Corrigendum: Kidney disease in adults with Prader-Willi syndrome: international cohort study and systematic literature review

[This corrects the article DOI: 10.3389/fendo.2023.1168648.].

Malignancies in Prader-Willi Syndrome: Results From a Large International Cohort and Literature Review

CONTEXT

Prader-Willi syndrome (PWS) is a complex disorder combining hypothalamic dysfunction, neurodevelopmental delay, hypotonia, and hyperphagia with risk of obesity and its complications. PWS is caused by the loss of expression of the PWS critical region, a cluster of paternally expressed genes on chromosome 15q11.2-q13. As life expectancy of patients with PWS increases, age-related diseases like malignancies might pose a new threat to health.

OBJECTIVE

To investigate the prevalence and risk factors of malignancies in patients with PWS and to provide clinical recommendations for cancer screening.

METHODS

We included 706 patients with PWS (160 children, 546 adults). We retrospectively collected data from medical records on past or current malignancies, the type of malignancy, and risk factors for malignancy. Additionally, we searched the literature for information about the relationship between genes on chromosome 15q11.2-q13 and malignancies.

RESULTS

Seven adults (age range, 18-55 years) had been diagnosed with a malignancy (acute lymphoblastic leukemia, intracranial hemangiopericytoma, melanoma, stomach adenocarcinoma, biliary cancer, parotid adenocarcinoma, and colon cancer). All patients with a malignancy had a paternal 15q11-13 deletion. The literature review showed that several genes on chromosome 15q11.2-q13 are related to malignancies.

CONCLUSION

Malignancies are rare in patients with PWS. Therefore, screening for malignancies is only indicated when clinically relevant symptoms are present, such as unexplained weight loss, loss of appetite, symptoms suggestive of paraneoplastic syndrome, or localizing symptoms. Given the increased cancer risk associated with obesity, which is common in PWS, participation in national screening programs should be encouraged.

Proteome profiling identifies circulating biomarkers associated with hepatic steatosis in subjects with Prader-Willi syndrome

Introduction

Prader-Willi syndrome (PWS) is a rare genetic disorder characterized by loss of expression of paternal chromosome 15q11.2-q13 genes. Individuals with PWS exhibit unique physical, endocrine, and metabolic traits associated with severe obesity. Identifying liver steatosis in PWS is challenging, despite its lower prevalence compared to non-syndromic obesity. Reliable biomarkers are crucial for the early detection and management of this condition associated with the complex metabolic profile and cardiovascular risks in PWS.

Methods

Circulating proteome profiling was conducted in 29 individuals with PWS (15 with steatosis, 14 without) using the Olink Target 96 metabolism and cardiometabolic panels. Correlation analysis was performed to identify the association between protein biomarkes and clinical variables, while the gene enrichment analysis was conducted to identify pathways linked to deregulated proteins. Receiver operating characteristic (ROC) curves assessed the discriminatory power of circulating protein while a logistic regression model evaluated the potential of a combination of protein biomarkers.

Results

CDH2, CTSO, QDPR, CANT1, ALDH1A1, TYMP, ADGRE, KYAT1, MCFD, SEMA3F, THOP1, TXND5, SSC4D, FBP1, and CES1 exhibited a significant differential expression in liver steatosis, with a progressive increase from grade 1 to grade 3. FBP1, CES1, and QDPR showed predominant liver expression. The logistic regression model, -34.19 + 0.85 * QDPR*QDPR + 0.75 * CANT1*TYMP - 0.46 * THOP1*ALDH1A, achieved an AUC of 0.93 (95% CI: 0.63-0.99), with a sensitivity of 93% and specificity of 80% for detecting steatosis in individuals with PWS. These biomarkers showed strong correlations among themselves and were involved in an interconnected network of 62 nodes, related to seven metabolic pathways. They were also significantly associated with cholesterol, LDL, triglycerides, transaminases, HbA1c, FLI, APRI, and HOMA, and showed a negative correlation with HDL levels.

Conclusion

The biomarkers identified in this study offer the potential for improved patient stratification and personalized therapeutic protocols.

Differences in spinal postures and mobility among adults with Prader-Willi syndrome, essential obesity, and normal-weight individuals

Introduction

Spinal kinematics/motion are reported to be altered in adolescents and adults with essential obesity, while no information is available in patients with Prader-Willi syndrome so far. The aim of this study was to examine cross-sectionally the characteristics of spinal postures and mobility in 34 patients with PWS, in 35 age- and sex-matched adults with essential obesity, and in 37 normal-weight individuals.

Methods

Spinal posture and mobility were assessed using a radiation-free back scan, the Idiag M360 (Idiag, Fehraltorf, Switzerland). Differences in spinal posture and mobility between the three groups were determined using a two-way analysis of variance.

Results

Adults with Prader-Willi syndrome had greater thoracic kyphosis [difference between groups (Δ) = 9.60, 95% CI 3.30 to 15.60, p = 0.001], less lumbar lordosis (Δ = -6.50, 95% CI -12.70 to -0.30, p = 0.03) as well as smaller lumbar and hip mobility than those with normal weight.

Discussion

Although the characteristics of the spine in patients with Prader-Will syndrome appear to be similar to that found in subjects with essential obesity, Prader-Willi syndrome was found to influence lumbar movements more than thoracic mobility. These results provide relevant information about the characteristics of the spine in adults with Prader-Willi syndrome to be taken into careful consideration in the management of spinal conditions. These findings also highlight the importance of considering the musculoskeletal assessment of spinal postures and approaches targeting spinal and hip flexibility in adults with Prader-Willi syndrome.

Kidney disease in adults with Prader-Willi syndrome: international cohort study and systematic literature review

Background

Prader-Willi syndrome (PWS) is a rare, complex, genetic disorder characterized by hyperphagia, hypotonia, delayed psychomotor development, low muscle mass and hypothalamic dysfunction. Adults with PWS often have obesity, hypertension and type 2 diabetes mellitus (DM2), known risk factors for cardiovascular disease (CVD) and chronic kidney disease (CKD). Early symptoms of CVD and CKD may be masked by intellectual disability and inability to express physical complaints. Furthermore, kidney diseases are often asymptomatic. Therefore, renal and cardiovascular disease might be missed in patients with PWS. Microalbuminuria is an early sign of microvascular damage in the kidneys and other vascular beds. Therefore, we screened our adult PWS cohort for the presence of elevated urinary albumin and (micro)albuminuria.

Methods

We retrospectively collected anthropometric measurements, blood pressure, medical history, medication use, urine dipstick and biochemical measurements form electronic patient files. In addition, we performed a systematic literature review on kidney disease in PWS.

Results

We included 162 adults with genetically confirmed PWS (56% male, median age 28 years), of whom 44 (27%) had DM2. None had known CVD. All subjects had normal estimated glomerular filtration rate (eGFR) according to non-PWS reference intervals. Elevated urinary albumin or (micro)albuminuria was present in 28 (18%); 19 out of 75 (25%) had an increased urinary albumin-to-creatinine ratio (UACR) and 10 out of 57 (18%) had an increased urinary protein-to-creatinine ratio. Elevated urinary albumin was present at a young age (median age 26 (IQR 24-32) years) and was associated with an significantly higher BMI and LDL-cholesterol levels and higher prevalence of DM2, hypertension and dyslipidemia than those with normal UACR (p=0.027, p=0.019, p<0.001, p<0.001, p=0.011 and respectively).

Conclusion

Upon screening, one in every five adults with PWS had increased urinary albumin or (micro)albuminuria, early signs of microvascular disease. All had normal eGFR, according to non-PWS reference intervals, and none had a formal diagnosis of CVD. As muscle mass is low in PWS, creatinine levels and eGFR may be spuriously normal. Urinalysis in this patient group can be used as a screening tool for microvascular (kidney) disease. We propose an algorithm for the detection and management of microvascular disease in adults with PWS.

