Measured resting energy expenditure by indirect calorimetry and energy intake in long-term growth hormone treated children with PWS

INTRODUCTION

Severe obesity can develop in children with PWS when food intake is not controlled. Maintenance of body weight requires an energy balance, of which energy intake and energy expenditure are important components. Previous studies described a decreased resting energy expenditure (REE) in growth hormone (GH)-untreated children with PWS. In short-term studies, no difference in REE was found between GH-treated and untreated children with PWS. However, there are limited data on REE in children with PWS who were GH-treated for a long period.

METHODS

This study describes measured REE (mREE), energy intake and body composition during long-term GH-treatment in children with PWS. Patients were treated with 1.0 mg GH/m2/day (~0.035mg/kg/day). REE was determined by indirect calorimetry; dietary energy intake was calculated using a 3-day dietary record. Body composition by Dual energy X-ray absorptiometry (DXA) scans.

RESULTS

We included 52 GH-treated children with PWS with mean (SD) age of 8.53 (4.35) years and median (IQR) GH-treatment duration of 7 (4-11) years. mREE increased with age, but was not associated with GH-treatment duration. A higher LBM was associated with higher mREE. Mean energy intake was significantly lower compared to daily energy requirements (DER) for age- and sex-matched healthy children (p<0.001), ranging from 23-36% less intake in children aged 3.5-12 years to 49% less intake in children aged 12-18 years. Fifty percent of children had a normal REE, 17.3 % a decreased REE and 32.7% an elevated REE, according to predicted REE based on measured REE in a large group of healthy children.

CONCLUSION

In children with PWS, mREE increases with age. GH-treatment duration is not associated, whereas LBM is an important determinant of mREE. Children with PWS have a low to very low energy intake compared to DER for age- and sex-matched children, with a declining intake when becoming older.

Longitudinal changes in acylated versus unacylated ghrelin levels may be involved in the underlying mechanisms of the switch in nutritional phases in Prader-Willi syndrome

INTRODUCTION

Prader-Willi syndrome (PWS) is characterized by a switch from failure to thrive to excessive weight gain and hyperphagia in early childhood. An elevated, more unfavorable ratio between acylated and unacylated ghrelin (AG/UAG ratio) might play a role in the underlying mechanisms of this switch. We aimed to assess the evolution of the appetite regulating hormones acylated ghrelin (AG) and unacylated ghrelin (UAG) and the AG/UAG ratio and their association with the change in eating behavior in children with PWS, compared to healthy age-matched controls.

METHODS

Longitudinal study in 134 children with PWS and 157 healthy controls, from The Netherlands, France and Belgium. Levels of AG and UAG and the AG/UAG ratio were measured and nutritional phases as reported for PWS were scored.

RESULTS

The AG/UAG ratio was in the first years of life lower in PWS than in controls and started to increase from the age of 3 years, resulting in a high-normal AG/UAG ratio compared to controls. The AG levels remained stable during the different nutritional phases (p=0.114), while the UAG levels decreased from 290 pg/ml in phase 1a to 137 pg/ml in phase 2b (p<0.001). The AG/UAG ratio increased significantly from 0.81 in phase 2a to 1.24 in phase 2b (p= 0.012).

CONCLUSIONS

The change from failure to thrive to excessive weight gain and hyperphagia in infants and children with PWS coincides with an increase in AG/UAG ratio. The increase in AG/UAG ratio occurred during phase 2a, thus before the onset of hyperphagia.

Cognitive function during 3 years of growth hormone in previously GH-treated young adults with PWS

CONTEXT

Most patients with Prader-Willi syndrome (PWS) have a mild to moderate cognitive impairment. Growth hormone (GH) treatment has positive short- and long-term effects on cognition in children with PWS. Few studies, however, have investigated the effects of GH on cognitive functioning in adults with PWS.

OBJECTIVE

To investigate the effects of 3 years GH treatment on cognitive functioning and behavior in young adults with PWS who were treated with GH during childhood.

DESIGN

Open-label, prospective study.

SETTING

Dutch PWS Reference Center.

METHODS

Patients were treated with 0.33 mg GH/m²/day (∼0.012 mg/kg/day; 33% of childhood dose). Cognitive functioning was measured by Wechsler Adult Intelligence (WAIS) tests. Behavior was studied by Developmental Behavior Checklist - Parents/caregivers (DBC-P).

