http://repub.eur.nl/res/aut/13824/ List of Publications en http://repub.eur.nl/static-eur/img/logo.png http://repub.eur.nl http://repub.eur.nl/res/pub/25377/ 2009-11-01T00:00:00Z Background: Children with Prader-Willi syndrome (PWS) have abnormal body composition and impaired growth. Short-term GH treatment has beneficial effects. Objectives: The aim of the study was to investigate effects of long-term continuous GH treatment on body composition, growth, bone maturation, and safety parameters. Setting: We conducted a multicenter prospective trial. Design: Fifty-five children with a mean ± SD age of 5.9 ± 3.2 yr were followed during 4 yr of continuous GH treatment (1mg/m2·d). Data were annually obtained in one center: fat percentage (fat%) and lean body mass (LBM) by dual-energy x-ray absorptiometry, height, weight, head circumference, bone age, blood pressure, and fasting IGF-I, IGF binding protein-3, glucose, insulin, glycosylated hemoglobin, total cholesterol, high-density lipoprotein, and low-density lipoprotein. SD scores (SDS) were calculated according to Dutch and PWS reference values (SDS and SDSPWS). Results: Fat%SDS was significantly lower after 4 yr of GH treatment (P < 0.0001). LBMSDS significantly increased during the first year (P = 0.02) but returned to baseline values the second year and remained unchanged thereafter. Mean ± SD height normalized from -2.27 ± 1.2 SDS to -0.24 ± 1.2 SDS (P < 0.0001). Head circumference SDS increased from -0.79 ± 1.0 at start to 0.07 ± 1.1 SDS after 4 yr. BMISDSPWSsignificantly decreased. Mean ± SD IGF-I and the IGF-I/IGF binding protein-3 ratio significantly increased to 2.08 ± 1.1 and 2.32 ± 0.9 SDS, respectively. GH treatment had no adverse effects on bone maturation, blood pressure, glucose homeostasis, and serum lipids. Conclusions: Our study in children with PWS shows that 4 yr of continuous GH treatment (1mg/m2·d) improves body composition by decreasing fat% SDS and stabilizing LBMSDS and head circumference SDS and normalizes heightSDS without adverse effects. Thus, long-term continuous GH treatment is an effective and safe therapy for children with PWS. Copyright http://repub.eur.nl/res/pub/25376/ 2009-10-19T00:00:00Z Background: Bone mineral density (BMD) is unknown in children with Prader-Willi syndrome (PWS), but is decreased in adults with PWS. In patients with GH deficiency, BMD increases during GH treatment. Objectives: The aim of the study was to evaluateBMDin children with PWS and to study the effects of GH treatment. Design: We conducted a randomized controlled GH trial. Forty-six prepubertal children were randomized into either a GH-treated group (1.0 mg/m2· d) or a control group for 2 yr. At start, 6, 12, and 24 months of study, total body and lumbar spine BMD were measured by dual-energy x-ray absorptiometry, and lumbar spine bone mineral apparent density (BMAD) was calculated. Results: Base line total body and lumbar spine BMDSD score (SDS) were normal [mean(SD),-0.2SDS(1.1) and -0.4 SDS (1.2), respectively]. BMADSDS, which corrects for short stature, was also normal [mean (SD), 0.40 SDS (1.1)]. Total body BMDSDS decreased during the first 6 months of GH (P < 0.0001), but increased during the second year of treatment. After 24 months of study, total body and lumbar spine BMDSDS, and the BMADSDS did not significantly differ between GH-treated children and randomized controls (P = 0.30, P = 0.44, and P = 0.47, respectively). Results were similar when corrected for body mass index SDS. Repeated measurements analysis showed a significant positive association between IGF-I SDS and total body and lumbar spine BMDSDS, but not with BMADSDS. Conclusions: Our results show that prepubertal children with PWS have a normal BMD. GH treatment had no effect on BMD, except for a temporary decrease of total body BMDSDS in the first 6 months. Copyright http://repub.eur.nl/res/pub/16430/ 2009-04-01T00:00:00Z Context: The prevalence of scoliosis in children with Prader-Willi syndrome (PWS) is 30-80%, depending on age. Although