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.

Development and validation of parent-reported gastrointestinal health scale in MECP2 duplication syndrome.

BACKGROUND/AIMS: We aimed to develop a validated patient-reported Gastrointestinal Health Scale (GHS) specific to MECP2 Duplication Syndrome (MDS) to be used in clinical trials. METHODS: MDS parents completed a Gastrointestinal Health Questionnaire (GHQ) to investigate the most relevant and important items associated with gastrointestinal problems in MECP2-related disorders. Item reduction was executed according to EORTC guidelines. We performed reliability and validity studies for the finalized scale. RESULTS: A total of 106 surveys were eligible for item reduction and validation processes. The initial 55 items were reduced to 38 items based on parent responses, expert opinion, and initial confirmatory factor analysis (CFA). The final MDS-specific GHS included 38 items and 7 factors that underwent further reliability and validity assessments. The power of the study was at least 0.982. The Cronbach's alphas of the instruments were General Health: 0.799, Eating-Chewing-Swallowing: 0.809, Reflux: 0.794, Motility: 0.762, Mood: 0.906, Medication: 0.595, Parenting: 0.942 and all items together: 0.928. The correlation coefficient between total and individual item scores ranged from 0.215 to 0.730. Because of the ordinal nature of the variables, the diagonal weighted least squares estimation (DWLS) method was used to execute the CFA and Structural Equation Modeling. The GHS had excellent model fit with the acceptable range of fit indices values. CONCLUSIONS: We developed a parent-reported, reliable, and valid MDS-specific GHS. This scale can be utilized in clinical settings or as an outcome measure in translational and clinical research.

Parental age effects and Rett syndrome.

Rett syndrome (RTT) is a progressive neurodevelopmental disorder, and pathogenic Methyl-CpG-binding Protein 2 (MECP2) variants are identified in >95% of individuals with typical RTT. Most of RTT-causing variants in MECP2 are de novo and usually on the paternally inherited X chromosome. While paternal age has been reported to be associated with increased risk of genetic disorders, it is unknown whether parental age contributes to the risk of the development of RTT. Clinical data including parental age, RTT diagnostic status, and clinical severity are collected from 1226 participants with RTT and confirmed MECP2 variants. Statistical analyses are performed using Student t-test, single factor analysis of variance (ANOVA), and multi-factor regression. No significant difference is observed in parental ages of RTT probands compared to that of the general population. A small increase in parental ages is observed in participants with missense variants compared to those with nonsense variants. When we evaluate the association between clinical severity and parental ages by multiple regression analysis, there is no clear association between clinical severity and parental ages. Advanced parental ages do not appear to be a risk factor for RTT, and do not contribute to the clinical severity in individuals with RTT.

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.

Anthropometric Measures Correspond with Functional Motor Outcomes in Females with Rett Syndrome.

OBJECTIVE: To characterize growth and anthropometric measurements in females with Rett syndrome and compare these measurements with functional outcomes. STUDY DESIGN: We obtained longitudinal growth and anthropometric measurements from 1154 females with classic and atypical Rett syndrome seen between 2006 and 2019 in the US Natural History Study. We calculated the Clinical Severity Score, Motor Behavior Assessment score, and arm and leg muscle areas and recorded the functional assessments of arm and hand use and ambulation. We compared growth and anthropometric variables from females with Rett syndrome in regard to normative data. We analyzed Clinical Severity Score, Motor Behavior Assessment, and anthropometric measurements in regard to functional assessments. RESULTS: Growth and anthropometric measurements were significantly lower in females with classic and severe atypical Rett syndrome compared with those classified as mild atypical Rett syndrome and deviated from normative patterns among all 3 groups. Suprailiac skinfold measurements correlated with body mass index measurements in each group. Lower leg muscle area measurements were significantly greater among females in all 3 Rett syndrome groups who ambulated independently compared with those who did not. In females with classic Rett syndrome, arm, thigh, and lower leg muscle area measurements increased significantly over time and were significantly greater among those who had purposeful arm and hand use and independent ambulation compared with those who did not. CONCLUSIONS: The pattern of growth and anthropometric measures in females with Rett syndrome differs from normative data and demonstrates clear differences between classic and mild or severe atypical Rett syndrome. Anthropometric measures correspond with functional outcomes and could provide markers supporting efficacy outcomes in clinical trials.

