The relationship between MECP2 mutation type and health status and service use trajectories over time in a Rett syndrome population

Genetic Instability and Disease Progression of Indian Rett Syndrome Patients

Rett syndrome (RTT) is the rare neurodevelopmental disorder caused by mutations in methyl CpG binding protein 2 (MECP2) gene with a prevalence of 1:10,000 worldwide. The hallmark clinical features of RTT are developmental delay, microcephaly, repetitive behaviours, gait abnormalities, respiratory abnormalities and seizures. Still, the understanding on the diagnosis of RTT among clinicians are less. The aim of our work was to study various clinical manifestations and a spectrum of MECP2 genetic heterogeneity in RTT patients from South Indian population. We screened 208 autistic patients and diagnosed 20 RTT patients, who were further divided into classical RTT (group I; N = 11) and variant RTT (group II; N = 9). The clinical severity of RTT was measured using RSSS, RSBQ, SSI, SSS and RTT gross motor scale. The biochemical analysis showed that thyroid-stimulating hormone (TSH), plasma dopamine and cholesterol levels were higher in group I when compared to group II, whereas the level of blood pressure, calcium, ferritin and high-density lipoprotein levels were significantly decreased in both RTT groups, when compared to the control group. The genetic mutational spectrum of MECP2 mutations were found in 12/20 of RTT patients, which revealed the occurrence of 60% pathogenic mutation and 20% unknown mutation and it was correlated with the clinical finding of respiratory dysfunction, scoliosis and sleeping problems. The significant results of this study provided clinical and genetic aspects of RTT diagnosis and proposed the clinicians to screen abnormal cholesterol, calcium and TSH levels tailed with MECP2 gene mutations for early prognosis of disease severity.

Profiling beneficial and potential adverse effects of MeCP2 overexpression in a hypomorphic Rett syndrome mouse model

De novo loss-of-function mutations in methyl-CpG-binding protein 2 (MeCP2) lead to the neurodevelopmental disorder Rett syndrome (RTT). Despite promising results from strategies aimed at increasing MeCP2 levels, additional studies exploring how hypomorphic MeCP2 mutations impact the therapeutic window are needed. Here, we investigated the consequences of genetically introducing a wild-type MECP2 transgene in the Mecp2 R133C mouse model of RTT. The MECP2 transgene reversed the majority of RTT-like phenotypes exhibited by male and female Mecp2 R133C mice. However, three core symptom domains were adversely affected in female Mecp2^R133C/+ animals; these phenotypes resemble those observed in disease contexts of excess MeCP2. Parallel control experiments in Mecp2^Null/+ mice linked these adverse effects to the hypomorphic R133C mutation. Collectively, these data provide evidence regarding the safety and efficacy of genetically overexpressing functional MeCP2 in Mecp2 R133C mice and suggest that personalized approaches may warrant consideration for the clinical assessment of MeCP2-targeted therapies.

Rehabilitation therapies in Rett syndrome across the lifespan: A scoping review of human and animal studies

PURPOSE

To perform a scoping review of the evidence for therapeutic interventions to manage functional impairments associated with Rett syndrome (RTT) throughout the lifespan.

METHODS

MEDLINE, EMBASE, PsycINFO, CENTRAL, CINAHL, Scopus and Index to Chiropractic Literature were searched systematically up to December 2019. Two investigators independently reviewed all search results and extracted those that met the inclusion criteria. Human and animal model studies pertaining to therapies that increase functional ability or treat RTT-associated symptoms in all age groups were included. Relevant studies were grouped into intervention categories and rated using the Oxford Centre of Evidence Based Medicine Levels of Evidence. Demographics of participants, interventions, and outcomes were summarized.

RESULTS

Ninety-one articles representing 88 studies met the inclusion criteria, of which 80 were human clinical studies and eight were studies using animal models. Study designs were primarily case series and only six studies involved participants above the age of 40.

CONCLUSION

A small number of rigorously studied rehabilitation interventions have been published. Published studies aim to address a wide variety of functional impairments. Research regarding implementation of therapies for older patients with RTT is lacking and requires further exploration.

Using directed-content analysis to identify a framework for understanding quality of life in adults with Rett syndrome

Purpose: Rett syndrome (RTT) is a rare neurodevelopmental disorder mainly affecting females and is caused by a mutation in the MECP2 gene. Recent research identified the domains of quality of life (QOL) important for children with RTT but there has been no investigation of domains important for adults. This qualitative study explored QOL in adults with RTT and compared domains with those previously identified for children.Methods: The sample comprised parents and/or primary caregivers of 20 adults, aged 18-38 years, who were registered with the Australian Rett Syndrome Database. Semi-structured telephone interviews were conducted to investigate aspects of life that were observed to be satisfying or challenging. Data were analyzed using directed content analysis, based on existing QOL domains for children with RTT that related to health and wellbeing, daily activities, and community immersion and services.Results: Each of the domains identified for children with RTT was represented in the adult dataset, with no new domains emerging.Conclusion: This is the first study to identify QOL domains important for adults with RTT. Health and therapy needs are ongoing during adulthood but services may be limited. Findings will guide choice of an appropriate QOL measure for this group.IMPLICATIONS FOR REHABILITATIONKnowing the important domains of quality of life enables clinicians and service providers to systematically review and address key management issues.Despite a high level of dependency and sometimes poor health, parent caregivers perceive potential for strong quality of life in adulthood.Services that maintain functional skills and health throughout the lifespan are valued for their support of quality of life in adults with Rett syndrome.

