Growth hormone treatment of children with Prader-Willi syndrome affects linear growth and body composition favourably

Hypothalamic syndrome

Hypothalamic syndrome (HS) is a rare disorder caused by disease-related and/or treatment-related injury to the hypothalamus, most commonly associated with rare, non-cancerous parasellar masses, such as craniopharyngiomas, germ cell tumours, gliomas, cysts of Rathke's pouch and Langerhans cell histiocytosis, as well as with genetic neurodevelopmental syndromes, such as Prader-Willi syndrome and septo-optic dysplasia. HS is characterized by intractable weight gain associated with severe morbid obesity, multiple endocrine abnormalities and memory impairment, attention deficit and reduced impulse control as well as increased risk of cardiovascular and metabolic disorders. Currently, there is no cure for this condition but treatments for general obesity are often used in patients with HS, including surgery, medication and counselling. However, these are mostly ineffective and no medications that are specifically approved for the treatment of HS are available. Specific challenges in HS are because the syndrome represents an adverse effect of different diseases, and that diagnostic criteria, aetiology, pathogenesis and management of HS are not completely defined.

Differential Diagnosis of the Short IGF-I-Deficient Child with Apparently Normal Growth Hormone Secretion

The current differential diagnosis for a short child with low insulin-like growth factor I (IGF-I) and a normal growth hormone (GH) peak in a GH stimulation test (GHST), after exclusion of acquired causes, includes the following disorders: (1) a decreased spontaneous GH secretion in contrast to a normal stimulated GH peak ("GH neurosecretory dysfunction," GHND) and (2) genetic conditions with a normal GH sensitivity (e.g., pathogenic variants of GH1 or GHSR) and (3) GH insensitivity (GHI). We present a critical appraisal of the concept of GHND and the role of 12- or 24-h GH profiles in the selection of children for GH treatment. The mean 24-h GH concentration in healthy children overlaps with that in those with GH deficiency, indicating that the previously proposed cutoff limit (3.0-3.2 μg/L) is too high. The main advantage of performing a GH profile is that it prevents about 20% of false-positive test results of the GHST, while it also detects a low spontaneous GH secretion in children who would be considered GH sufficient based on a stimulation test. However, due to a considerable burden for patients and the health budget, GH profiles are only used in few centres. Regarding genetic causes, there is good evidence of the existence of Kowarski syndrome (due to GH1 variants) but less on the role of GHSR variants. Several genetic causes of (partial) GHI are known (GHR, STAT5B, STAT3, IGF1, IGFALS defects, and Noonan and 3M syndromes), some responding positively to GH therapy. In the final section, we speculate on hypothetical causes.

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.

Human Growth and Growth Hormone: From Antiquity to the Recominant Age to the Future

Since antiquity Man has been fascinated by the variations in human (and animal) growth. Stories and art abound about giants and little people. Modern genetics have solved some of etiologies at both extremes of growth. Serious study began with the pathophysiology of acromegaly followed by early attempts at treatment culminating in modern endoscopic surgery and multiple pharmacologic agents. Virtually at the same time experiments with the removal of the pituitary from laboratory animals noted the slowing or stopping of linear growth and then over a few decades the extraction and purification of a protein within the anterior pituitary that restored, partially or in full, the animal's growth. Human growth hormone was purified decades after those from large animals and it was noted that it was species specific, that is, only primate growth hormone was metabolically active in primates. That was quite unlike the beef and pork insulins which revolutionized the care of children with diabetes mellitus. A number of studies included mild enzymatic digestion of beef growth hormone to determine if those "cores" had biologic activity in primates and man. Tantalizing data showed minimal but variable metabolic efficacy leading to the "active core" hypothesis, for these smaller peptides would be amenable to peptide synthesis in the time before recombinant DNA. Recombinant DNA changed the landscape remarkably promising nearly unlimited quantities of metabolically active hormone. Eight indications for therapeutic use have been approved by the Food and Drug Administration and a large number of clinical trials have been undertaken in multiple other conditions for which short stature in childhood is a sign. The future predicts other clinical indications for growth hormone therapy (and perhaps other components of the GH?IGF-1 axis), longer-acting analogues and perhaps a more physiologic method of administration as virtually all methods at present are far from physiologic.