Simple Energy Balance or Microbiome for Childhood Obesity Prevention?

Obesity prevention interventions generally have either not worked or had effects inadequate to mitigate the problem. They have been predicated on the simple energy balance model, which has been severely questioned by biological scientists. Numerous other etiological mechanisms have been proposed, including the intestinal microbiome, which has been related to childhood obesity in numerous ways. Public health research is needed in regard to diet and the microbiome, which hopefully will lead to effective child obesity prevention.

Assessment of the gut bacterial microbiome and metabolome of girls and women with Rett Syndrome.

BACKGROUND: Gastrointestinal problems affect the health and quality of life of individuals with Rett syndrome (RTT) and pose a medical hardship for their caregivers. We hypothesized that the variability in the RTT phenotype contributes to the dysbiosis of the gut microbiome and metabolome in RTT, predisposing these individuals to gastrointestinal dysfunction. OBJECTIVES: We characterized the gut bacterial microbiome and metabolome in girls and young women with RTT (n = 44) and unaffected controls (n = 21), and examined the relation between the composition of the microbiome and variations in the RTT phenotype. METHODS: Demographics and clinical information, including growth and anthropometric measurements, pubertal status, symptoms, clinical severity score, bowel movement, medication use, and dietary intakes were collected from the participants. Fecal samples were collected for analysis of the gut microbiome using Illumina MiSeq-based next-generation sequencing of the 16S rRNA gene followed by bioinformatics analysis of microbial composition, diversity, and community structure. Selected end-products of microbial protein metabolism were characterized by liquid chromatography-mass spectrometry. RESULTS: The gut bacterial microbiome differed within the RTT cohort based on pubertal status (p<0.02) and clinical severity scores (p<0.02) of the individuals and the type of diet (p<0.01) consumed. Although the composition of the gut microbiome did not differ between RTT and unaffected individuals, concentrations of protein end-products of the gut bacterial metabolome, including γ-aminobutyric acid (GABA) (p<0.001), tyrosine (p<0.02), and glutamate (p<0.06), were lower in the RTT cohort. Differences in the microbiome within RTT groups, based on symptomatic anxiety, hyperventilation, abdominal distention, or changes in stool frequency and consistency, were not detected. CONCLUSIONS: Although variability in the RTT phenotype contributes to the dysbiosis of the gut microbiome, we presently cannot infer causality between gut bacterial dysbiosis and gastrointestinal dysfunction. Nevertheless, alterations in the gut metabolome may provide clues to the pathophysiology of gastrointestinal problems in RTT.

Gastrointestinal Health Questionnaire for Rett Syndrome: Tool Development.

OBJECTIVES: We report the development and validation of a tool to assess gastrointestinal health in Rett syndrome (RTT). We hypothesized that the Gastrointestinal Health Questionnaire (GHQ) is a valid clinical outcomes measure of gastrointestinal health in RTT. PATIENTS AND METHODS: We used parent interviews, surveys, and literature review to generate a questionnaire related to gastrointestinal health and function, mood and behaviors, and parental concerns for individuals with RTT. Parents of affected and unaffected individuals provided responses to the GHQ, assessed the relevance and importance of statements, and completed 5 surveys related to gastrointestinal health, child-related mood and behaviors, and parent concerns. We used multivariate item analysis, 2-sample t tests, and correlations to assess the validity of the GHQ. RESULTS: We documented acceptable internal consistency of statements related to gastrointestinal health and function (Cronbach-α = 0.91), RTT-related mood and behaviors (Cronbach-α = 0.89), and parent concerns (Cronbach-α = 0.95) in the GHQ. We documented favorable external validity based on differences in response scores between parents of affected and unaffected individuals (P < 0.001) and correlations in parental response scores between the GHQ and 5 validated questionnaires addressing similar issues (P < 0.001). CONCLUSION: The GHQ is a valid tool for the assessment of gastrointestinal health in RTT and offers the opportunity to field test the safety and efficacy of novel drug therapies in clinical trials for individuals affected with this disorder.

Multisystem comorbidities in classic Rett syndrome: a scoping review.

