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.

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.

Autoimmune polyendocrine syndrome type 1: an Italian survey on 158 patients.

BACKGROUND: Autoimmune Polyglandular Syndrome type 1 (APS-1) is a rare recessive inherited disease, caused by AutoImmune Regulator (AIRE) gene mutations and characterized by three major manifestations: chronic mucocutaneous candidiasis (CMC), chronic hypoparathyroidism (CH) and Addison's disease (AD). METHODS: Autoimmune conditions and associated autoantibodies (Abs) were analyzed in 158 Italian patients (103 females and 55 males; F/M 1.9/1) at the onset and during a follow-up of 23.7 ± 15.1 years. AIRE mutations were determined. RESULTS: The prevalence of APS-1 was 2.6 cases/million (range 0.5-17 in different regions). At the onset 93% of patients presented with one or more components of the classical triad and 7% with other components. At the end of follow-up, 86.1% had CH, 77.2% AD, 74.7% CMC, 49.5% premature menopause, 29.7% autoimmune intestinal dysfunction, 27.8% autoimmune thyroid diseases, 25.9% autoimmune gastritis/pernicious anemia, 25.3% ectodermal dystrophy, 24% alopecia, 21.5% autoimmune hepatitis, 17% vitiligo, 13.3% cholelithiasis, 5.7% connective diseases, 4.4% asplenia, 2.5% celiac disease and 13.9% cancer. Overall, 991 diseases (6.3 diseases/patient) were found. Interferon-ω Abs (IFNωAbs) were positive in 91.1% of patients. Overall mortality was 14.6%. The AIRE mutation R139X was found in 21.3% of tested alleles, R257X in 11.8%, W78R in 11.4%, C322fsX372 in 8.8%, T16M in 6.2%, R203X in 4%, and A21V in 2.9%. Less frequent mutations were present in 12.9%, very rare in 9.6% while no mutations in 11% of the cases. CONCLUSIONS: In Italy, APS-1 is a rare disorder presenting with the three major manifestations and associated with different AIRE gene mutations. IFNωAbs are markers of APS-1 and other organ-specific autoantibodies are markers of clinical, subclinical or potential autoimmune conditions.

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.

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.

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.

High uric acid, reduced glomerular filtration rate and non-alcoholic fatty liver in young people with obesity.

OBJECTIVE: To evaluate the association between high uric acid (UA), reduced estimated glomerular filtration rate (eGFR), and non-alcoholic fatty liver disease (NAFLD) in outpatient children and adolescents with overweight (OW) or obesity (OB). METHODS: Anthropometric, biochemical, hepatic ultrasound and eGFR data were available from 2565 young people with OW/OB (age 5-18 years). eGFR was calculated using the Schwartz's bedside formula and reduced eGFR (ReGFR+) was defined by a value < 90 mL/min/1.73 m2. High UA was defined as ≥ 75th percentile by sex in children and adolescents. RESULTS: The population was stratified in four categories: (1) normal eGFR and absence of NAFLD (ReGFR-/NAFLD-) (n = 1,236); (2) ReGFR+ and absence of NAFLD (ReGFR+/NAFLD- (n = 155); (3) normal eGFR and presence of NAFLD (ReGFR-/NAFLD+) (n = 1019); (4) presence of both conditions (ReGFR+/NAFLD+) (n = 155). Proportions of youth with high UA across the four categories were 17%, 30%, 33% and 46%, respectively (P < 0.0001). Young people with high levels of UA had odds ratio (95% CI) of 2.11 (1.43-3.11) for ReGFR+; 2.82 (2.26-3.45) for NAFLD+; and 5.04 (3.45-7.39) for both conditions (P < 0.0001 for all), independently of major confounders. CONCLUSIONS: High levels of UA were independently associated with ReGFR, NAFLD and the combination of both conditions in young people with OW/OB. The strength of this association was the highest in cases presenting both reduced eGFR and NAFLD. UA may serve as marker to identify patients at risk for these conditions.

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.

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.

Disorders of glucose metabolism in Prader-Willi syndrome: Results of a multicenter Italian cohort study.