RESULTS

46 young adults with PWS with a median age of 19 (IQR 17-21) years were investigated. Estimated mean (95% CI) total, verbal and performance IQ remained stable during 3 years of GH-treatment. Total IQ being 66 (63-69) at start and 67 (64-71) after 3 years (p=0.30); Verbal IQ being 65 (62-68) and 66 (62-70), resp. (p=0.31) and performance IQ being 67 (63-70) and 67 (63-72) resp. (p=0.42). Estimated mean Total DBC score did not significantly change during 3 years of GH-treatment, being 36.3 at start and 36.5 after 3 years (p=0.94) (P50).

CONCLUSIONS

Three years of GH-treatment in young adults with PWS with 33% of the pediatric dose, maintains total, verbal and performance IQ. The emotional and behavioral disturbances remained stable and were similar compared to peers with other intellectual disabilities.

Acute stress response of the HPA-axis in children with Prader-Willi syndrome: new insights and consequences for clinical practice

Background

Prader-Willi syndrome (PWS) is associated with hypothalamic dysfunction. It has been reported that the HPA axis might show a delayed response during acute stress, and it is unknown whether the response of the HPA-axis during acute stress changes with age in children with PWS.

Aim

To investigate the HPA-axis response during an overnight single-dose metyrapone (MTP) test in children with PWS and to assess if the response changes with age, whether it is delayed and if it changes with repeated testing over time. In addition, we evaluated different cut-off points of ACTH and 11-DOC levels to assess stress-related central adrenal insufficiency (CAI).

Methods

An overnight single-dose MTP test was performed in 93 children with PWS. Over time, 30 children had a second test and 11 children a third one. Children were divided into age groups (0-2 years, 2-4 years, 4-8 years and > 8 years).

Results

Most children did not have their lowest cortisol level at 7.30h, but at 04.00h. Their ACTH and 11-DOC peaks appeared several hours later, suggesting a delayed response. When evaluated according to a subnormal ACTH peak (13-33 pmol/L) more children had an subnormal response compared to evaluation based on a subnormal 11-doc peak (< 200 nmol/L). The percentage of children with a subnormal ACTH response ranged from 22.2 to 70.0% between the age groups, while the percentage of a subnormal 11-DOC response ranged from 7.7 to 20.6%. When using the ACTH peak for diagnosing acute-stress-related CAI, differences between age groups and with repeated testing over time were found, whereas there was no age difference when using the 11-DOC peak.

Conclusion

Early morning ACTH or 11-DOC levels are not appropriate to determine acute stress-related CAI in children with PWS, thus multiple measurements throughout the night are needed for an accurate interpretation. Our data suggest a delayed response of the HPA-axis during acute stress. Using the 11-DOC peak for the test interpretation is less age-dependent than the ACTH peak. Repeated testing of the HPA-axis over time is not required, unless clinically indicated.

The Effects of 5 Years of Growth Hormone Treatment on Growth and Body Composition in Patients with Temple Syndrome

INTRODUCTION

Temple syndrome (TS14) is a rare imprinting disorder caused by maternal uniparental disomy of chromosome 14, paternal deletion of 14q32.2, or an isolated methylation defect. Most patients with TS14 develop precocious puberty. Some patients with TS14 are treated with growth hormone (GH). However, evidence for the effectiveness of GH treatment in patients with TS14 is limited.

METHODS

This study describes the effect of GH treatment in 13 children and provides a subgroup analysis of 5 prepubertal children with TS14. We studied height, weight, body composition by dual-energy X-ray absorptiometry, resting energy expenditure (REE), and laboratory parameters during 5 years of GH treatment.

RESULTS

In the entire group, mean (95% CI) height SDS increased significantly during 5 years of GH treatment from -1.78 (-2.52; -1.04) to 0.11 (-0.66; 0.87). Fat mass percentage SDS decreased significantly during the first year of GH, and lean body mass (LBM) SDS and LBM index increased significantly during 5 years of treatment. IGF-1 and IGF-BP3 levels rose rapidly during GH treatment, and the IGF-1/IGF-BP3 molar ratio remained relatively low. Thyroid hormone levels, fasting serum glucose, and insulin levels remained normal. In the prepubertal group, median (interquartile range [IQR]) height SDS, LBM SDS, and LBM index also increased. REE was normal at start and did not change during 1 year of treatment. Five patients reached adult height and their median (IQR) height SDS was 0.67 (-1.83; -0.01).

CONCLUSION

GH treatment in patients with TS14 normalizes height SDS and improves body composition. There were no adverse effects or safety concerns during GH treatment.