Longitudinal effects of caregiving on parental well-being: the example of Rett syndrome, a severe neurological disorder

Little longitudinal research has examined parental well-being in those with a child with specific genetic developmental disorder although the associated severe neurological impairments and multiple physical comorbidities likely place substantial burden of caregiving on the parent. We aimed to examine longitudinally the well-being of parents of individuals included in the Australian Rett Syndrome Database over the period from 2002 to 2011 using the Short Form 12 Health Survey. Residential remoteness, the child being a teenager at baseline, having frequent sleep disturbances or behavioural problems, and the type of MECP2 gene mutation were each associated with later poorer parental physical well-being scores. Being a single parent or on a low income was also associated with later poorer physical well-being, while the child having enteral feeding was associated with later poorer emotional well-being. Both the physical and emotional well-being of the parent improved if the child was living in out-of-home care. Our findings suggest that some opportunities do exist for clinicians to help optimise parental well-being. Being alert to the possibility and need for management of a child's sleep or emotional disturbance is important as is awareness of the additional likely parental burden as the child moves through adolescence into early adulthood and their need for additional support at that time. However, the findings also highlight the complex nature of parental well-being over time in parents of children with a severe neurological disorder and how they may be affected by a range of inter-related family and child factors.

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.

Technological aids to support choice strategies by three girls with Rett syndrome

This study was aimed at extending the use of assistive technology (i.e., photocells, interface and personal computer) to support choice strategies by three girls with Rett syndrome and severe to profound developmental disabilities. A second purpose of the study was to reduce stereotypic behaviors exhibited by the participants involved (i.e., body rocking, hand washing and hand mouthing). Finally, a third goal of the study was to monitor the effects of such program on the participants' indices of happiness. The study was carried out according to a multiple probe design across responses for each participant. Results showed that the three girls increased the adaptive responses and decreased the stereotyped behaviors during intervention phases compared to baseline. Moreover, during intervention phases, the indices of happiness augmented for each girl as well. Clinical, psychological and rehabilitative implications of the findings are discussed.

Twenty years of surveillance in Rett syndrome: what does this tell us?

Background

The clinical characteristics of children diagnosed with Rett syndrome are well described. Survival and how these characteristics persist or change in adulthood are less well documented. This study aimed to describe overall survival and adult health in those with Rett syndrome.

Methods

Using the Kaplan-Meier method, we estimated survival of individuals registered with the Australian Rett syndrome Database (ARSD) who had been followed for up to 20 years (n = 396). We then conducted logistic and linear regression analyses investigating epilepsy, musculoskeletal, gastrointestinal, autonomic dysfunction and behaviour of individuals aged 18 years and over using cross sectional cohorts from the ARSD (n = 150) and the international database InterRett (n = 273).

Results

The likelihood of survival was 77.6% at 20 years, 71.5% at 25 years and 59.8% at 37 years. The median age of the combined cross-sectional cohort was 25 years (range 18 to 54 years), the majority (71%) were living in their parental home and the remainder being cared for in group homes or other institutions. Just over half walked either independently (18%) or with assistance (43%). The majority (86%) had scoliosis with 40% of those having undergone corrective surgery. Almost two-thirds (64%) of the women were taking anti-epileptic medications at the time of data collection. Constipation was highly prevalent (83%) and many experienced bloating (53%). Biliary dyskinesia, inflammation or infection of the gallbladder was reported for 20 women (5%) and of those 13 had undergone gallbladder surgery. Sleep disturbance was relatively common (63%), and adverse mood events and anxiety were slightly more prevalent in those aged 26-30 years in comparison to the younger and older age groups. Other frequently reported medical conditions included urinary tract infections, pneumonia and other respiratory conditions.

Conclusions

Survival in Rett syndrome has now been estimated with the most accurate follow up to date. During adulthood, continuation of multidisciplinary services and programs is necessary to optimise health and wellbeing.

Pubertal trajectory in females with Rett syndrome: a population-based study

BACKGROUND

Rett syndrome is a severe genetic neurodevelopmental disorder mainly affecting females. The aim of this study was to describe pubertal development in a population-based cohort of females with Rett syndrome.

