth hormone (GH) deficiency in previously GH-treated young adults with Prader-Willi syndrome.

OBJECTIVE: Some features of subjects with Prader-Willi syndrome (PWS) resemble those seen in growth hormone deficiency (GHD). Children with PWS are treated with growth hormone (GH), which has substantially changed their phenotype. Currently, young adults with PWS must discontinue GH after attainment of adult height when they do not fulfil the criteria of adult GHD. Limited information is available about the prevalence of GHD in adults with PWS. This study aimed to investigate the GH/insulin-like growth factor (IGF-I) axis and the prevalence of GHD in previously GH-treated young adults with PWS. DESIGN: Cross-sectional study in 60 young adults with PWS. MEASUREMENTS: Serum IGF-I and IGFBP-3 levels, GH peak during combined growth hormone-releasing hormone (GHRH)-arginine stimulation test. RESULTS: Serum IGF-I was <-2 standard deviation scores (SDS) in 2 (3%) patients, and IGFBP-3 was within the normal range in all but one patient. Median (IQR) GH peak was 17.8 µg/L (12.2; 29.7) [~53.4 mU/L] and below 9 µg/L in 9 (15%) patients. Not one patient fulfilled the criteria for adult GHD (GH peak < 9 µg/L and IGF-I < -2 SDS), also when BMI-dependent criteria were used. A higher BMI and a higher fat mass percentage were significantly associated with a lower GH peak. There was no significant difference in GH peak between patients with a deletion or a maternal uniparental disomy (mUPD). CONCLUSIONS: In a large group of previously GH-treated young adults with PWS, approximately 1 in 7 exhibited a GH peak <9 µg/L during a GHRH-arginine test. However, none of the patients fulfilled the consensus criteria for adult GHD.

A rapid and accurate methylation-sensitive high-resolution melting analysis assay for the diagnosis of Prader Willi and Angelman patients.

BACKGROUND: Prader Willi (PWS) and Angelman (AS) syndromes are rare genetic disorders characterized by deletions, uniparental disomy, and imprinting defects at chromosome 15. The loss of function of specific genes caused by genetic alterations in paternal allele causes PWS while the absence in maternal allele results AS. The laboratory diagnosis of PWS and AS is complex and demands molecular biology and cytogenetics techniques to identify the genetic mechanism related to the development of the disease. The DNA methylation analysis in chromosome 15 at the SNURF-SNRPN locus through MS-PCR confirms the diagnosis and distinguishes between PWS and AS. Our study aimed to establish the MS-PCR technique associated with High-Resolution Melting (MS-HRM) in PWS and AS diagnostic with a single pair of primers. METHODS: We collected blood samples from 43 suspected patients to a cytogenetic and methylation analysis. The extracted DNA was treated with bisulfite to perform comparative methylation analysis. RESULTS: MS-HRM and MS-PCR agreed in 100% of cases, identifying 19(44%) PWS, 3(7%) AS, and 21(49%) Normal. FISH analysis detected four cases of PWS caused by deletions in chromosome 15. CONCLUSION: The MS-HRM showed good performance with a unique pair of primers, dispensing electrophoresis gel analysis, offering a quick and reproducible diagnostic.

Evaluation of IGF1/IGFBP3 Molar Ratio as an Effective Tool for Assessing the Safety of Growth Hormone Therapy in Small-for-gestational-age, Growth Hormone-Deficient and Prader-Willi Children

Objective: IGF1 concentration is the most widely used parameter for the monitoring and therapeutic adaptation of recombinant human growth hormone (rGH) treatment. However, more than half the variation of the therapeutic response is accounted for by variability in the serum concentrations of IGF1 and IGFBP3. We therefore compared the use of IGF1/IGFBP3 molar ratio with that of IGF1 concentration alone. Methods: We selected 92 children on rGH for this study and assigned them to three groups on the basis of growth deficiency etiology: small for gestational age (SGA), GH deficiency (GHD) and Prader-Willi syndrome (PWS). Plasma IGF1 and IGFBP3 concentrations and their molar ratio were determined. Results: Before rGH treatment, mean IGF1/IGFBP3 molar ratio in the SGA, GHD and PWS groups was 0.14±0.04, 0.07±0.01 and 0.12±0.02, respectively. After the initiation of rGH treatment, these averages were 0.19±0.07, 0.20±0.08 and 0.19±0.09, within the normal range for most children, even at puberty and despite some significant increases in serum IGF1 levels. Conclusion: We consider IGF1/IGFBP3 molar ratio to be a useful additional parameter for assessing therapeutic safety in patients on rGH, and for maintaning the values within the normal range for age and pubertal stage.

Hormonal and metabolic effects of carbohydrate restriction in children with Prader-Willi syndrome.

