Consensus clinical management guidelines for Friedreich ataxia

Early onset development of hypertrophic cardiomyopathy in less than 1 year in a patient with familial Friedrich's ataxia: Case report

Friedreich's ataxia (FRDA) is a neurodegenerative disease characterized by progressive ataxia, dysarthria, sensory loss. While neurological symptoms are prominent, cardiac manifestations significantly contribute to mortality. Cardiomyopathy in Friedreich's disease results from mitochondrial dysfunction, loss of contractile proteins and an accumulation of fibrosis in heart. To better characterize the severity of cardiac involvement, the MICONOS study group developed a classification system categorizing FRDA cardiomyopathy as "no," "mild," "intermediate," "severe." We report an uncommon case of early-onset development of hypertrophic cardiomyopathy (HCM) in a 25-year-old female diagnosed with Friedreich's ataxia (FRDA) at age 12. Through annual cardiac evaluations, no signs of cardiac disease were noted. Until presenting with dyspnea and palpitations. Clinical examination revealed truncal ataxia and dysarthria, but no signs of heart failure. However, a transthoracic echocardiography demonstrated nonobstructive hypertrophic cardiomyopathy with a maximal wall thickness of 20 mm, incomplete anterior systolic motion of the mitral valve, a significant development in less than 1 year after last normal cardiac assessment. Left ventricular systolic function was preserved (ejection fraction 50%). She was prescribed bisoprolol and dapagliflozin, with significant improvement at her latest checkup. Family screening revealed HCM in her 30 year female sibling, who also has FRDA. No cardiac abnormalities were detected in her younger brother or parents. Friedreich's hypertrophic cardiomyopathy has been reported as the most significant cause of mortality, especially among younger patients with early onset disease manifestations.

Comparison of specialist ataxia centres with non-specialist services in terms of care access and organisation, health services resource utilisation and costs in Germany using patient-reported data

Background

The ataxias are rare complex neurological disorders challenging to diagnose and manage. We explored the patient pathways, health care use and costs of individuals attending a specialist ataxia centre (SAC) compared with non-specialist settings in Germany.

Methods

We distributed a survey to people with ataxia to gather information about diagnosis and management of the ataxias, utilisation of health care services, and patients' satisfaction in both SAC and non-specialist settings. We compared mean resource use and health service costs per patient, stratifying by whether patients attended a SAC or not.

Results

We collected and analysed responses from 101 participants. For patients who visited both a SAC and a standard neurology clinic, 67.2 % reported that the care received at a SAC was better. Positive feedback about SAC services included understanding their condition (66.7 % positive feedback), giving practical advice to manage better their ataxia (66.7 % positive feedback) and offering opportunities to take part in research (79.2 % positive feedback). Costs were not significantly different between those attending a SAC and those who did not, although the average cost per patient per year found in SACs was higher compared with non-SACs. The mean total cost per patient over a one-year period was €2091 for non-SAC patients and €4043 for SAC patients (P = 0.19 in adjusted analyses). We identified barriers in accessing SACs including the lack of clear referral pathway and the travel required to such centres. We made recommendations about gaps identified in the care provided based on people's experience and feedback.

Conclusions

This study provides useful information about ataxia patient care pathways in Germany, with higher patients' satisfaction in SAC compared to non-SAC, without a significant difference in costs. The findings can be used to change policy for better care for people with these rare complex neurological diseases.

Drug Treatments for Neurodevelopmental Disorders: Targeting Signaling Pathways and Homeostasis

PURPOSE OF THE REVIEW

Preclinical and clinical evidence support the notion that neurodevelopmental disorders (NDDs) are synaptic disorders, characterized by excitatory-inhibitory imbalance. Despite this, NDD drug development programs targeting glutamate or gamma-aminobutyric acid (GABA) receptors have been largely unsuccessful. Nonetheless, recent drug trials in Rett syndrome (RTT), fragile X syndrome (FXS), and other NDDs targeting other mechanisms have met their endpoints. The purpose of this review is to identify the basis of these successful studies.

