Thyroid hormone levels in children with Prader-Willi syndrome before and during growth hormone treatment

Thyroid hormone levels in children with Prader-Willi syndrome: a randomized controlled growth hormone trial and 10-year growth hormone study

CONTEXT

Several endocrine abnormalities were reported in children with Prader-Willi syndrome (PWS), including hypothyroidism. Growth hormone (GH) treatment may impact the thyroid hormone axis by direct inhibition of T4 or TSH secretion or by increased peripheral conversion of free T4 (FT4) to T3.

OBJECTIVE

The objective of this study is to evaluate thyroid function during GH treatment in a large group of children with PWS.

METHODS

Serum FT4, T3, and TSH are measured in a 2-year randomized controlled GH trial (RCT) and 10-year longitudinal GH study (GH treatment with 1.0 mg/m²/day [∼0.035 mg/kg/day]).

RESULTS

Forty-nine children with PWS were included in the 2-year RCT (median [interquartile range, IQR] age: GH group 7.44 [5.47-11.80] years, control group 6.04 [4.56-7.39] years). During the first 6 months, median (IQR) FT4 standard deviation score (SDS) decreased in the GH group from -0.84 (-1.07 to -0.62) to -1.32 (-1.57 to -1.08) (P < .001) and T3 SDS increased from 0.31 (-0.01-0.63) to 0.56 (0.32-0.79) (P = .08), while in the control group, FT4 and T3 SDS remained unchanged. In our 10-year GH study, 240 children with PWS (median [IQR] age: 1.27 (0.54-4.17) years] were included. Between 2 and 10 years, median (IQR) FT4 SDS remained unchanged, being -0.87 (-0.98 to -0.77) after 2 years and -0.88 (-1.03 to -0.74) after 10 years (P = .13). TSH SDS decreased from -0.35 (-0.50 to -0.21) after 2 years to -0.68 (-0.84 to -0.53) after 10 years (P < .001).

CONCLUSIONS

Our findings suggest that GH treatment decreases FT4 levels, due to increased peripheral conversion of FT4 to T3 in the first months of treatment, but thereafter, FT4 and T3 normalize and remain stable during long-term GH treatment in almost all children and adolescents with PWS.

Relationship of thyroid function with genetic subtypes and treatment with growth hormone in Prader-Willi syndrome

Prader-Willi syndrome (PWS) is the most common genetic syndrome with obesity and results from loss of expression of paternally inherited genes on chromosome 15q11-q13 by a variety of mechanisms which include large deletions (70%-75%), maternal uniparental disomy (UPD) (20%-30%), and imprinting defects (2%-5%) or balanced translocations. Individuals often have a characteristic behavior disorder with mild intellectual disability, infantile hypotonia associated with poor sucking, short stature, and obesity. PWS is characterized by hypothalamic-pituitary axis dysfunction with growth hormone (GH) deficiency, hypogonadism, and several other hormonal deficiencies resulting in short stature, centrally driven excessive appetite (hyperphagia), central obesity, cryptorchidism, and decreased lean body mass. In this study, we determined and sought differences in the incidence of thyroid abnormalities among the common genetic subtypes in a cohort of 52 subjects with PWS because there was limited literature available. We also sought the effects of growth hormone (GH) treatment on the thyroid profile. Fifty-two subjects with a genetically confirmed diagnosis of PWS were included in this study at the University of California, Irvine. Blood samples for baseline thyroxine stimulating hormone (TSH) and free thyroxine (fT4) levels were obtained in the morning after an overnight fast for 8-12 h. Statistical analyses were performed with SPSS (SPSS Inc., 21.0). Mean values were analyzed by one-way ANOVA, and student's t-test and statistical significance were set at p < 0.05. The subjects included 26 males and 26 females with an age range of 3-38 years. There were 29 subjects with chromosome 15q11-q13 deletions and 23 with UPD; 28 were GH treated currently or in the past, and 24 never received GH. There was no significant difference in age or body mass index (BMI) (kg/m2) between GH-treated versus non-GH-treated groups. BMI was higher in the deletion group compared to the UPD group (p = 0.05). We identified two individuals who were clinically diagnosed and treated for hypothyroidism, one of whom was on GH supplements. We identified two additional individuals with subclinical hypothyroidism who were not on GH treatment, giving a frequency of 7.6% (4/52) in this cohort of patients. We did not find significant differences in thyroid function (TSH) in the deletion versus UPD groups. We found significant differences in thyroid function, however, between GH-treated and non-GH-treated groups. The mean TSH was lower (2.25 ± 1.17 uIU/M, range 0.03-4.92 uIU/M versus 2.80 ± 1.44 uIU/M, range 0.55-5.33 uIU/M respectively, p = 0.046), and the free T4 levels were significantly higher (1.13 ± 0.70 and 1.03 ± 0.11 ng/dL, respectively, p = 0.05) in the GH-treated individuals compared to non-GH-treated individuals. In this cohort of subjects with PWS, we identified two previously diagnosed individuals with hypothyroidism and two individuals with subclinical hypothyroidism (4/52, 7.6%), three of whom were not receiving GH treatment. We did not find any significant differences in thyroid function between molecular subtypes; however, we found that euthyroid status (lower TSH levels and higher free T4 levels) was significantly higher in individuals who were treated with GH compared to the untreated group. We recommend that individuals with PWS should be screened regularly for thyroid deficiency and start treatment early with GH in view of the potentially lower incidence of thyroid deficiency.

