Altered attainment of developmental milestones influences the age of diagnosis of rett syndrome

Psychological aspects of being a parent of an individual with Rett syndrome: A scoping review

BACKGROUND

Rett syndrome (RTT) causes multiple disabilities with a lifelong need for substantial care, placing a tremendous lifelong responsibility on the parents. Parenting an individual with RTT can therefore be challenging. Research on the psychological aspects of parenting individuals with RTT is limited and unclear. We aimed to identify and map the existing literature on this subject.

METHOD

A scoping review was conducted with systematic searches in PubMed, PsycINFO and CINAHL.

RESULTS

Eighteen studies were included. Negative and positive psychological aspects were described with the majority focusing on the negative. Three factors seemed to especially affect the parents: severity of the diagnosis, time (increasing age of parents or individual with RTT; years of caretaking), work-status of the mother.

CONCLUSIONS

Seemingly, parents are highly affected; however, the literature is scarce and has several gaps. Future research should include older parents, fathers, parents of individuals living in group homes, and positive aspects.

Can telehealth increase physical activity in individuals with Rett syndrome? A multicentre randomized controlled trial

AIM

To evaluate the effects of a physical activity programme on sedentary behaviour and physical activity in ambulant individuals with Rett syndrome (RTT).

METHOD

In this multicentre randomized waitlist-controlled trial, we recruited 43 ambulatory individuals with RTT in Australia and Denmark. Adequate baseline data were obtained from 38 participants (mean age 20 years, range 6-41, SD 10 years 6 months, one male). All completed the trial. Participants received 12 weeks of usual care (n = 19) or a goal-based, telehealth-supported programme in which activities occurred in their familiar environments (n = 19). Sedentary time and daily steps were assessed at baseline, post-test, and 12-week follow-up. The data analyst was blinded to group allocation.

RESULTS

Sedentary time decreased in the intervention group by 2.7% (95% confidence interval [CI] -6.0 to 0.6) and increased in the control group by 1.3% (95% CI -4.8 to 7.4). Intervention and control groups increased the number of their steps per day by 264.7 (95% CI -72.2 to 601.5) and 104.8 (95% CI -178.1 to 387.7) respectively. No significant differences were found on any outcomes at post-test. There were three minor adverse events.

INTERPRETATION

A goal-based telehealth intervention seemed to produce small improvements in physical activity for individuals with RTT. Families require more support to increase these individuals' extremely low physical activity levels.

WHAT THIS PAPER ADDS

A telehealth-supported intervention may produce small changes in physical activity in Rett syndrome (RTT). Increasing physical activity in individuals with RTT is challenging for caregivers. Families require substantial out-of-home support to increase their children's activity levels.

Interprofessional Collaboration Improves Quality of Life of a Young Adult With Rett Syndrome

Rett syndrome (RTT) is a genetic neurodevelopmental disease characterized by early normal development followed by regression in motor and language skills. Patients with RTT often exhibit seizure disorders, growth failure, heart and lung disorders, bruxism, and dental caries. We report on a female patient in her 20s with Rett syndrome who presented to her primary care clinic with increasing agitation and pain. This case reports describes a collaborative, interprofessional approach between medical and dental providers who work in an integrated outpatient setting. It demonstrates that interprofessional collaboration, goals of care discussions, and attention to social drivers of health can improve quality of life for a medically and socially complex patient.

Parent and therapist perspectives on "uptime" activities and participation in Rett syndrome

PURPOSE

People with a disability may spend more time sitting and lying ("downtime") and less time standing and walking ("uptime"). Caregivers and therapists supporting individuals with Rett syndrome were surveyed, aiming to gather insights on how to support participation in "uptime" activities.

METHOD

An anonymous online survey including open ended questions about the enablers and barriers to "uptime" was administered to parent/caregivers and therapists/health professionals in an international sample. Responses were coded to the International Classification of Functioning, Health and Disability (ICF) framework identifying barriers, enablers, and strategies for increasing uptime activities.

RESULTS

Parents (N = 115) and therapists (N = 49) completed the survey. Barriers and enablers to "uptime" were identified for all ICF domains and additional data coded to enabling access to the physical environment. Strategies to promote "uptime" activities and participation particularly related to the individual's physical capacity and personal factors as well as social and physical environmental factors.