RECENT FINDINGS

Despite increasing evidence of disruption in synaptic homeostasis, most genetic variants associated with NDDs implicate proteins involved in cell regulation and not in neurotransmission. Metabolic processes, in particular mitochondrial function, appear to play a role in NDD pathophysiology. NDDs are also characterized by distinctive cell signaling abnormalities, which link cellular and synaptic homeostasis. Recent successful trials in NDDs, including those of trofinetide, the first drug specifically approved for one of these disorders (i.e., RTT), implicate the targeting of downstream processes (i.e., signaling pathways) rather than neurotransmitter receptors. Recent positive drug studies in NDDs and their underlying mechanisms, in conjunction with new knowledge on the pathophysiology of these disorders, support the concept that targeting signaling and cellular and synaptic homeostasis may be a preferred approach for ameliorating synaptic abnormalities in many NDDs.

Comparison of specialist ataxia centres with non-specialist services in terms of treatment, care, health services resource utilisation and costs in the UK using patient-reported data

OBJECTIVES

This study aims to assess the patient-reported benefits and the costs of coordinated care and multidisciplinary care at specialist ataxia centres (SACs) in the UK compared with care delivered in standard neurological clinics.

DESIGN

A patient survey was distributed between March and May 2019 to patients with ataxia or carers of patients with ataxia through the Charity Ataxia UK's mailing list, website, magazine and social media to gather information about the diagnosis, management of the ataxias in SAC and non-specialist settings, utilisation of various healthcare services and patients' satisfaction. We compared mean resource use for each contact type and health service costs per patient, stratifying patients by whether they were currently attending a SAC or never attended one.

SETTING

Secondary care including SACs and general neurology clinics.

PARTICIPANTS

We had 277 participants in the survey, aged 16 years old and over, diagnosed with ataxia and living in the UK.

PRIMARY OUTCOME MEASURES

Patient experience and perception of the two healthcare services settings, patient level of satisfaction, difference in healthcare services use and costs.

RESULTS

Patients gave positive feedback about the role of SAC in understanding their condition (96.8% of SAC group), in coordinating referrals to other healthcare specialists (86.6%), and in offering opportunities to take part in research studies (85.2%). Participants who attended a SAC reported a better management of their symptoms and a more personalised care received compared with participants who never attended a SAC (p<0.001). Costs were not significantly different in between those attending a SAC and those who did not. We identified some barriers for patients in accessing the SACs, and some gaps in the care provided, for which we made some recommendations.

CONCLUSIONS

This study provides useful information about ataxia patient care pathways in the UK. Overall, the results showed significantly higher patient satisfaction in SAC compared with non-SAC, at similar costs. The findings can be used to inform policy recommendations on how to improve treatment and care for people with these very rare and complex neurological diseases. Improving access to SAC for patients across the UK is one key policy recommendation of this study.

Perioperative management and outcomes for posterior spinal fusion in patients with Friedreich ataxia: A single-center, retrospective study

BACKGROUND

Friedreich ataxia is a rare genetic disorder associated with progressive mitochondrial dysfunction leading to widespread sequelae including ataxia, muscle weakness, hypertrophic cardiomyopathy, diabetes mellitus, and neuromuscular scoliosis. Children with Friedreich ataxia are at high risk for periprocedural complications during posterior spinal fusion due to their comorbidities.

AIM

To describe our single-center perioperative management of patients with Friedreich ataxia undergoing posterior spinal fusion.

METHODS

Adolescent patients with Friedreich ataxia presenting for spinal deformity surgery between 2007 and 2023 were included in this retrospective case series performed at the Children's Hospital of Philadelphia. Perioperative outcomes were reviewed along with preoperative characteristics, intraoperative anesthetic management, and postoperative medical management.

