Prader-Willi Syndrome Cohort Research Articles

14 and 6 Hz like spike wave activity is a common finding in young patients with Prader-Willi syndrome.

Our aim was to characterize the 14 and 6 like spike wave activity seen on electroencephalograms (EEG) in children with Prader-Willi syndrome (PWS) undergoing polysomnograms. We performed a retrospective review of children with PWS and healthy controls who underwent diagnostic polysomnograms between January 1, 2007, and December 31, 2020, at SickKids, Toronto, Canada. EEGs from the polysomnograms were reviewed for the presence of the 14 and 6 like spike wave activity and its characteristics. Clinical correlation of the EEG variant with sleep-disordered breathing indices from the polysomnograms was also evaluated. A total of 94 children with PWS and 50 healthy controls were included. The median age and interquartile range for the cohort was 1.42 (0.6, 4.2) years. There were 50 (53.2%) males in the PWS cohort. The EEG variant prevalence in this cohort was 51.0% (n = 48) in children with PWS and 0% for the healthy controls. 14 and 6 Hz like spike wave activity was bilateral in 52% (25/48) children with PWS. The waves had a negative deflection in almost all patients, 44/48 (92%), with PWS. It was predominantly located in the frontal leads for children with PWS, 23/48 (47.9%). It most frequently occurred during non-rapid eye movement stage 2 sleep for children with PWS, 25/48 (52.0%). The mean (standard deviation) frequency was 6.8 (0.97) Hz. The median (interquartile range) length of the waves was 1.1 (0.8, 1.4) seconds in children with PWS. There was no correlation between the presence of the EEG variant and sleep-disordered breathing indices in children with PWS. The 14 and 6 Hz like spike wave activity EEG variant was present in more than 50% of a pediatric cohort of children with PWS compared with 0% in healthy children. This EEG variant did not appear to be associated with sleep-disordered breathing indices in children with PWS and is of unknown clinical significance. Alzaid M, Sunkonkit K, Massicotte C, Otsubo H, Amin R, Al-Saleh S. 14 and 6 Hz like spike wave activity is a common finding in young patients with Prader-Willi syndrome. J Clin Sleep Med. 2024;20(8):1227-1232.

Register-based and genetic studies of Prader-Willi syndrome show a high frequency of gonadal tumors and a possible mechanism for tumorigenesis through imprinting relaxation.

Prader-Willi syndrome (PWS) is a rare disease caused by a lack of expression of inherited imprinted genes in the paternally derived Prader-Willi critical region on chromosome 15q11.2-q13. It is characterized by poor feeding and hypotonia in infancy, intellectual disability, behavioral abnormalities, dysmorphic features, short stature, obesity, and hypogonadism. PWS is not a known cancer predisposition syndrome, but previous investigations regarding the prevalence of cancer in these patients suggest an increased risk of developing specific cancer types such as myeloid leukemia and testicular cancer. We present the results from a Swedish national population-based cohort study of 360 individuals with PWS and 18,000 matched comparisons. The overall frequency of cancer was not increased in our PWS cohort, but we found a high frequency of pediatric cancers. We also performed whole-genome sequencing of blood- and tumor-derived DNAs from a unilateral dysgerminoma in a 13-year-old girl with PWS who also developed bilateral ovarian sex cord tumors with annular tubules. In germline analysis, there were no additional findings apart from the 15q11.2-q13 deletion of the paternal allele, while a pathogenic activating KIT mutation was identified in the tumor. Additionally, methylation-specific multiplex ligation-dependent probe amplification revealed reduced methylation at the PWS locus in the dysgerminoma but not in the blood. In conclusion, our register-based study suggests an increased risk of cancer at a young age, especially testicular and ovarian tumors. We found no evidence of a general increase in cancer risk in patients with PWS. However, given our limited observational time, further studies with longer follow-up times are needed to clarify the lifetime cancer risk in PWS. We have also described the second case of locus-specific loss-of-imprinting in a germ cell tumor in PWS, suggesting a possible mechanism of carcinogenesis.

The relationship between endogenous oxytocin and vasopressin levels and the Prader-Willi syndrome behaviour phenotype.