Hormonal Imbalances in Prader-Willi and Schaaf-Yang Syndromes Imply the Evolution of Specific Regulation of Hypothalamic Neuroendocrine Function in Mammals

The hypothalamus regulates fundamental aspects of physiological homeostasis and behavior, including stress response, reproduction, growth, sleep, and feeding, several of which are affected in patients with Prader-Willi (PWS) and Schaaf-Yang syndrome (SYS). PWS is caused by paternal deletion, maternal uniparental disomy, or imprinting defects that lead to loss of expression of a maternally imprinted region of chromosome 15 encompassing non-coding RNAs and five protein-coding genes; SYS patients have a mutation in one of them, MAGEL2. Throughout life, PWS and SYS patients suffer from musculoskeletal deficiencies, intellectual disabilities, and hormonal abnormalities, which lead to compulsive behaviors like hyperphagia and temper outbursts. Management of PWS and SYS is mostly symptomatic and cures for these debilitating disorders do not exist, highlighting a clear, unmet medical need. Research over several decades into the molecular and cellular roles of PWS genes has uncovered that several impinge on the neuroendocrine system. In this review, we will discuss the expression and molecular functions of PWS genes, connecting them with hormonal imbalances in patients and animal models. Besides the observed hormonal imbalances, we will describe the recent findings about how the loss of individual genes, particularly MAGEL2, affects the molecular mechanisms of hormone secretion. These results suggest that MAGEL2 evolved as a mammalian-specific regulator of hypothalamic neuroendocrine function.

Prader-Willi Syndrome in Adults: An Update On Nutritional Treatment and Pharmacological Approach

PURPOSE OF REVIEW

Prader-Willi syndrome (PWS) is a rare and complex genetic disorder with multiple effects on the metabolic, endocrine, and neurological systems, as well as behavioral and intellectual difficulties. Despite advances in understanding the genetic basis of obesity in PWS, there are conflicting data on its management. Therefore, the present manuscript aims to provide an update on the nutritional treatment and pharmacological approach in adult patients with PWS.

RECENT FINDINGS

The management of obesity in patients with PWS is challenging and requires the cooperation of an experienced multidisciplinary team, including the nutritionist. An adequate clinical evaluation including nutritional and biochemical parameters should be performed to tailor the best therapeutic strategy. Both lifestyle and pharmacological interventions may represent useful strategies to prevent the high rate of morbidity and mortality related to PWS. The use of bariatric surgery is still controversial. Although it is imperative to adopt an obesity prevention strategy in childhood, there is promising evidence for the treatment of obesity in adulthood with current obesity medications in conjunction with lifestyle interventions.

Thyroid function in children with Prader-Willi syndrome in Southern China: a single-center retrospective case series

Background

To investigate hypothalamic-pituitary-thyroid function in children of different ages, nutritional phases, and genotypes that were diagnosed with Prader-Willi syndrome (PWS), as well as the effects of recombinant human growth hormone (rhGH) treatment on thyroid hormones in PWS patients.

Methods

One hundred and thirty PWS patients (87 boys and 43 girls) aged from newborn to 15 years (y) (median 1.25 y, mean, SD: 2.95 ± 3.45 y), were surveyed in this study. Serum thyroid hormone levels were examined at least once per3-6 months during the 2 years follow-up study. Central hypothyroidism (C-HT) was identified as low/normal thyroid-stimulating hormone (TSH) and low free thyroxine 4 (FT4).

Results

All study participants had normal neonatal TSH screening test results. The prevalence of C-HT is 36.2% (47/130). No C-HT cases were diagnosed in PWS either below 1 month (m) or above 12 y. The prevalence of C-TH would be increased with age before 3 y until reaching the peak, followed by a gradual decline over the years. The prevalence of C-HT varies significantly at different ages (Pearson's χ2 = 19.915; p < 0.01). However, there is no correlation between the C-HT prevalence and nutritional phases (Pearson's χ2 = 4.992; p = 0.288), genotypes (Pearson's χ2 = 0.292; p = 0.864), or rhGH therapy (Pearson's χ2 = 1.799; p = 0.180).

Conclusions

This study suggests the prevalence of C-TH was increased with the age before 3 y, and reached the peak in the 1 to 3 y group, then gradually declined over the years. There is no correlation between C-HT prevalence and nutritional phases, genotypes, or rhGH treatment.

