Recent insights into genotype-phenotype relationships in patients with Rett syndrome using a fine grain scale

Effects of Immersive Virtual Reality with Treadmill in Subjects with Rett Syndrome: A Pilot Study

BACKGROUND/OBJECTIVES

Rett syndrome is a rare neurodevelopmental disorder that can severely affect motor functioning, particularly walking. Previous training programs proposed treadmills as tools to increase walking endurance of patients with Rett syndrome, but these trainings did not include virtual reality (VR). The aim of this study was to assess the feasibility of a short treadmill training coupled to VR in girls with Rett syndrome.

METHODS

Nine patients with Rett syndrome underwent a 3-day treadmill walking program performed in semi-immersive VR. During the training, the happiness index and performance metrics were collected. At the end of the training parents filled out the Suitability Evaluation Questionnaire (SEQ) and, when feasible, patients underwent a gait assessment.

RESULTS

All the subjects recruited performed the three GRAIL sessions and parents showed a good satisfaction and considered the integration of treadmill and VR a good possibility for future rehabilitative programs. Participants showed greater satisfaction in environments requiring walking and their attention increased during training sessions, hypothesizing the feasibility of longer trainings with treadmill and VR. Data collected from gait analysis provided insights, although preliminary, concerning differences in gait pattern amongst the recruited subjects.

CONCLUSIONS

Despite the small sample size and limited training duration, the paper suggests that a walking training with a treadmill combined with VR can represent a new strategy for Rett rehabilitation.

Evaluation of seizure semiology, genetics, magnetic resonance imaging, and electroencephalogram findings in children with Rett syndrome: A multicenter retrospective study

OBJECTIVES

This study aimed to evaluate seizure semiology, electroencephalogram (EEG), magnetic resonance imaging (MRI), and genetic findings, as well as treatment choices in Rett syndrome (RTT).

METHODS

A retrospective analysis was conducted on one hundred and twenty cases diagnosed with RTT with a genetic mutation. Data were obtained from nine participating centers.

RESULTS

In this study, 93.3 % of patients were female, with typical RTT found in 70 % of cases. Genetic etiology revealed MECP2, FoxG1, and CDKL5 in 93.8 %, 2.7 %, and 1.8 % of cases, respectively. Atypical RTT clinics were observed in 50 % of male cases, with the first EEG being normal in atypical RTT cases (p = 0.01). Generalized tonic-clonic and myoclonic epilepsy were the most common seizure semiologies, while absence and focal epilepsy were less prevalent. Valproate, levetiracetam, lamotrigine, and clobazam were the most commonly used antiepileptic drugs, affecting the severity and frequency of seizures (p = 0.015, p=<0.001, p = 0.022, and p=<0.001, respectively). No significant differences were observed in EEG findings. The initiation of anti-seizure medications significantly altered seizure characteristics (Table 4). A ketogenic diet and vagal nerve stimulation (VNS) correlated with a 50 % improvement in cognitive function, while steroid treatment showed a 60 % improvement. Remarkably, seizures were substantially reduced after VNS application.

CONCLUSION

This study underscores the importance of genetic diagnosis in RTT cases with a clinical diagnosis. These preliminary results will be further validated with the inclusion of clinically diagnosed RTT cases in our ongoing study.

Rett Syndrome and the Role of MECP2: Signaling to Clinical Trials

Rett syndrome (RTT) is a neurological disorder that mostly affects females, with a frequency of 1 in 10,000 to 20,000 live birth cases. Symptoms include stereotyped hand movements; impaired learning, language, and communication skills; sudden loss of speech; reduced lifespan; retarded growth; disturbance of sleep and breathing; seizures; autism; and gait apraxia. Pneumonia is the most common cause of death for patients with Rett syndrome, with a survival rate of 77.8% at 25 years of age. Survival into the fifth decade is typical in Rett syndrome, and the leading cause of death is cardiorespiratory compromise. Rett syndrome progression has multiple stages; however, most phenotypes are associated with the nervous system and brain. In total, 95% of Rett syndrome cases are due to mutations in the MECP2 gene, an X-linked gene that encodes for the methyl CpG binding protein, a regulator of gene expression. In this review, we summarize the recent developments in the field of Rett syndrome and therapeutics targeting MECP2.