CONCLUSIONS

Findings can inform the design of interventions aiming to increase "uptime" in individuals with Rett syndrome. Strategies should create individualised support by considering how to build fitness using activities that are motivating, at the same time creating opportunities for social interactions within a range of environments.IMPLICATIONS FOR REHABILITATION"Uptime" participation comprised a dynamic interaction of "doing" the standing or walking activity, with a sense of self-engagement with the activities and interaction with others.Strategies to promote "uptime" participation should consider how to create support for person-related attributes, including building physical capacity for a greater volume of "uptime" in activities that are enjoyable and motivating.Strategies to promote "uptime participation should also include creating a supportive environment, comprising opportunities for social interaction within a range of environments".

Longitudinal Evaluation of the Stability of Hand Function in Rett Syndrome

OBJECTIVE

To investigate the longitudinal stability of hand function in Rett syndrome and to analyze further the relationships between stability of hand function and genotype, age, and walking ability.

STUDY DESIGN

Longitudinal video data of functional abilities of individuals with genetically confirmed Rett syndrome were collected by families of individuals registered with the Australian Rett Syndrome Database. A total of 120 individuals provided 290 recordings from which 170 observation pairs were available for comparison. The Rett Syndrome Hand Function Scale was used to classify a level of hand function observed in each video on a range from unable to grasp, pick up, and hold objects to skillful manipulation of large and small objects.

RESULTS

Approximately one-third of the population lost some hand function over time. Younger children (<6 years) rather than adults were at greater risk of deterioration in hand function. Clinical severity, as indicated by walking ability or genotype, played a lesser role. There was no identified pattern between genotype and the stability of hand function skills. Rather, mutations associated with milder (p.Arg133Cys, p.Arg294∗) and greater (p.Arg106Trp, p.Thr158Met) clinical severity were both associated with greater risks of decline.

CONCLUSIONS

Genotype was a lesser predictor of loss of hand function beyond the early regression period, and younger children were particularly vulnerable to further loss of hand function compared with adults.

The enhancement of activity rescues the establishment of Mecp2 null neuronal phenotypes

MECP2 mutations cause Rett syndrome (RTT), a severe and progressive neurodevelopmental disorder mainly affecting females. Although RTT patients exhibit delayed onset of symptoms, several evidences demonstrate that MeCP2 deficiency alters early development of the brain. Indeed, during early maturation, Mecp2 null cortical neurons display widespread transcriptional changes, reduced activity, and defective morphology. It has been proposed that during brain development these elements are linked in a feed-forward cycle where neuronal activity drives transcriptional and morphological changes that further increase network maturity. We hypothesized that the enhancement of neuronal activity during early maturation might prevent the onset of RTT-typical molecular and cellular phenotypes. Accordingly, we show that the enhancement of excitability, obtained by adding to neuronal cultures Ampakine CX546, rescues transcription of several genes, neuronal morphology, and responsiveness to stimuli. Greater effects are achieved in response to earlier treatments. In vivo, short and early administration of CX546 to Mecp2 null mice prolongs lifespan, delays the disease progression, and rescues motor abilities and spatial memory, thus confirming the value for RTT of an early restoration of neuronal activity.

Früherkennung von Entwicklungsstörungen: Kanonisches Lallen (k)‌ein diagnostischer Marker‍(!)?

Zusammenfassung. Theoretischer Hintergrund: Forschungsergebnisse zum frühen Spracherwerb bei Kindern mit spät erkannten Entwicklungsstörungen sind inkonsistent und angesichts unterschiedlicher Forschungsparadigmen und Definitionen nur bedingt vergleichbar. Fragestellung: Ziel dieser Übersichtsarbeit ist es, das Potenzial früher verbaler Fähigkeiten, vor allem des kanonischen Lallens, als Marker zur Früherkennung von Autismus-Spektrum-Störung, Rett-Syndrom und Fragilem-X-Syndrom zu beschreiben. Methode: Übersichtsarbeit über retrospektive und prospektive Studien zu frühen verbalen Fähigkeiten in der Prodromalphase dieser Störungsbilder. Ergebnisse: Einige Kinder mit spät erkannten Entwicklungsstörungen erwerben das kanonische Lallen nach dem kritischen Zeitfenster von 6 bis 10 Monaten und/oder haben oft qualitative Veränderungen in ihren Lautäußerungen. Diskussion und Schlussfolgerung: Eine abweichende Entwicklung des kanonischen Lallens kann auf spätere atypische Entwicklung hinweisen. Als funktioneller Marker für die spezifische Früherkennung von Entwicklungsstörungen scheint dieser Erwerbsmeilenstein jedoch nicht geeignet. Linguistische und signalbasierte Detailanalysen frühkindlicher Vokalisationen könnten zukünftig einen entscheidenden Beitrag hierzu leisten.

