A national survey of Rett syndrome: Age, clinical characteristics, current abilities, and health

Gastrointestinal manifestations in pediatric and adult patients with Rett syndrome: an analysis of US claims and physician survey data

Aim: Patients with Rett syndrome (RTT) experience gastrointestinal (GI) manifestations. This study aimed to describe the prevalence of GI manifestations and the associated medical costs in patients with RTT in the USA. Patients & Methods: The study combined an insurance claims database analysis with a survey of 100 physicians experienced in RTT management. Results: GI manifestations affected 43.0% of 5940 patients, with increased prevalence in pediatric patients (45.6%) relative to adult patients (40.2%). Annualized mean medical cost of managing GI manifestations was $4473. Only 5.9-8.2% of neurologists and pediatricians ranked GI symptom management among the five most important treatment goals. Conclusion: Patients with RTT experience a high burden of GI manifestations, which translate to considerable medical costs. Importantly, the prevalence of GI manifestations was likely underestimated in this study, as only those symptoms which resulted in a healthcare encounter were captured.

Teaching Requesting to Individuals with Rett Syndrome Using Alternative Augmentative Communication (AAC) Through Caregiver Coaching via Telehealth

Rett syndrome is a severe neurodevelopmental disorder that results in both motor and language skill regression with a wide range of severity in symptom presentation. Communication intervention may be particularly challenging for this population due to the decline in speech, motor skills, and motor planning difficulties that characterize the disorder (Townend et al., 2020), often resulting in the need for augmentative and alternative communication (AAC) technology. Very limited research has evaluated communication interventions for individuals with Rett syndrome and even fewer have targeted expressive communication, an important skill required for improved autonomy and quality of life (Sigafoos et al., 2009; Townend et al., 2020). The current study sought to systematically replicate the Simacek et al. (2017) mand training procedures to teach three girls with Rett Syndrome to use AAC to make requests through caregiver coaching by researchers via telehealth. Results suggest that mand training was successful in increasing AAC use for all three participants. Barriers to intervention for this population and implications of results for future research and clinical practice are discussed.

Caregiver Perspectives on Pain Sensitivity and Pain Experience in Rett Syndrome

Background

Although delayed or decreased responses to pain are commonly reported among caregivers of individuals with Rett syndrome (RTT), previous studies in relatively small samples have documented that caregivers are concerned about pain, particularly due to gastrointestinal and musculoskeletal conditions.

Aims

The purpose of the current study was to investigate in detail caregivers' perceptions of pain sensitivity, as well as the types, severity, and effect of pain experienced by individuals with RTT in a larger sample than previous studies.

Methods

A total of 51 caregivers (mostly mothers) participated in the study, which involved standardized questionnaires and interviews. The individuals with RTT ranged in age from 2 to 52 years of age, and most (n = 46; 90%) met criteria for classic RTT.

Results

Across the sample, 84% of caregivers reported that they believed that their child was less sensitive to pain compared to her typically developing peers. Despite this perception, 63% of caregivers reported that their child had experienced at least one form of pain in the previous 7 days, and 57% reported their child experienced at least one form of chronic pain. On average, caregivers reported that their child's pain was of moderate severity and interfered with at least one activity of daily living.

Conclusions

The results suggest that pain is a substantial concern among caregivers of individuals with RTT and indicate that additional research is needed to understand the apparent paradox of frequently reported pain experiences despite widespread perceptions of decreased pain sensitivity.

Movement disorders in patients with Rett syndrome: A systematic review of evidence and associated clinical considerations

AIM

This systematic review identified and thematically appraised clinical evidence of movement disorders in patients with Rett syndrome (RTT).

METHOD

Using PRISMA criteria, six electronic databases were searched from inception to April 2021. A thematic analysis was then undertaken on the extracted data to identify potential themes.

RESULTS

Following the thematic analysis, six themes emerged: (i) clinical features of abnormal movement behaviors; (ii) mutational profile and its impact on movement disorders; (iii) symptoms and stressors that impact on movement disorders; (iv) possible underlying neurobiological mechanisms; (v) quality of life and movement disorders; and (vi) treatment of movement disorders. Current guidelines for managing movement disorders in general were then reviewed to provide possible treatment recommendations for RTT.