Growth hormone treatment in Prader-Willi syndrome patients: systematic review and meta-analysis

BACKGROUND

Growth hormone (GH) treatment is currently recommended in Prader-Willi syndrome (PWS) patients.

OBJECTIVES

To evaluate the impact (efficacy and safety) of the use of recombinant human GH (rhGH) as a treatment for PWS.

METHOD

We performed a systematic review and, where possible, meta-analysis for the following outcomes: growth, body mass index, body composition, cognitive function, quality of life, head circumference, motor development/strength, behaviour and adverse effects. We included all PWS patients, with all types of genetic defects and with or without GH deficiency, who participated in rhGH studies performed in infancy, childhood and adolescence, that were either randomised controlled trials (RCTs) (double-blinded or not) or non-randomised controlled trials (NRCTs) (cohort and before and after studies). The databases used were MEDLINE, Embase and Cochrane Central.

RESULTS

In 16 RCTs and 20 NRCTs selected, the treated group had an improvement in height (1.67 SD scores (SDS); 1.54 to 1.81); body mass index z-scores (-0.67 SDS; -0.87 to -0.47) and fat mass proportion (-6.5% SDS; -8.46 to -4.54) compared with the control group. Data about cognition could not be aggregated. Conclusion Based on high quality evidence, rhGH treatment favoured an improvement of stature, body composition and body mass index, modifying the disease's natural history; rhGH treatment may also be implicated in improved cognition and motor development in PWS patients at a young age.

ETHICS AND DISSEMINATION

The current review was approved by the ethical committee of our institution. The results will be disseminated through conference presentations and publications in peer-reviewed journals.

PROSPERO REGISTRATION NUMBER

CRD42019140295.

Macronutrient Regulation of Ghrelin and Peptide YY in Pediatric Obesity and Prader-Willi Syndrome

BACKGROUND

The roles of macronutrients and GH in the regulation of food intake in pediatric obesity and Prader-Willi Syndrome (PWS) are poorly understood.

OBJECTIVE

We compared effects of high-carbohydrate (HC) and high-fat (HF) meals and GH therapy on ghrelin, insulin, peptide YY (PYY), and insulin sensitivity in children with PWS and body mass index (BMI) -matched obese controls (OCs).

METHODS

In a randomized, crossover study, 14 PWS (median, 11.35 y; BMI z score [BMI-z], 2.15) and 14 OCs (median, 11.97 y; BMI-z, 2.35) received isocaloric breakfast meals (HC or HF) on separate days. Blood samples were drawn at baseline and every 30 minutes for 4 hours. Mixed linear models were adjusted for age, sex, and BMI-z.

RESULTS

Relative to OCs, children with PWS had lower fasting insulin and higher fasting ghrelin and ghrelin/PYY. Ghrelin levels were higher in PWS across all postprandial time points (P < .0001). Carbohydrate was more potent than fat in suppressing ghrelin levels in PWS (P = .028); HC and HF were equipotent in OCs but less potent than in PWS (P = .011). The increase in PYY following HF was attenuated in PWS (P = .037); thus, postprandial ghrelin/PYY remained higher throughout. A lesser increase in insulin and lesser decrease in ghrelin were observed in GH-treated PWS patients than in untreated patients; PYY responses were comparable.

CONCLUSION

Children with PWS have fasting and postprandial hyperghrelinemia and an attenuated PYY response to fat, yielding a high ghrelin/PYY ratio. GH therapy in PWS is associated with increased insulin sensitivity and lesser postprandial suppression of ghrelin. The ratio Ghrelin/PYY may be a novel marker of orexigenic drive.

