Topiramate in the treatment of Prader-Willi syndrome: A case report

Topiramate for Weight Management in Children With Severe Obesity

Background: Topiramate has been shown to result in significant weight loss compared to placebo in adults with obesity. However, there are no consensus guidelines on the acceptability, safety, and efficacy of topiramate for weight loss in children. We present a literature review and case series on topiramate use in young children with severe obesity. Methods: We performed a PubMed search from January 2000 to February 2022 utilizing keywords, "topiramate" and "obesity" and "children" and "adolescent." For our case series, children were identified through retrospective chart review from a multidisciplinary weight management program. Eligibility criteria: age ≤12 years, class II or III obesity, completed 16 weeks of topiramate therapy as adjunct to lifestyle modifications. Semistructured interviews were conducted with one parent to review side effects. Results: Literature search yielded nine articles. All studies reported trends toward BMI reduction and weight loss with topiramate monotherapy. Five children met case series eligibility (mean age 10 years 3 months ±1.5 years, 60% female). After 16 weeks of topiramate, all children had a decrease in BMI as a percentage of the 95th percentile (mean -12% [-5% to -18%]). Parents reported improvement in impulsive eating and decreased desire to overeat compared to baseline. Four out of five reported no side effects, one reported drowsiness which resolved by dosing at nighttime. Conclusions: Results suggest that topiramate is well tolerated and may be utilized for weight management in younger children. A randomized controlled trial investigating the impact of topiramate for weight management in this age group is warranted.

Prader-Willi syndrome: Symptoms and topiramate response in light of genetics

Introduction

Prader-Willi Syndrome (PWS) is a rare genetic condition, which affects one in 25,000 births and results in various phenotypes. It leads to a wide range of metabolic and endocrine disorders including growth delay, hypogonadism, narcolepsy, lack of satiety and compulsive eating, associated with mild to moderate cognitive impairment. Prognosis is especially determined by the complications of obesity (diabetes, cardiorespiratory diseases) and by severe behavioral disorders marked by impulsivity and compulsion. This heterogeneous clinical picture may lead to mis- or delayed diagnosis of comorbidities. Moreover, when diagnosis is made, treatment remains limited, with high interindividual differences in drug response. This may be due to the underlying genetic variability of the syndrome, which can involve several different genetic mutations, notably deletion or uniparental disomy (UPD) in a region of chromosome 15. Here, we propose to determine whether subjects with PWS differ for clinical phenotype and treatment response depending on the underlying genetic anomaly.

Methods

We retrospectively included all 24 PWS patients who were referred to the Reference Center for Rare Psychiatric Disorders (GHU Paris Psychiatrie and Neurosciences) between November 2018 and July 2022, with either deletion (N = 8) or disomy (N = 16). The following socio-demographic and clinical characteristics were recorded: age, sex, psychiatric and non-psychiatric symptoms, the type of genetic defect, medication and treatment response to topiramate, which was evaluated in terms of eating compulsions and impulsive behaviors. We compared topiramate treatment doses and responses between PWS with deletion and those with disomy. Non-parametric tests were used with random permutations for p-value and bootstrap 95% confidence interval computations.

Results

First, we found that disomy was associated with a more severe clinical phenotype than deletion. Second, we observed that topiramate was less effective and less tolerated in disomy, compared to deletion.

Discussion

These results suggest that a pharmacogenomic-based approach may be relevant for the treatment of compulsions in PWS, thus highlighting the importance of personalized medicine for such complex heterogeneous disorders.

Promising therapeutic aspects in human genetic imprinting disorders

Genomic imprinting is an epigenetic phenomenon of monoallelic gene expression pattern depending on parental origin. In humans, congenital imprinting disruptions resulting from genetic or epigenetic mechanisms can cause a group of diseases known as genetic imprinting disorders (IDs). Genetic IDs involve several distinct syndromes sharing homologies in terms of genetic etiologies and phenotypic features. However, the molecular pathogenesis of genetic IDs is complex and remains largely uncharacterized, resulting in a lack of effective therapeutic approaches for patients. In this review, we begin with an overview of the genomic and epigenomic molecular basis of human genetic IDs. Notably, we address ethical aspects as a priority of employing emerging techniques for therapeutic applications in human IDs. With a particular focus, we delineate the current field of emerging therapeutics for genetic IDs. We briefly summarize novel symptomatic drugs and highlight the key milestones of new techniques and therapeutic programs as they stand today which can offer highly promising disease-modifying interventions for genetic IDs accompanied by various challenges.