A Severity Comparison between Italian and Israeli Rett Syndrome Cohorts

Rett syndrome (RTT) is a neurodevelopmental disorder marked by profound cognitive, communication, and motor impairments. Despite identified genotype/phenotype connections, the extent of clinical severity varies even among individuals sharing the same genetic mutation. Diverse sociocultural environments, such as the level of inclusivity of the scholar system, the time spent with family, and the intensity of the rehabilitative intervention provided, might influence their development diversely. This study examines the severity of RTT in people in Italy and Israel, countries with distinct contradictory approaches to caring for those with intricate disabilities, across two age groups. Data from 136 Italian and 59 Israeli girls and women with RTT were assessed and divided into two age categories: above and below 12 years. The RARS, a standardized RTT-specific clinical severity tool, was administered. Despite no differences in age and genetic characteristics, the Italian group showed better scores in the RARS motor and disease-related characteristics areas in both age groups. Moreover, the young Italian participants gathered better total RARS scores and emotional and behavioral characteristics area scores. Furthermore, the young group showed significantly less scoliosis, foot problems, and epilepsy than the older group. These findings endorse the inclusion of girls with RTT in the regular schooling system for a limited daily period, investing in high activity levels within the home and community environments, and suggest continuously providing the person with daily occasions of physical activity and socialization.

Evaluation Tools Developed for Rett Syndrome

Rett syndrome (RTT) is a complex neurodevelopmental X-linked disorder associated with severe functional impairments and multiple comorbidities. There is wide variation in the clinical presentation, and because of its unique characteristics, several evaluation tools of clinical severity, behavior, and functional motor abilities have been proposed specifically for it. This opinion paper aims to present up-to date evaluation tools which have specifically been adapted for individuals with RTT often used by the authors in their clinical and research practice and to provide the reader with essential considerations and suggestions regarding their use. Due to the rarity of Rett syndrome, we found it important to present these scales in order to improve and professionalize their clinical work. The current article will review the following evaluation tools: (a) the Rett Assessment Rating Scale; (b) the Rett Syndrome Gross Motor Scale; (c) the Rett Syndrome Functional Scale; (d) the Functional Mobility Scale-Rett Syndrome; (e) the Two-Minute Walking Test modified for Rett syndrome; (f) the Rett Syndrome Hand Function Scale; (g) the StepWatch Activity Monitor; (h) the activPALTM; (i) the Modified Bouchard Activity Record; (j) the Rett Syndrome Behavioral Questionnaire; and (k) the Rett Syndrome Fear of Movement Scale. The authors recommend that service providers consider evaluation tools validated for RTT for evaluation and monitoring to guide their clinical recommendations and management. In this article, the authors suggest factors that should be considered when using these evaluation tools to assist in interpreting scores.

Clinical and genetic correlations of scoliosis in Rett syndrome

AIM

To identify the clinical features correlating with the presence and severity of scoliosis in girls with Rett syndrome (RTT).

METHOD

Seventy-five girls with a clinical and genetically determined diagnosis of RTT participated in this cross-sectional study. Clinical scales administered included the Rett assessment rating scale, the modified Ashworth scale, the Rett syndrome motor evaluation scale, the PainAD, and the scale of evaluation of purposeful hand function. Multivariable analyses, such as ordinal logistic regression and ANCOVA, were used to assess the correlation between these scales and a clinical score of scoliosis.

RESULTS

About 60% of patients had scoliosis, in general mild or moderate. The severity of scoliosis correlated with age and important neurological factors such as muscular hypertonus and hyperreflexia, standing, walking (level walking and on stairs), and postural transitions. No association was found with global disease severity, hand function, pain, or type of genetic mutation.

INTERPRETATION

Scoliosis is a relevant problem in RTT. It should be carefully monitored along the life span, especially in conjunction with (loco-)motor impairment in these patients.

Mosaicism of common pathogenic MECP2 variants identified in two males with a clinical diagnosis of Rett syndrome

Rett (RTT) syndrome, a neurodevelopmental disorder caused by pathogenic variation in the MECP2 gene, is characterized by developmental regression, loss of purposeful hand movements, stereotypic hand movements, abnormal gait, and loss of spoken language. Due to the X-linked inheritance pattern, RTT is typically limited to females. Recent studies revealed somatic mosaicism in MECP2 in male patients with RTT-like phenotypes. While detecting mosaic variation using Sanger sequencing is theoretically possible for mosaicism over ~15%-20%, several variables, including efficiency of PCR, background noise, and/or human error, contribute to a low detection rate using this technology. Mosaic variants in two males were detected by next generation sequencing (NGS; Case 1) and by Sanger re-sequencing (Case 2). Both had targeted digital PCR (dPCR) to confirm the variants. In this report, we present two males with classic RTT syndrome in whom we identified pathogenic variation in the MECP2 gene in the mosaic state (c.730C > T (p.Gln244*) in Patient 1 and c.397C > T (p.Arg133Cys) in Patient 2). In addition, estimates and measures of mosaic variant fraction were surprisingly similar between Sanger sequencing, NGS, and dPCR. The mosaic state of these variants contributed to a lengthy diagnostic odyssey for these patients. While NGS and even Sanger sequencing may be viable methods of detecting mosaic variation in DNA or RNA samples, applying targeted dPCR to supplement these sequencing technologies would provide confirmation of somatic mosaicism and mosaic fraction.