Endocrine manifestations and management of Prader-Willi syndrome

Prader-Willi syndrome (PWS) is a complex genetic disorder, caused by lack of expression of genes on the paternally inherited chromosome 15q11.2-q13. In infancy it is characterized by hypotonia with poor suck resulting in failure to thrive. As the child ages, other manifestations such as developmental delay, cognitive disability, and behavior problems become evident. Hypothalamic dysfunction has been implicated in many manifestations of this syndrome including hyperphagia, temperature instability, high pain threshold, sleep disordered breathing, and multiple endocrine abnormalities. These include growth hormone deficiency, central adrenal insufficiency, hypogonadism, hypothyroidism, and complications of obesity such as type 2 diabetes mellitus. This review summarizes the recent literature investigating optimal screening and treatment of endocrine abnormalities associated with PWS, and provides an update on nutrition and food-related behavioral intervention. The standard of care regarding growth hormone therapy and surveillance for potential side effects, the potential for central adrenal insufficiency, evaluation for and treatment of hypogonadism in males and females, and the prevalence and screening recommendations for hypothyroidism and diabetes are covered in detail. PWS is a genetic syndrome in which early diagnosis and careful attention to detail regarding all the potential endocrine and behavioral manifestations can lead to a significant improvement in health and developmental outcomes. Thus, the important role of the provider caring for the child with PWS cannot be overstated.

GrowthHormone Research Society workshop summary: consensus guidelines for recombinant human growth hormone therapy in Prader-Willi syndrome

CONTEXT

Recombinant human GH (rhGH) therapy in Prader-Willi syndrome (PWS) has been used by the medical community and advocated by parental support groups since its approval in the United States in 2000 and in Europe in 2001. Its use in PWS represents a unique therapeutic challenge that includes treating individuals with cognitive disability, varied therapeutic goals that are not focused exclusively on increased height, and concerns about potential life-threatening adverse events.

OBJECTIVE

The aim of the study was to formulate recommendations for the use of rhGH in children and adult patients with PWS.

EVIDENCE

We performed a systematic review of the clinical evidence in the pediatric population, including randomized controlled trials, comparative observational studies, and long-term studies (>3.5 y). Adult studies included randomized controlled trials of rhGH treatment for ≥ 6 months and uncontrolled trials. Safety data were obtained from case reports, clinical trials, and pharmaceutical registries.

METHODOLOGY

Forty-three international experts and stakeholders followed clinical practice guideline development recommendations outlined by the AGREE Collaboration (www.agreetrust.org). Evidence was synthesized and graded using a comprehensive multicriteria methodology (EVIDEM) (http://bit.ly.PWGHIN).

CONCLUSIONS

Following a multidisciplinary evaluation, preferably by experts, rhGH treatment should be considered for patients with genetically confirmed PWS in conjunction with dietary, environmental, and lifestyle interventions. Cognitive impairment should not be a barrier to treatment, and informed consent/assent should include benefit/risk information. Exclusion criteria should include severe obesity, uncontrolled diabetes mellitus, untreated severe obstructive sleep apnea, active cancer, or psychosis. Clinical outcome priorities should vary depending upon age and the presence of physical, mental, and social disability, and treatment should be continued for as long as demonstrated benefits outweigh the risks.

Effects of growth hormone treatment in adults with Prader-Willi syndrome

OBJECTIVE

Since limited data exist on adults with Prader-Willi syndrome (PWS) and growth hormone (GH) treatment, we report our experience on the effects of treatment for one year on body composition, physical activity, strength and energy expenditure, diet, general chemistry and endocrine data with quality of life measures.

DESIGN

We studied 11 adults with PWS (6F:5M; average age=32 yrs) over a 2 year period with GH treatment during the first year only. Electrolytes, IGF-I, glucose, thyroid, insulin, lipids, body composition, physical activity and strength, diet, energy expenditure and quality of life data were collected and analyzed statistically using linear modeling at baseline, at 12 months following GH therapy and at 24 months after treatment cessation for 12 months.