Oxytocin and vasopressin systems are altered in Prader Willi syndrome (PWS). However, investigations into endogenous oxytocin and vasopressin levels as well as clinical trials evaluating the effect of exogenous oxytocin on PWS symptoms have had mixed results. It is also unknown whether endogenous oxytocin and vasopressin levels are associated with certain PWS behaviours. We compared plasma oxytocin and vasopressin and saliva oxytocin levels in 30 adolescents and adults with PWS to 30 typically developing age-matched controls. We also compared neuropeptide levels between gender and genetic subtypes within the PWS cohort and examined the relationship between neuropeptide levels and PWS behaviours. While we did not measure a group difference in plasma or saliva oxytocin levels, plasma vasopressin was significantly lower in individuals with PWS compared to controls. Within the PWS cohort, saliva oxytocin levels were higher in females compared to males and individuals with the mUPD compared to the deletion genetic subtype. We also found the neuropeptides correlated with different PWS behaviours for males and females and for genetic subtypes. For the deletion group, higher plasma and saliva oxytocin levels were related to fewer behaviour problems. For the mUPD group, higher plasma vasopressin levels were related to more behaviour problems. These findings support existing evidence of a vasopressin system defect in PWS and for the first time identify potential differences in the oxytocin and vasopressin systems across PWS genetic subtypes.

Chromosomal Microarray Study in Prader-Willi Syndrome.

A high-resolution chromosome microarray analysis was performed on 154 consecutive individuals enrolled in the DESTINY PWS clinical trial for Prader-Willi syndrome (PWS). Of these 154 PWS individuals, 87 (56.5%) showed the typical 15q11-q13 deletion subtypes, 62 (40.3%) showed non-deletion maternal disomy 15 and five individuals (3.2%) had separate unexpected microarray findings. For example, one PWS male had Klinefelter syndrome with segmental isodisomy identified in both chromosomes 15 and X. Thirty-five (40.2%) of 87 individuals showed typical larger 15q11-q13 Type I deletion and 52 individuals (59.8%) showed typical smaller Type II deletion. Twenty-four (38.7%) of 62 PWS individuals showed microarray patterns indicating either maternal heterodisomy 15 subclass or a rare non-deletion (epimutation) imprinting center defect. Segmental isodisomy 15 was seen in 34 PWS subjects (54.8%) with 15q26.3, 15q14 and 15q26.1 bands most commonly involved and total isodisomy 15 seen in four individuals (6.5%). In summary, we report on PWS participants consecutively enrolled internationally in a single clinical trial with high-resolution chromosome microarray analysis to determine and describe an unbiased estimate of the frequencies and types of genetic defects and address potential at-risk genetic disorders in those with maternal disomy 15 subclasses in the largest PWS cohort studied to date.

Alteration of serum leptin and LEP/LEPR promoter methylation in Prader-Willi syndrome

Prader-Willi syndrome (PWS) is a rare neurodevelopmental disorder based on a loss of paternally expressed but maternally imprinted genes in chromosome region 15q11–13. PWS individuals typically show insatiable appetite with subsequent obesity representing the major mortality factor unless food intake is inhibited. The neurobiological basis of PWS-typical hyperphagia has remained poorly understood. Many PWS-typical abnormalities are based on hypothalamic dysregulation, a region in which hunger and satiety are hormonally regulated, with the hormone leptin being a main long-term regulator of satiety. Previous studies in PWS have inconsistently shown leptin alterations solely in early childhood, without investigating the leptin system on an epigenetic level. The present study investigates serum leptin levels (S-leptin) and DNA methylation of the leptin (LEP) and leptin receptor gene (LEPR) promoter in 24 individuals with PWS compared to 13 healthy controls matched for sex, age, and body mass index (BMI) and relates the results to the extent of hyperphagia in PWS. S-Leptin levels were obtained by Enzyme-linked Immunosorbent Assay. LEP/LEPR-promoter DNA methylation was assessed by bisulfite-sequencing, hyperphagia by Hyperphagia Questionnaire for Clinical Trials (HQ-CT). PWS and control groups differed significantly in S-leptin levels with higher S-leptin in PWS. Methylation analysis showed significant differences in mean promoter methylation rate both for LEP and LEPR with a lower methylation rate in PWS. LEPR, but not LEP methylation correlated significantly with S-leptin levels. S-leptin and both LEP and LEPR methylation did not correlate with HQ-CT scores in PWS. The present study is the first to show significantly elevated S-leptin levels in an adult PWS cohort combined with an altered, downregulated LEP and LEPR promoter methylation status compared to sex-, age- and BMI-matched controls. Analogous to previous studies, no link to the behavioral dimension could be drawn. Overall, the results suggest an increased leptin dysregulation in PWS, whereby the findings partly mirror those seen in non-syndromic obesity.