Implementing telehealth support to increase physical activity in girls and women with Rett syndrome-ActivRett: protocol for a waitlist randomised controlled trial

INTRODUCTION

Individuals with Rett syndrome (RTT) experience impaired gross motor skills, limiting their capacity to engage in physical activities and participation in activities. There is limited evidence of the effectiveness of supported physical activity interventions. This study aims to evaluate the effects of a telehealth-delivered physical activity programme on physical activity, sedentary behaviour and quality of life in RTT.

METHODS AND ANALYSIS

This is a multicentre study, conducted in Australia, Denmark and Israel. It is a randomised waitlist-controlled trial comparing an intervention to support physical activity with usual care. Participants are children and adults with RTT, recruited from the Australian Rett Syndrome Database, the Danish Center for Rett Syndrome and the Rett Syndrome Association of Israel. The intervention duration is 12 weeks, including fortnightly telephone contact to plan, monitor and develop individual activity programmes. Outcomes are measured at baseline, at 13 weeks and then at 25 weeks. The primary outcomes are sedentary behaviour assessed with an activPAL accelerometer and the number of daily steps measured with a StepWatch Activity Monitor. Secondary outcomes include sleep, behaviour and quality of life. Caregiver experiences will be assessed immediately after the intervention using a satisfaction questionnaire. Group differences for each outcome will be evaluated with analysis of covariance, adjusting for baseline values on an intention-to-treat basis.

ETHICS AND DISSEMINATION

Ethics approval has been obtained in Western Australia from the Child and Adolescent Health Services (RGS3371), in Denmark from the Capital Region Ethics Committee (H-19040514) and in Israel from the Ariel University Institutional Review Board (AU-HEA-ML-20190331). Manuscripts on the development of the intervention from pilot work and the results of the intervention will be submitted to peer-reviewed journals. Results will be presented at conferences and consumer forums. We will develop an online resource documenting the physical activity programme and available supporting evidence.

TRIAL REGISTRATION NUMBER

NCT04167059; Pre-results.

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.

Rett syndrome: insights into genetic, molecular and circuit mechanisms

Rett syndrome (RTT) is a severe neurological disorder caused by mutations in the gene encoding methyl-CpG-binding protein 2 (MeCP2). Almost two decades of research into RTT have greatly advanced our understanding of the function and regulation of the multifunctional protein MeCP2. Here, we review recent advances in understanding how loss of MeCP2 impacts different stages of brain development, discuss recent findings demonstrating the molecular role of MeCP2 as a transcriptional repressor, assess primary and secondary effects of MeCP2 loss and examine how loss of MeCP2 can result in an imbalance of neuronal excitation and inhibition at the circuit level along with dysregulation of activity-dependent mechanisms. These factors present challenges to the search for mechanism-based therapeutics for RTT and suggest specific approaches that may be more effective than others.

Canonical Babbling: A Marker for Earlier Identification of Late Detected Developmental Disorders?

Purpose of Review

To summarize findings about the emergence and characteristics of canonical babbling in children with late detected developmental disorders (LDDDs), such as autism spectrum disorder, Rett syndrome, and fragile X syndrome. In particular, we ask whether infants’ vocal development in the first year of life contains any markers that may contribute to earlier detection of these disorders.

Recent Findings

Only a handful studies have investigated canonical babbling in infants with LDDDs. With divergent research paradigms and definitions applied, findings on the onset and characteristics of canonical babbling are inconsistent and difficult to compare. Infants with LDDDs showed reduced likelihood to produce canonical babbling vocalizations. If achieved, this milestone was more likely to be reached beyond the critical time window of 5–10 months.

Summary

Canonical babbling appears promising as a potential marker for early detection of infants at risk for developmental disorders. In-depth studies on babbling characteristics in LDDDs are warranted.