METHODS

To assess pubertal trajectory we used six waves of data provided by parents of girls and women, recruited through the Australian population-based Rett Syndrome Database. The age at which adrenarche, thelarche or menarche occurred was used as the parameter for time to event (survival) analysis. The relationships between BMI, mutation type and the trajectories were investigated, using Cox proportional hazards.

RESULTS

One quarter of girls reached adrenarche by 9.6 years, half by 11 years and three quarters by 12.6 years. Half reached menarche by 14 years (range 8-23). Being underweight was associated with later age at adrenarche, thelarche and menarche, while higher BMI (overweight) was associated with earlier onset. In general, girls with C-terminal deletions and early truncating mutations reached pubertal stages earlier and those with the p.R168X mutation reached them later.

CONCLUSION

The pubertal course in Rett syndrome may be abnormal, sometimes with early adrenarche but delayed menarche. These features may be genotype dependent and may have varying relationships with growth and bone acquisition.

Hospitalisation rates for children with intellectual disability or autism born in Western Australia 1983-1999: a population-based cohort study

OBJECTIVES

To describe the hospitalisation patterns in children with intellectual disability (ID) and/or autism spectrum disorder (ASD) after the first year of life and compare with those unaffected.

DESIGN

Prospective cohort study using data linkage between health, ID and hospitalisation population-based datasets.

SETTING

Western Australia.

PARTICIPANTS

416 611 individuals born between 1983 and 1999 involving 1 027 962 hospital admission records. Five case categories were defined (mild/moderate ID, severe ID, biomedically caused ID, ASD with ID and ASD without ID) and compared with the remainder of children and young people.

PRIMARY AND SECONDARY OUTCOME MEASURES

Time to event analysis was used to compare time hospitalisation and rate of hospitalisation between the different case-groups by estimating HR, accounting for birth year and preterm birth status.

RESULTS

ID and/or ASD were found to be associated with an increased risk of hospitalisation compared with the remainder of the population. The increase in risk was highest in those with severe ID and no ASD (HR=10.33, 95% CI 8.66 to 12.31). For those with ID of known biomedical cause or mild ID of unknown cause, the risk of hospitalisation was lower (HR=7.36, 95% CI 6.73 to 8.07 and HR=3.08, 95% CI 2.78 to 3.40, respectively). Those with ASDs had slightly increased risk (HR=2.82, 95% CI 2.26 to 3.50 for those with ID and HR=2.09, 95% CI 1.85 to 2.36 for those without ID).

CONCLUSIONS

Children with an ID or ASD experience an increased risk of hospitalisation after the first year of life which varied from 2 to 10 times that of the rest of the population. Findings can inform service planning or resource allocation for these children with special needs.

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 phenotype associated with a large deletion on MECP2

Multiplex ligation-dependent Probe Amplification (MLPA) has become available for the detection of a large deletion on the MECP2 gene allowing genetic confirmation of previously unconfirmed cases of clinical Rett syndrome. This study describes the phenotype of those with a large deletion and compares with those with other pathogenic MECP2 mutations. Individuals were ascertained from the Australian Rett Syndrome and InterRett databases with data sourced from family and clinician questionnaires, and two case studies were constructed from the longitudinal Australian data. Regression and survival analysis were used to compare severity and age of onset of symptoms in those with and without a large deletion. Data were available for 974 individuals including 51 with a large deletion and ages ranged from 1 year 4 months to 49 years (median 9 years). Those with a large deletion were more severely affected than those with other mutation types. Specifically, individuals with large deletions were less likely to have learned to walk (OR 0.42, 95% CI: 0.22-0.79, P=0.007) and to be currently walking (OR 0.53, 95% CI: 0.26-1.10, P=0.089), and were at higher odds of being in the most severe category of gross motor function (OR 1.84, 95% CI: 0.98-3.48, P=0.057) and epilepsy (OR 2.72, 95% CI: 1.38-5.37, P=0.004). They also developed epilepsy, scoliosis, hand stereotypies and abnormal breathing patterns at an earlier age. We have described the disorder profile associated with a large deletion from the largest sample to date and have found that the phenotype is severe with motor skills particularly affected.

Change in gross motor abilities of girls and women with rett syndrome over a 3- to 4-year period

Rett syndrome is a rare but severe neurological disorder typically associated with a mutation in the MECP2 gene. We describe change in gross motor function over 3 to 4 years for 70 subjects participating in the Australian Rett Syndrome Database. Linear regression was used to assess relationships with age, genotype, and general and complex gross motor skills scores measured on the Gross Motor Scale for Rett syndrome. Skills were slightly better or maintained in approximately 40% of subjects and slightly decreased in approximately 60%. Teenagers and women who walked in 2004 were less likely to lose complex skills than those younger. Girls with a p.R294X mutation were more likely to lose complex motor skills, otherwise skill changes were spread across the mutation categories. In conclusion, small changes were observed over this period with greater stability of skills in teenagers and women with the ability to walk.