Thyroid Function in Adults with Prader-Willi Syndrome; a Cohort Study and Literature Review

Prader–Willi syndrome (PWS) is a complex genetic syndrome combining hypotonia, hyperphagia, a PWS-specific neurocognitive phenotype, and pituitary hormone deficiencies, including hypothyroidism. The low muscle mass associated with PWS causes a low energy expenditure due to a low basal metabolic rate. Combined with increased energy intake due to hyperphagia, this results in a high risk of obesity and associated cardiovascular disease. To reduce the high mortality in PWS (3% yearly), exercise is extremely important. As hypothyroidism can impair exercise tolerance, early detection is crucial. We performed a literature search for articles on hypothyroidism in PWS, measured thyroid hormone (TH) levels in 122 adults with PWS, and performed a medical file search for medication use. Hypothyroidism (low free thyroxin) was present in 17%, and often central in origin (80%). Triiodothyronine levels were lower in patients who used psychotropic drugs, while other TH levels were similar. One in six patients in our cohort of adults with PWS had hypothyroidism, which is more than in non-PWS adults (3%). We recommend yearly screening of free thyroxin and thyroid-stimulating hormone levels to avoid the negative effects of untreated hypothyroidism on basal metabolic rate, body mass index, and cardiovascular risk. Additionally, we recommend measuring TH concentrations 3–4 months after the start of growth hormone treatment.

One-year follow-up of thyroid function in 23 infants with Prader- Willi syndrome at a single center in China

Endocrine disorders are common in patients with Prader-Willi syndrome (PWS). Whether hypothyroidism is present in patients with PWS, and especially infants and young children, remains unclear. The aims of this study were to evaluate thyroid function in patients with PWS, to assess the prevalence of thyroid dysfunction, and to evaluate the effect of growth hormone on thyroid function. Subjects were 23 patients with PWS ages 3 months to 3 years who were followed for up to one year. Four patients were lost to follow-up after the first visit. The remaining 19 patients were treated with recombinant human growth hormone (rhGH). PWS was diagnosed based on a genetic analysis. Free thyroxine (FT4), free triiodothyronine (FT3), and thyroid-stimulating hormone (TSH) levels were evaluated before and after growth hormone treatment. A total of 9 patients (9/23 = 39.1%) developed abnormal thyroid function. Five out of 23 patients (21.7%) had abnormal thyroid function before growth hormone treatment. Four patients developed thyroid dysfunction during the 3- to 9-month period of rhGH treatment. Of the 9 patients with abnormal thyroid function, 7 (5 boys, 2 girls) had central hypothyroidism, and the other 2 patients had subclinical hypothyroidism. TSH levels were higher in patients with PWS due to maternal uniparental disomy (UPD) than in patients with PWS due to a 15q11-q13 deletion. The prevalence of hypothyroidism was high in infants and young children with PWS. Thyroid function should be regularly monitored in patients with PWS at both diagnosis and follow-up.

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.

Sleep-Disordered Breathing in Children with Prader-Willi Syndrome in Relation to Growth Hormone Therapy Onset

OBJECTIVE

The aim of this study was to consider sleep apnea in Prader-Willi syndrome (PWS) children depending on age at growth hormone (GH) therapy onset.

STUDY DESIGN

We analyzed longitudinally cardiorespiratory polygraphy of 62 PWS children (aged 0-2.5 years at baseline). Twenty-one children (Group A) started GH-therapy during and 41 children (Group B) after their first year of life. Data were acquired before, at 3 and 6 months, then 1.2, 2.2, and 3.2 years after GH onset. Outcomes were determined with the obstructive apnea hypopnea index (OAHI), central apnea index (CAI), oxygen desaturation index (ODI), and by measuring obstructive sleep apnea (OSA) and peripheral blood oxygen saturation (SpO2).

RESULTS

We observed no significant differences in OAHI, CAI, ODI, and SpO2 depending on treatment onset. At baseline, 5/21 patients (23.8%) in Group A versus 15/41 patients (36.6%) in Group B showed pathological sleep apnea (OAHI ≥1.5). Pathological OSA increased significantly in Group A during the first 3 months of therapy but dropped below baseline after 1 year in both groups. ODI changed during GH therapy in both groups (from 4.0 to 2.6 in Group A, and 3.6 to 1.6 in Group B; baseline to 3.2 years; p < 0.05).

CONCLUSIONS

OSA in PWS children appears to develop independently of treatment onset. Treatment may therefore safely be initiated early but should be accompanied by regular sleep analysis.

Endocrine disorders in Prader-Willi syndrome: a model to understand and treat hypothalamic dysfunction

Prader-Willi syndrome is a rare genetic neurodevelopmental disorder resulting from the loss of expression of maternally imprinted genes located in the paternal chromosomal region, 15q11-13. Impaired hypothalamic development and function is the cause of most of the phenotypes comprising the developmental trajectory of Prader-Willi syndrome: from anorexia at birth to excessive weight gain preceding hyperphagia, and early severe obesity with hormonal deficiencies, behavioural problems, and dysautonomia. Growth hormone deficiency, hypogonadism, hypothyroidism, premature adrenarche, corticotropin deficiency, precocious puberty, and glucose metabolism disorders are the main endocrine dysfunctions observed. Additionally, as a result of hypothalamic dysfunction, oxytocin and ghrelin systems are impaired in most patients. Standard pituitary and gonadal hormone replacement therapies are required. In this Review, we discuss Prader-Willi syndrome as a model of hypothalamic dysfunction, and provide a comprehensive description of the accumulated knowledge on genetics, pathophysiology, and treatment approaches of this rare disorder.