Environmental enrichment intervention for Rett syndrome: an individually randomised stepped wedge trial

Background

Rett syndrome is caused by a pathogenic mutation in the MECP2 gene with major consequences for motor and cognitive development. One of the effects of impaired MECP2 function is reduced production of Brain Derived Neurotrophic Factor (BDNF), a protein required for normal neuronal development. When housed in an enriched environment, MECP2 null mice improved motor abilities and increased levels of BDNF in the brain. We investigated the effects of environmental enrichment on gross motor skills and blood BDNF levels in girls with Rett syndrome.

Methods

A genetically variable group of 12 girls with a MECP2 mutation and younger than 6 years participated in a modified individually randomised stepped wedge design study. Assessments were conducted on five occasions, two during the baseline period and three during the intervention period. Gross motor function was assessed using the Rett Syndrome Gross Motor Scale (maximum score of 45) on five occasions, two during the baseline period and three during the intervention period. Blood levels of BDNF were measured at the two baseline assessments and at the end of the intervention period. The intervention comprised motor learning and exercise supplemented with social, cognitive and other sensory experiences over a six-month period.

Results

At the first assessment, the mean (SD) age of the children was 3 years (1 year 1 month) years ranging from 1 year 6 months to 5 years 2 months. Also at baseline, mean (SD) gross motor scores and blood BDNF levels were 22.7/45 (9.6) and 165.0 (28.8) ng/ml respectively. Adjusting for covariates, the enriched environment was associated with improved gross motor skills (coefficient 8.2, 95%CI 5.1, 11.2) and a 321.4 ng/ml (95%CI 272.0, 370.8) increase in blood BDNF levels after 6 months of treatment. Growth, sleep quality and mood were unaffected.

Conclusions

Behavioural interventions such as environmental enrichment can reduce the functional deficit in Rett syndrome, contributing to the evidence-base for management and further understanding of epigenetic mechanisms. Environmental enrichment will be an important adjunct in the evaluation of new drug therapies that use BDNF pathways because of implications for the strengthening of synapses and improved functioning.

Trial registration

ACTRN12615001286538.

Early development in Rett syndrome - the benefits and difficulties of a birth cohort approach

PURPOSES

Typically, early (pre-diagnostic) development in individuals later diagnosed with Rett syndrome (RTT) has been investigated retrospectively using parent reports, medical records and analysis of home videos. In recent years, prospective research designs have been increasingly applied to the investigation of early development in individuals with late phenotypical onset disorders, for example, autism spectrum disorder.

METHODS

In this study, data collected by the Danish National Birth Cohort lent itself to prospective exploration of the early development of RTT, in particular early motor-, speech-language, and socio-communicative behaviors, mood, and sleep.

RESULTS AND CONCLUSIONS

Despite limitations, this quasi prospective methodology proved promising. In order to add substantially to the body of knowledge, however, specific questions relating to peculiarites in early development could usefully be added to future cohort studies. As this involves considerable work, it may be more realistic to consider a set of indicators which point to a number of developmental disorders rather than to one.

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.

Clinical and biological progress over 50 years in Rett syndrome

In the 50 years since Andreas Rett first described the syndrome that came to bear his name, and is now known to be caused by a mutation in the methyl-CpG-binding protein 2 (MECP2) gene, a compelling blend of astute clinical observations and clinical and laboratory research has substantially enhanced our understanding of this rare disorder. Here, we document the contributions of the early pioneers in Rett syndrome (RTT) research, and describe the evolution of knowledge in terms of diagnostic criteria, clinical variation, and the interplay with other Rett-related disorders. We provide a synthesis of what is known about the neurobiology of MeCP2, considering the lessons learned from both cell and animal models, and how they might inform future clinical trials. With a focus on the core criteria, we examine the relationships between genotype and clinical severity. We review current knowledge about the many comorbidities that occur in RTT, and how genotype may modify their presentation. We also acknowledge the important drivers that are accelerating this research programme, including the roles of research infrastructure, international collaboration and advocacy groups. Finally, we highlight the major milestones since 1966, and what they mean for the day-to-day lives of individuals with RTT and their families.

An Exploration of the Use of Eye Gaze and Gestures in Females With Rett Syndrome

PURPOSE

This study investigated the communicative use of eye gaze and gestures in females with Rett syndrome.