Outcome measurement instruments in Rett syndrome: A systematic review

OBJECTIVE

The aim of the study was to identify and characterize outcome measures for objective and subjective assessment in persons with Rett syndrome (RS).

METHODS

A systematic review was conducted consulting the EBSCO, Cochrane, Web of Science, Scielo, MEDLINE and PsycINFO databases for published studies describing the use of patient-reported outcome measures (PROMs) and other outcome measures in persons with RS. Validation studies and observational studies were included. The PROMs were first described, and then the measurement properties were evaluated using predefined criteria according to the COnsensus-based Standards for the selection of health Measurement Instruments (COSMIN). The outcome measures were then grouped according to the International Classification of Functioning, Disability and Health (ICF) to establish a relationship between outcome measures and ICF domains.

RESULTS

Twenty out of 2327 articles were appraised, and seventeen different outcome measures were identified and described. Ten outcome measures corresponded to evaluation questionnaires, while the remaining seven assessed functional outcomes: walking distance, physical activity level and ability to interact visually. A relation between these outcome measures that assess RS and the ICF allows understanding that most of the instruments (fifteen) include the assessment of activity limitations.

CONCLUSIONS

The findings of this study seem to be promising for their use by clinicians and researchers, although they have methodological limitations. The accuracy and quality of these individual outcome measures should continue to be assessed in an attempt to gather a consensus on the best tools used in RS.

Impact of a Remotely Supervised Motor Rehabilitation Program on Maternal Well-Being During the COVID-19 Italian Lockdown

COVID-19 Lockdown was particularly challenging for most mothers of people with intellectual disabilities, including those with Rett syndrome (RTT), leading to feelings of abandonment from healthcare services of their children. Within those days, telerehabilitation has represented a valid alternative to support physical activity and treatment, supporting parents in structuring their children’s daily routine at home. This article aims to describe the well-being level of two groups of mothers of girls and women with RTT who were involved in a home-based remotely supervised motor rehabilitation program, respectively, before and during the COVID-19 Italian lockdown. Forty participants with classic RTT were recruited before the lockdown and randomly assigned to two groups that performed the intervention immediately before (Group 1) and during (Group 2) the lockdown, respectively. The intervention included an individualized daily physical activity program carried out for 12 weeks by participants’ parents and fortnightly supervised throughout Skype contacts to plan, monitor, and accommodate individual activities in the participant’s life at home. The short form Caregivers Well-Being Scale was collected for the mothers in each group 12 weeks before intervention (T1), at intervention initiation (T2), immediately after intervention termination (T3), as well as at 12 weeks after intervention termination (T4). Mothers of participants in the Group 1 showed a stable level of well-being across all four evaluations with a slight improvement during the lockdown, without significant change. Similarly, the well-being level of mothers in the Group 2 showed a statistically significant increase in their well-being between T2 and T3 (during the lockdown) and its reduction to the pre-intervention level between T3 and T4 (after the lockdown). The results suggest that the lockdown did not negatively affect the participants’ mothers’ well-being, leading to its improvement. Moreover, the proposed intervention could have supported the mothers in managing the new daily routine at home, positively affecting maternal well-being.

The GAIRS Checklist: a useful global assessment tool in patients with Rett syndrome

Background

Rett Syndrome is a severe, neurodevelopmental disorder mainly caused by mutations in the MECP2 gene, affecting around 1 in 10,000 female births. Severe physical, language, and social impairments impose a wide range of limitations in the assessment of the abilities of Rett patients. This study proposes an analysis and first validation of a Global Assessment and Intervention in Rett syndrome (GAIRS) Checklist for assessing behavioral, intellectual, academic, neuropsychological and psychosocial manifestations in patients with Rett Syndrome. We administered the GAIRS Checklist to 113 Italian patients with Rett Syndrome aged 4–42.

Aims of this study

To examine the psychometric characteristics of the GAIRS Checklist. Moreover, the aim is also to examine the validity of GAIRS with test–retest correlation, convergent validity with similar functional measurements, such as the Vineland scales, and divergent validity with severity of disease scale, such as the RARS scale and severity of neuropsychiatric evaluations.

Results

All 10 subscales of GAIRS were positively and significantly related to each other and to the total GAIRS score, and the subscales showed high levels of Cronbach’s alpha values (from .77 to .95). Principal axis factoring suggested two factors that explain 60% of the variance. Test–retest reliability is 0.82. This means that psychometric properties are reliable. Correlation for Concurrent validity with Vineland score was high and Divergent Validity with RARS was also high.