CONCLUSION

Our study offers an enriched data set for clinical investigations and treatment of fine and gross motor issues in RTT. A detailed understanding of genotype-phenotype relationships of movement disorders allows for more robust genetic counseling for families but can also assist healthcare professionals in terms of monitoring disease progression in RTT. The synthesis also showed that environmental enrichment would be beneficial for improving some aspects of movement disorders. The cerebellum, basal ganglia, alongside dysregulation of the cortico-basal ganglia-thalamo-cortical loop, are likely anatomical targets. A review of treatments for movement disorders also helped to provide recommendations for treating and managing movement disorders in patients with RTT.

Oral health care and service utilisation in individuals with Rett syndrome: an international cross-sectional study

BACKGROUND

There is a dearth of literature available on the comparative oral health status of those with Rett syndrome (RTT) despite diurnal bruxism being a supportive diagnostic criterion for the disorder. This study was designed to investigate the dental experiences of individuals with RTT in terms of perceived at-home and professional dental care.

METHODS

Using data in the InterRett database, provided by English-speaking families of individuals with a confirmed MECP2 genetic mutation, the study investigated relationships between dental problems, oral care, child factors including bruxism and use of gastrostomy, and socioeconomic indicators. The study also explored relationships between dental presentations and socioeconomic, child, and family-related factors.

RESULTS

Individuals with RTT exhibiting bruxism were more likely to access dental treatment. Those who had full oral feeding had a higher incidence rate of dental treatment than those with full tube feeding. A conservative (under) estimation of the overall dental caries progression rate revealed that this may be similar to that of the normal population.

CONCLUSIONS

Drivers for dental treatment in RTT include bruxism as well as dental caries. Those who have full oral feeding experience more dental treatment than those with full tube feeding. A higher maternal education level may confer a protective effect for oral health outcomes in those with RTT. Nevertheless, families generally tended to value the importance of oral health despite reported difficulties in day-to-day mouth care.

Oral parafunction and bruxism in Rett syndrome and associated factors: An observational study

OBJECTIVES

To explore patterns of parafunction, and bruxism, and its relationships with genotype and snoring in individuals with Rett syndrome (RTT).

METHODS

Retrospective observational data of those with confirmed MECP2 mutations in the InterRett database (n = 216) were used to investigate experience of parafunctional habits, and bruxism and their relationships with genotype and snoring using multivariable linear regression.

RESULTS

The prevalence of parafunction was 98.2%. Bruxism was reported (66.2%) with the patterns mostly both diurnal and nocturnal (44.1%) and exclusively diurnal (42.7%). Compared to individuals with C-terminal deletion, individuals with p.Arg106Trp mutations were less likely to have bruxism reported (aOR = 0.15; 95% CI 0.02-0.98, p = 0.05) and those with p.Arg168* mutation were more likely to have frequent bruxism than none or occasional bruxism reported (aROR 3.4; 95% CI 1.1-10.7 p = 0.04). The relative odds of having nocturnal bruxism constantly, compared to none/occasionally, were higher among those 'always' snoring (aROR 6.24; 95% CI 2.1-18.2, p = 0.001) than those with no snoring.

CONCLUSIONS

There appeared to be genotypic association with bruxism in p.Arg168* and p.Arg106Trp mutations and association between nocturnal bruxism and frequent snoring in an international sample of individuals with RTT. Clinical significance of the high prevalence of bruxism should be highlighted in relation to difficulty communicating pain and increased dental treatment need in RTT.

Gross Motor, Physical Activity and Musculoskeletal Disorder Evaluation Tools for Rett Syndrome: A Systematic Review

In recent years, much attention has been paid to motor impairment of persons with Rett Syndrome (RTT), with increasing literature aimed to describe gross motor functioning and musculoskeletal disorders of the RTT population. The aim of this systematic review is to describe clinical evaluation tools used in the last decade to assess motor functioning and musculoskeletal abnormalities of patients with RTT. Thirty-four studies were reviewed and 20 tools were presented. Results showed that only two tools were used to measure functional change after rehabilitative or therapeutic interventions. This review underlies the lack of adequate evaluation tools to assess musculoskeletal abnormalities and deformities in RTT population. The absence of these assessments could be due to a statistical difficulty as it is challenging to build an evaluation tool that can score the entities of the abnormalities related to the amount of disability they cause.