The treatment of obesity in children and adolescents: consensus position statement of the Italian society of pediatric endocrinology and diabetology, Italian Society of Pediatrics and Italian Society of Pediatric Surgery

This Position Statement updates the different components of the therapy of obesity (lifestyle intervention, drugs, and surgery) in children and adolescents, previously reported in the consensus position statement on pediatric obesity of the Italian Society of Pediatric Endocrinology and Diabetology and the Italian Society of Pediatrics. Lifestyle intervention is the first step of treatment. In children older than 12 years, pharmacotherapy is the second step, and bariatric surgery is the third one, in selected cases. Novelties are available in the field of the medical treatment of obesity. In particular, new drugs demonstrated their efficacy and safety and have been approved in adolescents. Moreover, several randomized control trials with other drugs are in process and it is likely that some of them will become available in the future. The increase of the portfolio of treatment options for obesity in children and adolescents is promising for a more effective treatment of this disorder.

The neutrophil to lymphocyte ratio (NLR) positively correlates with the presence and severity of metabolic syndrome in obese adults, but not in obese children/adolescents

Metabolic syndrome (MetS) associated with obesity is a pathological condition increasing worldwide. Recent studies have demonstrated that the neutrophil to lymphocyte ratio (NLR) can be successfully used to stage MetS in obese adults. The aim of the study was to evaluate NLR values in 552 children/adolescents (M 219, F 333; 14.8 [12.9-16.3] years) and 231 adults (M 88, F 143; 52.3 [36.4-63.3] years) with morbid obesity, subdivided into subgroups according with the presence or absence of MetS. Adult patients with obesity showed a higher prevalence of MetS compared to the pediatric population (71% vs 26%), associated with a greater number of subjects with 3 and 4-5 altered components for MetS. NLR was higher (P-value = 0.041) in adults with MetS compared with those without. NLR values also positively correlated with the severity grade of the syndrome (P-value = 0.032). By contrast, in pediatric subjects with obesity with MetS, NLR values were comparable with those recorded in subjects without MetS (P-value = 0.861), no correlation being found with MetS severity (P-value = 0.441). Our study confirms the importance of NLR as an inflammatory indicator associated with MetS in adult subjects with severe obesity, while it excludes a similar role in children/adolescents.

Long-term effects of GH therapy in adult patients with Prader-Willi syndrome: a longitudinal study

Introduction

Prader-Willi syndrome (PWS) is a complex disorder resulting from the failure of expression of paternal alleles in the PWS region of chromosome 15. The PWS phenotype resembles that observed in the classic non-PWS GH deficiency (GHD), including short stature, excessive fat mass, and reduced muscle mass. To date, a small number of studies on the long-term effects of GH treatment are available in adult subjects with PWS.

Methods

In this longitudinal study, 12 obese subjects with PWS (GHD/non-GHD 6/6) were treated for a median of 17 years, with a median GH dose of 0.35 mg/day. The median age was 27.1 years. Anthropometric, body composition, hormonal, biochemical, and blood pressure variables were analyzed in all subjects.

Results

Waist circumference was significantly lower at the end of the treatment period (p-value=0.0449), while body mass index (BMI) did not differ significantly. Compared to the baseline, a highly significant reduction of Fat Mass % (FM%) was observed (p-value=0.0005). IGF-I SDS values significantly increased during GH therapy (p-value=0.0005). A slight impairment of glucose homeostasis was observed after GH therapy, with an increase in the median fasting glucose levels, while insulin, HOMA-IR, and HbA1c values remained unchanged. Considering GH secretory status, both subjects with and without GHD showed a significant increase in IGF-I SDS and a reduction of FM% after GH therapy (p-value= 0.0313 for all).

Discussion

Our results indicate that long-term GH treatment has beneficial effects on body composition and body fat distribution in adults with PWS associated with obesity. However, the increase in glucose values during GH therapy should be considered, and continuous surveillance of glucose metabolism is mandatory during long-term GH therapy, especially in subjects with obesity.

High levels of LIGHT/TNFSF14 in patients with Prader-Willi syndrome

PURPOSE/METHODS

Prader-Willi syndrome (PWS) is a rare genetic disorder displaying different clinical features, including obesity and bone impairment. LIGHT/TNFSF14 is a cytokine produced by immune cells affecting both fat and bone metabolism. The present study aimed to evaluate LIGHT serum levels in 28 children and 52 adult PWS patients compared to age and sex-matched controls, as well as correlations with parameters of bone and fat metabolism.

RESULTS

Median serum LIGHT levels were significantly increased in pediatric PWS with respect to controls [255.82 (284.43) pg/ml vs 168.11 (76.23) pg/ml, p ≤ 0.02] as well as in adult PWS compared to controls [296.85 (895.95) pg/ml vs 134.18 (141.18) pg/ml, p ≤ 0.001]. In pediatric PWS, LIGHT levels were positively correlated with weight-SDS, height-SDS, and glucose levels, and negatively with total 25 (OH) vitamin D, cholesterol, LDL cholesterol and triglycerides. Additionally, LIGHT levels were negatively correlated with total BMD and fat mass. In adult PWS, LIGHT levels were positively correlated with weight, HDL cholesterol and PTH, and negatively with glucose, insulin, HOMA-IR, total cholesterol, LDL cholesterol, triglycerides, calcium, phosphorus, 25(OH)Vitamin D as well as with instrumental parameters of bone and fat quality. Consistently, multiple regression analysis showed that LIGHT serum levels in pediatric and adult PWS were predicted by different parameters including 25 (OH) Vitamin D as well as DXA parameters of bone and fat quality.

CONCLUSIONS

In PWS children and adults the high levels of LIGHT could represent a marker of the altered bone and fat metabolism.

The Italian registry for patients with Prader-Willi syndrome

BACKGROUND

Prader-Willi syndrome (PWS) is a rare and complex genetic disease, with numerous implications on metabolic, endocrine, neuropsychomotor systems, and with behavioural and intellectual disorders. Rare disease patient registries are important scientific tools (1) to collect clinical and epidemiologic data, (2) to assess the clinical management including the diagnostic delay, (3) to improve patients' care and (4) to foster research to identify new therapeutic solutions. The European Union has recommended the implementation and use of registries and databases. The main aims of this paper are to describe the process of setting up the Italian PWS register, and to illustrate our preliminary results.

MATERIALS AND METHODS

The Italian PWS registry was established in 2019 with the aims (1) to describe the natural history of the disease, (2) to determine clinical effectiveness of health care services, (3) to measure and monitor quality of care of patients. Information from six different variables are included and collected into this registry: demographics, diagnosis and genetics, patient status, therapy, quality of life and mortality.

RESULTS

A total of 165 patients (50.3% female vs 49.7% male) were included into Italian PWS registry in 2019-2020 period. Average age at genetic diagnosis was 4.6 years; 45.4% of patients was less than 17 years old aged, while the 54.6% was in adult age (> 18 years old). Sixty-one percent of subjects had interstitial deletion of the proximal long arm of paternal chromosome 15, while 36.4% had uniparental maternal disomy for chromosome 15. Three patients presented an imprinting centre defect and one had a de novo translocation involving chromosome 15. A positive methylation test was demonstrated in the remaining 11 individuals but the underlying genetic defect was not identified. Compulsive food-seeking and hyperphagia was present in 63.6% of patients (prevalently in adults); 54.5% of patients developed morbid obesity. Altered glucose metabolism was present in 33.3% of patients. Central hypothyroidism was reported in 20% of patients; 94.7% of children and adolescents and 13.3% of adult patients is undergoing GH treatment.

CONCLUSIONS

The analyses of these six variables allowed to highlight important clinical aspects and natural history of PWS useful to inform future actions to be taken by national health care services and health professionals.

Multicentric Italian case-control study on 25OH vitamin D levels in children and adolescents with Prader-Willi syndrome

PURPOSE

25OHD levels in patients with Prader-Willi Syndrome (PWS), the most frequent cause of genetic obesity with a peculiar fat mass distribution, are still debated. Insulin resistance (IR), Body Mass Index-SDS (BMI-SDS), Growth Hormone Therapy (GHT), and puberty onset seem to interact with 25OHD levels. The objectives of the study are: (1) To analyze 25OHD levels in pediatric PWS patients in comparison with a control group (CNT) (2) To evaluate a possible correlation between BMI-SDS, HOMA-IR, puberty, GHT, and 25OHD levels.

METHODS

This is a retrospective case-control, multicenter study. Data were collected among 8 different Italian Hospitals (outpatient clinics), over a period of four years (2016-2020). We included 192 genetically confirmed PWS and 192 CNT patients, aged 3-18 years, matched 1:1 for age, gender, BMI-SDS, Tanner stage, sun exposure, and month of recruitment.