Conclusion

The GAIRS Checklist used for Rett syndrome is acceptable and feasible to complete assessment in a clinical setting. Moreover, it can detect the complexity of this disease and may suggest the next step in terms of specific training in Rett syndrome.

Circulating 4-F4t-Neuroprostane and 10-F4t-Neuroprostane Are Related to MECP2 Gene Mutation and Natural History in Rett Syndrome

Neuroprostanes, a family of non-enzymatic metabolites of the docosahexaenoic acid, have been suggested as potential biomarkers for neurological diseases. Objective biological markers are strongly needed in Rett syndrome (RTT), which is a progressive X-linked neurodevelopmental disorder that is mainly caused by mutations in the methyl-CpG binding protein 2 (MECP2) gene with a predominant multisystemic phenotype. The aim of the study is to assess a possible association between MECP2 mutations or RTT disease progression and plasma levels of 4(RS)-4-F_4t-neuroprostane (4-F_4t-NeuroP) and 10(RS)-10-F_4t-neuroprostane (10-F_4t-NeuroP) in typical RTT patients with proven MECP2 gene mutation. Clinical severity and disease progression were assessed using the Rett clinical severity scale (RCSS) in n = 77 RTT patients. The 4-F_4t-NeuroP and 10-F_4t-NeuroP molecules were totally synthesized and used to identify the contents of the plasma of the patients. Neuroprostane levels were related to MECP2 mutation category (i.e., early truncating, gene deletion, late truncating, and missense), specific hotspot mutations (i.e., R106W, R133C, R168X, R255X, R270X, R294X, R306C, and T158M), and disease stage (II through IV). Circulating 4-F_4t-NeuroP and 10-F_4t-NeuroP were significantly related to (i) the type of MECP2 mutations where higher levels were associated to gene deletions (p ≤ 0.001); (ii) severity of common hotspot MECP2 mutation (large deletions, R168X, R255X, and R270X); (iii) disease stage, where higher concentrations were observed at stage II (p ≤ 0.002); and (iv) deficiency in walking (p ≤ 0.0003). This study indicates the biological significance of 4-F_4t-NeuroP and 10-F_4t-NeuroP as promising molecules to mark the disease progression and potentially gauge genotype-phenotype associations in RTT.

Effects of short- and long-term neurostimulation (tDCS) on Alzheimer's disease patients: two randomized studies

BACKGROUND

Non-invasive brain stimulation is an effective treatment for Alzheimer's disease.

AIMS

The purpose of the two studies presented here is to compare the short- and long-term effects of transcranial direct current stimulation (t-DCS) on two samples of advanced AD patients.

METHODS

In Study 1 26 patients were involved in a 10-day anodal vs. sham tDCS intervention stimulating the left frontotemporal cortex. A pre-post test assessment was run using two different neurocognitive tests and EEG data. The same protocol was used in Study 2, which involved 18 different patients who underwent the same intervention 10 days a month for 8 months.

RESULTS

Results confirmed how the t-DCS intervention was effective both in the short- and the long-term to slow down the progression of AD on specific neurophysiological domains and, to a certain extent, on neurophysiological activity. Discussion tDCS appear to be effective and to affect differently neurocognitive and neurophysiological functions when comparing short and long-term outcomes. Conclusions Anodal-tDCS is an effective way to slow down the progression of Alzheimer's both in the short and long term. It can also affect the EEG patterns, but this requires a more protracted intervention.

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.

Computational and structural studies of MeCP2 and associated mutants

Rett Syndrome is a rare genetic disorder exclusively seen in girls. Approximately 95% of RTT cases is caused by mutations in the MeCP2 gene which codes for Methyl-CpG-binding protein 2 (MeCP2). In this review, first, a brief introductory review of Rett Syndrome, MeCP2 protein structure and function, mutation types and frequencies, and phenotype–genotype relationships were provided. After that, the current knowledge on the wild-type and mutant MeCP2 protein structure and dynamics as well as its binding to DNA is reviewed. The review particularly focuses on computational (such as molecular dynamics) and experimental (such as electrophoretic mobility shift assays) studies on the MeCP2 binding to different types of DNA as well as the computational and experimental (such as circular dichroism) studies on the stability changes upon mutations. In the end, a brief opinion on future outlook for further computational studies is provided.

Parenting girls with Rett syndrome: An investigation on self-perceived levels of stress

BACKGROUND

Although lives of parents of girls with Rett syndrome (RTT) are centred on the process of care, in the current literature their perceived levels of stress have been rarely investigated.

METHODS

We analysed levels of stress in a sample of 79 fathers and mothers parenting girls with RTT, who were required to compile the Parenting Stress Index (PSI) questionnaire.