METHOD

Data on 151 females with Rett syndrome participating in the Australian Rett Syndrome Database was used in this study. Items from the Communication and Symbolic Behavior Scales Developmental Profile Infant-Toddler Checklist (Wetherby & Prizant, 2002) were used to measure communication. Relationships between the use of eye gaze and gestures for communication were investigated using logistic regression. The influences of MECP2 mutation type, age, and level of motor abilities on the use of eye gaze and gestures were investigated using multivariate linear regression.

RESULTS

Both eye gaze and the use of gestures predicted the ability to make requests. Women aged 19 years or older had the lowest scores for eye gaze. Females with better gross motor abilities had higher scores for the use of eye gaze and gestures. The use of eye gaze did not vary across mutation groups, but those with a C-terminal deletion had the highest scores for use of gestures.

CONCLUSIONS

Eye gaze is used more frequently than gestures for communication, and this is related to age, MECP2 mutation type, and gross motor abilities.

Determinants of sleep disturbances in Rett syndrome: Novel findings in relation to genotype

Rett syndrome is a rare but severe neurological disorder associated with a mutation in the methyl CpG binding protein 2 (MECP2) gene. Sleep problems and epilepsy are two of many comorbidities associated with this disorder. This study investigated the prevalence and determinants of sleep problems in Rett syndrome using an international sample. Families with a child with a confirmed Rett syndrome diagnosis and a MECP2 mutation registered in the International Rett Syndrome Phenotype Database (InterRett) were invited to participate. Questionnaires were returned by 364/461 (78.9%) either in web-based or paper format. Families completed the Sleep Disturbance Scale for Children and provided information on the presence, nature, and frequency of their child's sleep problems. Multivariate multinomial regression was used to investigate the relationships between selected sleep problems, age group, and genotype and linear regression for the relationships between sleep disturbance scales and a range of covariates. Night waking was the most prevalent sleep problem affecting over 80% with nearly half (48.3%) currently waking often at night. Initiating and maintaining sleep was most disturbed for younger children and those with a p.Arg294* mutation. Severe seizure activity was associated with poor sleep after adjusting for age group, mutation type, and mobility. We were surprised to find associations between the p.Arg294* mutation and some sleep disturbances given that other aspects of its phenotype are milder. These findings highlight the complexities of aberrant MECP2 function in Rett syndrome and explain some of the variation in manifestation of sleep disturbances. © 2016 Wiley Periodicals, Inc.

The Natural History of Scoliosis in Females With Rett Syndrome

STUDY DESIGN

Population-based longitudinal observational study.

OBJECTIVE

To describe the prevalence of scoliosis in Rett syndrome, structural characteristics and progression, taking into account the influences of age, genotype, and ambulatory status.

SUMMARY OF BACKGROUND DATA

Scoliosis is the most common orthopedic comorbidity in Rett syndrome yet very little is known about its natural history and influencing factors such as age, genotype, and ambulatory status.

METHODS

The infrastructure of the Australian Rett Syndrome Database was used to identify all cases with confirmed Rett syndrome in Australia and collect data on genotype and walking status. We identified radiological records and described the Cobb angle of each curve. Time to event analysis was used to estimate the median age of onset of scoliosis and the log-rank test to compare by mutation type. Latent class group analysis was used to identify groups for the trajectory of walking status over time and a multilevel linear model used to assess trajectories of scoliosis development by mutation type and walking status. We used a logistic regression model to estimate the probability of developing a scoliosis with a Cobb angle >60° at 16 years in relation to Cobb angle and walking status at 10 years of age.

RESULTS

The median age of scoliosis onset was 11 years with earliest onset in those with a p.Arg255 mutation or large deletion. Scoliosis was progressive for all mutation types except for those with the p.Arg306Cys mutation. Scoliosis progression was reduced when there was capacity to walk independently or with assistance. Cobb angle and walking ability at age 10 can be reliably used to identify those who will develop a very severe scoliosis by age 16.

CONCLUSION

These data on prognosis of scoliosis inform clinical decision making about the likelihood of progression to very severe scoliosis and the need for surgical management.

LEVEL OF EVIDENCE

4.