RESULTS

No statistically significant differences in 25OHD levels were observed between the PWS population and the CNT (PWS 24.0 ng/mL vs CNT 22.5 ng/mL, p > 0.05), OR = 0.89 (95% CI 0.58-1.35). We observed a slight, although non-significant, reduction in 25OHD levels comparing NW and OB populations. HOMA-IR, puberty onset, genotype and GHT (previous or ongoing) did not show statistically significant correlation with 25OHD levels.

CONCLUSIONS

Our findings could be useful for clinicians to optimize the therapeutic management as well as to increase awareness of PWS.

Bone Health in Adults With Prader-Willi Syndrome: Clinical Recommendations Based on a Multicenter Cohort Study

CONTEXT

Prader-Willi syndrome (PWS) is a rare complex genetic syndrome, characterized by delayed psychomotor development, hypotonia, and hyperphagia. Hormone deficiencies such as hypogonadism, hypothyroidism, and growth hormone deficiency are common. The combination of hypotonia, low physical activity, and hypogonadism might lead to a decrease in bone mass and increase in fracture risk. Moreover, one would expect an increased risk of scoliosis due to hypotonia and low physical activity.

OBJECTIVE

To study the prevalence and risk factors for skeletal problems (reduced bone mineral density, fractures, and scoliosis) in adults with PWS.

METHODS

We retrospectively collected patient characteristics, medical history, medication, biochemical measurements, dual-energy X-ray absorptiometry scans, and spinal X-rays and reviewed the current literature.

RESULTS

We included 354 adults with PWS (median age 31 years; 43% males), of whom 51 (14%) had osteoporosis (T-score below -2.5) and 143 (54%) had osteopenia (T-score -1 to -2.5). The most prevalent modifiable risk factors for osteoporosis were hypogonadism, insufficient dairy intake, sedentary lifestyle, and corticosteroid use. Male sex was associated with osteoporosis (P = .005). Growth hormone treatment was not associated with osteoporosis. A history of vertebral fractures was present in 10 (3%) and nonvertebral fractures in 59 (17%). Scoliosis was present in 263 (80%), but no modifiable risk factors were identified.

CONCLUSION

Besides scoliosis, osteoporosis is common in adults with PWS. Based on the literature and the risk factors for osteoporosis found in our cohort, we provide practical clinical recommendations to avoid skeletal complications in these vulnerable patients.

OR27-5 Malignancies in Prader-Willi Syndrome: Practical Recommendations Based on a Large International Cohort

Introduction

Prader-Willi syndrome (PWS) is a complex disorder combining hypothalamic dysfunction, pituitary hormone deficiencies, neurodevelopmental delay, high pain threshold, hypotonia and hyperphagia with risk of obesity and its complications. PWS is caused by the loss of expression of a cluster of paternally expressed genes on chromosome 15q11.2-q13 called the PWS critical region, mostly due to paternal deletion (DEL) or maternal uniparental disomy. As life expectancy of patients with PWS increases, age-related diseases like malignancies might pose a new threat to health. Multiple genes in the PWS critical region have been associated with the development of malignancies and obesity is a risk factor for many types of malignancies. The aim of this study was to investigate the prevalence and pathogenesis of malignancies and to provide clinical recommendations for screening in patients with PWS.

Methods

We collected information on a (for rare disorders) exceptionally large cohort of 706 patients with PWS (160 children, 546 adults). All patients had visited the seven participating centers in Europe and Australia. Data was collected retrospectively from medical records on past or current malignancies, the type of malignancy and risk factors for malignancies. Genotype, age, gender, body mass index (BMI), tobacco use, presence of type 2 diabetes mellitus, growth hormone treatment and sex hormone replacement therapy were assessed in relation to the occurrence of malignancies. Additionally, we systematically searched the literature for information about the relationship between genes in the PWS critical region and malignancies.

Results

Seven adults (age range 18-55 years old) had been diagnosed with malignancies (acute lymphoblastic leukemia, intracranial hemangiopericytoma, melanoma, adenocarcinoma of the stomach, cholangiocarcinoma, parotid adenocarcinoma and colorectal carcinoma). Genetic subtype was DEL for 100% of the patients with malignancies, compared to 58% in patients without a malignancy (p=0.045). Age, gender, BMI, tobacco use, type 2 diabetes mellitus, growth hormone treatment and sex hormone replacement were not significantly related to the presence of malignancies.

Conclusion

In conclusion, malignancies are rare in patients with PWS. Remarkably, patients with the DEL genetic subtype have a significantly higher risk of developing malignancies compared to patients with other genotypes. Although malignancies are rare in PWS, participation in regular national screening programs for cervical, breast and colon cancer is important as the high pain threshold and intellectual disability make presentation of physical complaints less reliable. We recommend to perform additional diagnostic testing in case of symptoms suggestive of paraneoplastic syndrome, localizing symptoms, loss of appetite or unexplained weight loss.

Presentation: Tuesday, June 14, 2022 10:45 a.m. - 11:00 a.m.

High Tg/HDL-Cholesterol Ratio Highlights a Higher Risk of Metabolic Syndrome in Children and Adolescents with Severe Obesity

Few data are currently available on the reliability of the different anthropometric, instrumental and biochemical indexes in recognizing the presence of metabolic syndrome (MetS) in children and adolescents with severe obesity. Therefore, the objective of our study was to find out the simplest and most accurate predictive index of MetS in this population at-risk. In 1065 children and adolescents (563 f, 502 m), aged 14.6 ± 2.1 years (range 10–17), with severe obesity [BMI-SDS 3.50 ± 0.36 (range 3.00–5.17)], the following indexes were evaluated: BMI, BMI-SDS, Tri-Ponderal Mass Index, Waist-to-Height ratio, TG/HDL-Cholesterol ratio, Cardiometabolic Index (CMI), and Visceral Adiposity Index (VAI). For each subject, all the components of MetS, defined according to the IDF criteria, were determined. Overall, the presence of MetS was found in 324 patients (30.4%), 167 males (33.3%) and 157 females (27.9%). According to the ROC analysis, three indexes (VAI, CMI and TG/HDL-Cholesterol ratio), performed significantly better than the other ones in identifying MetS, with no difference among them. In conclusion, the TG/HDL ratio, which just needs the evaluation of two simple biochemical parameters, offers the same accuracy as other more sophisticated indexes in recognizing MetS in children and adolescents with severe obesity, thus making it the best predictor to be easily used.

The Hyperphagia Questionnaire: Insights From a Multicentric Validation Study in Individuals With Prader Willi Syndrome

BACKGROUND/OBJECTIVES

The present study aimed to validate the Italian version of the Hyperphagia Questionnaire (HQ), a 11-items questionnaire developed to assess hyperphagia in individuals with Prader-Willi syndrome (PWS). This is a complex neurodevelopmental disorder characterized by endocrine dysfunction, hypotonia, intellectual disability, psychiatric disorders and obesity.

METHODS

Parents of 219 individuals with PWS (age range 3-54 years; Mage = 17.90; 108 Males), recruited in 12 hospitals in Italy responded to HQ during routine visits. In function of the level of analyses the sample was divided into two subgroups (<18> years) or into four age-subgroups (2.5-4.5; 4.5-8; 8-18; >18 years) corresponding to different clinical stages.

RESULTS

Confirmatory factor analysis (CFA) confirmed the three hyperphagic subdimensions of the original structure (behavior, drive, and severity), but one item was dropped out, reducing the final version to 10 items. Using multi-group CFA, HQ showed satisfactory indexes of measurement invariance by age. Good indexes of internal consistency (Cronbach's alpha and McDonald's Omega coefficients) were found for each subdimension. The three hyperphagia subdimensions positively converged with other food-related measures: emotional overeating, food enjoyment, food responsiveness, and satiety responsiveness. A significant increase of all hyperphagic subdimensions was found across age groups. Higher hyperphagic levels were found in participants with higher body mass index. Hyperphagic drive differently increased in function of the interaction between age and underlying genetic mechanisms.

CONCLUSION

The Italian version of the HQ is a psychometrically valid and reliable instrument for assessing hyperphagia in individuals with PWS. This tool may prove useful to evaluate the efficacy of pharmacologic and rehabilitative treatments.

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.