reports about effects of GH treatment on scoliosis in children with PWS are limited, scoliosis is generally considered a contraindication for GH treatment. Objective: The aim was to study the effects of GH treatment on the onset of scoliosis and curve progression in children with PWS. Design: We conducted a multicenter, randomized, controlled GH study in infants and prepubertal and pubertal children. Infants and prepubertal children were randomized into a GH-treated group (1.0 mg/m2 · d) and a control group for 1 and 2 yr, respectively. Pubertal children were randomized to receive somatropin 1.0 or 1.5 mg/m2 · d. Yearly, x-rays of the spine were taken, and height, weight, truncal lean body mass (with dual energy x-ray absorptiometry), and IGF-I were measured. Patients: A total of 91 children with PWS (median age, 4.7 yr; interquartile range, 2.1-7.4) participated in the study. Main Outcome Measures: We measured the onset of scoliosis (Cobb <10°) and scoliotic curve progression. Results: GH-treated children had similar onset of scoliosis and curve progression as randomized controls (P = 0.27-0.79 and P = 0.18-0.98, respectively). GH treatment, IGF-I sd score (SDS), and catch-up growth had no adverse effect on the onset of scoliosis or curve progression, even after adjustment for confounders. Height SDS, truncal lean body mass, and IGF-I SDS were significantly higher in GH-treated children than in randomized controls. At baseline, a higher IGF-I SDS was associated with a lower severity of scoliosis. Conclusions: Scoliosis should no longer be considered a contraindication for GH treatment in children with PWS. http://repub.eur.nl/res/pub/30413/ 2008-12-01T00:00:00Z Prader-Willi syndrome (PWS) is characterized by hypotonia, hypogonadism, obesity, and short stature. Neurobehavioral abnormalities, cognitive impairment, and sleep-related breathing disorders (SRBD) are common. In the general population associations between neurobehavioral and cognitive abnormalities and SRBD have been found. We investigated cognition, behavior, and SRBD in children with PWS. Thirty-one pre-pubertal PWS children were evaluated (5 with paternal deletion, 14 with maternal disomy, 4 with imprinting-center mutation, and in 8 the defect was not specified). Cognition was assessed by Wechsler scale subtests, and behavior by parent-questionnaires. Polysomnography was performed. Cognition, behavior, and associations with SRBD were evaluated. All cognitive subtests were significantly below O SDS, with the lowest median (interquartile range) scores for the Block design subtest (-2.7 SDS (-3.0 to -0.3)). In 60%, verbal subtests were less affected than performance subtests. Parents reported problem behavior related to "emotions/behavior not adapted to the social situation" and "insensitivity to social information." All children had SRBD, with an Apnea Hypopnea Index of 4.1/hr (2.6-7.9). One performance subtest score was significantly higher in children with better sleep efficiency, and daytime sleepiness was associated with more autistic-like social impairment. In contrast to our expectations, behavior was worse in children with better sleep-related breathing. In pre-pubertal PWS children, cognition is impaired. Neurobehavioral abnormalities are common, particularly autistic-like social impairment. Sleep efficiency was associated with better performance on one of the performance subtests, and neurobehavioral abnormalities were associated with daytime sleepiness. In contrast, we could not confirm a positive association of neurobehavioral abnormalities with SRBD in PWS. http://repub.eur.nl/res/pub/29688/ 2008-09-01T00:00:00Z Background: Prader-Willi syndrome (PWS) children have impaired growth, and abnormal body composition. Previous 1-year controlled studies showed improvement of height and body composition during GH-treatment. Objective: To evaluate growth, body composition and body proportions during GH-treatment in a large group of PWS children. Design/patients: We performed a randomized controlled GH trial