BACKGROUND AND AIMS: Prader-Willi syndrome (PWS) is characterized by a high incidence of altered glucose metabolism (AGM). However, epidemiological data on impaired fasting glucose (IFG), impaired glucose tolerance (IGT) and type 2 diabetes mellitus (T2DM) are still discordant. METHODS AND RESULTS: We performed a multicenter study based on 274 PWS patients [144 females, aged 20.3 ± 10.4 yrs (range: 8.1-50.1 years)] evaluating the prevalence for AGM in the entire group, and according to age (children <10 yrs; adolescents 10-18 yrs, and adults >18 yrs), Body Mass Index (BMI = kg/m(2)), gender, genotypes (deletion or uniparental disomy for chromosome 15), and GH therapy (GHT) (untreated, previously or currently treated). Altogether, AGM was detected in 67 (24.4%) of patients (0.7% IFG, 10.2% IGT, 13.5% T2DM). The prevalence of AGM was correlated to age (p = 0.001), BMI (p = 0.001) and HOMA-IR (p = 0.001). However, gender, genotype, and GHT did not influence AGM development in univariate analysis. These data were confirmed as positive predictors when inserted in a multivariate analysis model. CONCLUSION: This study is the first report on the prevalence of AGM in a large population of PWS. Overall, PWS subjects show a high prevalence of AGM that appears more common in obese and adult subjects. Our data confirm the main role of obesity on the individual metabolic risk clustering in PWS, and thus reinforce the concept that improvement in weight control remains the most important goal of any PWS treatment program.

Non-Alcoholic Fatty Liver Disease (NAFLD) in children and adolescents with Prader-Willi Syndrome (PWS).

We tested the hypothesis that patients with Prader-Willi syndrome (PWS) may be at lower risk of developing non-alcoholic fatty liver disease (NAFLD) because of a higher insulin sensitivity. Twenty-one PWS patients and 42 control subjects closely similar for age, gender, pubertal stage and body mass index (CNT), were studied. Metabolic profile and body composition were assessed. NAFLD was established by a validated method of US grading (range from G0 to G3). PWS patients showed a significantly better metabolic profile (lower waist circumference, fasting glucose levels, HOMA-IR, cholesterol, transaminase levels and trunk fat mass/fat mass ratio). Furthermore, NAFLD G1stage was significantly more frequent in PWS subjects (P < 0.05), whereas G2 stage was significantly more frequent in control patients (P < 0.05). NAFLD grading seems to correlate with body composition in PWS, also after adjustment for sex and GH treatment. To our knowledge, this is the first report suggesting a reduced risk of NAFLD in PWS children.

Explorative function in Prader-Willi syndrome analyzed through an ecological spatial task.

This study was aimed at evaluating the spatial abilities in individuals with Prader-Willi syndrome (PWS) by using an ecological large-scale task with multiple rewards. To evaluate the extent of spatial deficit in PWS individuals, we compare their performances with those of individuals with Williams Syndrome (WS) in which the spatial deficits have been widely described. Participants had to explore an open space to search nine rewards placed in buckets arranged according to three spatial configurations: a Cross, a 3×3 Matrix and a Cluster composed by three groups of three buckets each. PWS individuals exhibited an explorative deficit in Cluster and Cross configurations, while WS participants in Matrix and Cross configurations. The findings indicate that the structural affordances of the environment influence the explorative strategies and can be related to how spatial information is processed.

[Health consequences of obesity in children and adolescents]. / Conseguenze dell'obesità sulla salute del bambino e dell' adolescente.

Obesity in childhood is associated with the presence of complications that can undermine health immediately or in the long term. Several conditions, such as pulmonary or orthopedic complications are strictly associated with the severity of overweight, since they are directly associated to the mechanic stress of fat tissue on the airways or on the bones. Other conditions, such as metabolic or liver complications, although increasing with the extent of overweight, are associated with insulin resistance, which can be modulated by different other factors (ethnicity, genetics, fat distribution) and can occur in overweight children as well. No less important are psychological correlates, such as depression and stigma, which can seriously affect the health related quality of life. Pediatric services for the care of childhood obesity need to be able to screen overweight and obese children for the presence of physical and psychological complications, which can be still reversed by weight loss. This article provides pediatricians a comprehensive update on the main complications in obese children and adolescents and their treatment.

The GHRH + arginine stimulated pituitary GH secretion in children and adults with Prader-Willi syndrome shows age- and BMI-dependent and genotype-related differences.