Hypogonadism in Women with Prader-Willi Syndrome-Clinical Recommendations Based on a Dutch Cohort Study, Review of the Literature and an International Expert Panel Discussion

Prader-Willi syndrome (PWS) is a rare neuroendocrine genetic syndrome. Characteristics of PWS include hyperphagia, hypotonia, and intellectual disability. Pituitary hormone deficiencies, caused by hypothalamic dysfunction, are common and hypogonadism is the most prevalent. Untreated hypogonadism can cause osteoporosis, which is already an important issue in PWS. Therefore, timely detection and treatment of hypogonadism is crucial. To increase understanding and prevent undertreatment, we (1) performed a cohort study in the Dutch PWS population, (2) thoroughly reviewed the literature on female hypogonadism in PWS and (3) provide clinical recommendations on behalf of an international expert panel. For the cohort study, we retrospectively collected results of a systematic health screening in 64 female adults with PWS, which included a medical questionnaire, medical file search, medical interview, physical examination and biochemical measurements. Our data show that hypogonadism is frequent in females with PWS (94%), but is often undiagnosed and untreated. This could be related to unfamiliarity with the syndrome, fear of behavioral changes, hygienic concerns, or drug interactions. To prevent underdiagnosis and undertreatment, we provide practical recommendations for the screening and treatment of hypogonadism in females with PWS.

Parameters of Glucose Homeostasis in the Recognition of the Metabolic Syndrome in Young Adults with Prader-Willi Syndrome

To verify the accuracy of different indices of glucose homeostasis in recognizing the metabolic syndrome in a group of adult patients with Prader–Willi syndrome (PWS), 102 PWS patients (53 females/49 males), age ±SD 26.9 ± 7.6 yrs, Body Mass Index (BMI) 35.7 ± 10.7, were studied. The following indices were assessed in each subject during an oral glucose tolerance test (OGTT): 1 h (>155 mg/dL) and 2 h (140–199 mg/dL) glucose levels, the oral disposition index (ODI), the insulinogenic index (IGI), the insulin resistance (HOMA-IR) were evaluated at baseline, 1 h and 2 h. Although minor differences among indices were found, according to the ROC analysis, no index performed better in recognizing MetS. Furthermore, the diagnostic threshold levels changed over the years and therefore the age-related thresholds were calculated. The easily calculated HOMA-IR at baseline may be used to accurately diagnose MetS, thus avoiding more complicated procedures.

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.

Frequent Medical Supervision Increases the Effectiveness of a Longitudinal Multidisciplinary Body Weight Reduction Program: A Real-World Experience in a Population of Children and Adolescents with Obesity

Regular medical supervision represents a fundamental component of the clinical management of obesity. In fact, when frequently supplied it reduces the risk of failure associated with any body weight reduction program (BWRP), resulting in body weight gain. The aim of the present study was to establish the potential beneficial effects of increasing medical supervision on weight loss and other auxometric and cardiometabolic parameters in a population of children and adolescents with obesity (n = 158; F/M = 94/64; age range 9.7-17.3 years; body mass index, BMI = 37.8 ± 6.9 kg/m²), followed up for one year in a real-world setting, after and before a 3-week in-hospital BWRP. Weight loss was significantly associated with medical supervision and changes in several auxometric and cardiometabolic parameters such as fat mass, fat-free mass, waist and hip circumferences, total and LDL cholesterols, triglycerides, glucose, insulin, HOMA-IR, systolic blood pressure and IDF criteria for the diagnosis of metabolic syndrome. As expected, weight loss and, congruently, medical supervision, were significantly higher in responsive and stable subjects than in those belonging to the non-responsive group and in responsive subjects than those belonging to the stable group. While weight loss was significantly higher in subjects having class 2 and 3 obesity than those belonging to class 1 obesity group, medical supervision was significantly higher in subjects having class 3 than those having class 1 obesity. Weight loss was significantly higher in subjects suffering from metabolic syndrome than those without; nevertheless, no significant difference was found in medical supervision between these groups. Finally, sex was associated with no differences in weight loss and medical supervision. In conclusion, based on the results of a real-world experience, frequent medical supervision increases the weight loss associated with a longitudinal multidisciplinary BWRP, with a parallel improvement of a set of auxometric and cardiometabolic parameters. Prospectively, incentivising regular medical supervision should reduce the risk of BWRP failure and body weight gain, thus contributing to counteract the detrimental transition from simple obesity to metabolic syndrome in pediatric patients.

Hypogonadism in Adult Males with Prader-Willi Syndrome-Clinical Recommendations Based on a Dutch Cohort Study, Review of the Literature and an International Expert Panel Discussion

Prader-Willi syndrome (PWS) is a complex genetic syndrome characterized by hyperphagia, intellectual disability, hypotonia and hypothalamic dysfunction. Adults with PWS often have hormone deficiencies, hypogonadism being the most common. Untreated male hypogonadism can aggravate PWS-related health issues including muscle weakness, obesity, osteoporosis, and fatigue. Therefore, timely diagnosis and treatment of male hypogonadism is important. In this article, we share our experience with hypogonadism and its treatment in adult males with PWS and present a review of the literature. In order to report the prevalence and type of hypogonadism, treatment regimen and behavioral issues, we retrospectively collected data on medical interviews, physical examinations, biochemical measurements and testosterone replacement therapy (TRT) in 57 Dutch men with PWS. Fifty-six (98%) of the patients had either primary, central or combined hypogonadism. Untreated hypogonadism was associated with higher body mass index and lower hemoglobin concentrations. TRT was complicated by behavioral challenges in one third of the patients. Undertreatment was common and normal serum testosterone levels were achieved in only 30% of the patients. Based on the Dutch cohort data, review of the literature and an international expert panel discussion, we provide a practical algorithm for TRT in adult males with PWS in order to prevent undertreatment and related adverse health outcomes.

Hyponatremia in Children and Adults with Prader-Willi Syndrome: A Survey Involving Seven Countries

In Prader–Willi syndrome (PWS), conditions that are associated with hyponatremia are common, such as excessive fluid intake (EFI), desmopressin use and syndrome of inappropriate antidiuretic hormone (SIADH) caused by psychotropic medication. However, the prevalence of hyponatremia in PWS has rarely been reported. Our aim was to describe the prevalence and severity of hyponatremia in PWS. In October 2020, we performed a retrospective study based on the medical records of a large cohort of children and adults with PWS from seven countries. Among 1326 patients (68% adults), 34 (2.6%) had at least one episode of mild or moderate hyponatremia (125 ≤ Na < 135 mmol/L). The causes of non-severe hyponatremia were often multi-factorial, including psychotropic medication in 32%, EFI in 24% and hyperglycemia in 12%. No obvious cause was found in 29%. Seven (0.5%) adults experienced severe hyponatremia (Na < 125 mmol/L). Among these, five recovered completely, but two died. The causes of severe hyponatremia were desmopressin treatment for nocturnal enuresis (n = 2), EFI (n = 2), adrenal insufficiency (n = 1), diuretic treatment (n = 1) and unknown (n = 1). In conclusion, severe hyponatremia was very rare but potentially fatal in PWS. Desmopressin treatment for nocturnal enuresis should be avoided. Enquiring about EFI and monitoring serum sodium should be included in the routine follow-ups of patients with PWS.

Stimulated GH levels during the transition phase in Prader-Willi syndrome

PURPOSE

Early institution of GH therapy in children with Prader-Willi syndrome (PWS) yields beneficial effects on their phenotype and is associated with a persistent improvement of body composition, both in the transition age and in adulthood. Reports from GH stimulation testing in PWS adults, however, suggest that GH deficiency (GHD) is not a universal feature of the syndrome, and the current Consensus Guidelines suggest to perform a reassessment of persistent GHD so as to continue GH therapy after reaching adult height. Few data about GH responsiveness to stimulation testing throughout the transitional period in PWS are available to date. Thus, we investigated the prevalence of GHD in a large cohort of patients with PWS during the transition phase.

PATIENTS AND METHODS

One hundred forty-one PWS patients, 72 females and 69 males, aged 15.4-24.9 years, were evaluated by dynamic testing with growth hormone-releasing hormone (GHRH) plus arginine (GHRH + ARG). To define GHD, both BMI-dependent and BMI-independent diagnostic cut-off limits were considered.