RESULTS

We found clinical levels of stress in about 39% of fathers, as compared with 44% of the mothers. Severity of RTT, but not other factors such as the genetic domain, presence of epilepsy or scoliosis, predicted Total Stress scores in both fathers' subsample and mothers' subsample. A cumulative effect of caring, that is association of higher levels of stress with longer process of care, did also emerge from estimation of smoothing splines.

CONCLUSIONS

Fathers' resources should be taken more into account, especially in the rehabilitation and socialization process of adults with RTT.

Unusual double mutation in MECP2 and CDKL5 genes in Rett-like syndrome: Correlation with phenotype and genes expression

INTRODUCTION

Rett syndrome (RTT) is a neuro-developmental disorder affecting almost exclusively females and it divided into classical and atypical forms of the disease. RTT-like syndrome was also described and presents an overlapping phenotype of RTT. RTT-like syndrome has been associated with several genes including MECP2 and CDKL5 having common biological pathways and regulatory interactions especially during neural maturation and synaptogenesis.

METHODS

We report patient with Rett-like syndrome for whom clinical features and their progression guided toward the screening of two candidate genes MECP2 and CDKL5 by sequencing. Severity score was evaluated by "Rett Assessment Rating Scale" (R.A.R.S.). Predictions of pahogenicity and functional effects used several bioinformatic tools and qRT-PCR was conducted to evaluate gene expression.

RESULTS

Mutational screening revealed two mutations c.1065 C > A (p.S355R) in MECP2 gene and c.616 G > A (p.D206N) mutation in CDKL5 gene in the patient with a high R.A.R.S. Bioinformatic investigations predicted a moderate effect of p.S355R in MECP2 gene but a more pathogenic one of p.D206N mutation in CDKL5. Effect of c.616 G > A mutation on structure and stability of CDKL5 mRNA was confirmed by qRT-PCR. Additionally, analysis of gene expression revealed a drastic effect of CDKL5 mutant on its MeCP2 and Dnmt1 substrates and also on its MYCN regulator.

CONCLUSIONS

The co-existence of the two mutations in CDKL5 and MECP2 genes could explain the severe phenotype in our patient with RTT-Like and is consistent with the data related to the interactions of CDKL5 with MeCP2 and Dnmt1 proteins.

Effects of Combined Transcranial Direct Current Stimulation with Cognitive Training in Girls with Rett Syndrome

Background: Transcranial Direct Current Stimulation (tDCS) combined with traditional rehabilitative techniques has not been widely applied to Rett Syndrome (RTT). The aim of this study was to examine the effects of combined cognitive traditional training with tDCS applied to attention and language measures in subjects with RTT. Methods: 31 subjects with RTT were randomly allocated into two groups: non-sham tDCS (n = 18) and sham tDCS (n = 13). The former received the integrated intervention non-sham tDCS plus cognitive empowerment during the treatment phase. The latter received sham stimulation plus cognitive empowerment. All participants underwent neurological and cognitive assessment to evaluate attention and language measures: before integrated treatment (pre-test phase), at the conclusion of the treatment (post-test phase), and at 1 month after the conclusion of the treatment (follow-up phase). Results: the results indicated longer attention time in the non-sham tDCS group compared to the sham tDCS group with a stable trend also in the follow-up phase; an increase of the number of vowel/phoneme sounds in the non-sham tDCS group; and an improvement in the neurophysiological parameters in the non-sham tDCS group. Conclusions: This study supports the use of tDCS as a promising and alternative approach in the RTT rehabilitation field.

Experimental Examination and Social Validation of a Microswitch Intervention to Improve Choice-Making and Activity Engagement for Six Girls with Rett Syndrome

Background: The use of assistive technology, specifically microswitches, with children with RTT has been shown to effectively moderate the impact of their disability on their quality of life^- by facilitating access to meaningful leisure and other activities. Objectives: This study aimed to evaluate the effectiveness of a microswitch intervention on increased choice making, engagement in a targeted sorting activity, and indices of happiness, and decreased stereotypic behaviors for six girls with Rett syndrome. Targeted dependent variables were also assessed at six months post-intervention. Following the intervention study, 90 external raters completed a social validation procedure. Method: An ABABAB experimental sequence was implemented for each participant with a cross-over effect. A social validation assessment involving 90 external raters was carried out. Results: Data emphasized an improved performance for each participants involved (i.e., adaptive responses). Five participants showed a capacity of independent choice. One participant seemed to be closely linked to the position of the container. Social raters favorably endorsed the use of the program since they positively evaluated the use of the technology on all the dimensions investigated. Conclusion: A microswitch intervention may improve choice making and activity engagement for children with Rett syndrome. Further research is needed on the development of more sophisticated forms of individualized technological options to improve opportunities for enhanced engagement and choice-making for individuals with RTT.