OBJECTIVE: The quantitative and qualitative aspects of the pituitary response in children and adults with Prader-Willi syndrome (PWS) are compared in order to verify the possible age-dependent and genotype-related differences in terms of GH secretion. DESIGN: 29 young subjects (21 males and 8 females) and 65 adults (24 males and 41 females) with PWS were studied. All subjects underwent a standard GH Releasing Hormone (GHRH 1-29, 1 µg/kg as i.v. bolus at 0 minutes)+arginine (0.5 g/kg) test. Peak GH values, standard GH area under the curve (AUC), AUC of the instantaneous secretion rate (ISR), and secretion response analysis (i.e. half-secretion time) were evaluated. A regression analysis was performed to investigate which are the patient characteristics that affect the amplitude and shape of the GH secretion response. RESULTS: Peak GH values and AUCGH were significantly higher in PWS children than in PWS adults, these differences being also significant both in PWS DEL15 (only peak GH value) and PWS UPD15. Moreover, PWS children showed significantly lower half secretion time than PWS adults, this delayed response being present both in PWS DEL15 and PWS UPD15. Significant negative correlations between AUCGH and BMISDS were observed in the two groups (adults and children), as well as in adults and children DEL15, but not in adults and children PWS UPD15. A regression analysis performed on the whole dataset showed that for PWS DEL15 the statistically significant variable explaining GH responsiveness was BMISDS (p<0.0001), while for UPD15 no statistically significant covariate was found. Conversely, when the delay of the secretion response was considered, the regression model yielding the best performances was the one with only age as a regressor (p<0.001). CONCLUSIONS: The quantitative and qualitative analyses of GH responsiveness to GHRH+arginine highlight relevant differences between PWS children and PWS adults and genotype-related traits. The negative influence of BMISDS on GH secretion reinforces the need for an early start of life-long weight management in PWS subjects.

Metabolic syndrome in adult patients with Prader-Willi syndrome.

BACKGROUND AND AIMS: Prader-Willi syndrome (PWS), the most common genetic cause of obesity, is characterized by elevated morbility and mortality in all ages. In this context, non-obese PWS children showed low frequency of metabolic syndrome (MetS), while a comparable prevalence was observed in obese PWS and obese controls. Aim of this study was to estimate the occurrence of MetS and its components in a large group of PWS adults, according to obesity status. METHODS AND RESULTS: A cross-sectional study was performed in 108 PWS aged 18.0-43.2 years (87 obese and 21 non-obese) and in 85 controls with nonsyndromic obesity matched for age, gender, and BMI with obese PWS. Non-obese PWS showed lower waist circumference, insulin, HOMA-index, triglycerides, diastolic blood pressure, and higher HDL-C than both obese PWS and obese controls (p < 0.017). Obese PWS showed higher glucose and systolic blood pressure than both non-obese PWS and obese controls (p < 0.017). MetS was found in 1/21 (4.8%) non-obese PWS, 36/87 (41.4%) obese PWS and 39/85 (45.9%) obese controls. Non-obese PWS showed lower frequency for each MetS component as compared with obese PWS and obese controls. PWS patients with deletion of the chromosome 15q11-13 showed a lower risk for low HDL-C (p < 0.01) and a trend towards a lower MetS risk (p < 0.06) compared to subjects without deletion. CONCLUSION: Our findings suggest the main role that obesity status plays on the individual metabolic risk clustering in PWS adults. Early identification of MetS could be helpful to improve morbidity and prevent mortality in such patients.

[Management of children and adolescents with severe obesity]. / Il percorsi terapeutico del bambino e dell' adolescente con obesità grave.

Obesity is a complex public health issue. Recent data indicate the increasing prevalence and severity of obesity in children. Severe obesity is a real chronic condition for the difficulties of long-term clinical treatment, the high drop-out rate, the large burden of health and psychological problems and the high probability of persistence in adulthood. A staged approach for weight management is recommended. The establishment of permanent healthy lifestyle habits aimed at healthy eating, increasing physical activity and reducing sedentary behavior is the first outcome, because of the long-term health benefits of these behaviors. Improvement in medical conditions is also an important sign of long-term health benefits. Rapid weight loss is not pursued, for the implications on growth ad pubertal development and the risk of inducing eating disorders. Children and adolescents with severe obesity should be referred to a pediatric weight management center that has access to a multidisciplinary team with expertise in childhood obesity. This article provides pediatricians a comprehensive and evidence based update on treatment recommendations of severe obesity in children and adolescents.

Multiple forms of hypogonadism of central, peripheral or combined origin in males with Prader-Willi syndrome.

BACKGROUND: Hypogonadism in Prader-Willi syndrome (PWS) is generally attributed to hypothalamic dysfunction or to primary gonadal defect, but pathophysiology is still unclear. OBJECTIVES: To investigate the aetiology of hypothalamic-pituitary-gonadal axis dysfunction in PWS males. METHODS: Clinical examination and blood sampling for luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone, inhibin B and sexhormone-binding globulin (SHBG) were performed in 34 PWS patients, age 5·1-42·7 years, and in 125 healthy males of same age range. All participants were divided into two groups : < or ≥13·5 years. RESULTS: Pubertal PWS patients showed an arrest of pubertal development. Patients <13·5 years had normal LH, FSH, testosterone and 7/10 had low inhibin B. Among those ≥13·5 years, 8/24 patients had normal LH and testosterone, high FSH and low inhibin B. 5/24 had low FSH, LH, testosterone and inhibin B; one showed normal LH and FSH despite low testosterone and inhibin B; 4/24 had low testosterone and LH but normal FSH despite low inhibin B; 6/24 showed high FSH, low inhibin B and normal LH despite low testosterone. Compared with controls, patients <13·5 years had lower LH, inhibin B, similar FSH, testosterone, SHBG levels and testicular volume; those ≥13·5 years had smaller testicular volume, near-significantly lower LH, testosterone, SHBG, inhibin B and higher FSH. CONCLUSION: PWS patients display heterogeneity of hypogonadism: (i) hypogonadotropic hypogonadism of central origin for LH and/or FSH; (ii) early primary testicular dysfunction (Sertoli cells damage); and (iii) a combined hypogonadism (testicular origin for FSH-inhibin B axis and central origin for LH-T axis).