RESULTS

According to BMI-dependent criteria, 10.7% of normal weight (NW), 18.5% of overweight and 22.1% of obese PWS maintained a status of GHD. Similar results were obtained by adopting a cut-off limit specific for the adult age (26.2%), as well as criteria for the transition phase in NW subjects (25%).

CONCLUSION

Our study shows that about 20% of patients with PWS fulfilled the criteria for GHD during the transitional age, suggesting the need of an integrated analysis of GH/IGF-I axis, in the context of the general clinical picture and other endocrine abnormalities, in all subjects after attainment of final stature.

Angiopoietin-like 8 (ANGPTL8) as a potential predictor of NAFLD in paediatric patients with Prader-Willi Syndrome

PURPOSE

Angiopoietin-like 8 (ANGPTL8) is a liver- and adipose tissue-produced protein that predicts non-alcoholic fatty liver disease (NAFLD) and altered metabolic homeostasis in the general population as well as in persons with common and genetic obesity, including the Prader-Willi syndrome (PWS). However, its metabolic correlate in paediatric patients with respect to PWS is unknown.

METHODS

This cross-sectional study investigated circulating ANGPTL8 and adipocytokines levels in 28 PWS and 28 age-, sex- and BMI-matched children and adolescents (age, 7.0-17.8y) in relation to NAFLD and metabolic homeostasis assessed by OGTT, paediatric metabolic index (PMI) and fatty liver index (FLI), liver ultrasonography (US), as well as dual-energy X-ray absorptiometry (DEXA) for analysis of fat (FM) and fat-free mass (FFM).

RESULTS

At the set level of significance, PWS children showed lower values of FFM (p < 0.01) but healthier insulin profiles (p < 0.01) and PMI values (p < 0.05) than matched controls. By US, the prevalence of NAFLD was similar between groups but less severe in PWS than controls. Analysis of ANGPTL8 levels showed no difference between groups, yet only in PWS ANGPTL8 levels were associated with ALT levels, FLI values and NAFLD. In stepwise multivariable regression analysis on merged data, ANGPTL8 levels were independently predicted by BMI SDS, leptin levels and NAFLD.

CONCLUSION

ANGPTL8 levels are similar in PWS and controls and, overall, they are directly associated with the presence and severity of NAFLD in patients with PWS.

The Role of Different Indexes of Adiposity and Body Composition for the Identification of Metabolic Syndrome in Women with Obesity

The aim of this study was to compare the accuracy of different indexes of adiposity and/or body composition in identifying the metabolic syndrome (MetS) in a group of 1528 Caucasian women with obesity: (age ± standard deviation (SD): 50.8 ± 14 years (range 18–83); body mass index (BMI) 43.3 ± 5.9 kg/m² (30.7–72.9 kg/m²)). The following indexes were assessed in each subject: BMI, fat-free mass index (FFMI), fat mass index (FMI), tri-ponderal mass index (TMI), waist-to-height ratio (WtHR), and the body mass fat index (BMFI). Thereafter, a threshold value adjusted for age, which could identify MetS, was calculated for each index. A significant correlation was found among all indexes (p < 0.0001 for all). However, when the area under the curve (AUC) was compared, WtHR performed significantly better in the whole group and in the different age groups, apart from a lack of statistical difference between WtHR and BMFI in the 45–55 years age group. In conclusion, WtHR seems to be a fair index useful for identifying MetS in women with obesity. The use of thresholds appropriate for age can help further improve its accuracy, thus reinforcing the clinical evaluation for MetS screening.

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.

Changes of Body Weight and Body Composition in Obese Patients with Prader-Willi Syndrome at 3 and 6 Years of Follow-Up: A Retrospective Cohort Study

Few short-term studies of weight loss have been performed in adult patients with Prader–Willi syndrome (PWS) undergoing metabolic rehabilitation. We performed a retrospective cohort study of 45 adult obese PWS patients undergoing a long-term multidisciplinary metabolic rehabilitation program based on diet and physical activity. Body composition was evaluated by dual-energy X-ray absorptiometry in 36 (80%) patients. The mean (95% CI) weight change was −3.6 (−7.6 to 0.4, p = 0.08) kg at 3 years and −4.6 (−8.5 to −0.8, p = 0.02) kg at 6 years, and that of BMI was −1.7 (−3.4 to 0.1, p = 0.06) kg/m² at 3 years and −2.1 (−3.8 to −0.4, p = 0.02) kg/m² at 6 years. A decrease of about 2% in fat mass per unit of body mass was observed, which is in line with the expectations for moderate weight loss. A possibly clinically relevant decrease in total and low-density lipoprotein cholesterol was also observed. These long-term results are important for patients with PWS, which is characterized by severe hyperphagia, behavioral disturbances, and cognitive impairment and is generally considered “resistant” to classical weight loss interventions.

Caring and living with Prader-Willi syndrome in Italy: integrating children, adults and parents' experiences through a multicentre narrative medicine research

OBJECTIVES

Prader-Willi syndrome (PWS) significantly impacts health-related quality of life; however, its relational and existential aspects remain unknown in Italian clinical and social debate. The project aimed to investigate the impact of PWS on illness experience through narrative medicine (NM) to understand the daily life, needs and resources of patients with PWS and their caregivers, and to furnish insights for clinical practice.

DESIGN AND SETTING

The project involved 10 medical centres of the Italian Network for Rare Diseases and PWS family associations and targeted underage and adult patients with PWS and their caregivers. Written interviews, composed by a sociodemographic survey and a narrative, were collected through the project's website. Three dedicated illness plots employed evocative and open words to facilitate individual expression and to encourage reflection. Narratives were analysed through NVivo software. Researchers discussed the results with the project's steering committee.

PARTICIPANTS

Twenty-one children and adolescents and 34 adults with PWS joined the project, as well as 138 caregivers. A PWS diagnosis or the caregiving of a patient with PWS older than 5 years represented the eligibility criteria, as well as the willingness to share their illness experience by writing and the ability to communicate in Italian.

RESULTS

The analysis of narratives led to understanding the PWS social and relational issues concerning diagnosis and current management, PWS daily experiences and social contexts, PWS implications in the working sphere and participants' future perspectives. Narratives demonstrated that PWS management affects relationships and work-life balance and that social stigma remains present.

CONCLUSION

The project represented the first effort to investigate the impact of PWS on illness experience in Italy through NM while considering the perspectives of patients with PWS and their caregivers. The findings indicated that a multiprofessional approach is fundamental to ensure adequate treatment and provided elements for its improvement.

Changes in symmetry during gait in adults with Prader-Willi syndrome

Most studies on locomotion of individuals with the Prader-Willi Syndrome (PWS) have been performed in a laboratory setting using quantitative motion analysis. Recently, wireless inertial sensors have been successfully employed for gait analysis in different pathological states with the advantages of reproducing a testing condition very close to those encountered in daily living. Using such devices, it is possible not only to characterize the conventional spatio-temporal parameters, but also extract information on further less conventional metrics, such as the harmonic ratio (HR), a measure of step-to-step symmetry based on trunk acceleration processing. In the present study, this technique was used to quantify gait parameters during level walking in 20 adults with PWS who were compared to 20 unaffected individuals. While no differences between the two groups were found in terms of spatio-temporal parameters, individuals with PWS exhibited significantly reduced values of HR in the antero-posterior and vertical directions. Such results, which indicate a poorer gait symmetry in PWS, suggest that upper body accelerations, as well as HR, provide novel information on gait in people with PWS that could not be extracted from spatio-temporal parameters only.

Central Adrenal Insufficiency Is Rare in Adults With Prader-Willi Syndrome

CONTEXT

Prader-Willi syndrome (PWS) is associated with several hypothalamic-pituitary hormone deficiencies. There is no agreement on the prevalence of central adrenal insufficiency (CAI) in adults with PWS. In some countries, it is general practice to prescribe stress-dose hydrocortisone during physical or psychological stress in patients with PWS. Side effects of frequent hydrocortisone use are weight gain, osteoporosis, diabetes mellitus, and hypertension-already major problems in adults with PWS. However, undertreatment of CAI can cause significant morbidity-or even mortality.

OBJECTIVE

To prevent both over- and undertreatment with hydrocortisone, we assessed the prevalence of CAI in a large international cohort of adults with PWS. As the synacthen test shows variable results in PWS, we only use the metyrapone test (MTP) and insulin tolerance test (ITT).