Pharmacogenetic Testing of Cytochrome P450 Drug Metabolizing Enzymes in a Case Series of Patients with Prader-Willi Syndrome

Prader-Willi syndrome (PWS) is associated with co-morbid psychiatric symptoms (disruptive behavior, anxiety, mood disorders, and psychosis) often requiring psychotropic medications. In this clinical case series of 35 patients with PWS, pharmacogenetic testing was obtained to determine allele frequencies predicting variations in activity of cytochrome (CYP) P450 drug metabolizing enzymes 2D6, 2B6, 2C19, 2C9, 3A4, and 1A2. Results were deidentified, collated, and analyzed by PWS genetic subtype: 14 deletion (DEL), 16 maternal uniparental disomy (UPD) and 5 DNA-methylation positive unspecified molecular subtype (PWS Unspec). Literature review informed comparative population frequencies of CYP polymorphisms, phenotypes, and substrate specificity. Among the total PWS cohort, extensive metabolizer (EM) activity prevailed across all cytochromes except CYP1A2, which showed greater ultra-rapid metabolizer (UM) status (p < 0.05), especially among UPD. Among PWS genetic subtypes, there were statistically significant differences in metabolizing status for cytochromes 2D6, 2C19, 2C9, 3A4 and 1A2 acting on substrates such as fluoxetine, risperidone, sertraline, modafinil, aripiprazole, citalopram, and escitalopram. Gonadal steroid therapy may further impact metabolism of 2C19, 2C9, 3A4 and 1A2 substrates. The status of growth hormone treatment may affect CYP3A4 activity with gender specificity. Pharmacogenetic testing together with PWS genetic subtyping may inform psychotropic medication dosing parameters and risk for adverse events.

Impact of genetic subtypes of Prader-Willi syndrome with growth hormone therapy on intelligence and body mass index.

Prader-Willi syndrome (PWS) is a genomic imprinting disorder characterized by infantile hypotonia with a poor suck and failure to thrive, hypogenitalism/hypogonadism, behavior and cognitive problems, hormone deficiencies, hyperphagia, and obesity. The Stanford Binet and Wechsler (WAIS-R; WISC-III) intelligence (IQ) tests were administered on 103 individuals with PWS from two separate cohorts [University of California, Irvine (UCI) (N = 56) and Vanderbilt University (N = 47)] and clinical information obtained including growth hormone (GH) treatment, PWS molecular classes, weight and height. Significantly higher IQ scores (p < .02) were found representing the vocabulary section of the Stanford Binet test in the growth hormone (GH) treated group when compared with non-GH treatment in the pediatric-based UCI PWS cohort with a trend for stabilization of vocabulary IQ scores with age in the GH treated maternal disomy (UPD) 15 subject group. Significant differences (p = .05) were also found in the adult-based Vanderbilt PWS cohort with 15q11-q13 deletion subjects having lower Verbal IQ scores compared with UPD 15. No difference in body mass index was identified based on the PWS molecular class or genetic subtype. Medical care and response to treatment with growth hormone may influence intelligence impacted by PWS genetic subtypes and possibly age, but more studies are needed.