in 91 prepubertal PWS children (42 infants, 49 children, aged 3-14 years). After stratification for age, infants were randomized to GH-treatment (GH-group; 1 mg/m2/day; n = 20), or no treatment (control group; n = 22) for 1 year. In the second year all infants were treated with GH. After stratification for BMI, children > 3 years of age were randomized to GH-treatment (GH-group; 1 mg/m2/day; n = 27) or no treatment (control group; n = 22) for 2 years. Anthropometric parameters were assessed once in every 3 months. Body composition was measured by Dual Energy X-ray Absorptiometry. Results: Median (interquartile range, iqr) height SDS increased during 2 years of GH in infants from -2.3 (-2.8 to -0.7) to -0.4 (-1.1-0.0) and in prepubertal children from -2.0 (-3.1 to -1.7) to -0.6 (-1.1 to -0.1). In non-GH-treated children height SDS did not increase. Head circumference completely normalized during 1 and 2 years of GH in infants and children, respectively. Body fat percentage and body proportions improved in GH-treated children, but did not completely normalize. Lean body mass SDS improved compared to the control group. Serum IGF-I increased to levels above the normal range in most GH-treated children. Conclusions: Our randomized study shows that GH-treatment in PWS children significantly improves height, BMI, head circumference, body composition and body proportions. PWS children are highly sensitive to GH, suggesting that monitoring of serum IGF-I is indicated. http://repub.eur.nl/res/pub/29612/ 2008-06-01T00:00:00Z Background: Prader-Willi syndrome (PWS) is a neurogenetic disorder characterized by muscular hypotonia, psychomotor delay, feeding difficulties and failure to thrive in infancy. GH treatment improves growth velocity and body composition. Research on the effects of GH on psychomotor development in infants with PWS is limited. Objective: To evaluate psychomotor development in PWS infants and toddlers during GH treatment compared to randomized controls. Design/patients: Forty-three PWS infants were evaluated at baseline. Twenty-nine of them were randomized into a GH group (n = 15) receiving 1 mg/m2/day GH or a non-GH-treated control group (n = 14). At baseline and after 12 months of follow-up, analysis with Bayley Scales of Infant Development II (BSID-II) was performed. Data were converted to percentage of expected development for age (%ed), and changes during follow-up were calculated. Results: Infants in the GH group had a median age of 2.3 years [interquartile range (IQR) 1.7-3.0] and in the control group of 1.5 years (IQR 1.2-2.7) (P = 0.17). Both mental and motor development improved significantly during the first year of study in the GH group vs. the control group: median (IQR) change was +9.3% (-5.3 to 13.3) vs. -2.9% (-8.1 to 4.9) (P < 0.05) in mental development and +11.2% (-4.9 to 22.5) vs. -18.5% (-27.9 to 1.8) (P < 0.05) in motor development, respectively. Conclusion: One year of GH treatment significantly improved mental and motor development in PWS infants compared to randomized controls. http://repub.eur.nl/res/pub/28758/ 2008-05-01T00:00:00Z Context: The annual death rate of Prader-Willi syndrome (PWS) patients is very high (3%). Many of these deaths are sudden and unexplained. Objective: Because most deaths occur during moderate infections and PWS patients suffer from various hypothalamic insufficiencies, we investigated whether PWS patients suffer from central adrenal insufficiency (CAI) during stressful conditions. Design: Overnight single-dose metyrapone tests were performed. Metyrapone (30 mg/kg) was administered at 2330 h. At 0400, 0600, and 0730 h, ACTH, 11-deoxycortisol, cortisol, and glucose levels were measured. Diurnal salivary cortisol profiles were assessedona different day at wake-up, 30 min after wake-up, at 1400 h, and at 2000 h. Setting: The study was conducted in a pediatric intensive care unit. Patients: Patients included 25 randomly selected PWS patients. Main Outcome Measure: Patients were considered as having CAI when ACTH levels