A New Scale to Evaluate Motor Function in Rett Syndrome: Validation and Psychometric Properties

BACKGROUND

We aim to describe and psychometrically validate the Rett Syndrome Motor Evaluation Scale, a 25-item ordinal scale examining (loco-)motor function across six sections: standing, sitting, transitions, walking, running, and walking up or downstairs.

METHODS

We illustrate the process of item construction and validation, report findings and normative data obtained on a standardization sample of 60 patients with Rett syndrome. We investigate the validity and reliability of the scale and illustrate its psychometric properties using modern multivariate techniques of data analysis.

RESULTS

Sixty patients with Rett syndrome were included (all female; mean age 12.45 (S.D. 8.75) years). The multidimensional latent structure of the scale was supported by the results of the confirmatory factor analysis. Rett Syndrome Motor Evaluation Scale showed strong internal consistency reliability as well as excellent inter-rater agreement. The Rett Syndrome Motor Evaluation Scale scores were not predicted by age, but were associated with disease severity, degree of spasticity, and hand dysfunction. We also identified three latent classes with different degrees of impairment.

CONCLUSIONS

Rett Syndrome Motor Evaluation Scale is a new, valid, and reliable scale that can be introduced in clinical practice when assessing (loco-)motor function in Rett syndrome.

Motor function in Rett syndrome: comparing clinical and parental assessments

AIM

To describe a new clinical tool, the Rett Syndrome Motor Evaluation Scale (RESMES) and to assess (loco-)motor function in people with Rett syndrome (RTT).

METHOD

Formal assessment provided by physicians was followed by parents' direct observation at home using the RESMES. Sixty females (mean [SD] age 12y 5mo [8y 9mo], range 3-40y) with a clinical diagnosis and genetically determined RTT participated in the study. Spearman's/Pearson's coefficients assessed the correlation between the clinicians' and caregivers' evaluations, as well as the correlation of RESMES scores with other scales, namely the Pain Assessment in Advanced Dementia, the Rett Assessment Rating Scale, the Modified Ashworth Scale, and hand function (assessed with a scale of evaluation of purposeful hand function). Scores provided by parents and clinicians were tested statistically by Mann-Whitney U test.

RESULTS

Approximately 88% of patients had moderate to severe RTT symptoms and, on average, moderate motor impairment based on the RESMES. RESMES total scores provided by clinicians and caregivers were highly correlated (r=0.91), as were the subscale scores. Postural transition was a critical area of the RESMES, where parents systematically provided lower scores than clinicians, indicating milder degrees of disability. Severity of scoliosis and mutation type emerged as significant predictors of motor function.

INTERPRETATION

The RESMES characterized the (loco-)motor impairments of the patients with RTT well. It also showed a close correlation between the evaluations of clinicians and caregivers, with the possible exception of postural transition tasks, which should be carefully addressed in a clinical setting. The type of mutation and presence of scoliosis should be evaluated, as they predicted the ability to walk.

WHAT THIS PAPER ADDS

Caregivers at home can reliably assess motor function in Rett syndrome using the Rett Syndrome Motor Evaluation Scale (RESMES). RESMES scores provided by clinicians and parents were highly correlated. The severity of scoliosis and the genetic mutation predicted standing and walking abilities.

Variation factors of stereotypical hand movements in subjects with Rett syndrome

Background: Stereotypical hand movements have been observed in most individuals diagnosed with Rett syndrome. Objectives: To investigate factors that increase or decrease hand stereotypies in individuals with Rett syndrome. Methods: A questionnaire regarding hand stereotypies or purposeful hand behaviours was sent to 1016 schools for special needs education and 204 facilities in Japan. Results: Information was acquired from 216 cases (3-53 years old) with Rett syndrome; 81.9% and 87.6% of individuals had factors that increased and decreased stereotypical hand movements, respectively. Stereotypies were mainly increased by displeasure (63.8%) or pleasure (48.5%), and decreased by somnolence (43.5%), pleasure (30.0%), or food (24.1%). Conclusion: Emotion was the main factor increasing stereotypical hand movements, whereas there were a large number of factors that decreased these movements. The factors that decrease stereotypies could be useful to prevent the skin problems or joint contracture observed in patients with Rett syndrome.

Parents' perception of health care services for girls with Rett syndrome

BACKGROUND

Rett syndrome (RTT) is a severe neurodevelopmental disorder, implying impairment and disability across several domains.

METHOD

We investigated parents' perception of the caregiving process in a sample of 55 mothers and fathers of girls with RTT using the MPOC-20 questionnaire. The association of parents' satisfaction with clinical variables has also been explored.

RESULTS

We obtained intermediate levels of satisfaction on the MPOC-20 Coordinated and Comprehensive Care and Respectful and Supportive Care scales. The performance was lower on the scales Providing General Information and Providing Specific Information. Mothers' assessment was not associated with clinical variables such as walking disability, presence of scoliosis, or epilepsy. For children with greater degree of walking impairment, fathers expressed the need of having more information available.