SAT-100 Trial-in-Progress: ZEPHYR, a Pivotal Phase 2b/3 Randomized, Placebo-Controlled Study of Livoletide, a Novel Unacylated Ghrelin Analog, for the Treatment of Hyperphagia and Food-Related Behaviors in Patients with Prader-Willi Syndrome

Background: Prader-Willi syndrome (PWS) is a rare and complex endocrine disease characterized by hyperphagia and abnormal food-related behaviors that contribute to severe morbidity and early mortality and to a significant burden on patients and caregivers. There is no approved treatment for hyperphagia in PWS. Patients with PWS have increased circulating levels of the orexigenic hormone acylated ghrelin (AG) with a relative deficit of unacylated ghrelin (UAG). Livoletide (AZP-531) is a first-in-class UAG analog that was previously shown in a Phase 2 randomized placebo-controlled study in a 47-patient PWS cohort to significantly improve hyperphagia, food related behaviors, and metabolic parameters and to be well-tolerated with no serious adverse events or treatment discontinuations over a 14-day period. [Allas S et al. (2018) PLoS ONE 13(1): e0190849] Objective: ZEPHYR (EudraCT 2018-003062-13) is a pivotal Phase 2b/3 study that is designed to evaluate the long-term safety and efficacy of livoletide in patients with PWS. Methods: The ZEPHYR study will be conducted in centers in North America and Europe. In its Phase 2b portion, approximately 150 patients with PWS will be randomized in a 1:1:1 ratio to receive livoletide low exposure (8 mg/mL), livoletide high exposure (16 mg/mL), or placebo, once a day by sc injection for a three-month core period. Then, patients who received placebo will cross over to livoletide low or high exposure and be treated for 9 months. Patients who received livoletide will continue at their original dose for an additional 9 months. The Phase 3 portion will be initiated following results of the Phase 2b core period with patients randomized 1:1 to livoletide at a dose based on Phase 2b core data or to placebo for a six-month duration. Subsequently, patients who received placebo will be crossed over to livoletide for six months, while patients on livoletide initially will continue for six more months. Main entry criteria for ZEPHYR include genetic diagnosis of PWS, age 8-65 years, single primary caregiver available for the duration of the study, BMI ≤65 kg/m2 for adult patients. Patients with type 2 diabetes with HbA1C ≤10% and stable therapy may be enrolled. Use of human growth hormone will be allowed if dosage is stable. Patients enrolled in Phase 2b will not be eligible for Phase 3. The primary outcome measure is the Hyperphagia Questionnaire-Clinical Trials (HQ-CT) score. The HQ-CT has been validated and is considered by regulatory authorities as a valid primary endpoint. Secondary outcome measures include fat mass as assessed by DEXA, BMI, and body weight in overweight/obese patients. Results: The study is ongoing: enrollment began in early 2019 and an updated status will be reported. Conclusion: ZEPHYR is a pivotal study that will provide data on the long-term safety and efficacy on hyperphagia and food-related behaviors of the novel UAG analog livoletide in patients with PWS.

Prader-Willi syndrome and early-onset morbid obesity NIH rare disease consortium: A review of natural history study.

We describe the National Institutes of Health rare disease consortium for Prader-Willi syndrome (PWS) developed to address concerns regarding medical care, diagnosis, growth and development, awareness, and natural history. PWS results from errors in genomic imprinting leading to loss of paternally expressed genes due to 15q11-q13 deletion, maternal disomy 15 or imprinting defects. The 8 year study was conducted at four national sites on individuals with genetically confirmed PWS and early-onset morbid obesity (EMO) with data accumulated to gain a better understanding of the natural history, cause and treatment of PWS. Enrollment of 355 subjects with PWS and 36 subjects with EMO began in September 2006 with study completion in July 2014. Clinical, genetic, cognitive, behavior, and natural history data were systematically collected along with PWS genetic subtypes, pregnancy and birth history, mortality, obesity, and cognitive status with study details as important endpoints in both subject groups. Of the 355 individuals with PWS, 217 (61%) had the 15q11-q13 deletion, 127 (36%) had maternal disomy 15, and 11 (3%) had imprinting defects. Six deaths were reported in our PWS cohort with 598 cumulative years of study exposure and one death in the EMO group with 42 years of exposure. To our knowledge, this description of a longitudinal study in PWS represents the largest and most comprehensive cohort useful for investigators in planning comparable studies in other rare disorders. Ongoing studies utilizing this database should have a direct impact on care and services, diagnosis, treatment, genotype-phenotype correlations, and clinical outcomes in PWS.

