The digestive system and nutritional considerations for individuals with Rett syndrome

Recommendations for the management of gastrointestinal comorbidities with or without trofinetide use in Rett syndrome

INTRODUCTION

Although gastrointestinal (GI) comorbidities are experienced by over 90% of individuals with Rett syndrome (RTT), a neurodevelopmental disorder associated with mutations in the MECP2 gene, many neurologists and pediatricians do not rank the management of these comorbidities among the most important treatment goals for RTT. Trofinetide, the first approved pharmacologic treatment for RTT, confers improvements in RTT symptoms but is associated with adverse GI events, primarily diarrhea and vomiting. Treatment strategies for GI comorbidities and drug-associated symptoms in RTT represent an unmet clinical need.

AREAS COVERED

This perspective covers GI comorbidities experienced by those with RTT, either with or without trofinetide treatment. PubMed literature searches were undertaken on treatment recommendations for the following conditions: constipation, diarrhea, vomiting, aspiration, dysphagia, gastroesophageal reflux, nausea, gastroparesis, gastritis, and abdominal bloating.

EXPERT OPINION

The authors recommend a proactive approach to management of symptomatic GI comorbidities and drug-associated symptoms in RTT to enhance drug tolerance and improve the quality of life of affected individuals. Management strategies for common GI comorbidities associated with RTT are reviewed based on authors' clinical experience and augmented by recommendations from the literature.

Fiberoptic Endoscopic Evaluation of Swallowing Findings in Children With Rett Syndrome

Feeding abnormalities, swallowing dysfunction, and gastrointestinal issues cause poor weight gain, oral motor dysfunction, and air swallowing in children with Rett syndrome (RTT). Pneumonia is the leading cause of death. Our study describes fiberoptic endoscopic swallowing findings in 11 female RTT children. Each patient was evaluated using the 8-point Penetration/Aspiration Scale (PAS). The average age was 7 years. All patients had tongue dyskinesis and prolonged oral stage. Eight girls exhibited liquid entering the airway without coughing, whereas 6 did well with pureed meal. Three girls had pneumonia. Age was not correlated with pneumonia episodes (P = .18). Pureed material was related with pneumonia (P = .006), whereas liquids were not. Pureed PAS was positively correlated with Liquid PAS (P = .008) and age (P = .004). All aspiration/penetration incidents occurred before the pharyngeal phase. No patient under 7 years experienced pneumonia episodes. Silent aspiration can occur early in infancy, although pneumonia episodes can occur later.

Exploring gastrointestinal health in MECP2 duplication syndrome

BACKGROUND

MECP2 duplication syndrome (MDS) is a rare neurogenetic syndrome caused by duplications of MECP2 at the Xq28 region. Although constipation and gastrointestinal reflux are reported in MDS, a comprehensive characterization of gastrointestinal health has not been fully explored.

METHODS

We conducted a parent survey to explore the characteristics of gastrointestinal health in individuals with MDS using a secure online registry and compared differences in gastrointestinal symptoms between individuals with MDS and those with Rett syndrome (RTT).

KEY RESULTS

One hundred six surveys were analyzed. Symptoms commonly associated with constipation occurred in 72% to 89% of MDS individuals. Eleven percent of MDS individuals underwent surgery for complications associated with constipation. We observed a bimodal distribution for gastroesophageal reflux disease (GERD) and gastrostomy feeding, with higher prevalence in 0-3 and >12-year-old MDS individuals. Constipation and GERD were significantly more common, and gas bloating was significantly less common in MDS than in RTT. Biliary tract disease requiring surgery was an unrecognized problem in 5% of MDS individuals. We determined that gastrointestinal problems in MDS individuals contribute to caretaker burden.

CONCLUSION AND INFERENCES

Our study is the first in-depth investigation that characterizes gastrointestinal health in MDS and enumerates differences in gastrointestinal symptoms between MDS and RTT. Strategies to reduce gastrointestinal symptoms will alleviate caregiver burden in MDS. Further studies are needed to examine the mechanisms that cause gastrointestinal problems in MDS.

Exploring the characteristics and most bothersome symptoms in MECP2 duplication syndrome to pave the path toward developing parent-oriented outcome measures

BACKGROUND

MECP2 Duplication Syndrome (MDS), resulting from the duplication of Xq28 region, including MECP2, is a rare disorder with a nascent understanding in clinical features and severity. Studies using antisense oligonucleotides revealed a broad phenotypic rescue in transgenic mice. With human clinical trials on the horizon, there is a need to develop clinical outcome measures for MDS.

METHODS

We surveyed caregivers of MDS individuals to explore the frequency and severity of MDS clinical features, and identify the most meaningful symptoms/domains that need to be included in the outcome measure scales.

RESULTS

A total of 101 responses were eligible for the survey. The top six most meaningful symptoms to caregivers in descending order included epilepsy, gross motor, fine motor, communication, infection, and constipation problems. Epilepsy was present in 58.4% of the subjects and 75% were drug-resistant, Furthermore, ~12% required intensive care unit (ICU) admission. Infections were present in 55% of the subjects, and one-fourth of them required ICU admission. Constipation was present in ~85% of the subjects and one-third required enemas/suppositories.

CONCLUSION

Our study is one of the largest cohorts conducted on MDS individuals characterizing the frequency and severity of MDS symptoms. Additionally, these study results will contribute to establishing a foundation to develop parent-reported outcomes in MDS.