DESIGN

Metyrapone test or ITT in adults with PWS (N = 82) and review of medical files for symptoms of hypocortisolism related to surgery (N = 645).

SETTING

Outpatient clinic.

PATIENTS OR OTHER PARTICIPANTS

Eighty-two adults with genetically confirmed PWS.

MAIN OUTCOME MEASURE

For MTP, 11-deoxycortisol > 230 nmol/L was considered sufficient. For ITT, cortisol > 500 nmol/L (Dutch, French, and Swedish patients) or > 450 nmol/L (British patients) was considered sufficient.

RESULTS

Central adrenal insufficiency was excluded in 81 of 82 patients. Among the 645 patients whose medical files were reviewed, 200 had undergone surgery without perioperative hydrocortisone treatment. None of them had displayed any features of hypocortisolism.

CONCLUSIONS

Central adrenal insufficiency is rare (1.2%) in adults with PWS. Based on these results, we recommend against routinely prescribing hydrocortisone stress-doses in adults with PWS.

SUN-308 Central Adrenal Insufficiency Is Rare in Adults with Prader-Willi Syndrome

Introduction: Prader-Willi syndrome (PWS) is associated with several hypothalamic-pituitary hormone deficiencies. There is no agreement on the prevalence of central adrenal insufficiency (CAI) in adults with PWS. This is partly due to the variable results of the synacthen test, compared with the more robust metyrapone test (MTP) and insulin tolerance test (ITT). In some countries, patients with PWS receive stress-dose corticosteroids during physical or psychological stress. Side effects of frequent corticosteroids use are weight gain, osteoporosis, diabetes mellitus and hypertension, already major problems in adults with PWS. However, undertreatment of CAI can cause significant morbidity or even mortality. To prevent over- and undertreatment with corticosteroids, we assessed the prevalence of CAI in a large international cohort of adults with this rare disorder.

Methods: The hypothalamic-pituitary-adrenal axis was tested in 81 adult subjects (55 Dutch, 10 British, 10 French, 6 Swedish) with genetically confirmed PWS. For multiple-dose MTP, 11-deoxycortisol >230 nmol/L (7.6 g/dL) was considered sufficient. For Dutch, French and Swedish patients who underwent ITT, cortisol >500 nmol/L (18.1 μg/dL) was considered sufficient. For British patients cortisol >450 nmol/L (16.3 μg/dL) was considered sufficient, as this center used a different assay. Additionally, we reviewed medical files of 645 adults with PWS from Italy (240), France (110), the Netherlands (110), Australia (60), Spain (45), Sweden (38) and the United Kingdom (42) for symptoms of hypocortisolism/adrenal crisis during surgery.

Results: Data on 81 adult subjects (46 males and 35 females), median age (range) 25.2 yr (18.0 – 55.5), median BMI (range) 29.1 kg/m² (20.0 – 62.0), with genetically confirmed PWS were collected. 33 subjects (41%) were using GH treatment since childhood. Multiple-dose MTP was performed in 45 subjects and ITT in 36 subjects. Both tests were well tolerated by all individuals. CAI was excluded in 80 of 81 patients. One patient with a peak cortisol level of 494 nmol/L (just below cut-off level of 500 nmol/L) was prescribed hydrocortisone for use during physical stress. There was no relation between baseline cortisol and ITT/multiple-dose MTP results. Even patients with a low baseline cortisol level (lowest: 102.0 nmol/L) had normal responses. Among the 645 patients whose medical files were reviewed, 200 had undergone surgery without perioperative corticosteroids treatment. None of them displayed any features of hypocortisolism/adrenal crisis.

Conclusions: CAI is rare (1.2%) in adults with PWS. Based on these results, we recommend against routinely prescribing corticosteroids stress-doses in adults with PWS.

Funding: CZ foundation.

Update on Diabetes Mellitus and Glucose Metabolism Alterations in Prader-Willi Syndrome

PURPOSE OF REVIEW

This review summarizes our current knowledge on type 2 diabetes mellitus (T2DM) and glucose metabolism alterations in Prader-Willi syndrome (PWS), the most common syndromic cause of obesity, and serves as a guide for future research and current best practice.

RECENT FINDINGS

Diabetes occurs in 10-25% of PWS patients, usually in adulthood. Severe obesity is a significant risk factor for developing of T2DM in PWS. Paradoxically, despite severe obesity, a relative hypoinsulinemia, without the expected insulin resistance, is frequently observed in PWS. The majority of PWS subjects with T2DM are asymptomatic and diabetes-related complications are infrequent. Long-term growth hormone therapy does not adversely influence glucose homeostasis in all ages, if weight gain does not occur. Early intervention to prevent obesity and the regular monitoring of glucose levels are recommended in PWS subjects. However, further studies are required to better understand the physiopathological mechanisms of T2DM in these patients.

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.

Indexes of adiposity and body composition in the prediction of metabolic syndrome in obese children and adolescents: Which is the best?

BACKGROUND AND AIM

There is no agreement about which index of adiposity and/or body composition is the most accurate in identifying the metabolic syndrome (METS). The aim of our study was to compare the accuracy of the different indexes in order to recognize the most reliable.

METHODS AND RESULTS

We evaluated 1332 obese children and adolescents (778 females and 554 males), aged 14.4 ± 1.8 yrs, Body Mass Index (BMI) standard deviation scores (SDS) 2.99 ± 0.55, followed at the Istituto Auxologico Italiano, a tertiary center for childhood obesity. For each subject the following indexes were assessed: BMI, BMI SDS, Fat-Free Mass Index (FFMI), Fat Mass Index (FMI), Tri-Ponderal Mass Index (TMI), Waist-to-Height ratio (WtHR) and a new one, the Body Mass Fat Index (BMFI), which normalizes the BMI for percentage of body fat and the waist circumference. Thereafter we calculated for each index a threshold value for age and sex, in order to compare their accuracy, sensitivity and specificity in identifying the METS. There was a good correlation among indexes (p < 0.0001 for all). However, when the area under the curve (AUC) was compared, some of them, in particular the BMFI and the BMI, performed better than the other ones, although the differences were small.

CONCLUSIONS

BMI, which neither considers body composition nor fat distribution, performs as good as other indexes, and should therefore be the preferred one, also because of the easiness of its calculation.

Uniparental disomy and pretreatment IGF-1 may predict elevated IGF-1 levels in Prader-Willi patients on GH treatment

Pediatric patients with Prader-Willi syndrome (PWS) can be treated with recombinant human GH (rhGH). These patients are highly sensitive to rhGH and the standard doses suggested by the international guidelines often result in IGF-1 above the normal range. We aimed to evaluate 1 the proper rhGH dose to optimize auxological outcomes and to avoid potential overtreatment, and 2 which patients are more sensitive to rhGH. In this multicenter real-life study, we recruited 215 patients with PWS older than 1 year, on rhGH at least for 6 months, from Italian Centers for PWS care. We collected auxological parameters, rhGH dose, IGF-1 at recruitment and (when available) at start of treatment. The rhGH dose was 4.3 (0.7/8.4) mg/m²/week. At recruitment, IGF-1 was normal in 72.1% and elevated in 27.9% of the patients. In the group of 115 patients with IGF-1 available at start of rhGH, normal pretreatment IGF-1 and uniparental disomy were associated with elevated IGF-1 during the therapy. No difference in height and growth velocity was found between patients treated with the highest and the lowest range dose. The rhGH dose prescribed in Italy seems lower than the recommended one. Normal pretreatment IGF-1 and uniparental disomy are risk factors for elevated IGF-1. The latter seems to be associated with higher sensitivity to GH. In case of these risk factors, we recommend a more accurate titration of the dose to avoid overtreatment and its potential side effects.