Long-term health outcomes in patients with Prader-Willi Syndrome: a nationwide cohort study in Denmark.

Prader-Willi syndrome (PWS) is a rare congenital disease that affects growth, sexual development, cognitive function and behavior. Individuals exhibit food preoccupation and hyperphagia, which may lead to obesity with premature morbidity and mortality. The aim of this work was to evaluate the risk of venous thromboembolisms (VTEs), myocardial infarction, pulmonary hypertension, sleep apnea, depression, anxiety and all-cause mortality among persons with PWS as compared with an age- and sex-matched general-population cohort. All persons diagnosed with PWS (n=155) were identified in the Danish Health Registries; an age- and sex-matched comparison group was selected from the general population of Denmark (n=15 500); diseases of interest were identified through the health registry and cause of death register. Follow-up began on date of birth or first medical record availability through to first occurrence of an outcome of interest; follow-up ceased at emigration from Denmark or end of study. Incidence rates (IRs) were calculated and Cox's proportional hazards models were used to understand the relative risk (RR) of disease. The IRs for VTE among patients with PWS was 144 (60-347) per 100 000 person-years. Risks for VTE events and all-cause mortality were 9.4 times (95% confidence interval (CI): 3.7-23.5) and 11.0 times (95% CI: 5.7-21.1) higher, respectively, for patients with PWS versus the general population. Increased risks were also found individually for deep venous thromboses (DVTs) (RR: 9.1; 95% CI: 3.2-25.2), pulmonary embolisms (RR: 11.0; 95% CI: 1.4-86.9), myocardial infarction (RR: 7.2; 95% CI: 1.7-30.2) and anxiety (RR: 2.8; 95% CI: 1.0-7.5). No cases of pulmonary hypertension, sleep apnea or depressive disorders were identified within this PWS cohort. Multiple cardiovascular and behavioral illnesses are more likely to occur among patients with PWS than within the general population. These increased risks may provide an impetus for enhanced disease prevention, screening, diagnosis and treatment.

IGF-1 Levels, Complex Formation, and IGF Bioactivity in Growth Hormone-Treated Children With Prader-Willi Syndrome.

Children with Prader-Willi syndrome (PWS) attain high-serum immunoreactive IGF-1 levels during a standard-dose GH treatment, which leads to concern, but lowering the dose deteriorates their body composition. The objective of the study was to evaluate serum IGF-1, IGF binding protein (IGFBP)-3, and acid-labile subunit (ALS) levels, complex formation, and IGF bioactivity in GH-treated PWS children. This was a cross-sectional study. The setting of the study was a Dutch PWS cohort. Forty GH-treated PWS children compared with 41 age- and sex-matched healthy controls participated in the study. Interventions included GH treatment (1.0 mg/m(2) · d = ∼0.035 mg/kg · d). Serum IGF-1, IGFBP-3, and ALS levels, complex formation, and IGF bioactivity by IGF-1 receptor kinase activation assay were measured. Serum IGF-1, IGFBP-3, and ALS levels and IGF-1 to IGFBP-3 ratio were significantly higher in GH-treated PWS children than in healthy controls. The 150-kDa ternary complex formation was, however, also significantly higher than in controls, indicating that most of serum IGF-1 is sequestered in the ternary 150-kDa complex with ALS and IGFBP-3. Young GH-treated PWS children [median (interquartile range) aged 5.2 (4.3-7.2) y] exhibited higher serum IGF bioactivity than controls, but no difference was observed in IGF bioactivity between older GH-treated PWS children, aged 14.9 (13.8-16.2) years, and controls. The proportion of IGF bioactivity of total serum IGF-1 was, however, lower in GH-treated PWS children than in controls. Serum immunoreactive IGF-1 levels did not correlate with IGF bioactivity in GH-treated children with PWS, in contrast to a strong positive correlation in healthy controls. In GH-treated PWS children, most serum IGF-1 is sequestered in the 150-kDa complex. Higher IGF bioactivity was found only in young GH-treated PWS children and not in the older ones. IGF bioactivity during GH showed a wide variation, and there was a disrupted correlation with immunoreactive IGF-1 levels, which makes immunoreactive IGF-1 levels an inappropriate indicator for GH dosing in PWS children.