RESULTS

Total lean muscle mass was significantly increased (p<0.05) during GH treatment along with moderate-vigorous physical activity and plasma IGF-I and HDL levels, but returned to near baseline after treatment. Percent body fat decreased during the 12 months of GH treatment but increased after treatment.

CONCLUSIONS

Previously reported beneficial effects of GH treatment in children with PWS were found in our adults regarding body composition, physical activity and plasma HDL and IGF-I levels. Several beneficial effects diminished to near baseline after cessation of GH treatment for 12 months supporting the continuation of treatment in PWS into adulthood and possibly adults not previously treated during childhood.

Prader-Willi Syndrome: Obesity due to Genomic Imprinting

Prader-Willi syndrome (PWS) is a complex neurodevelopmental disorder due to errors in genomic imprinting with loss of imprinted genes that are paternally expressed from the chromosome 15q11-q13 region. Approximately 70% of individuals with PWS have a de novo deletion of the paternally derived 15q11-q13 region in which there are two subtypes (i.e., larger Type I or smaller Type II), maternal disomy 15 (both 15s from the mother) in about 25% of cases, and the remaining subjects have either defects in the imprinting center controlling the activity of imprinted genes or due to other chromosome 15 rearrangements. PWS is characterized by a particular facial appearance, infantile hypotonia, a poor suck and feeding difficulties, hypogonadism and hypogenitalism in both sexes, short stature and small hands and feet due to growth hormone deficiency, mild learning and behavioral problems (e.g., skin picking, temper tantrums) and hyperphagia leading to early childhood obesity. Obesity is a significant health problem, if uncontrolled. PWS is considered the most common known genetic cause of morbid obesity in children. The chromosome 15q11-q13 region contains approximately 100 genes and transcripts in which about 10 are imprinted and paternally expressed. This region can be divided into four groups: 1) a proximal non-imprinted region; 2) a PWS paternal-only expressed region containing protein-coding and non-coding genes; 3) an Angelman syndrome region containing maternally expressed genes and 4) a distal non-imprinted region. This review summarizes the current understanding of the genetic causes, the natural history and clinical presentation of individuals with PWS.

Systematic review of the clinical effectiveness of Genotropin (somatropin) in children with short stature

Genotropin (somatropin) is licensed for the treatment of children with growth hormone deficiency, Prader-Willi syndrome, Turner syndrome, chronic renal insufficiency and in children born small for gestational age. This systematic review (SR) evaluated the clinical efficacy and effectiveness of Genotropin in these conditions to inform a NICE Technology Appraisal of growth hormone for the treatment of growth failure in children. Search terms were used to search seven databases, including Medline and Embase, for English language studies. Randomised controlled trials (RCTs) or observational studies investigating Genotropin in children were included. Out of 30 RCTs identified, one reported final height data. Eleven observational studies reported final height and seven were based on the Pfizer International Growth Survey (KIGS). This SR highlights the lack of long-term RCTs reporting final height data and other important qualitative outcomes, such as quality of life. Observational data, such as those from KIGS, remain vital for informing therapy.

Early diagnosis and multidisciplinary care reduce the hospitalization time and duration of tube feeding and prevent early obesity in PWS infants

BACKGROUND/AIMS

To describe and evaluate the impact of very early diagnosis and multidisciplinary care on the evolution and care of infants presenting with Prader-Willi syndrome (PWS).

METHODS

19 infants diagnosed with PWS before the second month of life were followed by a multidisciplinary team. Median age at the time of analysis was 3.1 years [range 0.4-6.5]. The data were compared with data collected in 1997 from 113 questionnaires filled out by members of the French PWS Association. The patients from this latter data set were 12.0 years [range 4 months to 41 years] at the time of analysis, with a median age of 36 months at diagnosis.