CONCLUSIONS

Although parents seemed satisfied of the caregiving process, clinicians should put more emphasis on their need of receiving general and specific information on RTT along the entire rehabilitation program.

Transcriptome level analysis in Rett syndrome using human samples from different tissues

The mechanisms of neuro-genetic disorders have been mostly investigated in the brain, however, for some pathologies, transcriptomic analysis in multiple tissues represent an opportunity and a challenge to understand the consequences of the genetic mutation. This is the case for Rett Syndrome (RTT): a neurodevelopmental disorder predominantly affecting females that is characterised by a loss of purposeful movements and language accompanied by gait abnormalities and hand stereotypies. Although the genetic aetiology is largely associated to Methyl CpG binding protein 2 (MECP2) mutations, linking the pathophysiology of RTT and its clinical symptoms to direct molecular mechanisms has been difficult.One approach used to study the consequences of MECP2 dysfunction in patients, is to perform transcriptomic analysis in tissues derived from RTT patients or Induced Pluripotent Stem cells. The growing affordability and efficiency of this approach has led to a far greater understanding of the complexities of RTT syndrome but is also raised questions about previously held convictions such as the regulatory role of MECP2, the effects of different molecular mechanisms in different tissues and role of X Chromosome Inactivation in RTT.In this review we consider the results of a number of different transcriptomic analyses in different patients-derived preparations to unveil specific trends in differential gene expression across the studies. Although the analyses present limitations- such as the limited sample size- overlaps exist across these studies, and they report dysregulations in three main categories: dendritic connectivity and synapse maturation, mitochondrial dysfunction, and glial cell activity.These observations have a direct application to the disorder and give insights on the altered mechanisms in RTT, with implications on potential diagnostic criteria and treatments.

Neurophysiological and cognitive effects of Transcranial Direct Current Stimulation in three girls with Rett Syndrome with chronic language impairments

BACKGROUND

this study was based on both neurophysiological decelerated activity and communication deficits in Rett Syndrome (RTT).

AIMS

the aim was to examine the neurophysiological and cognitive effects of Transcranial Direct Current Stimulation (tDCS) in three girls with RTT with chronic language impairments.

METHODS AND PROCEDURES

we proposed an integrated intervention: tDCS and cognitive empowerment applied to language in order to enhance speech production (new functional sounds and new words). Because maximal gains usually are achieved when tDCS is coupled with behavioral training, we applied tDCS stimulation on Broca's area together with linguistic training.

OUTCOMES AND RESULTS

the results indicated a general enhancement in language abilities (an increase in the number of vowel/consonant sounds and words and the production and comprehension through discrimination), motor coordination (functional movements), and neurophysiological parameters (an increase in the frequency and power of alpha, beta and theta bands).

CONCLUSION AND IMPLICATIONS

we assume that tDCS stimulation combined with the cognitive empowerment applied to language can significantly influence a chronic impairment even in genetic syndromes. Our results provide data that support the role of tDCS in fostering brain plasticity and in particular in empowering speech production and comprehension in girls with RTT.

First report of an unusual novel double mutation affecting the transcription repression domain of MeCP2 and causing a severe phenotype of Rett syndrome: Molecular analyses and computational investigation

Rett syndrome is an X-linked neurodevelopmental disorder that develops a profound intellectual and motor disability and affects 1 from 10 000 to 15 000 live female births. This disease is characterized by a period of apparently normal development until 6-18 months of age when motor and communication abilities regress which is caused by mutations occurred in the X-linked MECP2 gene, encoding the methyl-CpG binding protein 2. This research study reports a molecular analysis via an exhaustive gene sequencing which reveals an unusual novel double mutation (c.695 G > T; c.880C > T) located in a highly conserved region in MECP2 gene affecting the transcription repression domain (TRD) of MeCP2 protein and leading for the first time to a severe phenotype of Rett syndrome. Moreover, a computational investigation of MECP2 mutations demonstrates that the novel mutation c.695 G > T is highly deleterious which affects the MeCP2 protein showing also an adverse impact on MECP2 gene expression and resulting in an affected folding and decreased stability of MECP2 structures. Thus, the altered TRD domain engenders a disrupted process of MECP2 functions. Therefore, this is the first study which highlights a novel double mutation among the transcription repression domain (TRD) of MeCP2 protein in Rett patient with a severe clinical phenotype in North Africa region.