Ovarian Function and Reproductive Hormone Levels in Girls with Prader-Willi Syndrome: A Longitudinal Study

The etiology of hypogonadism in girls with Prader-Willi syndrome (PWS) remains uncertain. The aim of the study was to evaluate gonadal function longitudinally in girls and female adolescents with PWS. We performed a longitudinal assessment of anti-müllerian hormone (AMH), gonadotropins, estradiol (E(2)), inhibin B and A, and pubertal development in girls and female adolescents with PWS. Sixty-one girls participating in the Dutch PWS Cohort study participated in the study. Serum AMH, gonadotropins, E(2), and inhibin B and A levels were compared with reference values. AMH levels in girls and female adolescents with PWS were comparable to reference levels between 6 months and 22 yr of age. From 10 yr of age, FSH and LH levels increased to above the 5th percentile compared to reference levels. E(2) and inhibin B levels were in the low normal range in the majority, and inhibin A levels were low but detectable in almost half the female adolescents with PWS. The median age at puberty onset was comparable, but the median ages at attaining Tanner M3 (P = 0.05) and M4 (P < 0.0001) were significantly higher in girls with PWS than in healthy references. Our study shows that the primordial follicle pool and number of small antral follicles are conserved in girls and female adolescents with PWS. We found no classical hypogonadotropic hypogonadism. However, maturation of follicles and progression of pubertal development are impaired, which might be due to dysregulation of LH secretion. Because these impairments are not absolute, ovulation and thus conception cannot be ruled out in individual female adolescents with PWS.

Assessment of central adrenal insufficiency in children and adolescents with Prader–Willi syndrome

A recent study evidenced by metyrapone test a central adrenal insufficiency (CAI) in 60% of Prader-Willi syndrome (PWS) children. These results were not confirmed in investigations with low [Low-Dose Tetracosactrin Stimulation Test (LDTST), 1 μg] or standard-dose tetracosactrin stimulation tests. We extended the research by LDTST in paediatric patients with PWS. Cross-sectional evaluation of adrenal stress response to LDTST in a PWS cohort of a tertiary care referral centre. Eighty-four children with PWS. Assessment of adrenal response by morning cortisol and ACTH dosage, and 1-μg tetracosactrin test. Response was considered appropriate when cortisol reached 500 nm; below this threshold, patients were submitted to a second test. Responses were correlated with the patients' clinical and molecular characteristics to assess genotype-phenotype correlation. Pathological cortisol peak responses to the LDTST were registered in 12 patients (14.3%) who had reduced basal (169.4 ± 83.3 nm) and stimulated (428.1 ± 69.6 nm) cortisol levels compared to patients with normal responses (367.1 ± 170.6 and 775.9 ± 191.3 nm, P < 0.001). Body mass index standard deviation score was negatively correlated with basal and peak cortisol levels (both P < 0.001), and the patients' ages (P < 0.001). In patients with deletion on chromosome 15, the cortisol peak was significantly lower than that in uniparental disomy (UPD) cases (P = 0.030). At multiple regression analysis, the predictors of peak response were basal cortisol, age, and UPD subclass (r(2) = 0.353, P < 0.001). Standard-dose (250 μg) tetracosactrin test confirmed CAI in 4/12 patients (4.8% of the cohort). Our results support the hypothesis that, albeit rare, CAI may be part of the PWS in childhood.

Testicular Failure in Boys with Prader-Willi Syndrome: Longitudinal Studies of Reproductive Hormones