Computer-aided facial analysis as a tool to identify patients with Silver-Russell syndrome and Prader-Willi syndrome

Genetic syndromes often show facial features that provide clues for the diagnosis. However, memorizing these features is a challenging task for clinicians. In the last years, the app Face2Gene proved to be a helpful support for the diagnosis of genetic diseases by analyzing features detected in one or more facial images of affected individuals. Our aim was to evaluate the performance of the app in patients with Silver-Russell syndrome (SRS) and Prader-Willi syndrome (PWS). We enrolled 23 pediatric patients with clinically or genetically diagnosed SRS and 29 pediatric patients with genetically confirmed PWS. One frontal photo of each patient was acquired. Top 1, top 5, and top 10 sensitivities were analyzed. Correlation with the specific genetic diagnosis was investigated. When available, photos of the same patient at different ages were compared. In the SRS group, Face2Gene showed top 1, top 5, and top 10 sensitivities of 39%, 65%, and 91%, respectively. In 41% of patients with genetically confirmed SRS, SRS was the first syndrome suggested, while in clinically diagnosed patients, SRS was suggested as top 1 in 33% of cases (p = 0.74). Face2Gene performed better in younger patients with SRS: in all patients in whom a photo taken at a younger age than the age of enrollment was available, SRS was suggested as top 1, albeit with variable degree of probability. In the PWS group, the top 1, top 5, and top 10 sensitivities were 76%, 97%, and 100%, respectively. PWS was suggested as top 1 in 83% of patients genetically diagnosed with paternal deletion of chromosome 15q11-13 and in 60% of patients presenting with maternal uniparental disomy of chromosome 15 (p = 0.17). The performance was uniform throughout the investigated age range (1-15 years).

CONCLUSION

In addition to a thorough medical history and detailed clinical examination, the Face2Gene app can be a useful tool to support clinicians in identifying children with a potential diagnosis of SRS or PWS.

WHAT IS KNOWN

• Several genetic syndromes present typical facial features that may provide clues for the diagnosis. • Memorizing all syndromic facial characteristics is a challenging task for clinicians.

WHAT IS NEW

• Face2Gene may represent a useful support for pediatricians for the diagnosis of genetic syndromes. • Face2Gene app can be a useful tool to integrate in the diagnostic path of patients with SRS and PWS.

Long-Term Growth Hormone Treatment of Children with PWS: The Earlier the Start, the Better the Outcomes?

Long-term effects of growth hormone (GH) treatment in young children with Prader-Willi syndrome (PWS) have never been compared with untreated age-matched controls with PWS, and it is unclear if starting GH in the first year of life is safe and more effective than starting GH in early childhood. We investigated the effects of long-term GH on body composition, anthropometrics and cognition in young children with PWS compared to untreated controls and assessed whether starting GH in the first year of life is optimal and safe. An open-label, prospective study was performed, comparing GH-treated children with untreated controls, and comparing children who started GH in the first year of life (subgroup A) with children who started between 2–5 years (subgroup C). A total of 82 GH-treated children with PWS and 22 age-matched controls with PWS were included. The main outcome measures were body composition, anthropometrics, IQ, and safety parameters. After 8 years, GH-treated children had significantly better body composition and were taller than age-matched controls. Subgroup A had a lower FM% trajectory during treatment than subgroup C and showed a greater and longer-term increase in the LBM index. After 8 years, subgroup A had a lower trunk/peripheral fat ratio (p = 0.043) and higher IQ (p = 0.043). No adverse effects of starting GH in the first year were found. Children with PWS who received long-term GH had a better body composition and growth than untreated age-matched controls and starting GH in the first year of life was optimal and safe.

Long-term cortisol levels in hair of children and adolescents with Prader-Willi Syndrome

CONTEXT

Prader-Willi syndrome (PWS) is characterized by hypothalamic dysfunction. In children with PWS, stress-induced central adrenal insufficiency (CAI) has been described, however, daily life cortisol production may be normal. Hair cortisol concentration (HCC) is a marker of long-term systemic cortisol production. Cortisol awakening response (CAR) is the increase in cortisol level after awakening. A negative CAR might suggest hypothalamic-pituitary-adrenal (HPA)-axis reactivity problems. Little is known about HCC and CAR in children with PWS.

OBJECTIVE

To investigate long-term cortisol levels in hair and CAR in children with PWS.

DESIGN

Cross-sectional study.

PATIENTS

41 children with PWS.

SETTING

Dutch PWS Reference Center.

MAIN OUTCOME MEASURES

HCC and salivary cortisol measured by LCMS.

RESULTS

Median (IQR) HCC was 1.90 (1.02-3.30) pg/mg at a median (IQR) age of 14.5 (8.20-19.0) years, with median HCC in age-matched references being 2.63 pg/mg. Five patients (13.2%) had HCC < 2.5th percentile for age and these patients had a repeatedly negative CAR. Median HCC was significantly lower in patients with negative CAR than in patients with normal CAR (1.00 (0.22-1.59) vs. 2.25 (1.47-3.26) pg/mg, p = 0.007). One patient had both HCC < 2.5th percentile and repeatedly low morning salivary cortisol levels and negative CAR, and was diagnosed with adrenal insufficiency by overnight metyrapone test.