Developmental Dynamics of Rett Syndrome

Rett Syndrome was long considered to be simply a disorder of postnatal development, with phenotypes that manifest only late in development and into adulthood. A variety of recent evidence demonstrates that the phenotypes of Rett Syndrome are present at the earliest stages of brain development, including developmental stages that define neurogenesis, migration, and patterning in addition to stages of synaptic and circuit development and plasticity. These phenotypes arise from the pleotropic effects of MeCP2, which is expressed very early in neuronal progenitors and continues to be expressed into adulthood. The effects of MeCP2 are mediated by diverse signaling, transcriptional, and epigenetic mechanisms. Attempts to reverse the effects of Rett Syndrome need to take into account the developmental dynamics and temporal impact of MeCP2 loss.

Validating the Rett Syndrome Gross Motor Scale

Rett syndrome is a pervasive neurodevelopmental disorder associated with a pathogenic mutation on the MECP2 gene. Impaired movement is a fundamental component and the Rett Syndrome Gross Motor Scale was developed to measure gross motor abilities in this population. The current study investigated the validity and reliability of the Rett Syndrome Gross Motor Scale. Video data showing gross motor abilities supplemented with parent report data was collected for 255 girls and women registered with the Australian Rett Syndrome Database, and the factor structure and relationships between motor scores, age and genotype were investigated. Clinical assessment scores for 38 girls and women with Rett syndrome who attended the Danish Center for Rett Syndrome were used to assess consistency of measurement. Principal components analysis enabled the calculation of three factor scores: Sitting, Standing and Walking, and Challenge. Motor scores were poorer with increasing age and those with the p.Arg133Cys, p.Arg294* or p.Arg306Cys mutation achieved higher scores than those with a large deletion. The repeatability of clinical assessment was excellent (intraclass correlation coefficient for total score 0.99, 95% CI 0.93-0.98). The standard error of measurement for the total score was 2 points and we would be 95% confident that a change 4 points in the 45-point scale would be greater than within-subject measurement error. The Rett Syndrome Gross Motor Scale could be an appropriate measure of gross motor skills in clinical practice and clinical trials.

Is it possible to diagnose Rett syndrome before classical symptoms become obvious? Review of 24 Danish cases born between 2003 and 2012

BACKGROUND/PURPOSE

Rett syndrome (RTT) is a neurodevelopmental disorder that affects mainly females; it results in multiple disabilities and carries a risk of medical comorbidities. Early diagnosis is important to help establish the best treatment opportunities and preventive care in order to slow down the progression of symptoms. We wanted to test our hypothesis that it is possible to diagnose RTT before the classical symptoms become obvious.

METHODS

We analysed development and symptoms before and at the time of the RTT diagnosis, as well as the symptoms that triggered MECP2 mutation analysis, in a cohort of girls with RTT born in Denmark between 2003 and 2012.

RESULTS

Twenty-four girls were included, and 87.5% of these girls were diagnosed when the classical RTT symptoms were recognized. However, parents were concerned about their daughters between 3 and 58 months prior to the RTT diagnosis, and they felt that the professionals did not share their concern in the beginning. When reviewing medical files and questionnaires, we noted that the majority of girls did have combinations of concerning symptoms such as developmental delay and a collection of subtle signs such as autistic traits, placidity, floppiness with suspicion of muscular or mitochondrial diseases, hair pulling, teeth grinding, development of incontinence and problems with initiating movements.

CONCLUSION

We conclude that many individuals with MECP2 mutation exhibit characteristics that should raise suspicion for RTT, prior to evolution of the core clinical criteria. As RTT is a rare disease, it is of importance to constantly educate clinicians for heightened awareness of RTT.

Age of diagnosis in Rett syndrome: patterns of recognition among diagnosticians and risk factors for late diagnosis

PURPOSE

Diagnosis of Rett syndrome (RTT) is often delayed. We sought to determine the type of physician who typically makes the RTT diagnosis and to identify risk factors for delayed diagnosis.

METHODS

A total of 1085 participants from the multicenter longitudinal RTT natural history study with classic and atypical RTT were recruited between 2006 and 2014. Age of diagnosis, diagnostician, diagnostic criteria, and clinical and developmental data were collected.