MECP2 mutation spectrum and its clinical characteristics in a Chinese cohort

The dysfunction of methyl-CpG-binding protein 2 (MeCP2) is associated with several neurological disorders, of which Rett syndrome (RTT) is the most prominent. This study focused on a Chinese patient cohort with MECP2 mutations, and analyzed the characteristics of these mutations and their clinical manifestations. In total, 666 patients were identified with 126 different MECP2 mutations, including 22 novel mutations. Over 80% of patients carried an MECP2 mutation on exon 4. Nonsense and missense mutations were the most commonly reported types. Missense mutations were mainly located on methyl-CpG-binding domain (MBD), and nonsense mutations predominantly occurred on transcription repression domain (TRD) and inter domain. The predilection site of large deletion was exon 3 and/or exon 4. Patients with p.R133C, p.R294*, p.R306C, and C-terminal domain (CTD) deletions were less severely affected. Significant differences were found in ambulation ability, hand function, and language among different mutation groups. Three female patients with MECP2 mutations (1 with p.R306P and 2 with p.R309W) only presented with intellectual disability/developmental delay (ID/DD), and no obvious RTT symptoms were reported. Eight male individuals with MECP2 mutations were also identified in this study, including 2 diagnosed with typical RTT, 3 with atypical RTT and 3 with ID/DD.

Caregiver- and Clinician-Reported Adaptive Functioning in Rett Syndrome: a Systematic Review and Evaluation of Measurement Strategies

Rett syndrome is the second most common cause of intellectual disability in females worldwide. The severity of many individuals' impairment limits the effectiveness of traditional assessment. However, clinician and parent reports of adaptive functioning may provide insight into these patients' abilities. This review aims to synthesize the current literature assessing adaptive functioning in Rett syndrome and evaluate existing measurement tools in this population. A search was conducted on PubMed using the search term "Rett syndrome." Studies that quantitatively assessed adaptive functioning outcomes in Rett syndrome with published and normed questionnaire measures were included. Twenty-three studies met inclusion criteria. Overall results indicate that the population of people with Rett syndrome is highly impaired, both in overall adaptive functioning as well as in specific subdomains (e.g., mobility, activities of daily living). Atypical Rett syndrome groups performed better on measures of adaptive functioning relative to patients with classic Rett syndrome. Our findings identified measurement weaknesses, as many of the studies found floor effects and therefore were unable to capture meaningful variability in outcomes. Individuals with Rett syndrome are highly reliant on caregivers due to disrupted adaptive functioning abilities. Optimizing measurement of adaptive skills in Rett syndrome will facilitate the quantification of meaningful change in skills and the identification of efficacious interventions aimed at improving outcomes and quality of life.

Motor, Somatosensory, Viscerosensory and Metabolic Impairments in a Heterozygous Female Rat Model of Rett Syndrome

Rett Syndrome (RTT), an autism-related disorder caused by mutation of the X-linked Methyl CpG-binding Protein 2 (MECP2) gene, is characterized by severe cognitive and intellectual deficits. While cognitive deficits are well-documented in humans and rodent models, impairments of sensory, motor and metabolic functions also occur but remain poorly understood. To better understand non-cognitive deficits in RTT, we studied female rats heterozygous for Mecp2 mutation (Mecp2^−/x); unlike commonly used male Mecp2^−/y rodent models, this more closely approximates human RTT where males rarely survive. Mecp2^−/x rats showed rapid, progressive decline of motor coordination through six months of age as assessed by rotarod performance, accompanied by deficits in gait and posture. Mecp2^−/x rats were hyper-responsive to noxious pressure and cold, but showed visceral hyposensitivity when tested by colorectal distension. Mecp2^−/x rats ate less, drank more, and had more body fat resulting in increased weight gain. Our findings reveal an array of progressive non-cognitive deficits in this rat model that are likely to contribute to the compromised quality of life that characterizes RTT.