RESULTS

Seventeen patients were included in the final analysis. The mean age was 15 ± 2 years old and 47% were female. Preoperatively, 35% were wheelchair dependent, 100% had mild-to-moderate hypertrophic cardiomyopathy with preserved systolic function and no left ventricular outflow tract obstruction, 29% were on cardiac medications, and 29% were on pain medications. Intraoperatively, 53% had transesophageal echocardiography monitoring; 12% had changes in volume status on echo but no changes in function. Numerous combinations of total intravenous anesthetic agents were used, most commonly propofol, remifentanil, and ketamine. Baseline neuromonitoring signals were poor in four patients and one patient lost signals, resulting in 4 (24%) wake-up tests. The majority (75%) were extubated in the operating room. Postoperative complications were high (88%) and ranged from minor complications like nausea/vomiting (18%) to major complications like hypotension/tachycardia (29%) and need for extracorporeal membrane oxygenation support in one patient (6%).

CONCLUSIONS

Patients with Friedreich ataxia are at high risk for perioperative complications when undergoing posterior spinal fusion and coordinated multidisciplinary care is required at each stage. Future research should focus on the utility of intraoperative echocardiography, optimal anesthetic agent selection, and targeted fluid management to reduce postoperative cardiac complications.

The Care and Management of Children and Young People with Ataxia Telangiectasia Provided by Nurses and Allied Health Professionals: a Scoping Review

Ataxia telangiectasia (A-T) is a rare, multisystem progressive condition that typically presents in early childhood. In the absence of cure, people with A-T require coordinated multidisciplinary care to manage their complex array of needs and to minimize the disease burden. Although symptom management has proven benefits for this population, including improved quality of life and reduced complications, there is a need for guidance specific to the nursing and allied healthcare teams who provide care within the community. A scoping review, adopting the Joanna Briggs Institute methodology, was undertaken. It aimed to identify and map the available expertise from nursing and allied healthcare and management of children and young people with A-T ≤ 18 years of age. A rigorous search strategy was employed which generated a total of 21,118 sources of evidence, of which 50 were selected for review following screening by experts. A range of interventions were identified that reported a positive impact on A-T-related impairments, together with quality of life, indicating that outcomes can be improved for this population. Most notable interventions specific to A-T include therapeutic exercise, inspiratory muscle training, and early nutritional assessment and intervention. Further research will be required to determine the full potential of the identified interventions, including translatability to the A-T setting for evidence related to other forms of ataxia. Large gaps exist in the nursing and allied health evidence-base, highlighting a need for robust research that includes children and young people with A-T and their families to better inform and optimize management strategies.

Targeted genetic therapies for inherited disorders that affect both cardiac and skeletal muscle

Skeletal myopathies and ataxias with secondary cardiac involvement are complex, progressive and debilitating conditions. As life expectancy increases across these conditions, cardiac involvement often becomes more prominent. This highlights the need for targeted therapies that address these evolving cardiac pathologies. Musculopathies by and large lack cures that directly target the genetic basis of the diseases; however, as our understanding of the genetic causes of these conditions has evolved, it has become tractable to develop targeted therapies using biologics, to design precision approaches to target the primary genetic causes of these varied diseases. Using the examples of Duchenne muscular dystrophy, Friedreich ataxia and Pompe disease, we discuss how the genetic causes of such diseases derail diverse homeostatic, energetic and signalling pathways, which span multiple cellular systems in varied tissues across the body. We outline existing therapeutics and treatments in the context of emerging novel genetic approaches. We discuss the hurdles that the field must overcome to deliver targeted therapies across the many tissue types affected in primary myopathies.

Propensity matched comparison of omaveloxolone treatment to Friedreich ataxia natural history data

OBJECTIVE

The natural history of Friedreich ataxia is being investigated in a multi-center longitudinal study designated the Friedreich ataxia Clinical Outcome Measures Study (FACOMS). To understand the utility of this study in analysis of clinical trials, we performed a propensity-matched comparison of data from the open-label MOXIe extension (omaveloxolone) to that from FACOMS.

METHODS

MOXIe extension patients were matched to FACOMS patients using logistic regression to estimate propensity scores based on multiple covariates: sex, baseline age, age of onset, baseline modified Friedreich Ataxia Rating scale (mFARS) score, and baseline gait score. The change from baseline in mFARS at Year 3 for the MOXIe extension patients compared to the matched FACOMS patients was analyzed as the primary efficacy endpoint using mixed model repeated measures analysis.