RESULTS

Among 919 classic and 166 atypical RTT participants, the median diagnosis age was 2.7 years (interquartile range 2.0-4.1) in classic and 3.8 years (interquartile range 2.3-6.9) in atypical RTT. Pediatricians made the diagnosis of classic RTT rarely (5.2%); however, the proportion diagnosed by pediatricians has increased since 2006. Since the first diagnostic criteria, the age of diagnosis decreased among subspecialists but not pediatricians. Odds of a pediatrician making the diagnosis of classic RTT were higher if a child stopped responding to parental interaction, and lower if they possessed gastroesophageal reflux, specific stereotypies, lost babbling, or the ability to follow commands. Delayed acquisition of basic gross motor skills or finger feeding was associated with younger diagnosis; delayed acquisition of higher level fine motor skills, later onset of supportive features, and normal head circumference were associated with late diagnosis. Thirty-three percent with microcephaly before 2.5 years were diagnosed after the median age of 2.7 years.

CONCLUSIONS

Age of RTT diagnosis has improved among subspecialists, and pediatricians have made the diagnosis of classic RTT more frequently since 2006. Strategies for educating diagnosticians should incorporate specific risk factors for delayed diagnosis.

Defects During Mecp2 Null Embryonic Cortex Development Precede the Onset of Overt Neurological Symptoms

MeCP2 is associated with several neurological disorders; of which, Rett syndrome undoubtedly represents the most frequent. Its molecular roles, however, are still unclear, and data from animal models often describe adult, symptomatic stages, while MeCP2 functions during embryonic development remain elusive. We describe the pattern and timing of Mecp2 expression in the embryonic neocortex highlighting its low but consistent expression in virtually all cells and show the unexpected occurrence of transcriptional defects in the Mecp2 null samples at a stage largely preceding the onset of overt symptoms. Through the deregulated expression of ionic channels and glutamatergic receptors, the lack of Mecp2 during early neuronal maturation leads to the reduction in the neuronal responsiveness to stimuli. We suggest that such features concur to morphological alterations that begin affecting Mecp2 null neurons around the perinatal age and become evident later in adulthood. We indicate MeCP2 as a key modulator of the transcriptional mechanisms regulating cerebral cortex development. Neurological phenotypes of MECP2 patients could thus be the cumulative result of different adverse events that are already present at stages when no obvious signs of the pathology are evident and are worsened by later impairments affecting the central nervous system during maturation and maintenance of its functionality.

Fostering Ambulation for a Preschool Child with Rett Syndrome: A Case Report

Children with Rett Syndrome (RS) have neuromotor impairments that impact their mobility. Poor hand function among children with RS limits the selection of an assistive device for ambulation.

PURPOSE

The purpose of this case report is to describe the process of selecting an assistive device for a child with RS to promote ambulation.

METHOD

This single subject case reports on a 5-year-old girl with RS at a suburban mid-western early childhood special education setting.

RESULTS

The child in this case was able to walk the farthest distances with a metal toy shopping cart and then with an anterior facing four-wheeled walker.

CONCLUSION

The outcome suggests that physical therapists and health professionals caring for young children with RS consider using a metal toy shopping cart to establish and practice ambulation prior to selection of a longer term, adjustable anterior facing walker like the one in this case report.

Aspects of speech-language abilities are influenced by MECP2 mutation type in girls with Rett syndrome

This study investigates relationships between methyl-CpG-binding protein 2 gene (MECP2) mutation type and speech-language abilities in girls with Rett syndrome. Cross-sectional data on 766 girls, aged 15 years and under, with genetically confirmed Rett syndrome was obtained from the Australian Rett Syndrome Database (ARSD) (n = 244) and the International Rett Syndrome Phenotype Database (InterRett) (n = 522). Relationships between MECP2 mutation type and age of regression in speech-language abilities, and the level of speech-language abilities before and after this regression were investigated. The females had a median age of 4.95 years in the ARSD and 5.25 years in InterRett. The majority (89%, 685/766) acquired speech-language abilities in the form of babble or words at some point in time. Of those who acquired babble or words, 85% (581/685) experienced a regression in these abilities. Those with a p.Arg133Cys mutation were the most likely to use one or more words, prior to (RRR = 3.45; 95% CI 1.15-10.41) and after (RRR = 5.99; 95% CI 2.00-17.92), speech-language regression. Girls with Rett syndrome vary in their use of speech and language, and in their experience of speech-language regression and these variations are partly explained by genotype.