BACKGROUND: Rett syndrome (RTT) is a severe, progressive neurodevelopmental disorder with multisystem comorbidities that evolve across a patient's lifespan requiring attentive coordination of subspecialty care by primary care providers. A comprehensive, up-to-date synthesis of medical comorbidities in RTT would aid care coordination and anticipatory guidance efforts by healthcare providers. Our objective was to review and summarise published evidence regarding prevalence of RTT medical comorbidities across all relevant organ systems. METHODS: Search of PubMed from January 2000 to July 2019 was performed using the search terms (Rett and MECP2 AND patient) OR (Rett and MECP2 AND cohort). Articles reporting the prevalence of clinical findings in RTT were assessed with respect to the size and nature of the cohorts interrogated and their relevance to clinical care. RESULTS: After review of over 800 records, the multisystem comorbidities of RTT were summarised quantitatively from 18 records comprising both retrospective and prospective cohorts (31-983 subjects). Neurological comorbidities had the highest prevalence, occurring in nearly all individuals with gastrointestinal and orthopaedic concerns almost as prevalent as neurological. With the exception of low bone mineral content which was relatively common, endocrine comorbidities were seen in only around one-third of patients. Although more prevalent compared with the general population, cardiac conduction abnormalities were the least common comorbidity in RTT. CONCLUSIONS: Effective care coordination for RTT requires knowledge of and attention to multiple comorbidities across multiple unrelated organ systems. Many issues common to RTT can potentially be managed by a primary care provider but the need for sub-specialist referral can be anticipated. Since the median life expectancy extends into the sixth decade with evolving subspecialty requirements throughout this time, paediatric providers may be tasked with continued coordination of these comorbidities or transitioning to adult medicine and specialists with experience managing individuals with complex medical needs.

Consensus guidelines on managing Rett syndrome across the lifespan.

BACKGROUND: Rett syndrome (RTT) is a severe neurodevelopmental disorder with complex medical comorbidities extending beyond the nervous system requiring the attention of health professionals. There is no peer-reviewed, consensus-based therapeutic guidance to care in RTT. The objective was to provide consensus on guidance of best practice for addressing these concerns. METHODS: Informed by the literature and using a modified Delphi approach, a consensus process was used to develop guidance for care in RTT by health professionals. RESULTS: Typical RTT presents early in childhood in a clinically recognisable fashion. Multisystem comorbidities evolve throughout the lifespan requiring coordination of care between primary care and often multiple subspecialty providers. To assist health professionals and families in seeking best practice, a checklist and detailed references for guidance were developed by consensus. CONCLUSIONS: The overall multisystem issues of RTT require primary care providers and other health professionals to manage complex medical comorbidities within the context of the whole individual and family. Given the median life expectancy well into the sixth decade, guidance is provided to health professionals to achieve current best possible outcomes for these special-needs individuals.

Growth failure in focal dermal hypoplasia.

Focal dermal hypoplasia (FDH) is a rare genetic disorder caused by mutations in the PORCN gene located on the X chromosome. Short stature was previously noted to be a common finding in FDH, however the etiology of this is unclear. The present study sought to elucidate specific causes for short stature by assessing growth charts, determining bone ages and auxologic measurements, examining laboratory data for the common causes of growth failure, assessing dietary intake, and performing a growth hormone stimulation test. Sixteen patients with FDH between the ages of 3 and 18 years of age consented to the study. While 11 out of 16 patients had short stature based on height less than 2 standard deviations below mid-parental target height percentile and bone age not suggestive of likely catch-up growth, only four had a BMI less than the 5th percentile for age. Laboratory studies did not support a gastrointestinal, allergy or autoimmune cause of growth failure. Three patients had results suggestive of possible growth hormone deficiency. Although short stature is a common feature in FDH, our data suggests that severe undernutrition is not common in this group and that there may be underlying treatable causes for this short stature in some patients.

Biliary Tract Disease in Girls and Young Women With Rett Syndrome.