Neuronal cytoskeletal gene dysregulation and mechanical hypersensitivity in a rat model of Rett syndrome

Children with Rett syndrome show abnormal cutaneous sensitivity. The precise nature of sensory abnormalities and underlying molecular mechanisms remain largely unknown. Rats with methyl-CpG binding protein 2 (MeCP2) mutation, characteristic of Rett syndrome, show hypersensitivity to pressure and cold, but hyposensitivity to heat. They also show cutaneous hyperinnervation by nonpeptidergic sensory axons, which include subpopulations encoding noxious mechanical and cold stimuli, whereas peptidergic thermosensory innervation is reduced. MeCP2 knockdown confined to dorsal root ganglion sensory neurons replicated this phenotype in vivo, and cultured MeCP2-deficient ganglion neurons showed augmented axonogenesis. Transcriptome analysis revealed dysregulation of genes associated with cytoskeletal dynamics, particularly those controlling actin polymerization and focal-adhesion formation necessary for axon growth and mechanosensory transduction. Down-regulation of these genes by topoisomerase inhibition prevented abnormal axon sprouting. We identified eight key affected genes controlling actin signaling and adhesion formation, including members of the Arhgap, Tiam, and cadherin families. Simultaneous virally mediated knockdown of these genes in Rett rats prevented sensory hyperinnervation and reversed mechanical hypersensitivity, indicating a causal role in abnormal outgrowth and sensitivity. Thus, MeCP2 regulates ganglion neuronal genes controlling cytoskeletal dynamics, which in turn determines axon outgrowth and mechanosensory function and may contribute to altered pain sensitivity in Rett syndrome.

Autonomic breathing abnormalities in Rett syndrome: caregiver perspectives in an international database study

BACKGROUND

Rett syndrome is a severe neurodevelopmental disorder associated with mutations in the MECP2 gene. Irregular breathing patterns and abdominal bloating are prominent but poorly understood features. Our aims were to characterize the abnormal breathing patterns and abdominal bloating, investigate the distribution of these by age and mutation type and examine their impact and management from a caregiver perspective.

METHODS

We invited previously recruited families from the International Rett Syndrome Study to complete a web-based questionnaire concerning their family member with Rett syndrome aged between 2 and 57 years. We used logistic regression to investigate presence, frequency and impact of breath-holding, hyperventilation, or abdominal bloating by age group and mutation type. Age of onset for both breathing abnormalities was investigated using time-to-onset analysis, and the Kaplan-Meier method was used to estimate the failure function for the study sample. Descriptive statistics were used to characterize the management of irregular breathing.

RESULTS

Questionnaires were returned by 413/482 (85.7%) families. Breath-holding was reported for 68.8%, hyperventilation for 46.4% and abdominal bloating for 42.4%. Hyperventilation was more prevalent and frequent in those younger than 7 years of age and abdominal bloating in those aged over 20 years. Onset of breathing irregularities usually occurred during early childhood. Caregivers perceived that daily life was considerably impacted for almost half (44.1%) of those with abdominal bloating and in just over than a third of those with breath-holding (35.8%) or hyperventilation (35.1%). Although perceived impact was broadly comparable between age and mutation groups for breath-holding, hyperventilation and abdominal bloating, girls and women with a p.Arg294* mutation were considered to be more affected by all three conditions. Only 31 individuals had received medically prescribed treatments including 12 different medications, added oxygen, rebreathing apparatus or non-invasive ventilation.

CONCLUSIONS

Autonomic disturbances are prevalent and burdensome in Rett syndrome. This information may guide the design of inclusion criteria and outcome measures for clinical intervention trials targeting autonomic abnormalities. Further investigation of available treatments is necessary to delineate evidence-based management pathways.

Choice making in Rett syndrome: a descriptive study using video data

PURPOSE

To describe the choice-making abilities of girls and women with Rett syndrome.

METHOD

Females with Rett syndrome registered with the Australian Rett Syndrome Database with a pathogenic MECP2 mutation were included in this study. Video clips showing choice making in 64 females at a median age of 11.6 years (range 2.3-35.6 years) were analysed. Video clips were coded for the location and nature of the choice-making interaction, and the actions of the communication partner and female with Rett syndrome.

RESULTS

The majority (82.8%, 53/64) of females made a choice, most using eye gaze. Just under half (24/53) used one modality to communicate their choice, 52.8% used two modalities and one used three modalities. Of those who made a choice, 50% did so within 8 s. The length of time to make a choice did not appear to vary with age. During choice making, 57.8% (37/64) of communication partners used language and gestures, 39.1% (25/64) used only language and two used language, gestures and symbols within the interaction.