remained below 33 pmol/liter at 0730 h. Results: Median (interquartile range) age was 9.7 (6.8-13.6) yr. Fifteen patients (60%) had an insufficient ACTH response (CAI, P < 0.001). There was no significant difference in age, gender, genotype, and body mass index SD score between patients with CAI and those without. Morning salivary cortisol levels and diurnal profiles were normal in all children, suggesting that CAI becomes apparent only during stressful conditions. Conclusions: Strikingly, 60% of our PWS patients had CAI. The high percentage of CAI in PWS patients might explain the high rate of sudden death in these patients, particularly during infection-related stress. Based on our data, one should consider treatment with hydrocortisone during acute illness in PWS patients unless CAI has recently been ruled out with a metyrapone test. Copyright http://repub.eur.nl/res/pub/15237/ 2008-02-08T00:00:00Z BACKGROUND: The reported prevalence of scoliosis in children with Prader-Willi syndrome varies from 15% to 86%. OBJECTIVE: To study the prevalence of scoliosis and the effects of age, gender, body mass index (BMI), total lean body mass (LBM), LBM of the trunk (trunkLBM) and genotype. DESIGN: Radiographs were taken, length and weight were measured (BMI standard deviation scores (BMI SDS) and body surface area (BSA)), and dual energy x-ray absorptiometry was performed, measuring LBM and trunkLBM. PATIENTS: 96 children, median (interquartile range) age 4.8 years (2.1 to 7.5), were included in a multicentre study. None received growth hormone treatment. MAIN OUTCOME MEASURES: Two types of scoliosis were identified: (1) long C-curve type scoliosis (LCS) and (2) idiopathic scoliosis (IS). Children were divided into age categories (infants, 0-3 years; juveniles, 3-10 years; adolescents, 10-16 years). RESULTS: The prevalence of scoliosis was 37.5% and increased with age (infants and juveniles, approximately 30%; adolescents, 80%); 44% of children with scoliosis had a Cobb angle above 20 degrees . Children with scoliosis were significantly older than those without. Children with LCS were younger and more hypotonic than those with IS: median (interquartile range) age 4.4 years (1.7-5.9) vs 11.1 years (6.5-12.1) (p = 0.002) and trunkLBM/BSA ratio 7080 (6745-7571) vs 7830 (6932-8157) (p = 0.043). CONCLUSIONS: The prevalence of scoliosis in children with Prader-Willi syndrome is high (37.5%). Many children with scoliosis (13%) had undergone brace treatment or surgery. The type of scoliosis is affected by age and trunkLBM/BSA ratio. http://repub.eur.nl/res/pub/10645/ 2007-11-16T00:00:00Z This thesis presents a detailed description of several studies on growth, metabolism, psychomotor development, cognition, behaviour and breathing in PWS children. In chapter 2, growth, body composition and body proportions before and during growth hormone (GH) treatment are evaluated. In chapter 3, the effects of GH treatment on psychomotor development, as measured with Bayley Scales of Infant Development in PWS infants and toddlers are reported In chapter 4, studies on sleep-related breathing, as measured with polysomnography in pre-pubertal children with PWS are summarized, including the effects of GH treatment and upper respiratory tract infections on sleep-related breathing. Chapter 5 describes the associations between sleep-related breathing, cognition, and neurobehavioral abnormalities. Chapter 6 describes in infants whether psychomotor development is affected by sleep-disordered breathing, particularly obstructive sleep apnea syndrome (OSAS), as was recently shown for healthy infants. In chapter 7, thyroid hormone function is reported in a large group of pre-pubertal PWS children, including effects of GH treatment on thyroid hormone function. In chapter 8, serum adiponectin levels are evaluated both before and during GH-treatment. Adiponectin is strongly related to insulin sensitivity and is considered cardioprotective. In chapter 9, the general discussion our data are discussed in relation to