OBJECTIVE: We reviewed medical records and conducted a nationwide survey to characterize the clinical features and determine the prevalence of biliary tract disease in girls and women with Rett syndrome (RTT). METHODS: Sixty-two individuals with RTT and biliary tract disease were identified from the membership of Rett Syndrome Organization and patient files of the principal investigator. Medical records of 46 individuals were reviewed for presenting features, diagnostic tests, and treatment outcomes of biliary tract disease. We designed a questionnaire that probed the frequency of risk factors and treatment outcomes of biliary tract disease in RTT. The questionnaire was completed by 271 parents whose daughters met the clinical criteria for RTT and/or had MECP2 mutations and participated in the Natural History of Rett Syndrome Study. RESULTS: Presenting symptoms identified by record review included abdominal pain (94%), irritability (88%), weight loss (64%), and vomiting (52%). Biliary dyskinesia, cholecystitis, and cholelithiasis were identified in 90%, 77%, and 70%, respectively, by cholescintigraphy, surgical pathology, and abdominal ultrasound. The prevalence of biliary tract disease was 4.4% (n = 12) in the RTT cohort. Risk factors included older age (P < 0.001) and a positive family history (P < 0.01). Diagnoses included cholecystitis (n = 5), biliary dyskinesia (n = 6), and cholelithiasis (n = 7). Ten individuals underwent surgery; 7 had resolution of symptoms after surgical intervention. CONCLUSIONS: Biliary tract disease is not unique to RTT, but may be under-recognized because of the cognitive impairment of affected individuals. Early diagnostic evaluation and intervention may improve the health and quality of life of individuals affected with RTT and biliary tract disease.

Multi-etiological Perspective on Child Obesity Prevention.

PURPOSE OF REVIEW: The simple energy balance model of obesity is inconsistent with the available findings on obesity etiology, prevention, and treatment. Yet, the most commonly stated causes of pediatric obesity are predicated on this model. A more comprehensive biological model is needed upon which to base behavioral interventions aimed at obesity prevention. In this light, alternative etiologies are little investigated and thereby poorly understood. RECENT FINDINGS: Three candidate alternate etiologies are briefly presented: infectobesity, the gut microbiome, and circadian rhythms. Behavioral child obesity preventive investigators need to collaborate with biological colleagues to more intensively analyze the behavioral aspects of these etiologies and to generate innovative procedures for preventing a multi-etiological problem, e.g., group risk analysis, triaging for likely causes of obesity.

The course of awake breathing disturbances across the lifespan in Rett syndrome.

Rett syndrome (RTT), an X-linked dominant neurodevelopmental disorder caused by mutations in MECP2, is associated with a peculiar breathing disturbance exclusively during wakefulness that is distressing, and can even prompt emergency resuscitation. Through the RTT Natural History Study, we characterized cross sectional and longitudinal characteristics of awake breathing abnormalities in RTT and identified associated clinical features. Participants were recruited from 2006 to 2015, and cumulative lifetime prevalence of breathing dysfunction was determined using the Kaplan-Meier estimator. Risk factors were assessed using logistic regression. Of 1205 participants, 1185 had sufficient data for analysis, including 922 females with classic RTT, 778 of whom were followed longitudinally for up to 9.0 years, for a total of 3944 person-years. Participants with classic or atypical severe RTT were more likely to have breathing dysfunction (nearly 100% over the lifespan) compared to those with atypical mild RTT (60-70%). Remission was common, lasting 1 year on average, with 15% ending the study in terminal remission. Factors associated with higher odds of severe breathing dysfunction included poor gross and fine motor function, frequency of stereotypical hand movements, seizure frequency, prolonged corrected QT interval on EKG, and two quality of life metrics: caregiver concern about physical health and contracting illness. Factors associated with lower prevalence of severe breathing dysfunction included higher body mass index and head circumference Z-scores, advanced age, and severe scoliosis or contractures. Awake breathing dysfunction is common in RTT, more so than seizures, and is associated with function, quality of life and risk for cardiac dysrhythmia.

Longitudinal course of epilepsy in Rett syndrome and related disorders.