Anthropometric characteristics of newborns with Prader-Willi syndrome

This is a retrospective multicenter nationwide Italian study collecting neonatal anthropometric data of Caucasian subjects with Prader-Willi syndrome (PWS) born from 1988 to 2018. The aim of the study is to provide percentile charts for weight and length of singletons with PWS born between 36 and 42 gestational weeks. We collected the birth weight and birth length of 252 male and 244 female singleton live born infants with both parents of Italian origin and PWS genetically confirmed. Percentile smoothed curves of birth weight and length for gestational age were built through Cole's lambda, mu, sigma method. The data were compared to normal Italian standards. Newborns with PWS showed a lower mean birth weight, by 1/2 kg, and a shorter mean birth length, by 1 cm, than healthy neonates. Females with a 15q11-13 deletion were shorter than those with maternal uniparental maternal disomy of chromosome 15 (p < .0001). The present growth curves may be useful as further traits in supporting a suspicion of PWS in a newborn. Because impaired prenatal growth increases risk of health problems later in life, having neonatal anthropometric standards could be helpful to evaluate possible correlations between the presence or absence of small gestational age and some clinical and metabolic aspects of PWS.

Thyroid function in patients with Prader-Willi syndrome: an Italian multicenter study of 339 patients

Background Prader-Willi syndrome (PWS) is a genetic disorder due to loss of expression of paternally transcribed genes of the imprinted region of chromosome 15q11-13. PWS is characterized by peculiar signs and symptoms and many endocrine abnormalities have been described (growth hormone deficiency, hypogonadotropic hypogonadism). The abnormalities of thyroid function are discussed in literature and published data are discordant. The aim of our study was to report the thyroid function in patients with PWS to identify the prevalence of thyroid dysfunction. Methods Thyroid function tests were carried out in 339 patients with PWS, aged from 0.2 to 50 years. A database was created to collect personal data, anthropometric data, thyroid function data and possible replacement therapy with L-thyroxine. Subjects were classified according to thyroid function as: euthyroidism (EuT), congenital hypothyroidism (C-HT), hypothyroidism (HT - high thyroid-stimulating hormone [TSH] and low free thyroxine [fT4]), central hypothyroidism (CE-H - low/normal TSH and low fT4), subclinical hypothyroidism (SH - high TSH and normal fT4), and hyperthyroidism (HyperT - low TSH and high fT4). Results Two hundred and forty-three out of 339 PWS patients were younger than 18 years (71.7%). The prevalence of thyroid dysfunction was 13.6%. Specifically, C-HT was found in four children (1.18%), HT in six patients (1.77%), CE-H in 23 patients (6.78%), SH in 13 patients (3.83%), and HyperT in none. All other subjects were in EuT (86.4%). Conclusions Hypothyroidism is a frequent feature in subjects with PWS. Thyroid function should be regularly investigated in all PWS patients both at the diagnosis and annually during follow-up.

Assessment of fat-free mass from bioelectrical impedance analysis in men and women with Prader-Willi syndrome: cross-sectional study

We have recently shown that population-specific formulae are required to estimate fat-free mass (FFM) from bioelectrical impedance analysis (BIA) in obese women with Prader-Willi syndrome (PWS) matched by age and percent fat mass (FM) to non-PWS women. The present cross-sectional study was aimed at developing generalised BIA equations that could be used in PWS subjects independently of sex and FM. We used dual-energy X-ray absorptiometry to measure FFM and BIA to measure whole-body impedance at 50 kHz (Z₅₀) in 34 women and 21 men with PWS. The impedance index, that is, height (cm)²/Z₅₀ (Ω), explained 77% (BCa-bootstrapped 95% CI 65 to 85%) of the variance of FFM with a root mean squared error of the estimate of 3.7 kg (BCa-bootstrapped 95% CI 3.2 to 4.5 kg). BIA can be used to estimate FFM in obese and non-obese PWS men and women by means of population-specific equations.

Differences in circulating microRNA signature in Prader-Willi syndrome and non-syndromic obesity

Prader-Willi syndrome (PWS) represents the most common genetic-derived obesity disorder caused by the loss of expression of genes located on the paternal chromosome 15q11.2-q13. The PWS phenotype shows peculiar physical, endocrine and metabolic characteristics compared to those observed in non-syndromic essential obesity. Since miRNAs have now a well-established role in many molecular pathways, including regulatory networks related to obesity, this pilot study was aimed to characterize the expression of circulating miRNAs in PWS compared to essential obesity. The circulating miRNome of 10 PWS and 10 obese subjects, adequately matched for age, BMI and sex, was profiled throughout Genechip miRNA 4.0 microarray analysis. We identified 362 out of 2578 mature miRNAs to be expressed in serum of the studied population. The circulating miRNA signature significantly characterising the two populations include 34 differently expressed RNAs. Among them, miR-24-3p, miR-122 and miR-23a-3p highly differ between the two groups with a FC >10 in obese compared to PWS. In the obese subjects, miR-7107-5p, miR-6880-3p, miR-6793-3p and miR-4258 were associated to the presence of steatosis. A different signature of miRNAs significantly distinguished PWS with steatosis from PWS without steatosis, involving miR-619-5p, miR-4507, miR-4656, miR-7847-3p and miR-6782-5p. The miRNA target GO enrichment analysis showed the different pathway involved in these two different forms of obesity. Although the rarity of PWS actually represents a limitation to the availability of large series, the present study provides novel hints on the molecular pathogenesis of syndromic and non-syndromic obesity.

Autoimmune pituitary involvement in Prader-Willi syndrome: new perspective for further research

The role of antipituitary antibodies in the pathophysiology of pituitary hormone deficiency has been increasingly elucidated over the last decade. Prader-Willi syndrome is a genetic disorder which includes hypothalamic/pituitary dysfunction as one of its main features. We looked for autoimmune pituitary involvement in 55 adults with Prader-Willi syndrome, discovering that about 30% of them have a positive titer of antipituitary antibodies. Although the presence of these autoantibodies could only be an "epiphenomenon", our results suggest that autoimmune mechanisms might contribute, at least in part, to the pituitary impairment of Prader-Willi syndrome, and in addition to genetically determined dysfunction of the central nervous system. This paper provides a new perspective on pituitary impairment in these patients, suggesting that the search for hypophisitis could be a reasonable and interesting field for further research.

Diagnosis, treatment and prevention of pediatric obesity: consensus position statement of the Italian Society for Pediatric Endocrinology and Diabetology and the Italian Society of Pediatrics

The Italian Consensus Position Statement on Diagnosis, Treatment and Prevention of Obesity in Children and Adolescents integrates and updates the previous guidelines to deliver an evidence based approach to the disease. The following areas were reviewed: (1) obesity definition and causes of secondary obesity; (2) physical and psychosocial comorbidities; (3) treatment and care settings; (4) prevention.The main novelties deriving from the Italian experience lie in the definition, screening of the cardiometabolic and hepatic risk factors and the endorsement of a staged approach to treatment. The evidence based efficacy of behavioral intervention versus pharmacological or surgical treatments is reported. Lastly, the prevention by promoting healthful diet, physical activity, sleep pattern, and environment is strongly recommended since the intrauterine phase.

25OH vitamin D levels in pediatric patients affected by Prader-Willi syndrome

PURPOSE

Obesity, insulin resistance, and puberty seem to influence and been inversely associated with 25-hydroxy vitamin D (25OHD) levels. To our knowledge, a study on 25OHD in children and adolescents with Prader-Willi syndrome (PWS), a genetic form of obesity, is not yet available.

OBJECTIVE

To analyze the 25OHD values in pediatric PWS subjects in comparison with a control group (CNT), highlighting the possible correlations with IR, BMD, body composition, pubertal stage, and GH therapy (GHT).

METHODS

Auxological and laboratory parameters, HOMA-IR, Vitamin D status, and bone density and body composition by DEXA scan were analyzed in 52 PWS and 110 controls (CNT), gender-, age-, and BMI-SD matched. None of them was on calcium or vitamin D. 20 PWS were on growth hormone (GH) therapy and 32 were previously treated.

RESULTS AND CONCLUSION

Altogether, PWS had similar values of 25OHD compared to CNT.16 PWS (30.7%) and 27 CNT (24.5%) had low 25OHD levels (< 20 ng/ml) (p = NS). 25OHD of PWS on GHT were comparable to those previously treated. In both groups, univariate analysis showed a negative correlation between 25OHD and fat mass% (FM%). GH therapy and pubertal stage were positively correlated with bone parameters analyzed by DXA. Multivariate regression confirmed only FM% as negative predictor of 25HOD in PWS patients, as previously described. GHT does not seem to influence 25OHD in PWS.