Central hypothyroidism improves with age in very young children with Prader-Willi syndrome

OBJECTIVE

Abnormalities in the hypothalamic-pituitary-thyroid (HPT) axis have been implicated in Prader-Willi syndrome (PWS); however, limited information is currently available on age-dependent alterations in the HPT axis. We herein investigated age-dependent differences in thyroid hormone levels in PWS children.

DESIGN/PATIENTS/MEASUREMENTS

Free T4 (FT4), free T3 (FT3) and thyroid-stimulating hormone (TSH) concentrations were retrospectively compared between genetically confirmed PWS children (N = 43, median age: 11.2 months) and controls (N = 85, median age: 14.5 months) matched for age, sex, body weight-SD score (SDS), height-SDS, body mass index-SDS and serum albumin level, a marker of the nutritional status. Subjects were subdivided into two groups based on their age: an infant group aged between 1 and 11 months (PWS: N = 22, controls: N = 30) and a toddler group aged between 12 and 47 months (PWS: N = 21, controls: N = 55). None of the subjects had ever been treated with growth hormone or levothyroxine.

RESULTS

After adjustments for confounding variables, in the infant group, FT4 levels (pmol/L) were significantly lower in PWS (11.24 in PWS vs 14.32 in controls, P = .0002), whereas no significant differences were observed in FT3 or TSH levels. In the toddler group, no significant differences were noted in FT4 (12.23 in PWS vs 15.31 in controls, P = .10), FT3 or TSH levels. The FT3/FT4 ratio was significantly increased in PWS in both groups. FT4 levels were positively correlated with age in PWS.

CONCLUSIONS

Infants with PWS had lower FT4 levels, but FT3 levels were normal, indicating that the levothyroxine replacement therapy may not need to be routinely performed.

Early start of growth hormone is associated with positive effects on auxology and metabolism in Prader-Willi-syndrome

BACKGROUND

Prader-Willi-Syndrome (PWS) is characterized by hypothalamic-pituitary dysfunction. Recent research suggests starting growth hormone-treatment (GHT) as soon as possible. The aim of this study is to analyze possible differences in auxological parameters, carbohydrate and lipid metabolism between two groups of children with PWS that started GHT either during or after their first year of life.

STUDY DESIGN

Retrospective longitudinal study of 62 children (31 males) with genetically confirmed PWS. Upon diagnosis all children were offered GHT, some started immediately, others commenced later. Cohort A (n = 21; 11 males) started GHT at 0.3-0.99 yrs. (mean 0.72 yrs) and Cohort B (n = 41; 20 males) commenced GHT at 1.02-2.54 yrs. (mean 1.42 yrs) of age. Fasting morning blood samples and auxological parameters were obtained before the start of therapy and semi-annually thereafter. Differences between the two cohorts were estimated with a linear mixed-effect model.

RESULTS

Mean length/height-SDS_PWS differed significantly between the groups [1 yr: A: 0.37 (±0.83) vs B: 0.05 (±0.56); 5 yrs.: A: 0.81 (±0.67) vs B: 0.54 (±0.64); p = 0.012]. No significant differences were found in BMI, lean body mass or body fat. Low-density cholesterol was significantly lower in A than in B [LDL: 1 yr: A: 79 (±20) mg/dl vs B: 90 (±19) mg/dl; 5 yrs.: A: 91(±18) mg/dl vs 104 (±26) mg/dl; p = 0.024]. We found significant differences in the glucose homeostasis between the groups [fasting insulin: p = 0.012; HOMA-IR: p = 0.006; HbA1c: p < 0.001; blood glucose: p = 0.022].

CONCLUSIONS

An early start of GHT during the first year of life seems to have a favorable effect on height-SDS and metabolic parameters.

Prader-Willi syndrome: endocrine manifestations and management

Prader-Willi syndrome (PWS) is a genetic disorder caused by the absence of gene expression in the 15q11.2-q13 paternal chromosome. Patients with PWS develop hypothalamic dysfunction that can lead to various endocrine changes such as: obesity, growth hormone deficiency, hypogonadism, hypothyroidism, adrenal insufficiency and low bone mineral density. In addition, individuals with PWS have increased risk of developing type 2 diabetes mellitus. This review summarizes and updates the current knowledge about the prevention, diagnosis and treatment of endocrine manifestations associated with Prader Willi syndrome, especially diagnosis of growth hormone deficiency, management and monitoring of adverse effects; diagnosis of central adrenal insufficiency and management in stressful situations; screening for central hypothyroidism; research and treatment of hypogonadism; prevention and treatment of disorders of glucose metabolism. Careful attention to the endocrine aspects of PWS contributes significantly to the health of these individuals. Arch Endocrinol Metab. 2020;64(3):223-34.