CONCLUSIONS

HCC were normal in the majority of children with PWS. Our data suggest that children with HCC < 2.5th percentile and (repeatedly) negative CAR might possibly have adrenal insufficiency or delayed HPA-axis responsiveness.

Effects of Childhood Multidisciplinary Care and Growth Hormone Treatment on Health Problems in Adults with Prader-Willi Syndrome

Prader-Willi syndrome (PWS) is a complex hypothalamic disorder. Features of PWS include hyperphagia, hypotonia, intellectual disability, and pituitary hormone deficiencies. The combination of growth hormone treatment and multidisciplinary care (GHMDc) has greatly improved the health of children with PWS. Little is known about the effects of childhood GHMDc on health outcomes in adulthood. We retrospectively collected clinical data of 109 adults with PWS. Thirty-nine had received GHMDc during childhood and adolescence (GHMDc+ group) and sixty-three had never received growth hormone treatment (GHt) nor multidisciplinary care (GHMDc− group). Our systematic screening revealed fewer undetected health problems in the GHMDc+ group (10%) than in the GHMDc− group (84%). All health problems revealed in the GHMDc+ group had developed between the last visit to the paediatric and the first visit to the adult clinic and/or did not require treatment. Mean BMI and the prevalence of diabetes mellitus type 2 were significantly lower in the GHMDc+ group compared to the GHMDc− group. As all patients who received GHt were treated in a multidisciplinary setting, it is unknown which effects are the result of GHt and which are the result of multidisciplinary care. However, our data clearly show that the combination of both has beneficial effects. Therefore, we recommend continuing GHMDc after patients with PWS have reached adult age.

Effects of 8 years of growth hormone treatment on scoliosis in children with Prader-Willi syndrome

OBJECTIVE

Scoliosis is frequently seen in children with Prader-Willi syndrome (PWS). There is still concern that growth hormone (GH) treatment might increase the risk of onset or progression of scoliosis. Short-term data suggested no adverse effects of GH on scoliosis, but long-term effects of GH treatment on development of scoliosis in PWS are unknown. This study investigated the effects of 8 years of GH treatment on scoliosis in children with PWS.

DESIGN

Open-label, prospective cohort study in 103 children with PWS receiving GH for 8 years was analyzed. Prevalence and severity of scoliosis were compared to a group of 23 age-matched GH-untreated children with PWS.

METHODS

Spine X-rays and DEXA-scans were performed, and Cobb angel was measured by two independent observers.

RESULTS

After 8 years of GH treatment, at median age of 10.8 years, prevalence of scoliosis was 77.7%. No difference in prevalence or severity of scoliosis was found between GH-treated and age-matched untreated children with PWS (P = 0.409 and P = 0.709, respectively). Height SDS and trunkLBM were significantly higher in GH-treated children. Higher bone mineral density of the lumbar spine was found in children without scoliosis after 8 years of GH. Bone mineral apparent density of lumbar spine (BMADLS) SDS was associated with lower Cobb angle (r = -0.270, P = 0.008).

CONCLUSIONS

Eight years of GH treatment has no adverse effects on the prevalence and severity of scoliosis in children with PWS until 11 years of age. As BMADLS SDS is inversely associated with Cobb angle, it is pivotal to optimize the BMD status in children with PWS.

Bone mineral density during 3 years of growth hormone in previously GH-treated young adults with PWS

OBJECTIVE

In children with Prader-Willi syndrome (PWS), growth hormone (GH) treatment has positive effects on bone mineral density (BMD). Two 1-year studies did not show a difference between GH or placebo on BMD in young adults with PWS. However, there are no studies investigating BMD during longer-term GH treatment in young adults with PWS.

DESIGN

Open-label, a prospective study in 43 young adults with PWS.

METHODS

BMD of the total body (BMDTBSDS) and lumbar spine (BMADLSSDS) measured by DXA.

RESULTS

In the total group, estimated mean (95% CI) of BMDTB remained similar during 3 years of GH, being -0.76 (-1.11 to -0.41) SDS at start and -0.90 (-1.27 to -0.54) SDS after 3 years (P = 0.11), as did BMADLS, being -0.36 (-0.72 to 0.01) SDS and -0.46 (-0.77 to -0.16) SDS, respectively (P = 0.16). In men, there was a significant decrease in BMDTBSDS during 3 years of GH, while BMADLSSDS remained similar. In women, both BMDTBSDS and BMADLSSDS remained similar. BMDTBSDS was associated with female sex, lean body mass and age. The majority of patients received sex steroid replacement therapy (SSRT).