RESULTS

The duration of their hospitalization time was significantly reduced from 30.0 [range 0-670] to 21 [range 0-90] days (p = 0.043). The duration of gastric tube feeding was significantly reduced from 30.5 [range 0-427] to 15 [range 0-60] days (p = 0.017). Growth hormone treatment was started at a mean age of 1.9 +/- 0.5 years in 10 infants and L-thyroxine in 6 infants. Only 1 infant became obese at 2.5 years.

CONCLUSION

Early diagnosis combined with multidisciplinary care decreases the hospitalization time, duration of gastric tube feeding and prevents early obesity in PWS infants.

Effects of Growth Hormone Therapy on Glucose Metabolism and Insulin Sensitivity Indices in Prepubertal Children with Prader-Willi Syndrome

In Prader-Willi syndrome (PWS) growth hormone therapy (GHT) improves height, body composition, agility and muscular strength. In such patients it is necessary to consider the potential diabetogenic effect of GHT, since they tend to develop type 2 diabetes, particularly after the pubertal age. The aim of our study was to investigate the effects of GHT on glucose and insulin homeostasis in PWS children. An oral glucose tolerance test (OGTT) was performed in 24 prepubertal PWS children (15 male, 9 female, age: 5.8 +/- 2.8 years), 16 were obese (group A) and 8 had normal weight (group B), before and after 2.7 +/- 1.3 years GHT (0.22 +/- 0.03 mg/kg/week) and, only at baseline, in 35 prepubertal children with simple obesity (19 male, 16 female) (group C). Fasting glucose and insulin, glucose tolerance, insulin sensitivity index (ISI), homeostasis model assessment of insulin resistance (HOMA-IR), quick insulin check index (QUICKI), area under the curves (AUC) of glucose and insulin were estimated. At the start of GHT, all PWS children were normoglycaemic and normotolerant but two developed impaired glucose tolerance after 2.2 and 1.9 years of therapy, respectively. At baseline, group A showed lower fasting insulin levels, HOMA-IR and AUC of insulin, higher ISI, QUICKI and AUC of glucose than group C. Comparing groups A and B, AUC of insulin was higher and ISI lower in group A. During GHT, a significant increase of fasting insulin and glucose, a worsening of insulin resistance (HOMA-IR) and insulin sensitivity (QUICKI) was found only in group A while ISI did not change. The AUC of glucose decreased in both groups instead AUC of insulin did not change. BMI-SDS decreased in group A and increased in group B. The increased insulin resistance and decreased insulin sensitivity in obese PWS patients, as well as the occurrence of impaired glucose tolerance during GHT, suggest that a close monitoring of glucose and insulin homeostasis is mandatory, especially in treated obese PWS children.

Bridging Regional and Global Perspectives

In recent years, medical practice has evolved towards greater reliance on evidence-based medicine. Societies and reimbursement agencies often publish recommendations for treatment based on literature review and trial data. Despite this, growth hormone (GH) replacement therapy in adults varies substantially from region to region. The reasons for this include differing beliefs in quality of life benefits, the cost-effectiveness of GH and the role of GH in reducing cardiovascular mortality. Reimbursement varies from almost complete take-up in Sweden and Germany, to strict guidelines in the UK, while in some countries GH is not reimbursable for adults with GH deficiency, leaving patients open to the short- and long-term consequences of the condition. Clearly, there is a need for further evidence regarding the overall value of GH replacement. Randomized, controlled trials are the foundation of evidence-based medicine, but long-term treatment is difficult to assess in such trials. Thus, there is an important role for large-scale registries in gathering evidence. For example, the MEGHA (Metabolic Endocrinology and Growth Hormone Assessment) database provides participants with a sub- studies function, allowing them to create and design collective, observational studies to investigate areas of GH medicine that are of particular interest or concern to them and their patients.