Growth hormone secretion among adult patients with Prader-Willi syndrome due to different genetic subtypes.

BACKGROUND: Patients with Prader-Willi syndrome (PWS) due to maternal uniparental disomy of the chromosome 15 (UPD15) have fewer facial features, less hypopigmentation and higher levels of psychosis compared to subjects with deletion in chromosome 15 (del15q11-q13). PWS individuals carrying the larger type I (TI) deletion suffer from greater behavioral problems than patients with the smaller type II (TII) deletion. Few data are currently available on the relationship existing between endocrine abnormalities in PWS subjects and the different genotypes. AIM: To investigate the stimulated GH levels in PWS patients with different types of deletion and those with UPD15. SUBJECTS AND METHODS: Thirty-seven patients, 14 males, aged 17.5-41.2 yr, with PWS due to TI deletion (no.=6), TII deletion (no.=15) or UPD15 (no.=16), were studied. Pituitary GH secretion was evaluated by dynamic testing with GHRH+arginine. RESULTS: Both the mean peak GH response and the integrated GH secretion (GH area under the curve and GH area under the curve corrected for basal values) for the UPD15 patients (4.6 ± 1.6 µg/l, 241.6 ± 71.7 µg/l/h and 228.3 ± 71.6 µg/l/h, respectively) were lower than that observed in all subjects with del15q11-q13 (9.1±1.8 µg/l, 547.0 ± 132.3 µg/l/h and 514.9 ± 127.6 µg/l/h: p<0.005), as well as in TI (7.7 ± 1.2 µg/l: p<0.02; 424.2 ± 88.8 and 393.4 ± 88.8 µg/l/h: p<0.05) and TII (9.6 ± 2.6 µg/l, 587.9 ± 174.2 µg/l/h and 555.4 ± 167.6 µg/l/h: p<0.01) deletion groups. TI and TII groups had similar stimulated GH levels and integrated GH secretion. CONCLUSIONS: Our results point at differentiating the pattern of GH secretion by genetic subtypes, with higher GH responses in typical deletion subjects when compared to patients with UPD15.

Metabolic syndrome in children with Prader-Willi syndrome: the effect of obesity.

BACKGROUND AND AIMS: Prader-Willi syndrome (PWS), the most frequent syndromic obesity, is associated with elevated morbidity and mortality in pediatric and adult ages. In PWS, the presence of metabolic syndrome (MS) has not yet been established. The aim of the study was to estimate the frequency of MS and its components in pediatric subjects according to obesity status. METHODS AND RESULTS: A cross-sectional study was performed in 109 PWS children aged 2-18 years (50 obese and 59 non-obese) and in 96 simple obese controls matched for age, gender, and also for BMI with obese PWS. Obesity was defined when SDS-BMI was >2. Non-obese PWS showed significantly lower frequency of hypertension (12%) than obese PWS (32%) and obese controls (35%)(p=0.003). The same was observed for low HDL-cholesterol (3% vs 18% and 24%, p=0.001) and high triglycerides (7% vs 23% and 16%, p=0.026). Frequency of altered glucose metabolism was not different among groups (2% vs 10% and 5%), but type 2 diabetes (four cases) was present only in obese PWS. Non-obese PWS showed lower insulin and HOMA-index respect to obese PWS and obese controls (p ≤ 0.017). Overall MS frequency in PWS was 7.3%. None of the non-obese PWS showed MS compared with 16% of obese PWS and controls (p<0.001). When obesity was excluded from the analysis, a significantly lower frequency for clustering of ≥ 2 factors was still found in non-obese PWS (p=0.035). CONCLUSION: Non-obese PWS showed low frequency of MS and its components, while that observed in obese PWS was very close to those of obese controls, suggesting the crucial role of obesity status. Prevention of obesity onset remains the most important goal of PWS treatment. Early identification of MS could be helpful to improve morbidity and mortality in such patients.