the present literature. Chapter 10 summarizes our findings in English, and chapter 11 presents a Dutch summary. http://repub.eur.nl/res/pub/36040/ 2007-09-01T00:00:00Z Background: Prader-Willi syndrome (PWS) is a neurogenetic disorder characterized by muscular hypotonia, psychomotor delay, obesity and short stature. Several endocrine abnormalities have been described, including GH deficiency and hypogonadotrophic hypogonadism. Published data on thyroid hormone levels in PWS children are very limited. Objective: To evaluate thyroid function in children with PWS, before and during GH treatment. Design/patients: At baseline, serum levels of T4, free T4 (fT4), T3, reverse T3 (rT3) and TSH were assessed in 75 PWS children. After 1 year, assessments were repeated in 57 of the them. These children participated in a randomized study with two groups: group A (n = 34) treated with 1 mg GH/m2/day and group B (n = 23) as controls. Results: Median age (interquartile range, IQR) of the total group at baseline was 4.7 (2.7-7.6) years. Median (IQR) TSH level was -0.1 SDS (-0.5 to 0.5), T4 level -0.6 SDS (-1.7 to 0.0) and fT4 level -0.8 SDS (-1.3 to -0.3), the latter two being significantly lower than 0 SDS. T3 level, at 0.3 SDS (-0.3 to 0.9), was significantly higher than 0 SDS. After 1 year of GH treatment, fT4 decreased significantly from -0.8 SDS (-1.5 to -0.2) to -1.4 SDS (-1.6 to -0.7), compared to no change in untreated PWS children. However, T3 did not change, at 0.3 SDS (-0.1 to 0.8). Conclusions: We found normal fT4 levels in most PWS children. During GH treatment, fT4 decreased significantly to low-normal levels. TSH levels remained normal. T3 levels were relatively high or normal, both before and during GH treatment, indicating that PWS children have increased T4 to T3 conversion. http://repub.eur.nl/res/pub/35263/ 2007-08-01T00:00:00Z Prader-Willi syndrome (PWS) is a neurogenetic disorder with hypotonia, psychomotor delay, obesity, short stature, and sleep-related breathing disorders. The aim of this study was to evaluate the association between psychomotor development and sleep-related breathing disorders in PWS infants. Bayley Scales of Infant Development were performed in 22 PWS infants, with a median (interquartile range, IQR) age of 1.8 (1.1-3.4) y, and a body mass index SD score (BMISDS) of -0.5 (-1.3 to 1.6). We evaluated psychomotor development in relation to results of polysomnography. Median (IQR) mental and motor development was 73.1% (64.3-79.6%) and 55.2% (46.5-63.1%) of normal children, respectively. All infants had sleep-related breathing disorders, mostly of central origin. The apnea hypopnea index was not associated with psychomotor development. Only four infants had obstructive sleep apnea syndrome (OSAS). They had a significantly delayed mental development of 65.5% (60.0-70.3%) of normal. They had a median BMISDS of 1.4 (0.1-1.6), which tended to be higher than in those without OSAS. Our data indicate that psychomotor development in PWS infants is not related to central sleep-related breathing disorders, but infants with OSAS have more severely delayed mental development, suggesting that PWS infants should be screened for OSAS. http://repub.eur.nl/res/pub/37113/ 2007-07-01T00:00:00Z Prader-Willi syndrome is a neurogenetic disorder characterized by a number of signs and symptoms, including muscular hypotonia in infancy, hypogonadism, obesity and short stature. Neurobehavioral abnormalities and cognitive impairment are common. In addition, breathing abnormalities have been described, including sleep-related breathing disorders, abnormal chemoreceptor sensitivity and pulmonary function abnormalities. Growth hormone treatment is now widely used in children with Prader-Willi syndrome to improve growth and body composition. Over the last 4 years, case reports have been published concerning unexpected death, many of which were related to respiratory abnormalities. This review focuses on breathing abnormalities in Prader-Willi syndrome individuals and the influence