Effects of growth hormone treatment on thyroid function in pediatric patients with Prader-Willi syndrome

It is unclear whether hypothyroidism is present in patients with Prader-Willi syndrome (PWS). This study aimed to clarify the state of the hypothalamic-pituitary-thyroid axis and the effects of growth hormone (GH) treatment on thyroid function in pediatric patients with PWS. We retrospectively evaluated thyroid function in 51 patients with PWS before GH treatment using a thyroid-releasing hormone (TRH) stimulation test (29 males and 22 females; median age, 22 months). We also evaluated the effect of GH therapy on thyroid function by comparing serum free triiodothyronine (fT3), free thyroxine (fT4), and thyroid stimulating hormone (TSH) levels at baseline, 1 year, and 2 years after GH therapy. TSH, fT4, and fT3 levels were 2.28 μU/ml (interquartile range [IQR]; 1.19-3.61), 1.18 ng/dl (IQR; 1.02-1.24), and 4.02 pg/dl (IQR; 3.54-4.40) at baseline, respectively. In 49 of 51 patients, the TSH response to TRH administration showed a physiologically normal pattern; in two patients (4.0%), the pattern suggested hypothalamic hypothyroidism (delayed and prolonged TSH peak after TRH administration). TSH, fT4, and fT3 levels did not change significantly during 1 or 2 years after GH treatment. The TSH response to TRH showed a normal pattern in most patients, and thyroid function did not change significantly during the 2 years after initiating GH treatment.

Autoimmune Thyroid Disease in Specific Genetic Syndromes in Childhood and Adolescence

Autoimmune thyroid disease (ATD) is the most frequent cause of acquired thyroid dysfunction, most commonly presenting either as Hashimoto's thyroiditis or Graves' Disease. Hashimoto's thyroiditis is characterized by the presence of thyroid-specific autoantibodies, more commonly anti-thyroperoxidase antibodies in the serum and the typical inhomogeneous echostructure of the thyroid on a thyroid ultrasound examination. Hashimoto's thyroiditis can for a long time be accompanied by normal thyroid function and hypothyroidism can only progressively be established. Graves' disease is much less frequent in childhood and adolescence and presents with overt hyperthyroidism. After the onset of puberty, ATD affects females with a higher incidence than males, while during the prepubertal period there is not such a clear preponderance of affected females. ATD can occur either isolated or in the context of other autoimmune disorders, such as type 1 Diabetes mellitus (T1D), celiac disease, alopecia areata, vitiligo, etc. Especially at the pediatric age, a higher incidence of ATD is also observed in the context of specific genetic syndromes, such as trisomy 21 (Down syndrome), Klinefelter syndrome, Turner syndrome, or 22q11.2 deletion syndrome. Nevertheless, although thyroid dysfunction may also be observed in other genetic syndromes, such as Prader-Willi or Williams syndrome, the thyroid dysfunction in these syndromes is not the result of thyroid autoimmunity. Interestingly, there is emerging evidence supporting a possible link between autoimmunity and RASopathies. In this review article the incidence, as well as the clinical manifestation and accompanied pathologies of ATD in specific genetic syndromes will be presented and regular follow-up for the early identification of the disorder will be proposed.

Effects of recombinant human growth hormone treatment on growth, body composition, and safety in infants or toddlers with Prader-Willi syndrome: a randomized, active-controlled trial

Background

Prader-Willi syndrome (PWS) is a rare complex genetic disorder and is characterized by short stature, muscular hypotonia, abnormal body composition, psychomotor retardation, and hyperphagia. Recombinant human growth hormone (rhGH) treatment improves the symptoms in children with PWS, and early treatment results in more favorable outcomes. However, systematic studies in infants and toddlers under 2 years of age are lacking. This multicenter, randomized, active-controlled, parallel-group, open-label, Phase III study aimed to evaluate the safety of rhGH (Eutropin, LG Chem, Ltd.) and its efficacy on growth, body composition, and motor and cognitive development in infants and toddlers with PWS compared with a comparator treatment (Genotropin, Pfizer, Inc.). Eligible Korean infants or toddlers with PWS were randomly assigned to receive Eutropin or comparator (both 0.24 mg/kg/week, 6 times/week) for 1 year. Height standard deviation score (SDS), body composition, and motor and cognitive development were measured.

Results

Thirty-four subjects (less than 24 months old) were randomized into either the Eutropin (N = 17) group or the comparator (N = 17) group. After 52 weeks of rhGH treatment, height SDS and lean body mass increased significantly from baseline in both groups: the mean height SDS change (SD) was 0.75 (0.59) in the Eutropin group and 0.95 (0.66) in the comparator group, and the mean lean body mass change (SD) was 2377.79 (536.25) g in the Eutropin group and 2607.10 (641.36) g in the comparator group. In addition, percent body fat decreased significantly: the mean (SD) change from baseline was − 8.12% (9.86%) in the Eutropin group and − 7.48% (10.26%) in the comparator group. Motor and cognitive developments were also improved in both groups after the 1-year treatment. The incidence of adverse events was similar between the groups.