Evidence-Based Physical Therapy for Individuals with Rett Syndrome: A Systematic Review

Rett syndrome is a rare genetic disorder that affects brain development and causes severe mental and physical disability. This systematic review analyzes the most recent evidence concerning the role of physical therapy in the management of individuals with Rett syndrome. The review was carried out in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. A total of 17319 studies were found in the main scientific databases. Applying the inclusion/exclusion criteria, 22 studies were admitted to the final phase of the review. Level of evidence of the included studies was assessed using the Oxford Centre for Evidence-Based Medicine—Levels of Evidence guide. Nine approaches to physical therapy for patients with Rett syndrome were identified: applied behavior analysis, conductive education, environmental enrichment, traditional physiotherapy with or without aids, hydrotherapy, treadmill, music therapy, computerized systems, and sensory-based treatment. It has been reported that patients had clinically benefited from the analysed approaches despite the fact that they did not have strong research evidence. According to the results, a multimodal individualized physical therapy program should be regularly recommended to patients with Rett syndrome in order to preserve autonomy and to improve quality of life. However, more high-quality studies are needed to confirm these findings.

Correlation Between Dysphagia and Malocclusion in Rett Syndrome: A preliminary study

Objectives

Rett syndrome (RS) is a severe neurological developmental disorder characterised by stereotypical hand movements, epileptic seizures, craniofacial dysmorphism and digestive dysfunction. This study aimed to examine the correlation between the severity of malocclusion and dysphagia in patients with RS.

Methods

This preliminary study was conducted at the Ear, Nose & Throat Clinic of the University Hospital of Siena, Siena, Italy, from January 2014 to December 2017. A total of 56 patients with RS were examined and grouped according to the severity of dysphagia (absent, mild, moderate or severe) and malocclusion (<2 mm, 2-3 mm, 3-4 mm or >4 mm).

Results

All of the patients were female and the mean age was 11.3 years. Eight (14.3%) patients had mild, 18 (32.1%) had moderate and 30 (53.6%) had severe dysphagia. Four (7.1%) patients had <2 mm occlusion, 10 (17.9%) had 2-3 mm occlusion, 26 (46.4%) had 3-4 mm occlusion and 16 (28.6%) had >4 mm occlusion. Mild dysphagia was observed in 100% and 40% of patients with <2 and 2-3 mm malocclusion, respectively, while moderate dysphagia was present in 60% and 38.5% of patients with 2-3 and 3-4 mm malocclusion, respectively. Severe dysphagia was observed in 28.6% and 87.5% of patients with 3-4 and >4 mm malocclusion, respectively. There was a significant correlation between dysphagia and malocclusion severity (P <0.001).

Conclusion

A higher degree of malocclusion was associated with more severe dysphagia among a cohort of patients with RS.

Evaluation of current pharmacological treatment options in the management of Rett syndrome: from the present to future therapeutic alternatives

Neurodevelopmental disorders are a large family of conditions of genetic or environmental origin that are characterized by deficiencies in cognitive and behavioral functions. The therapeutic management of individuals with these disorders is typically complex and is limited to the treatment of specific symptoms that characterize each disorder. The neurodevelopmental disorder Rett syndrome (RTT) is the leading cause of severe intellectual disability in females. Mutations in the gene encoding the transcriptional regulator methyl-CpG-binding protein 2 (MECP2), located on the X chromosome, have been confirmed in more than 95% of individuals meeting diagnostic criteria for classical RTT. RTT is characterized by an uneventful early infancy followed by stagnation and regression of growth, motor, language, and social skills later in development. This review will discuss the genetics, pathology, and symptoms that distinguish RTT from other neurodevelopmental disorders associated with intellectual disability. Because great progress has been made in the basic and clinical science of RTT, the goal of this review is to provide a thorough assessment of current pharmacotherapeutic options to treat the symptoms associated with this disorder. Furthermore, we will highlight recent discoveries made with novel pharmacological interventions in experimental preclinical phases, and which have reversed pathological phenotypes in mouse and cell culture models of RTT and may result in clinical trials.

Longitudinal brain MRI study in a mouse model of Rett Syndrome and the effects of choline

Rett Syndrome (RTT), the second most common cause of mental retardation in girls, is associated with mutations of an X-linked gene encoding the transcriptional repressor protein MeCP2. Mecp2(1lox) mutant mice express no functional MeCP2 protein and exhibit behavioral abnormalities similar to those seen in RTT patients. Here we monitor the development of both whole brain and regional volumes between 21 and 42 days of age in this model of RTT using MRI. We see decreases in whole brain volumes in both male and female mutant mice. Cerebellar and ventricular volumes are also decreased in RTT males. Previous work has suggested that perinatal choline supplementation alleviates some of the behavioral deficits in both male and female Mecp2(1lox) mutant mice. Here we show that perinatal choline supplementation also positively affects whole brain volume in heterozygous females, and cerebellar volume in male RTT mice.

Nutritional factors in a mouse model of Rett syndrome

Environmental factors such as nutrition and housing can influence behavioral and anatomical characteristics of several neurological disorders, including Rett syndrome (RTT). RTT is associated with mutations in the X-linked gene encoding MeCP2, a transcriptional repressor that binds methylated DNA. While direct genetic intervention in humans is impossible at this time, motor and cognitive deficits in RTT may be ameliorated through manipulations of epigenetic/environmental factors. For example, studies in rodents suggest that choline nutrient supplementation during critical periods of brain development enhances cholinergic neurotransmission, alters neuronal size and distribution, and facilitates performance of memory and motoric tasks. Recent work in a mouse model of RTT shows that enhancing maternal nutrition through choline supplementation improves both anatomical and behavioral symptoms in the mutant offspring. We describe here cellular and molecular mechanisms that may underlie this specific enhancement and may provide more general insights into mechanisms underlying gene-environment interactions in neurological disorders.