CONCLUSIONS

The provision of adequate time allowing for a response and observation for the use of multiple modalities could promote effective choice making in females with Rett syndrome. Implications for Rehabilitation The provision of adequate time allowing for a response will promote effective choice making in girls and women with Rett syndrome. Although almost all girls and women with Rett syndrome used eye gaze to indicate their choice, communication partners also need to recognise and respond to other communication modalities that are sometimes used like body movements.

MeCP2 deficiency results in robust Rett-like behavioural and motor deficits in male and female rats

Since the identification of MECP2 as the causative gene in the majority of Rett Syndrome (RTT) cases, transgenic mouse models have played a critical role in our understanding of this disease. The use of additional mammalian RTT models offers the promise of further elucidating critical early mechanisms of disease as well as providing new avenues for translational studies. We have identified significant abnormalities in growth as well as motor and behavioural function in a novel zinc-finger nuclease model of RTT utilizing both male and female rats throughout development. Male rats lacking MeCP2 (Mecp2^ZFN/y) were noticeably symptomatic as early as postnatal day 21, with most dying by postnatal day 55, while females lacking one copy of Mecp2 (Mecp2^ZFN/+) displayed a more protracted disease course. Brain weights of Mecp2^ZFN/y and Mecp2^ZFN/+rats were significantly reduced by postnatal day 14 and 21, respectively. Early motor and breathing abnormalities were apparent in Mecp2^ZFN/y rats, whereas Mecp2^ZFN/+rats displayed functional irregularities later in development. The large size of this species will provide profound advantages in the identification of early disease mechanisms and the development of appropriately timed therapeutics. The current study establishes a foundational basis for the continued utilization of this rat model in future RTT research.

Prevalence and associated features of depression in women with Rett syndrome

BACKGROUND

Little is known about depression among women with Rett syndrome (RTT) despite recent advances in knowledge about RTT. In this study, we aimed to establish the prevalence of depression among women with RTT as identified by a screening telephone interview and to explore the clinical factors associated with this.

METHODS

The study employed the cross-sectional analysis of data from telephone interviews with carers of 56 women with RTT, using validated questionnaires for assessing mental health problems, challenging behaviour and RTT severity.

RESULTS

Scores on the mental health assessment reached the affective/neurotic threshold in eight cases (14.3%). No significant differences were found between those reaching the threshold and those who did not in terms of severity of RTT phenotype, health problems or social circumstances. There was a significant association between screening identified depression and higher lethargy and social withdrawal.

CONCLUSIONS

Screening identified depression was found among a sizeable minority of women with RTT. Further investigation is needed to establish a clinically validated prevalence of depression among this group and to identify behavioural features that would lead to prompt psychiatric assessment.

Psychological Well-Being of Mothers and Siblings in Families of Girls and Women with Rett Syndrome

Few published studies have reported on the psychological well-being of family members of individuals with Rett syndrome (RTT). Eighty-seven mothers of girls and women with RTT completed a questionnaire survey about their daughters' behavioral phenotype, current health, and behavior problems, and their own and a sibling's well-being. Mothers reported increased anxiety but similar levels of depression when compared to a normative sample. Across all problem domains on the Strengths and Difficulties Questionnaire, child and adolescent siblings (n = 39) were reported by mothers to have fewer difficulties than a normative sample. The severity of their daughters' RTT behavioral phenotype predicted increased anxiety and stress for mothers. Increased RTT daughters' current health problems predicted more maternal perceptions of positive gain.

Direct Observation of the Behaviour of Females with Rett Syndrome

The aim was to observe the behaviour of a sample of females with RTT and explore how it was organized in relation to environmental events. Ten participants, all with a less severe form of classic (n = 9) or atypical (n = 1) Rett syndrome (RTT), were filmed at home and at school or day centre. Analysis used real-time data capture software. Observational categories distinguished engagement in social and non-social pursuits, hand stereotypies, self-injury and the receipt of attention from a parent, teacher or carer. Associations between participant behaviour and intake variables and receipt of attention were explored. Concurrent and lagged conditional probabilities between behavioural categories and receipt of attention were calculated. Receipt of adult attention was high. Engagement in activity using the hands was associated with a less severe condition and greater developmental age. Engagement in activity, whether using the hands or not, and social engagement were positively associated with receipt of support. The extent of hand stereotypies varied greatly across participants but was independent of environmental events. Six participants self-injured. There was some evidence that self-injury was related to adult attention. Participants appeared to experience a carer and attention rich environment and their levels of engagement seemed high as a result. As in the more general literature, engagement in activity was related to personal development and to social support. Self-injury contrasted with hand stereotypies in having possible environmental function.