RESULTS

Data from the MOXIe extension show that omaveloxolone provided persistent benefit over 3 years when compared to an untreated, matched cohort from FACOMS. At each year, in all analysis populations, patients in the MOXIe extension experienced a smaller change from baseline in mFARS score than matched FACOMS patients. In the primary pooled population (136 patients in each group) by Year 3, patients in the FACOMS matched set progressed 6.6 points whereas patients treated with omaveloxolone in MOXIe extension progressed 3 points (difference = -3.6; nominal p value = 0.0001).

INTERPRETATION

These results suggest a meaningful slowing of Friedreich ataxia progression with omaveloxolone, and consequently detail how propensity-matched analysis may contribute to understanding of effects of therapeutic agents. This demonstrates the direct value of natural history studies in clinical trial evaluations.

Novel intragenic deletion within the FXN gene in a patient with typical phenotype of Friedreich ataxia: may be more prevalent than we think?

BACKGROUND

Friedreich ataxia is the most common inherited ataxia in Europe and is mainly caused by biallelic pathogenic expansions of the GAA trinucleotide repeat in intron 1 of the FXN gene that lead to a decrease in frataxin protein levels. Rarely, affected individuals carry either a large intragenic deletion or whole-gene deletion of FXN on one allele and a full-penetrance expanded GAA repeat on the other allele.

CASE PRESENTATION

We report here a patient that presented the typical clinical features of FRDA and genetic analysis of FXN intron 1 led to the assumption that the patient carried the common biallelic expansion. Subsequently, parental sample testing led to the identification of a novel intragenic deletion involving the 5'UTR upstream region and exons 1 and 2 of the FXN gene by MLPA.

CONCLUSIONS

With this case, we want to raise awareness about the potentially higher prevalence of intragenic deletions and underline the essential role of parental sample testing in providing accurate genetic counselling.

Patient pathways for rare diseases in Europe: ataxia as an example

BACKGROUND

Progressive ataxias are rare and complex neurological disorders that represent a challenge for the clinicians to diagnose and manage them. This study explored the patient pathways of individuals attending specialist ataxia centres (SAC) compared with non-specialist settings. We investigated specifically how diagnosis was reached, the access to healthcare services, treatments, and care satisfaction. The focus of this study was on early intervention, coordination of treatment to understand the care provision in different countries.

METHODS

A patient survey was done in the UK, Germany and Italy to gather information about diagnosis and management of the ataxias in specialist (SAC) and non-specialist settings, utilisation of other primary and secondary health care services, and patients' satisfaction of received treatment.

RESULTS

Patients gave positive feedback about the role of SAC in understanding their condition, ways to manage their ataxia (p < 0.001; UK) and delivering care adapted to their needs (p < 0.001; UK), in coordinating referrals to other healthcare specialists, and in offering opportunities to take part in research studies. Similar barriers for patients were identified in accessing the SACs among the selected countries, UK, Germany, and Italy.

CONCLUSIONS

This study provides crucial information about the ataxia patients care pathways in three European countries. Overall, the results showed a trend in patients' satisfaction being better in SAC compared to non-SAC. The outcomes can be used now for policy recommendations on how to improve treatment and care for people with these very rare and complex neurological diseases across Europe.

A natural history study to track brain and spinal cord changes in individuals with Friedreich's ataxia: TRACK-FA study protocol

INTRODUCTION

Drug development for neurodegenerative diseases such as Friedreich's ataxia (FRDA) is limited by a lack of validated, sensitive biomarkers of pharmacodynamic response in affected tissue and disease progression. Studies employing neuroimaging measures to track FRDA have thus far been limited by their small sample sizes and limited follow up. TRACK-FA, a longitudinal, multi-site, and multi-modal neuroimaging natural history study, aims to address these shortcomings by enabling better understanding of underlying pathology and identifying sensitive, clinical trial ready, neuroimaging biomarkers for FRDA.