CONCLUSIONS

During 3 years of combined GH and SSRT treatment, BMD remained stable in the normal range in young adults with PWS. However, men showed a decline in BMDTBSDS, probably due to insufficient SSRT. We recommended to continue GH treatment in young adults with PWS and to start SSRT during adolescence unless puberty progresses normally.

Oxytocin in young children with Prader-Willi syndrome: Results of a randomized, double-blind, placebo-controlled, crossover trial investigating 3 months of oxytocin

CONTEXT

Prader-Willi syndrome (PWS) is characterized by hypothalamic dysfunction, hyperphagia and a typical behavioural phenotype, with characteristics of autism spectrum disorder (ASD) like stubbornness, temper tantrums and compulsivity. It has been suggested that the oxytocin system in patients with PWS is dysfunctional. In ASD, intranasal oxytocin treatment has favourable effects on behaviour.

OBJECTIVE

To evaluate the effects of 3 months of twice daily intranasal oxytocin (dose range 16-40 IU/day), compared to placebo, on behaviour and hyperphagia in children with PWS.

DESIGN

Randomized, double-blind, placebo-controlled, crossover study in the Dutch PWS Reference Center.

PATIENTS

Twenty-six children with PWS aged 3-11 years.

MAIN OUTCOME MEASURES

(Change in) behaviour and hyperphagia measured by Oxytocin Questionnaire and Dykens hyperphagia questionnaire.

RESULTS

In the total group, no significant effects of oxytocin on social behaviour or hyperphagia were found. However, in boys, the Oxytocin Questionnaire scores improved significantly during oxytocin treatment, compared to a deterioration during placebo (4.5 (-0.8 to 15.3) vs. -4.0 (-11.3 to 0.8), P = .025). The Dykens hyperphagia questionnaire scores remained similar during oxytocin treatment, while there was a deterioration during placebo (0.0 (-0.8 to 4.3) vs. -3.5 (-6.0 to 0.0), P = .046). Patients with a deletion had significant improvements in both questionnaire scores during oxytocin treatment, but deteriorations during placebo. Oxytocin treatment was well tolerated, and there were no serious adverse events.

CONCLUSIONS

Intranasal oxytocin treatment has positive effects on social and eating behaviour in 3-11 years aged boys with PWS and in children with a deletion without safety concerns. Intranasal oxytocin in children with PWS might be considered, but individual effects should be carefully evaluated and treatment discontinued if no effects are found.

Three years of growth hormone treatment in young adults with Prader-Willi Syndrome previously treated with growth hormone in childhood: Effects on glucose homeostasis and metabolic syndrome

CONTEXT

Growth hormone (GH) has been approved for children with Prader-Willi syndrome (PWS) and significantly improves body composition in adults with PWS. Adults with PWS are predisposed to develop impaired glucose tolerance (IGT) and diabetes mellitus type 2 (DMT2). Continuation of GH maintains body composition, but GH is known to induce insulin resistance, which might affect glucose homeostasis. Studies on long-term effects of GH treatment in adults are very limited.

OBJECTIVE

To investigate effects of 3 years of GH treatment on glucose homeostasis and prevalence of metabolic syndrome (MS) in adults with PWS.

DESIGN

Open-label, prospective study.

PATIENTS

43 young adults with PWS.

SETTING

Dutch PWS Reference Center.

MAIN OUTCOME MEASURES

Glucose and insulin during oral glucose tolerance test.

RESULTS

Estimated mean (95% CI) fasting glucose and insulin levels remained stable during 3 years of GH treatment. Glucose being 4.6 (4.4-4.8) mmol/l at start and 4.7 (4.6-4.9) mmol/l after 3 years (P = .07); insulin being 59.5 (45.2-75.8) pmol/l and 56.7 (45.2-69.6) pmol/l resp. (P = .72). Sex, ethnicity and fat mass percentage were significantly associated with fasting glucose levels, while IGF-I or GH-dose were not. Blood pressure, lipids and prevalence of MS remained stable during 3 years of GH. IGT prevalence was variable over time, six patients had IGT at start and eleven after 3 years of GH. One patient developed DMT2. However, prevalence of IGT or DMT2 was not significantly higher after 3 years than at study start.

CONCLUSIONS

Three years of GH treatment in adults with PWS does not impair glucose homeostasis and does not lead to an increased prevalence of DMT2.