Management of sleep disorders in neurodevelopmental disorders and genetic syndromes

PURPOSE OF REVIEW

Sleep disorders in individuals with developmental difficulties continue to be a significant challenge for families, carers, and therapists with a major impact on individuals and carers alike. This review is designed to update the reader on recent developments in this area.

RECENT FINDINGS

A systematic search identified a variety of studies illustrating advances in the regulation of circadian rhythm and sleep disturbance in neurodevelopmental disorders. Specific advances are likely to lead in some disorders to targeted therapies. There is strong evidence that behavioural and sleep hygiene measures should be first line therapy; however, studies are still limited in this area. Nonpharmacological measures such as exercise, sensory interventions, and behavioural are reported. Behavioural regulation and sleep hygiene demonstrate the best evidence for improved sleep parameters in individuals with neurodisability.

SUMMARY

Although the mainstay of management of children with sleep problems and neurodevelopmental disability is similar to that of typically developing children, there is emerging evidence of behavioural strategies being successful in large-scale trials and the promise of more targeted therapies for more specific resistant disorders.

Ageing in Rett syndrome

BACKGROUND

The aim was to gain a UK national sample of people with Rett syndrome across the age range and (1) conduct a cross-sectional comparison of age groups and (2) undertake a longitudinal follow-up.

METHODS

From 308 potential participants approached to take part, a sample of 91 girls and women was achieved (29.5%). Their ages ranged from 4 to 47 years, and 71 were known to have a mutation in the methyl-CpG binding protein-2 (MECP2) gene. Seventy-two of the initial sample were followed up 16 months later, and 50 returned completed assessments (69.4%). Their ages ranged from 7 to 48 years, and 42 were MECP2 positive. Parental questionnaire measures of Rett syndrome specific characteristics, impulsivity, overactivity, mood, interest and pleasure, repetitive behaviour and self-injury were administered.

RESULTS

Adaptive behaviour and behavioural characteristics of Rett syndrome were similar across age groups and, where assessed, stable over time, as were repetitive behaviours generally and self-injury. There was some suggestion of deterioration in health arising with ageing, principally contributed to by deteriorations in dental and gastro-intestinal problems both with moderate effect sizes. Indicators of mood, interest and pleasure differed significantly across age groups. The total scale score significantly deteriorated over time, with a moderate effect size.

CONCLUSIONS

This study provides further evidence for the post-regression stability that characterises Rett syndrome. Emergent low mood in Rett syndrome requires further research.

A national survey of Rett syndrome: behavioural characteristics

BACKGROUND

The aim was to gain a UK national sample of people with Rett syndrome (RTT) across the age range and compare their characteristics using a variety of relevant behavioural measures with a well-chosen contrast group.

METHODS

The achieved sample was 91 girls and women, aged from 4 to 47 years, of whom 71 were known to be MECP2 positive. The contrast group (n = 66), matched for age, gender, language and self-help skills, comprised individuals with six other syndromes associated with intellectual disability. Parental questionnaire measures of RTT specific characteristics, impulsivity, overactivity, mood, interest and pleasure, repetitive behaviour and self-injury were administered.

RESULTS

Hand stereotypies, breathing irregularities, night-time unrest and anxiety or inappropriate fear were commonly reported among the RTT sample. Problems of low mood were also reported as common. However, mood and interest and pleasure were no lower than found in the contrast group. In addition, self-injury was lower than in the contrast group and was associated with factors found to predict self-injury in other groups of people with severe intellectual disabilities.

CONCLUSIONS

There is variability in the manifestation of problem behaviours potentially associated with the syndrome across individuals, with some more severely affected in most areas than others. Some of this variability appears to be underpinned by genetic mutation.