Conclusions

rhGH treatment for 52 weeks in infants and toddlers with PWS improved growth, body composition, and motor and cognitive development, and efficacy and safety outcomes of Eutropin were comparable to those of Genotropin. Hence, Eutropin is expected to provide safe and clinically meaningful improvements in pediatric patients with PWS.

Trial registration

The study was registered at ClinicalTrials.gov (identifier: NCT02204163) on July 30, 2014.

URL: https://clinicaltrials.gov/ct2/show/NCT02204163?term=NCT02204163&rank=1

Prader- Willi syndrome: An uptodate on endocrine and metabolic complications

Prader-Willi syndrome (PWS) is a genetic disorder characterized by short stature, low lean body mass, muscular hypotonia, mental retardation, behavioral abnormalities, dysmorphic features, and excessive appetite with progressive obesity. It is caused by lack of expression of genes on the paternally inherited chromosome 15q11.2-q13. This genetic disorder has an estimated prevalence that ranges between 1/10,000-1/30,000. Hypothalamic dysfunction is a common finding in PWS and it has been implicated in several manifestations of this syndrome such as hyperphagia, temperature instability, high pain threshold, sleep disordered breathing, and multiple endocrine abnormalities. These include growth hormone deficiency, central adrenal insufficiency, hypogonadism, hypothyroidism, and obesity often complicated by type 2 diabetes. The aim of this manuscript is to overview the current literature on metabolic and endocrine complications of PWS, focusing on human studies and providing insights on the physio pathological mechanisms. A careful management of metabolic and endocrine complications can contribute to improve quality of life, prevent complications, and prolong life expectancy of PW patients.

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

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

Pediatric endocrinology through syndromes

In everyday practice, a pediatric endocrinologist will face a variety of different endocrine issues (such as short or tall stature, dysthyroidism, abnormal pubertal timing or impaired glucose metabolism), which relevantly contribute to the global care of a number of syndromic conditions. On the other hand, the presence of endocrine features may assist in the diagnostic process, leading to final diagnosis of a syndromic disorder. The intention of this review is to provide a referenced overview of different genetic syndromes characterized by endocrine features, and to present a possible classification, based on whether the endocrinopathy or the syndrome is typically recognized first. Thus, the first part of the manuscript deals with the most common syndromes associated with endocrine dysfunctions, while the second part describes the conditions by which a syndrome is most frequently diagnosed after an endocrine finding. The aim is to provide a practical overview of the assessment of syndromic patients, so that they can be recognized and managed in an integrated, multidisciplinary fashion.

Less known aspects of central hypothyroidism: Part 2 - Congenital etiologies

Central hypothyroidism (CH) occurs approximately in 1:50,000, and therefore is expected to be one thousand times rarer compared with primary hypothyroidism. Despite its rarity in the general population, it is much more common in certain disorders, in which it is frequently associated with other pituitary hormone deficiencies. The aim of this paper is to provide an updated review on the frequency of congenital CH, which is <1:50,000, and on its etiology, disregarding CH caused by other genetic defects, such as mutations of transcription factors involved in pituitary organogenesis or mutations of the genes encoding TRH or TRH receptor.

Review of Prader-Willi syndrome: the endocrine approach

Prader-Willi syndrome (PWS) is a complex genetic disorder with implications on the endocrine and neurologic systems, metabolism, and behavior. Early in life, PWS is characterized by hypotonia and failure to thrive, followed by obesity and hyperphagia. Patients with PWS develop hypothalamic dysfunction which may lead growth hormone deficiency (GHD), hypogonadism, hypothyroidism, adrenal insufficiency, and poor bone mineral density (BMD). In addition to hypothalamic dysfunction, individuals with PWS have increased risk for obesity which may be complicated by metabolic syndrome and type 2 diabetes mellitus (T2DM). In this paper, we will review the current literature pertaining to the endocrine concerns of PWS and current recommendations for screening and management of these conditions.

Congenital hypothyroidism due to ectopic sublingual thyroid gland in Prader-Willi Syndrome: a case report

Background

Thyroid gland disorders are variably associated with Prader-Willi syndrome (PWS).

Many of the clinical features in newborns with PWS are similar to those found in congenital hypothyroidism (CH).

Case presentation

We report a case of a girl with CH and PWS. At the age of 9 months CH caused by an ectopic sublingual thyroid was diagnosed, and hormone replacement therapy was started. In spite of this treatment a decrease in growth velocity, weight excess and delayed development were observed. At the age of 9 years PWS was suspected on the basis of phenotype and genetic tests confirmed a maternal uniparental disomy of chromosome 15. This is the second reported case of hypothyroidism due to an ectopic sublingual thyroid gland in PWS suggesting that, although rare, an association between CH and PWS may exist. In our case diagnosis of PWS was delayed because mental retardation, hypotonia, obesity and short stature were initially attributed to hypothyroidism.