The pathophysiology of hypogonadism in boys with Prader-Willi Syndrome (PWS) remains uncertain. Several reports described hypogonadotropic hypogonadism, some reported primary gonadal failure, and others a combination of both. The aim of the study was to evaluate gonadal function over time in boys with PWS and the effect of GH treatment. We made a longitudinal assessment of inhibin B, FSH, testosterone, and LH levels in prepubertal boys and male adolescents with PWS. We studied 68 boys participating in the Dutch PWS Cohort study. Serum inhibin B, FSH, LH, and testosterone levels were compared with reference values. Boys with PWS had normal inhibin B levels between 6 months and 10 yr of age, but after onset of puberty, inhibin B levels declined to less than the 5th percentile, and FSH levels increased to more than the 95th percentile. Two years after the onset of puberty and in young adults, inhibin B levels were significantly lower (P=0.008 and P<0.0001), and FSH levels were significantly higher (P=0.034 and P<0.0001) than at onset of puberty. Testosterone levels increased but remained below the 5th percentile, and LH levels increased but not above the 95th percentile. Age showed a significant correlation with inhibin B levels (r=-0.31; P=0.001) after 9 yr of age. GH treatment had no significant effect on inhibin B levels. Our study indicates that the majority of male patients with PWS have primary testicular failure, which becomes apparent after onset of puberty. Hypogonadotropic hypogonadism did not appear to be the main reason of hypogonadism in most boys.

Pubarche and serum dehydroepiandrosterone sulphate levels in children with Prader–Willi syndrome

Premature pubarche (PP) is reported in children with Prader-Willi Syndrome (PWS). Pubarche is preceded by adrenarche - an increase in serum levels of adrenal androgens, most specifically dehydroepiandrosterone sulphate (DHEAS). To assess DHEAS levels, the age at and progression of pubarche and the prevalence of PP in children with PWS. In the Dutch PWS Cohort Study, 120 children (6 months-17 years) are prospectively followed. Their age at onset of pubarche and various pubic hair stages and prevalence of PP were determined. Serum DHEAS levels were assessed in 97 children. Median serum DHEAS levels were significantly higher in children with PWS than in healthy age-matched controls at ages 3-6 years (girls: P = 0·004 and boys: P = 0·010) and 6-10 years (girls: P = 0·045 and boys: P = 0·001). Age and gender significantly influenced DHEAS levels in children with PWS. The median [P10-P90] age at onset of pubarche in children with PWS was significantly younger than in healthy peers, 9·04[6·75-11·84] years in PWS girls (P < 0·0001) and 10·31 [8·65-12·29] years in PWS boys (P = 0·003). The prevalence of PP in children with PWS was 30·0% in girls and 16·1% in boys. Compared to healthy children, children with PWS have significantly higher DHEAS levels from 3 to 10 years of age. They are younger at onset of pubarche and have a higher prevalence of premature pubarche. DHEAS levels in PWS are influenced by age and gender. Our findings indicate earlier maturation of the zona reticularis of the adrenal glands in children with PWS.

Normal Cortisol Response to High-Dose Synacthen and Insulin Tolerance Test in Children and Adults with Prader-Willi Syndrome

Prader-Willi syndrome (PWS) is a genetic disease associated with hypogonadism and partial GH insufficiency, possibly explained in part by a hypothalamic dysfunction. Partial insufficiency of the hypothalamic-pituitary-adrenal (HPA) axis has recently been suggested. The objective of the study was to further explore the HPA axis in PWS by use of routine tests. Nonselected PWS patients were examined with a standard high-dose synacthen test or the insulin tolerance test (ITT). A random serum (s) cortisol was measured in case of acute illness. The study was conducted at university hospitals in Denmark and Sweden. Sixty-five PWS patients with a confirmed genetic diagnosis participated in the study. A s-cortisol value above 500 nmol/liter as well as an increase of 250 nmol/liter or greater was considered a normal response. Fifty-seven PWS patients (median age 22 yr, total range 0.5-48 yr) were examined with the high-dose synacthen test. The median s-cortisol at the time of 30 min was 699 (474-1578) nmol/liter. Only one patient had a s-cortisol level below 500 nmol/liter but an increase of 359 nmol/liter. This patient subsequently showed a normal ITT response. Two patients had increases less than 250 nmol/liter but a time of 30-min s-cortisol values of 600 nmol/liter or greater. These three patients were interpreted as normal responders. Eight patients [aged 26 (16-36) yr] examined with the ITT had a median peak s-cortisol of 668 (502-822) nmol/liter. Four children admitted for acute illnesses had s-cortisol values ranging from 680 to 1372 nmol/liter. In this PWS cohort, the function of the HPA axis was normal, suggesting that clinically significant adrenal insufficiency in PWS is rare.