OBJECTIVE: Macronutrient regulation of hyperphagia and adiposity in Prader-Willi syndrome (PWS) is poorly understood. We compared fasting and postprandial concentrations of hormones and metabolites in eight PWS children (age 9-18 years) fed, in random order, low carbohydrate, high-fat (LC, 15% carb; 65% fat; 20% protein) and low-fat, high carbohydrate (LF, 65% carb, 15% fat, 20% protein) diets matched for calories and protein. METHODS: Participants were randomized to consume either the LC or LF diet during a first hospital admission and the second diet during a subsequent admission. Blood samples were obtained after overnight fasting and 1 hour after a mixed meal. RESULTS: Relative to subjects consuming the LF diet, subjects consuming the LC diet had: lower postprandial insulin concentrations (P = 0.02); higher fasting GLP-1 AND GIP concentrations and increased postprandial GLP-1 (P < 0.02); reduced ratio of fasting ghrelin to GLP-1 (P = 0.0078); increased FFA and fatty acid oxidation, as assessed by concentrations of even-chain acylcarnitines (P < 0.001); lower fasting TG and TG/HDL ratio (P < 0.01); and higher concentrations of branch chain amino acids (P < 0.01). There were no changes in glucose, PYY, or adiponectin. CRP, AST and ALT were all higher (P < 0.01) on the LC diet. CONCLUSIONS: Increases in GLP-1 with low carbohydrate feeding and reductions in the ratio of ghrelin to GLP-1 might limit food intake and improve glycaemic control in PWS. Other potential benefits of carbohydrate restriction may include fat mobilization and oxidation and reductions in the TG/HDL ratio, a marker of insulin resistance. However, increases in CRP, AST and ALT necessitate longer-term studies of low carbohydrate efficacy and safety.

An update on the role of RANKL-RANK/osteoprotegerin and WNT-ß-catenin signaling pathways in pediatric diseases.

BACKGROUND: Bone remodeling is a lifelong process due to the balanced activity of osteoclasts (OCs), the bone-reabsorbing cells, and osteoblasts (OBs), and the bone-forming cells. This equilibrium is regulated by numerous cytokines, but it has been largely demonstrated that the RANK/RANKL/osteoprotegerin and Wnt/ß-catenin pathways play a key role in the control of osteoclastogenesis and osteoblastogenesis, respectively. The pro-osteoblastogenic activity of the Wnt/ß-catenin can be inhibited by sclerostin and Dickkopf-1 (DKK-1). RANKL, sclerostin and DKKs-1 are often up-regulated in bone diseases, and they are the target of new monoclonal antibodies. DATA SOURCES: The authors performed a systematic literature search in PubMed and EMBASE to June 2018, reviewed and selected articles, based on pre-determined selection criteria. RESULTS: We re-evaluated the role of RANKL, osteoprotegerin, sclerostin and DKK-1 in altered bone remodeling associated with some inherited and acquired pediatric diseases, such as type 1 diabetes mellitus (T1DM), alkaptonuria (AKU), hemophilia A, osteogenesis imperfecta (OI), 21-hydroxylase deficiency (21OH-D) and Prader-Willi syndrome (PWS). To do so, we considered recent clinical studies done on pediatric patients in which the roles of RANKL-RANK/osteoprotegerin and WNT-ß-catenin signaling pathways have been investigated, and for which innovative therapies for the treatment of osteopenia/osteoporosis are being developed. CONCLUSIONS: The case studies taken into account for this review demonstrated that quite frequently both bone reabsorbing and bone deposition are impaired in pediatric diseases. Furthermore, for some of them, bone damage began in childhood but only manifested with age. The use of denosumab could represent a valid alternative therapeutic approach to improve bone health in children, although further studies need to be carried out.

Newborn screening for Prader-Willi syndrome is feasible: Early diagnosis for better outcomes.

Prader-Willi syndrome (PWS), is a complex genetic disease affecting 1/15,000 individuals, characterized by lack of expression of genes on the paternal chromosome 15q11-q13 region. Clinical features include central hypotonia, poor suck, learning and behavior problems, growth hormone deficiency with short stature, hyperphagia, and morbid obesity. Despite significant advances in genetic testing, the mean age for diagnosis in PWS continues to lag behind. Our goal was to perform a pilot feasibility study to confirm the diagnosis utilizing different genetic technologies in a cohort of 34 individuals with genetically confirmed PWS and 16 healthy controls from blood samples spotted and stored on newborn screening (NBS) filter paper cards. DNA was isolated from NBS cards, and PWS testing performed using DNA methylation-specific PCR (mPCR) and the methylation specific-multiplex ligation dependent probe amplification (MS-MLPA) chromosome 15 probe kit followed by DNA fragment analysis for methylation and copy number status. DNA extraction was successful in 30 of 34 PWS patients and 16 controls. PWS methylation testing was able to correctly identify all PWS patients and MS-MLPA was able to differentiate between 15q11-q13 deletion and non-deletion status and correctly identify deletion subtype (i.e., larger Type I or smaller Type II). mPCR can be used to diagnose PWS and MS-MLPA testing to determine both methylation status as well as the type of deletion or non-deletion status from DNA extracted from NBS filter paper. We propose that PWS testing in newborns is possible and could be included in the Recommended Uniform Screening Panel after establishing a validated cost-effective method.

Obestatin and adropin in Prader-Willi syndrome and nonsyndromic obesity: Associations with weight, BMI-z, and HOMA-IR.

The roles of obestatin and adropin in paediatric obesity are poorly understood. We compared obestatin and adropin concentrations in younger (n = 21) and older children (n = 14) with Prader-Willi syndrome (PWS) and age and BMI-z-matched controls (n = 31). Fasting plasma obestatin and adropin were higher in younger children with PWS than controls; adropin was also higher in older children with PWS. Growth hormone treatment had no effects on obestatin or adropin in PWS. The ratio of ghrelin to obestatin declined from early to late childhood but was higher in older PWS than older controls. Adropin correlated with fasting glucose in the PWS group only. Changes in the ratio of ghrelin to obestatin may suggest changes in the processing of preproghrelin to ghrelin and obestatin during development and differential processing of preproghrelin in PWS.