METHODS

200 individuals with FRDA and 104 control participants will be recruited across seven international study sites. Inclusion criteria for participants with genetically confirmed FRDA involves, age of disease onset ≤ 25 years, Friedreich's Ataxia Rating Scale (FARS) functional staging score of ≤ 5, and a total modified FARS (mFARS) score of ≤ 65 upon enrolment. The control cohort is matched to the FRDA cohort for age, sex, handedness, and years of education. Participants will be evaluated at three study visits over two years. Each visit comprises of a harmonized multimodal Magnetic Resonance Imaging (MRI) and Spectroscopy (MRS) scan of the brain and spinal cord; clinical, cognitive, mood and speech assessments and collection of a blood sample. Primary outcome measures, informed by previous neuroimaging studies, include measures of: spinal cord and brain morphometry, spinal cord and brain microstructure (measured using diffusion MRI), brain iron accumulation (using Quantitative Susceptibility Mapping) and spinal cord biochemistry (using MRS). Secondary and exploratory outcome measures include clinical, cognitive assessments and blood biomarkers.

DISCUSSION

Prioritising immediate areas of need, TRACK-FA aims to deliver a set of sensitive, clinical trial-ready neuroimaging biomarkers to accelerate drug discovery efforts and better understand disease trajectory. Once validated, these potential pharmacodynamic biomarkers can be used to measure the efficacy of new therapeutics in forestalling disease progression.

CLINICAL TRIAL REGISTRATION

ClinicalTrails.gov Identifier: NCT04349514.

Clinical management guidelines for Friedreich ataxia: best practice in rare diseases

BACKGROUND

Individuals with Friedreich ataxia (FRDA) can find it difficult to access specialized clinical care. To facilitate best practice in delivering healthcare for FRDA, clinical management guidelines (CMGs) were developed in 2014. However, the lack of high-certainty evidence and the inadequacy of accepted metrics to measure health status continues to present challenges in FRDA and other rare diseases. To overcome these challenges, the Grading of Recommendations Assessment and Evaluation (GRADE) framework for rare diseases developed by the RARE-Bestpractices Working Group was adopted to update the clinical guidelines for FRDA. This approach incorporates additional strategies to the GRADE framework to support the strength of recommendations, such as review of literature in similar conditions, the systematic collection of expert opinion and patient perceptions, and use of natural history data.

METHODS

A panel representing international clinical experts, stakeholders and consumer groups provided oversight to guideline development within the GRADE framework. Invited expert authors generated the Patient, Intervention, Comparison, Outcome (PICO) questions to guide the literature search (2014 to June 2020). Evidence profiles in tandem with feedback from individuals living with FRDA, natural history registry data and expert clinical observations contributed to the final recommendations. Authors also developed best practice statements for clinical care points that were considered self-evident or were not amenable to the GRADE process.

RESULTS

Seventy clinical experts contributed to fifteen topic-specific chapters with clinical recommendations and/or best practice statements. New topics since 2014 include emergency medicine, digital and assistive technologies and a stand-alone section on mental health. Evidence was evaluated according to GRADE criteria and 130 new recommendations and 95 best practice statements were generated.

DISCUSSION AND CONCLUSION

Evidence-based CMGs are required to ensure the best clinical care for people with FRDA. Adopting the GRADE rare-disease framework enabled the development of higher quality CMGs for FRDA and allows individual topics to be updated as new evidence emerges. While the primary goal of these guidelines is better outcomes for people living with FRDA, the process of developing the guidelines may also help inform the development of clinical guidelines in other rare diseases.

Prevalence of neurodegenerative/demyelinating disorders in patients with achalasia

Introduction

Esophageal achalasia is a primary motility disorder. Although the exact pathogenesis is unknown, autoimmune, and neurodegenerative processes seem to be involved similarly to neurodegenerative and/or demyelinating disorders (NDDs). We hypothesized that the prevalence of NDD may be higher among patients with achalasia and vice versa as the background pathogenetic mechanisms are similar.

Methods

This was a prospective, comparative questionnaire-based study. Patients with achalasia and patients with NDD were enrolled. Selected patients with achalasia were thoroughly examined by a neurologist and selected patients with NDD were examined by a gastroenterologist to confirm or rule out NDD or achalasia. We assessed the prevalence of both achalasia and NDD and compared them with their prevalence in general population.