Epilepsy is common in Rett syndrome, an X-linked dominant disorder caused by mutations in the MECP2 gene, and in Rett-related disorders, such as MECP2 duplication. However, neither the longitudinal course of epilepsy nor the patterns of seizure onset and remission have been described in Rett syndrome and related conditions. The present study summarizes the findings of the Rett syndrome Natural History study. Participants with clinical Rett syndrome and those with MECP2 mutations without the clinical syndrome were recruited through the Rett Natural History study from 2006 to 2015. Clinical details were collected, and cumulative lifetime prevalence of epilepsy was determined using the Kaplan-Meier estimator. Risk factors for epilepsy were assessed using Cox proportional hazards models. Of 1205 participants enrolled in the study, 922 had classic Rett syndrome, and 778 of these were followed longitudinally for 3939 person-years. The diagnosis of atypical Rett syndrome with a severe clinical phenotype was associated with higher prevalence of epilepsy than those with classic Rett syndrome. While point prevalence of active seizures ranged from 30% to 44%, the estimated cumulative lifetime prevalence of epilepsy using Kaplan-Meier approached 90%. Specific MECP2 mutations were not significantly associated with either seizure prevalence or seizure severity. In contrast, many clinical features were associated with seizure prevalence; frequency of hospitalizations, inability to walk, bradykinesia, scoliosis, gastrostomy feeding, age of seizure onset, and late age of diagnosis were independently associated with higher odds of an individual having epilepsy. Aggressive behaviour was associated with lower odds. Three distinct patterns of seizure prevalence emerged in classic Rett syndrome, including those who did not have seizures throughout the study, those who had frequent relapse and remission, and those who had relentless seizures. Although 248 of those with classic Rett syndrome and a history of seizures were in terminal remission at last contact, only 74 (12% of those with a history of epilepsy) were seizure free and off anti-seizure medication. When studied longitudinally, point prevalence of active seizures is relatively low in Rett syndrome, although lifetime risk of epilepsy is higher than previously reported. While daily seizures are uncommon in Rett syndrome, prolonged remission is less common than in other causes of childhood onset epilepsy. Complete remission off anti-seizure medications is possible, but future efforts should be directed at determining what factors predict when withdrawal of medications in those who are seizure free is propitious.

Growth, nutritional, and gastrointestinal aspects of focal dermal hypoplasia (Goltz-Gorlin syndrome).

Focal dermal hypoplasia (FDH) is a rare genetic disorder caused by mutations in the PORCN gene located on the X-chromosome. In the present study, we characterized the pattern of growth, body composition, and the nutritional and gastrointestinal aspects of children and adults (n = 19) affected with this disorder using clinical anthropometry and a survey questionnaire. The mean birth length (P < 0.06) and weight (P < 0.001) z-scores of the participants were lower than the reference population. The mean head circumference (P < 0.001), height (length) (P < 0.001), weight (P < 0.01), and BMI (P < 0.05) for age z-scores of the participants were lower than the reference population. The height-for-age and weight-for-age z-scores of the participants did not differ significantly between birth and current measurements. Three-fourths of the group reported having one or more nutritional or gastrointestinal problems including short stature (65%), underweight (77%), oral motor dysfunction (41%), gastroesophageal reflux (24%), gastroparesis (35%), and constipation (35%). These observations provide novel clinical information about growth, body composition, and nutritional and gastrointestinal aspects of children and adults with FDH and underscore the importance of careful observation and early clinical intervention in the care of individuals affected with this disorder.

Clinical Guidelines for Management of Bone Health in Rett Syndrome Based on Expert Consensus and Available Evidence.

OBJECTIVES: We developed clinical guidelines for the management of bone health in Rett syndrome through evidence review and the consensus of an expert panel of clinicians. METHODS: An initial guidelines draft was created which included statements based upon literature review and 11 open-ended questions where literature was lacking. The international expert panel reviewed the draft online using a 2-stage Delphi process to reach consensus agreement. Items describe the clinical assessment of bone health, bone mineral density assessment and technique, and pharmacological and non-pharmacological interventions. RESULTS: Agreement was reached on 39 statements which were formulated from 41 statements and 11 questions. When assessing bone health in Rett syndrome a comprehensive assessment of fracture history, mutation type, prescribed medication, pubertal development, mobility level, dietary intake and biochemical bone markers is recommended. A baseline densitometry assessment should be performed with accommodations made for size, with the frequency of surveillance determined according to individual risk. Lateral spine x-rays are also suggested. Increasing physical activity and initiating calcium and vitamin D supplementation when low are the first approaches to optimizing bone health in Rett syndrome. If individuals with Rett syndrome meet the ISCD criterion for osteoporosis in children, the use of bisphosphonates is recommended. CONCLUSION: A clinically significant history of fracture in combination with low bone densitometry findings is necessary for a diagnosis of osteoporosis. These evidence and consensus-based guidelines have the potential to improve bone health in those with Rett syndrome, reduce the frequency of fractures, and stimulate further research that aims to ameliorate the impacts of this serious comorbidity.