CONCLUSION

Our data showed that PWS had similar values of 25OHD compared to CNT. As already described, FM seems to be the only parameter influencing 25OHD levels. Finally, GHT does not seem to influence 25OHD metabolism in PWS.

Analysis of Circulating Mediators of Bone Remodeling in Prader-Willi Syndrome

We tested the hypothesis that the levels of bone remodeling mediators may be altered in Prader-Willi syndrome (PWS). We assessed RANKL, OPG, sclerostin, DKK-1 serum levels, and bone metabolism markers in 12 PWS children (7.8 ± 4.3 years), 14 PWS adults (29.5 ± 7.2 years), and 31 healthy controls matched for sex and age. Instrumental parameters of bone mineral density (BMD) were also evaluated. Lumbar spine BMD Z-scores were reduced in PWS children (P < 0.01), reaching osteopenic levels in PWS adults. PWS patients showed lower 25(OH)-vitamin D serum levels than controls (P < 0.001). Osteocalcin was increased in PWS children but reduced in adults respect to controls (P < 0.005 and P < 0.01, respectively). RANKL levels were higher in both pediatric and PWS adults than controls (P < 0.004), while OPG levels were significantly reduced (P < 0.004 and P < 0.006, respectively). Sclerostin levels were increased in children (P < 0.04) but reduced in adults compared to controls (P < 0.01). DKK-1 levels did not show significant difference between patients and controls. In PWS patients, RANKL, OPG, and sclerostin significantly correlated with metabolic and bone instrumental parameters. Consistently, with adjustment for age, multiple linear regression analysis showed that BMD and osteocalcin were the most important predictors for RANKL, OPG, and sclerostin in children, and GH and sex steroid replacement treatment in PWS adults. We demonstrated the involvement of RANKL, OPG, and sclerostin in the altered bone turnover of PWS subjects suggesting these molecules as markers of bone disease and new potential pharmacological targets to improve bone health in PWS.

GHRH plus arginine and arginine administration evokes the same ratio of GH isoforms levels in young patients with Prader-Willi syndrome

Human GH is present in pituitary and circulation as several isoforms, the prevalent being 22kDa- and 20kDa-GH. Recently, we have demonstrated the preservation of a normal balance in GH isoforms after GH releasing hormone (GHRH) plus arginine (ARG) administration in adult patients with Prader-Willi syndrome (PWS), one of the most common causes of syndromic obesity, often associated with GH deficiency (GHD). Aim of the present study was to measure circulating levels of 22kDa- and 20kDa-GH in young PWS patients (n=24; F/M: 10/14; genotype UPD/DEL/met+: 11/11/2; age: 10.8±5.3years; BMI SDS: 2.0±2.0; GHD: 16/24; obesity: 12/24) after combined GHRH+ARG or ARG administration. The results were analysed subdividing the GHRH+ARG and ARG groups on the basis of PWS genotype, GHD status and obesity. Circulating levels of 22kDa- and 20kDa-GH were measured by a chemiluminescent or fluorescent method based on specific pairs of monoclonal antibodies. GHRH+ARG or ARG significantly stimulated the secretion of 22kDa-GH but not that of 20kDa-GH in all PWS patients. No significant GHRH+ARG- vs. ARG-induced changes in the ratios of 22kDa- to 20kDa-GH peaks were observed in all PWS patients, although 22kDa- or 20kDa-GH peaks were significantly higher in the GHRH+ARG than ARG group. When subdividing PWS patients in UPD vs. DEL, obese vs. non obese and GHD vs. non GHD subgroups, GH peaks were significantly higher in nonobese than obese patients and in non GHD than GHD patients administered with either GHRH+ARG or ARG test, apart from the comparisons in the DEL/UPD subgroups. Anyway, the ratios of peak levels of 22kDa- to 20kDa-GH were similar after GHRH+ARG vs. ARG in all subgroups investigated. In conclusion, this study shows that administration of two different pharmacological tests, i.e. ARG, capable of reducing hypothalamic somatostatinergic tone, and GHRH (+ARG), that directly acts at pituitary level on the somatotropic cell, evokes the same ratios of GH isoforms in young PWS patients, suggesting that the hypothalamic dysfunction in this genetic disorder does not alter the qualitative and quantitative composition of GH isoforms present in circulation.

Obesity management in Prader-Willi syndrome: current perspectives

Prader-Willi syndrome (PWS) is a complex multisystem disorder due to the absent expression of the paternally active genes in the PWS critical region on chromosome 15 (15q11.2-q13). The syndrome is considered the most common genetic cause of obesity, occurring in 1:10,000-1:30,000 live births. Its main characteristics include neonatal hypotonia, poor feeding, and lack of appetite in infancy, followed by weight gain, lack of satiety, and uncontrolled appetite, frequently after the age of 2-3 years. The clinical picture includes short stature, multiple endocrine abnormalities (hypogonadism, growth hormone/insulin-like growth factor-I axis dysfunction, hypothyroidism, central adrenal insufficiency), dysmorphic features, scoliosis, osteoporosis, mental retardation, and behavioral and psychiatric problems. Subjects with PWS will become severely obese unless their food intake is strictly controlled. Constant and obsessive food seeking behavior can make life very difficult for both the family and caretakers. Prevention of obesity is mandatory in these patients from the first years of life, because once obesity develops it is difficult to maintain the control of food intake. In fact, PWS subjects die prematurely from complications conventionally related to obesity, including diabetes mellitus, metabolic syndrome, sleep apnea, respiratory insufficiency, and cardiovascular disease. The mechanisms underlying hyperphagia in PWS are not completely known, and to date no drugs have proven their efficacy in controlling appetite. Consequently, dietary restriction, physical activity, and behavior management are fundamental in the prevention and management of obesity in PWS. In spite of all available therapeutic tools, however, successful weight loss and maintenance are hardly accomplished. In this context, clinical trials with new drugs have been initiated in order to find new possibilities of a therapy for obesity in these patients. The preliminary results of these studies seem to be encouraging. On the other hand, until well-proven medical treatments are available, bariatric surgery can be taken into consideration, especially in PWS patients with life-threatening comorbidities.

The relationship between hyperthyrotropinemia and metabolic and cardiovascular risk factors in a large group of overweight and obese children and adolescents

PURPOSE

Mild TSH elevations are frequently observed in obese patients, in the absence of any detectable thyroid disease. Our objective is to evaluate the relationship between the raised TSH levels and the biochemical and clinical consequences of obesity.

METHODS

This is a retrospective cross-sectional study of a large population of obese children and adolescents. We evaluated 833 subjects (340 m, 493 f), aged 14.4 ± 2.5 (range 5.2-18.5) years, height SDS 0.27 ± 1.04 (-3.49-4.35), and BMI SDS 2.94 ± 0.59 (1.60-4.68). Body composition, free T4, TSH, anti-TPO antibodies, anti-TG antibodies, inflammation markers (total WBC and the subtypes, ultrasensitive C-reactive protein), and metabolic parameters [AST, ALT, γGT, ALP, glycaemia, insulin, total cholesterol (TC), HDL-cholesterol (HDL-C), and LDL-cholesterol (LDL-C), triglycerides (TG)] were measured, and oral disposition index (ODI) and cardiovascular risk factors (TC/HDL-C and TG/HDL-C) were calculated. After exclusion of the subjects showing anti-thyroid antibodies, the remaining 779 (325 m, 454 f) were then subdivided into two subgroups according to a TSH value below (group A) or above (group B) 4.5 mU/L.

RESULTS

Clinical characteristics and hematological markers of patients with and without positive anti-thyroid antibodies were similar, with the exception of higher TSH levels in the latter group. Using analysis of covariance, the subjects of group B had significantly higher values of TC (170.3 ± 28.7 vs 163.3 ± 32.9 mg/dL; p < 0.05), systolic (125.8 ± 13.5 vs 124.5 ± 13.1 mm/Hg), and diastolic blood pressure (79.2 ± 8.0 vs 77.9 ± 8.2 mm/Hg) than subjects of group A. No difference was observed in body composition, ODI, and the cardiovascular risk factors between these two groups.

CONCLUSION

TSH elevation in overweight and obese children and adolescents, being associated with a higher TC and blood pressure, might negatively influence the cardiac status. Longitudinal studies are requested, however, to confirm this hypothesis and, therefore, to conclude whether a substitutive treatment with l-thyroxine is really needed in these patients.