Conclusions

In this context PWS should be considered in obese children with CH who do not improve adequately with l-thyroxine therapy. Also, thyroid function in all PWS children should be assessed regularly in order to avoid delayed diagnosis of hypothyroidism.

Altered functional resting-state hypothalamic connectivity and abnormal pituitary morphology in children with Prader-Willi syndrome

Background

Prader-Willi syndrome (PWS) is a complex neurodevelopmental disorder, characterized by endocrine problems and hyperphagia, indicating hypothalamic-pituitary dysfunction. However, few studies have explored the underlying neurobiology of the hypothalamus and its functional connectivity with other brain regions. Thus, the aim of this study was to examine the anatomical differences of the hypothalamus, mammillary bodies, and pituitary gland as well as resting state functional connectivity of the hypothalamus in children with PWS.

Methods

Twenty-seven children with PWS (13 DEL, 14 mUPD) and 28 typically developing children were included. Manual segmentations by a blinded investigator were performed to determine the volumes of the hypothalamus, mammillary bodies, and pituitary gland. In addition, brain-wide functional connectivity analysis was performed using the obtained masks of the hypothalamus.

Results

Children with PWS showed altered resting state functional connectivity between hypothalamus and right and left lateral occipital complex, compared to healthy controls. In addition, children with PWS had on average a 50% smaller pituitary volume, an irregular shape of the pituitary, and a longer pituitary stalk. Pituitary volume did not increase in volume during puberty in PWS. No volumetric differences in the hypothalamus and mammillary bodies were found. In all subjects, the posterior pituitary bright spot was observed.

Conclusions

We report altered functional hypothalamic connectivity with lateral occipital complexes in both hemispheres, which are implicated in response to food and reward system, and absence of connectivity might therefore at least partially contribute to the preoccupation with food in PWS.

Long-term side effects of growth hormone treatment in children with Prader-Willi syndrome

The main motivations of growth hormone (GH) treatment of Prader-Willi syndrome (PWS) are the stimulation of growth and lean muscle mass. Furthermore GH therapy in Prader-Willi children seems to favorably affect their behavior and mental performances. It is still a matter of discussion whether GH therapy in PWS should be considered responsible for specific adverse events. The most significant of them are scoliosis and breathing disorders, the latter considered being responsible for some deaths, reported in children with PWS, mainly at the beginning of GH therapy. Obstructive sleep apnea was occasionally reported also in patients treated with GH for several years. The review reports and discusses the latest data related to side effects of long-term GH treatment in children with PWS.

Divergent structural brain abnormalities between different genetic subtypes of children with Prader-Willi syndrome

Background

Prader–Willi syndrome (PWS) is a complex neurogenetic disorder with symptoms that indicate not only hypothalamic, but also a global, central nervous system (CNS) dysfunction. However, little is known about developmental differences in brain structure in children with PWS. Thus, our aim was to investigate global brain morphology in children with PWS, including the comparison between different genetic subtypes of PWS. In addition, we performed exploratory cortical and subcortical focal analyses.

Methods

High resolution structural magnetic resonance images were acquired in 20 children with genetically confirmed PWS (11 children carrying a deletion (DEL), 9 children with maternal uniparental disomy (mUPD)), and compared with 11 age- and gender-matched typically developing siblings as controls. Brain morphology measures were obtained using the FreeSurfer software suite.

Results

Both children with DEL and mUPD showed smaller brainstem volume, and a trend towards smaller cortical surface area and white matter volume. Children with mUPD had enlarged lateral ventricles and larger cortical cerebrospinal fluid (CSF) volume. Further, a trend towards increased cortical thickness was found in children with mUPD. Children with DEL had a smaller cerebellum, and smaller cortical and subcortical grey matter volumes. Focal analyses revealed smaller white matter volumes in left superior and bilateral inferior frontal gyri, right cingulate cortex, and bilateral precuneus areas associated with the default mode network (DMN) in children with mUPD.

Conclusions

Children with PWS show signs of impaired brain growth. Those with mUPD show signs of early brain atrophy. In contrast, children with DEL show signs of fundamentally arrested, although not deviant brain development and presented few signs of cortical atrophy. Our results of global brain measurements suggest divergent neurodevelopmental patterns in children with DEL and mUPD.

Thyroid function from birth to adolescence in Prader-Willi syndrome

OBJECTIVES

To describe the response of thyroid-stimulating hormone (TSH) to thyroid-releasing hormone in children and adolescents with Prader-Willi syndrome (PWS), and to compare TSH and total thyroxine (TT4) concentrations measured on neonatal screening for congenital hypothyroidism in children with PWS and controls.

STUDY DESIGN

All participants had genetically confirmed PWS. The TSH responses to thyroid-releasing hormone, free thyroxine (fT4), and free triiodothyronine (fT3) were measured in 21 subjects (14 females and 7 males; mean age, 6.4 years). Capillary TT4 was measured on neonatal screening samples from 23 subjects with PWS (14 females and 9 males), each of whom was matched for birth weight and sex with 4 anonymized controls.