The trajectories of sleep disturbances in Rett syndrome

Rett syndrome is a rare neurodevelopmental disorder usually affecting females, and is associated with a mutation in the MECP2 gene. Sleep problems occur commonly and we investigated the trajectories and influences of age, mutation and treatments. Data were collected at six time points over 12 years from 320 families registered with the Australian Rett Syndrome Database. Regression analysis was used to investigate relationships between sleep disturbances, age, mutation type and use of treatment, and latent class growth analysis was performed to identify sleep problem phenotypes and model the effect of mutation type. The age range of subjects was 2.0-35.8 years. The study showed that sleep problems occurred in more than 80% of individuals and the prevalence decreased with age. Night laughing and night screaming occurred in 77 and 49%, respectively, when younger. Those with a large deletion had a higher prevalence of night laughing, which often occurred frequently. Treatment was associated with a 1.7% reduction in risk of further sleep problems. High and low baseline prevalence groups were identified. Approximately three-quarters of girls and women with sleep disturbances were in the high baseline group and problems persisted into adulthood. Conversely, 57% with night laughing and 42% with night screaming in the high baseline group exhibited mild improvement over time. Mutation type was not found to be a significant predictor of group membership. In conclusion, the evolution of sleep problems differed between subgroups of girls and women with Rett syndrome, in part explained by age and genotype. Treatment was not associated with improvement in sleep problems.

Adolescent onset cognitive regression and neuropsychiatric symptoms associated with the A140V MECP2 mutation

The phenotype attributed to MECP2 mutations continues to expand. In addition to classic and variant Rett syndrome, phenotypes include non-specific intellectual disability and autism spectrum disorder in females, and fatal neonatal encephalopathy in males. One particular phenotype of parkinsonism, pyramidal signs, and neuropsychiatric symptoms (PPM-X) has been described only in males. We report on the first female with the A140V MECP2 mutation presenting with late onset cognitive regression, pyramidal symptoms, parkinsonism, and bipolar symptoms. This finding emphasizes the need to consider MECP2 sequencing in females with non-classic Rett phenotypes, particularly those with intellectual disability and neuropsychiatric features.

Caring for a child with severe intellectual disability in China: the example of Rett syndrome

PURPOSE

Rett syndrome is one of several genetic disorders known to cause severe intellectual and physical disability, mostly in girls. Girls affected by Rett syndrome appear to develop normally in the first 6 months of life, after which the usual clinical presentation comprises regression of communication and hand skills, the appearance of hand stereotypies and impaired gait. Intellectual disability affects more than 1.5% of the population of children in developing countries yet we know little about the daily lives and support services available for them and their caregivers.

METHOD

This qualitative study explored the daily experiences of 14 mothers and one grandmother caring for a child with Rett syndrome in China via telephone interviews.

RESULTS

Participants reported a lack of education, rehabilitation and support services available to them. Limited access to information reduced families' capacity to adequately meet the needs of their child. These gaps were further exacerbated by discrimination and perceived stigma from some members of the community.

CONCLUSIONS

Additional support services and educational programs at the governmental level can improve the quality of life of persons with an intellectual disability and their families and programs involving community participation in the care of people with disabilities may help to address discrimination.

The CDKL5 disorder is an independent clinical entity associated with early-onset encephalopathy

The clinical understanding of the CDKL5 disorder remains limited, with most information being derived from small patient groups seen at individual centres. This study uses a large international data collection to describe the clinical profile of the CDKL5 disorder and compare with Rett syndrome (RTT). Information on individuals with cyclin-dependent kinase-like 5 (CDKL5) mutations (n=86) and females with MECP2 mutations (n=920) was sourced from the InterRett database. Available photographs of CDKL5 patients were examined for dysmorphic features. The proportion of CDKL5 patients meeting the recent Neul criteria for atypical RTT was determined. Logistic regression and time-to-event analyses were used to compare the occurrence of Rett-like features in those with MECP2 and CDKL5 mutations. Most individuals with CDKL5 mutations had severe developmental delay from birth, seizure onset before the age of 3 months and similar non-dysmorphic features. Less than one-quarter met the criteria for early-onset seizure variant RTT. Seizures and sleep disturbances were more common than in those with MECP2 mutations whereas features of regression and spinal curvature were less common. The CDKL5 disorder presents with a distinct clinical profile and a subtle facial, limb and hand phenotype that may assist in differentiation from other early-onset encephalopathies. Although mutations in the CDKL5 gene have been described in association with the early-onset variant of RTT, in our study the majority did not meet these criteria. Therefore, the CDKL5 disorder should be considered separate to RTT, rather than another variant.