Growth charts for Down's syndrome from birth to 18 years of age

BACKGROUND

Growth in children with Down's syndrome (DS) differs markedly from that of normal children. The use of DS specific growth charts is important for diagnosis of associated diseases, such as coeliac disease and hypothyroidism, which may further impair growth.

AIMS

To present Swedish DS specific growth charts.

METHODS

The growth charts are based on a combination of longitudinal and cross sectional data from 4832 examinations of 354 individuals with DS (203 males, 151 females), born in 1970-97.

RESULTS

Mean birth length was 48 cm in both sexes. Final height, 161.5 cm for males and 147.5 cm for females, was reached at relatively young ages, 16 and 15 years, respectively. Mean birth weight was 3.0 kg for boys and 2.9 kg for girls. A body mass index (BMI) >25 kg/m(2) at 18 years of age was observed in 31% of the males and 36% of the females. Head growth was impaired, resulting in a SDS for head circumference of -0.5 (Swedish standard) at birth decreasing to -2.0 at 4 years of age.

CONCLUSION

Despite growth retardation the difference in height between the sexes is the same as that found in healthy individuals. Even though puberty appears somewhat early, the charts show that DS individuals have a decreased pubertal growth rate. Our growth charts show that European boys with DS are taller than corresponding American boys, whereas European girls with DS, although being lighter, have similar height to corresponding American girls.

Auxological and endocrine evolution of 28 children with Prader-Willi syndrome: effect of GH therapy in 14 children

We report on the auxological and endocrine evolution of 28 patients presenting with Prader-Willi syndrome. Half of them received growth hormone (GH) therapy (group 2). The spontaneous auxological evolution was analyzed in the two groups from 2 to 8 years; the mean SDS for height remained stable (-0.6 +/- 0.6) in group 1 and decreased (from -2.0 +/- 0.9 to -2.7 +/- 0.6) in group 2. Magnetic resonance imaging showed marked pituitary hypoplasia in the two groups. In group 2, the mean GH peak after two provocative tests was 3.8 +/- 2.4 microg/l, the mean SDS values for insulin-like growth factor I levels were -2.0 +/- 1.5 (range from -0.5 to -5.0). The mean duration of GH treatment was 3.6 +/- 2.9 (range 1-9.3) years. 14 children completed 1 year of treatment. The two groups had opposite evolutions in Delta SDS for height (-0.8 +/- 0.8 vs. +1.1 +/- 0.8), for growth velocity (-1.9 +/- 2.2 vs. +2.9 +/- 2.7), and for Z score of the body mass index (+0.37 +/- 1.3 vs. -0.14 +/- 0.76; group 1 vs. group 2). This retrospective study shows that, in children with Prader-Willi syndrome and true GH deficiency, long-term GH therapy is effective in increasing growth velocity and in maintaining body mass index.

Growth hormone treatment of children with Prader-Willi syndrome: effects on glucose and insulin homeostasis. Swedish National Growth Hormone Advisory Group

Insulin and glucose homeostasis have been studied during growth hormone (GH) treatment in 19 prepubertal children with Prader-Willi syndrome (PWS) and compared with 11 healthy prepubertal obese children. Before treatment, insulin levels in children with PWS were lower (p < 0.01) than in healthy obese children. During GH treatment, fasting insulin levels increased in children with PWS (p < 0.001). Glucose levels were similar for PWS and obese children before treatment. Children with PWS showed a slow glucose disappearance rate (k = 1.7%) which deteriorated (k = 1.3%, p < 0.001) during GH treatment. HbA1c and fasting glucose levels remained normal. Thus, GH treatment of children with PWS resulted in increased insulin blood levels, unchanged fasting glucose and HbA1c but decreased glucose elimination rate after an intravenous glucose test. However, the observed dose-dependent increase in insulin levels during GH treatment, that reached supranormal concentrations in 6/19 patients, and the occurrence of NIDDM in 1 patient during follow-up suggest that close surveillance and low doses of GH should be applied, especially if the PWS patient is very obese.