RESULTS

One subject with PWS had tertiary hypothyroidism. TSH level increased from 1.37 mU/L at baseline to 39.6 mU/L at 20 minutes, 47.2 mU/L at 40 minutes, 44.5 mU/L at 60 minutes, and 47.2 mU/L at 120 minutes. fT4 concentration was 6.3 pmol/L, and fT3 concentration was 4.6 pmol/L. In the other 20 subjects, mean TSH level was 1.9 mU/L (range, 0.8-4.2 mU/L) at baseline and 21.8 mU/L (range, 10.0-46.7 mU/L) at 20 minutes (peak). Mean fT4 concentration (10.4 pmol/L; range, 8.2-13.5 pmol/L) was in the lower one-third of the normal range in 18 subjects, and mean fT3 concentration (6.1 pmol/L; range, 4.8-8.4 pmol/L) was above the median in 13 subjects. In neonates, mean TSH level was 3.1 mU/L (range, 0.4-10.0 mU/L) in subjects with PWS versus 3.3 mU/L (range, 0.0-7.0 mU/L) in controls, and mean TT4 in subjects with PWS was 111% (range, 17%-203%) that of controls (P = not significant).

CONCLUSION

Thyroid function was normal in our newborn subjects. In older children, frank hypothyroidism was found in only 1 of our 21 subjects. Thus, levothyroxine treatment should not be routinely prescribed to youth with PWS.

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.

Endocrine problems in children with Prader-Willi syndrome: special review on associated genetic aspects and early growth hormone treatment

Prader-Willi syndrome (PWS) is a complex multisystem genetic disorder characterized by hypothalamic-pituitary dysfunction. The main clinical features include neonatal hypotonia, distinctive facial features, overall developmental delay, and poor growth in infancy, followed by overeating with severe obesity, short stature, and hypogonadism later in development. This paper reviews recent updates regarding the genetic aspects of this disorder. Three mechanisms (paternal deletion, maternal disomy, and deficient imprinting) are recognized. Maternal disomy can arise because of 4 possible mechanisms: trisomy rescue (TR), gamete complementation (GC), monosomy rescue (MR), and postfertilization mitotic nondisjunction (Mit). Recently, TR/GC caused by nondisjunction at maternal meiosis 1 has been identified increasingly, as a result of advanced maternal childbearing age in Korea. We verified that the d3 allele increases the responsiveness of the growth hormone (GH) receptor to endogenous GH. This paper also provides an overview of endocrine dysfunctions in children with PWS, including GH deficiency, obesity, sexual development, hypothyroidism, and adrenal insufficiency, as well as the effects of GH treatment. GH treatment coupled with a strictly controlled diet during early childhood may help to reduce obesity, improve neurodevelopment, and increase muscle mass. A more active approach to correct these hormone deficiencies would benefit patients with PWS.

Growth hormone: the expansion of available products and indications

Growth hormone is a widely used hormone. This article describes its historical use, current indications and studies for possible future uses.

Impaired hypothalamic regulation of endocrine function and delayed counterregulatory response to hypoglycemia in Magel2-null mice

Hypothalamic dysfunction may underlie endocrine abnormalities in Prader-Willi syndrome (PWS), a genetic disorder that features GH deficiency, obesity, and infertility. One of the genes typically inactivated in PWS, MAGEL2, is highly expressed in the hypothalamus. Mice deficient for Magel2 are obese with increased fat mass and decreased lean mass and have blunted circadian rhythm. Here, we demonstrate that Magel2-null mice have abnormalities of hypothalamic endocrine axes that recapitulate phenotypes in PWS. Magel2-null mice had elevated basal corticosterone levels, and although male Magel2-null mice had an intact corticosterone response to restraint and to insulin-induced hypoglycemia, female Magel2-null mice failed to respond to hypoglycemia with increased corticosterone. After insulin-induced hypoglycemia, Magel2-null mice of both sexes became more profoundly hypoglycemic, and female mice were slower to recover euglycemia, suggesting an impaired hypothalamic counterregulatory response. GH insufficiency can produce abnormal body composition, such as that seen in PWS and in Magel2-null mice. Male Magel2-null mice had Igf-I levels similar to control littermates. Female Magel2-null mice had low Igf-I levels and reduced GH release in response to stimulation with ghrelin. Female Magel2-null mice did respond to GHRH, suggesting that their GH deficiency has a hypothalamic rather than pituitary origin. Female Magel2-null mice also had higher serum adiponectin than expected, considering their increased fat mass, and thyroid (T(4)) levels were low. Together, these findings strongly suggest that loss of MAGEL2 contributes to endocrine dysfunction of hypothalamic origin in 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.

Growth hormone: the expansion of available products and indications

Growth hormone is a widely used hormone. This article describes its historical use, current indications and studies for possible future uses.

Randomized controlled GH trial: effects on anthropometry, body composition and body proportions in a large group of children with Prader-Willi syndrome

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/m(2)/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/m(2)/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.

Mental and motor development before and during growth hormone treatment in infants and toddlers with Prader-Willi syndrome

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/m(2)/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.