Abnormal protein glycoforms in Prader‐Willi syndrome

Background: Prader‐Willi syndrome (PWS) is a contiguous gene disorder characterized by a range of neurological and endocrine abnormalities. Genetically, PWS arises from a loss of paternal chromosome 15q11‐q13 with associated maternal imprinting of genes in this region. The most common molecular mechanisms are either paternal interstitial deletions or maternal uniparental disomy leading to haploinsufficiency. A number of genes involved in protein processing are present in the PWS region. After synthesis, proteins are frequently glycosylated as a post‐translational modification. Proteins with incorrect processing or other cellular damage are postulated to be cleared by certain putative genes within the common PWS deletion breakpoints. Method: We undertook investigations into protein post‐translational modifications in our PWS cohort (n = 23, age range = 1–18 years) using isoelectric focusing (IEF) of the serum O‐linked glycoprotein, apolipoprotein C‐III (apoC‐III). Through apoC‐III IEF, three isoforms differing in sialic acid content may be resolved. Non affected individuals typically contain relatively equal amounts of the disialylate d and monosialylated isoforms with low levels of the asialylated isoform. The glycans observed in PWS were further characterized by mass spectrometry. Results: Our study revealed nine PWS patients (∼40%) had an abnormal apoC‐III IEF profile with increases in the asialylated isoform (9.1–16.9%; normal range 0–8.0%) and decreases in the disialylated isoform (22–39%; normal range 26–59%). The abnormal apoC‐III IEF patterns observed in our study were independent of genotype. Mass spectrometry confirmed the abnormal structures. Conclusion: Although no genes involved in glycosylation are situated in 15q11–q13, there are two genes that have been given putative roles as ubiquitin E3 enzymes. We propose the increase in asialylated apoC‐III isoforms in PWS is a reflection of an abnormality in the clearance of abnormal proteins rather than from a defect in glycan biosynthesis. Accumulation of other abnormal proteins in PWS is hypothesized.

Cognitive, emotional, physical and social effects of growth hormone treatment in adults with Prader–Willi syndrome

Prader-Willi syndrome (PWS) is a multisystem genetic disorder characterized by short stature, muscular hypotonia, hyperphagia, obesity, maladaptive behaviour, hypogonadism and partial growth hormone (GH) deficiency (GHD). Severe GHD of other aetiologies has been shown to affect mood and quality of life negatively, and there are reports of improvements with GH replacement. We have studied cognitive, emotional, physical and social parameters in PWS adults at baseline, during and after GH treatment. Nineteen patients, 9 females and 10 males, median age 25 years, mean BMI 35 kg/m2 participated in this study. Approximately half of the group had GHD. All patients fulfilled the clinical criteria for PWS and 13 had a positive genotype. The patients were randomized to 6 months of treatment with either GH [1.6 IU/day (0.53 mg/day)] or placebo, followed by 12 months of active GH treatment. Treatment was then stopped, and the patients were followed for an additional period of 6 months. A test battery for general cognitive evaluation and a computer-based measurement of reaction time, motor speed and fluency were employed at baseline, after 6 months and at the end of GH treatment. At the same time intervals, a self-evaluation questionnaire was answered at the end of each test session. Other questionnaires reflecting the patients' cognitive, emotional, physical and social status were answered by relatives/caretakers at baseline and at 3 and 6 months following cessation of GH treatment. Baseline cognitive level was estimated to be moderately to mildly impaired; IQ range was 40-90. The results from some of the cognitive and the motor performance tests improved significantly after 6 and 18 months of GH treatment. According to the questionnaires, both the patients and the relatives/caretakers evaluated physical status rather negatively at baseline, but still, impairments in both physical and social status and overall functioning were observed when GH treatment was discontinued. The self-evaluation did not change in any aspect during GH treatment. In this pilot study of an adult PWS cohort, we were able to document beneficial effects in mental speed and flexibility and in motor performance during GH treatment. Impairment was seen in physical and social status as well as overall functioning, when GH treatment stopped. Studies of larger cohorts are needed to further elucidate the role of GH treatment in this group of patients.