Rett Syndrome: A Genetic Update and Clinical Review Focusing on Comorbidities

Rett syndrome (RTT) is a unique neurodevelopmental disorder that primarily affects females resulting in severe cognitive and physical disabilities. Despite the commendable collective efforts of the research community to better understand the genetics and underlying biology of RTT, there is still no cure. However, in the past 50 years, since the first report of RTT, steady progress has been made in the accumulation of clinical and molecular information resulting in the identification of a number of genes associated with RTT and associated phenotypes, improved diagnostic criteria, natural history studies, curation of a number of databases capturing genotypic and phenotypic data, a number of promising clinical trials and exciting novel therapeutic options which are currently being tested in laboratory and clinical settings. This Review focuses on the current knowledge of the clinical aspects of RTT, with particular attention being paid to clinical trials and the comorbidities of the disorder as well as the genetic etiology and the recognition of new diseases genes.

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.

Cognitive training modifies frequency EEG bands and neuropsychological measures in Rett syndrome

Rett syndrome (RS) is a childhood neurodevelopmental disorder characterized by a primary disturbance in neuronal development. Neurological abnormalities in RS are reflected in several behavioral and cognitive impairments such as stereotypies, loss of speech and hand skills, gait apraxia, irregular breathing with hyperventilation while awake, and frequent seizures. Cognitive training can enhance both neuropsychological and neurophysiological parameters. The aim of this study was to investigate whether behaviors and brain activity were modified by training in RS. The modifications were assessed in two phases: (a) after a short-term training (STT) session, i.e., after 30 min of training and (b) after long-term training (LTT), i.e., after 5 days of training. Thirty-four girls with RS were divided into two groups: a training group (21 girls) who underwent the LTT and a control group (13 girls) that did not undergo LTT. The gaze and quantitative EEG (QEEG) data were recorded during the administration of the tasks. A gold-standard eye-tracker and a wearable EEG equipment were used. Results suggest that the participants in the STT task showed a habituation effect, decreased beta activity and increased right asymmetry. The participants in the LTT task looked faster and longer at the target, and show increased beta activity and decreased theta activity, while a leftward asymmetry was re-established. The overall result of this study indicates a positive effect of long-term cognitive training on brain and behavioral parameters in subject with RS.

Rett syndrome: disruption of epigenetic control of postnatal neurological functions

Loss-of-function mutations in the X-linked gene Methyl-CpG-binding protein 2 (MECP2) cause a devastating pediatric neurological disorder called Rett syndrome. In males, these mutations typically result in severe neonatal encephalopathy and early lethality. On the other hand, owing to expression of the normal allele in ∼50% of cells, females do not suffer encephalopathy but instead develop Rett syndrome. Typically females with Rett syndrome exhibit a delayed onset of neurologic dysfunction that manifests around the child's first birthday and progresses over the next few years. Features of this disorder include loss of acquired language and motor skills, intellectual impairment and hand stereotypies. The developmental regression observed in patients with Rett syndrome arises from altered neuronal function and is not the result of neurodegeneration. Maintenance of an appropriate level of MeCP2 appears integral to the function of healthy neurons as patients with increased levels of MeCP2, owing to duplication of the Xq28 region encompassing the MECP2 locus, also present with intellectual disability and progressive neurologic symptoms. Despite major efforts over the past two decades to elucidate the molecular functions of MeCP2, the mechanisms underlying the delayed appearance of symptoms remain unclear. In this review, we will highlight recent findings that have expanded our knowledge of MeCP2's functions, and we will discuss how epigenetic regulation, chromatin organization and circuit dynamics may contribute to the postnatal onset of Rett syndrome.

The methyl-CpG-binding domain (MBD) is crucial for MeCP2's dysfunction-induced defects in adult newborn neurons

Mutations in the human X-linked gene MECP2 are responsible for most Rett syndrome (RTT) cases, predominantly within its methyl-CpG-binding domain (MBD). To examine the role of MBD in the pathogenesis of RTT, we generated two MeCP2 mutant constructs, one with a deletion of MBD (MeCP2-ΔMBD), another mimicking a mutation of threonine 158 within the MBD (MeCP2-T158M) found in RTT patients. MeCP2 knockdown resulted in a decrease in total dendrite length, branching, synapse number, as well as altered spontaneous Ca(2+) oscillations in vitro, which could be reversed by expression of full length human MeCP2 (hMeCP2-FL). However, the expression of hMeCP2-ΔMBD in MeCP2-silenced neurons did not rescue the changes in neuronal morphology and spontaneous Ca(2+) oscillations, while expression of hMeCP2-T158M in these neurons could only rescue the decrease in dendrite length and branch number. In vivo over expression of hMeCP2-FL but not hMeCP2-ΔMBD in adult newborn neurons of the dentate gyrus also rescued the cell autonomous effect caused by MeCP2 deficiency in dendrites length and branching. Our results demonstrate that an intact and functional MBD is crucial for MeCP2 functions in cultured hippocampal neurons and adult newborn neurons.