of obesity, growth hormone treatment and upper respiratory tract infections. http://repub.eur.nl/res/pub/35479/ 2007-04-01T00:00:00Z Context: Children with Prader-Willi syndrome (PWS) may have obesity and an abnormal body composition with a high body fat percentage, even if they have a normal body weight. Adiponectin has been inversely related to obesity and insulin resistance. Objective: The objective of the study was to evaluate in prepubertal PWS children the following: 1) adiponectin levels, body composition, carbohydrate metabolism, and triglyceride levels; 2) associations between adiponectin and body composition, carbohydrate metabolism, and triglycerides; and 3) effects of GH treatment on these outcome measures. Patients: Twenty prepubertal PWS children participated in the study. Intervention: The subjects were randomized into a GH treatment group (n = 10, 1 mg/m2·d) and a non-GH-treated control group (n = 10). Main Outcome Measures: At baseline, after 1 and 2 yr of GH treatment, fasting levels of adiponectin, glucose, insulin, and triglycerides were assessed. Body composition and fat distribution were measured by dual energy x-ray absorptiometry. Results: PWS children had significantly higher median (interquartile range) adiponectin levels [17.1 mg/liter (13.9 -23.2)] than healthy sex- and age-matched controls [11.8 mg/liter (9.7-12.5), P < 0.005]. Body fat percentage was significantly higher than 0 SD score [1.8 SD score (1.5-2.1), P < 0.001]. Adiponectin levels were inversely related to triglyceride levels (r = -0.52, P < 0.03). There was a tendency to an inverse relation with body fat percentage and body mass index, but no correlation with fasting insulin or glucose levels, the insulin to glucose ratio, or homeostasis model assessment index. During GH treatment, adiponectin levels increased significantly and did not change in randomized controls. Conclusion: Adiponectin levels were increased, and inversely associated with triglyceride levels, in prepubertal, not overweight PWS children, although they had a relatively high body fat percentage. During GH treatment, adiponectin levels further increased, whereas no change was found in the controls, which is reassuring with respect to the development of insulin resistance during GH treatment. Copyright http://repub.eur.nl/res/pub/14098/ 2006-12-01T00:00:00Z CONTEXT: Recently, several cases of sudden death in GH-treated and non-GH-treated, mainly young Prader-Willi syndrome (PWS), patients were reported. GH treatment in PWS results in a remarkable growth response and an improvement of body composition and muscle strength. Data concerning effects on respiratory parameters, are however, limited. OBJECTIVE: The objective of the study was to evaluate effects of GH on respiratory parameters in prepubertal PWS children. DESIGN: Polysomnography was performed before GH in 53 children and repeated after 6 months of GH treatment in 35 of them. PATIENTS: Fifty-three prepubertal PWS children (30 boys), with median (interquartile range) age of 5.4 (2.1-7.2) yr and body mass index of +1.0 sd score (-0.1-1.7). INTERVENTION: Intervention included treatment with GH 1 mg/m2.d. RESULTS: Apnea hypopnea index (AHI) was 5.1 per hour (2.8-8.7) (normal 0-1 per hour). Of these, 2.8 per hour (1.5-5.4) were central apneas and the rest mainly hypopneas. Duration of apneas was 15.0 sec (13.0-28.0). AHI did not correlate with age and body mass index, but central apneas decreased with age (r = -0.34, P = 0.01). During 6 months of GH treatment, AHI did not significantly change from 4.8 (2.6-7.9) at baseline to 4.0 (2.7-6.2; P = 0.36). One patient died unexpectedly during a mild upper respiratory tract infection, although he had a nearly normal polysomnography. CONCLUSIONS: PWS children have a high AHI, mainly due to central apneas. Six months of GH treatment does not aggravate the sleep-related breathing disorders in young PWS children. Our study also shows that monitoring during upper respiratory tract infection in PWS children should be considered.