Prader–Willi Syndrome: Possibilities of Weight Gain Prevention and Treatment

Prader–Willi syndrome (PWS) is a complex genetic disorder which involves the endocrine and neurologic systems, metabolism, and behavior. The aim of this paper is to summarize current knowledge on dietary management and treatment of PWS and, in particular, to prevent excessive weight gain. Growth hormone (GH) therapy is the recommended standard treatment for PWS children, because it improves body composition (by changing the proportion of body fat and lean body mass specifically by increasing muscle mass and energy expenditure), linear growth, and in infants, it promotes psychomotor and IQ development. In early childhood, the predominant symptom is hyperphagia which can lead to early onset, severe obesity with different obesity-related comorbidities. There are several studies on anti-obesity medications (metformin, topiramate, liraglutide, setmelanotide). However, these are still limited, and no widely accepted consensus guideline exists concerning these drugs in children with PWS. Until there is a specific treatment for hyperphagia and weight gain, weight must be controlled with the help of diet and exercise. Below the age of one year, children with PWS have no desire to eat and will often fail to thrive, despite adequate calories. After the age of two years, weight begins to increase without a change in calorie intake. Appetite increases later, gradually, and becomes insatiable. Managing the progression of different nutritional phases (0–4) is really important and can delay the early onset of severe obesity. Multidisciplinary approaches are crucial in the diagnosis and lifelong follow-up, which will determine the quality of life of these patients.

Anti-Obesity Medication Use in Children and Adolescents with Prader-Willi Syndrome: Case Review and Literature Search

(1) Background: children with Prader-Willi syndrome (PWS) have high obesity rates due to hyperphagia and decreased metabolic rates. Although anti-obesity medications (AOMs) are prescribed to this population, there are no consensus guidelines on acceptability, safety, and efficacy. We present literature review and case series on AOMs in youth with PWS. (2) Methods: we performed PubMed review from January 2000 to April 2021 utilizing keywords: "Prader-Willi syndrome" or "PWS" and "medication" including: topiramate, metformin, phentermine, liraglutide, orlistat, oxytocin, semaglutide, naltrexone-bupropion. For our case series, patients were identified through retrospective chart reviews from a multi-disciplinary PWS clinic. Eligibility criteria: age ≤ 18 years, genetically confirmed PWS, AOM use for at least 16 weeks, and recent anthropometric data. (3) Results: a literature search yielded 14 articles (3 topiramate, 1 metformin, 4 liraglutide, 5 oxytocin, 1 naltrexone-bupropion). All studies reported improved hyperphagia with variable BMI effects. Ten adolescents met case series eligibility (mean age 13.2 ± 2.6 years, 40% female; AOMs: 6 metformin, 5 topiramate, 2 semaglutide, 3 liraglutide). After AOM course, 60% had decreased or stable BMI z-score. No significant side effects. (4) Conclusions: results suggest AOMs may be useful for weight management in youth with PWS. Additional studies are required to validate findings and support AOM treatment guidelines.

Case Report: Clinical Analysis of Seven Neonates With Prader-Willi Syndrome and Review of the Literature

Objective: The clinical symptoms of neonatal Prader-Willi syndrome (PWS) are not typical and are easy to miss. The aim of the study was to investigate the clinical features and genetic characteristics of seven cases of neonatal PWS from northern China, and to improve the understanding of PWS in neonates. Methods: We retrospectively analyzed seven infants diagnosed by methylation specific multiplex ligation probe amplification technology (MS-MLPA) in the Neonatology Unit of Shengjing Hospital of China Medical University from September 2016 to July 2020. Results: All seven cases involved full term or nearly full-term infants born to mothers without a history of abnormal pregnancy or delivery. Difficulty in feeding occurred immediately after birth in infants with decreased hypotonia. Five patients had characteristic craniofacial morphology, such as a prominent forehead, narrow face, almond-shaped eyes, small mouth, and downturned mouth. Further, three of the seven infants had patent ductus arteriosus (PDA). In addition, three neonates had hyperammonemia, hypoglycemia, and idiopathic edema, respectively. PWS could be effectively diagnosed and genotyped by MS-MLPA. Conclusion: Neonates with PWS have hypotonia and feeding difficulty. Characteristic facial features and genital hypoplasia are common in neonatal PWS. Infants with PWS may be predisposed to PDA, hypoglycemia, hyperammonemia, and edema.