Results

A total of 150 patients with achalasia and 112 patients with NDD were enrolled. We observed an increased prevalence of NDD among patients with achalasia (6.0% (9/150); 95% CI (confidence interval): 3.1–11.2%) as compared to the estimated 2.0% prevalence in general population (p = 0.003). Although 32 out of 112 patients (28.6%) with NDD reported dysphagia, we did not observe significantly increased prevalence of achalasia in these patients (1.8% (2/112) vs 0.8% in general population, p = 0.226).

Conclusion

The prevalence of NDD was significantly higher among patients with achalasia (6.0%) compared to general population (2.0%), suggesting an association of these disorders. Large-volume studies are necessary to confirm this finding.

Friedreich ataxia: clinical features and new developments

Friedreich's ataxia (FRDA), a neurodegenerative disease characterized by ataxia and other neurological features, affects 1 in 50,000-100,000 individuals in the USA. However, FRDA also includes cardiac, orthopedic and endocrine dysfunction, giving rise to many secondary disease characteristics. The multifaceted approach for clinical care has necessitated the development of disease-specific clinical care guidelines. New developments in FRDA include the advancement of clinical drug trials targeting the NRF2 pathway and frataxin restoration. Additionally, a novel understanding of gene silencing in FRDA, reflecting a variegated silencing pattern, will have applications to current and future therapeutic interventions. Finally, new perspectives on the neuroanatomy of FRDA and its developmental features will refine the time course and anatomical targeting of novel approaches.

The Use of Enhanced Recovery After Surgery Protocols and Sugammadex in a Friedreich Ataxia Patient Who Underwent Robotic Surgery: A Case Report of a Patient Who Required No Postoperative Opioids and Was Discharged Home Earlier Than Anticipated

Robotic surgery has shown to have numerous benefits over traditional and laparoscopic surgery, namely, superior precision and improved recovery with shorter hospital stays. However, robotic surgery also presents several issues, including hemodynamic changes related to positioning and the use of pneumoperitoneum. These matters can be problematic in patients with neuromuscular conditions such as Friedreich ataxia (FRDA). Due to a baseline weakened musculature and a higher prevalence of cardiac disease and scoliosis, patients with FRDA may not be as likely to tolerate the cardiopulmonary physiologic changes associated with robotic surgery. Additionally, positioning for robotic surgery can be challenging in FRDA patients who have progressed to spasticity and contractures. To the best of our knowledge, there are no case reports of approaches specifically discussing anesthesia management for robotic surgery in the FRDA patient population.

Anesthesia in general must be carefully planned in FRDA patients to allow for the best possible recovery and minimize complications. Due to the underlying neuromuscular compromise seen in these patients, their ability to recover from the pharmacologic and physiologic changes associated with anesthesia can be more difficult. They are prone to sensitivity to opioids, sedatives, and neuromuscular blocking agents (NMBAs) and are less likely to tolerate hemodynamic changes. Our review revealed no literature to suggest the routine use of Enhanced Recovery After Surgery (ERAS) protocols in FRDA patients or in patients with neuromuscular disease in general.

The use of sugammadex has also been shown to be safe, and literature suggests superiority in both the general population and those with neuromuscular conditions. Our understanding is that there is very limited literature in regard to the safe use of sugammadex in FRDA patients.

Respiratory Function in Friedreich’s Ataxia

Background: Friedreich’s ataxia is an inherited, rare, progressive disorder of children and young adults. It is characterized by ataxia, loss of gait, scoliosis, cardiomyopathy, dysarthria and dysphagia, with reduced life expectancy. Alterations of respiratory dynamics and parameters are frequently observed. However, in the literature there are few, dated studies with small cohorts. Our study aims to make an objective analysis of the respiratory condition of both early and late stage FRDA patients, looking for correlations with the motor, skeletal, speech and genetic aspects of this condition. Materials and methods: This retrospective observational study is based on the collection of clinical and instrumental respiratory data of 44 subjects between 13 and 51 years attending a tertiary rehabilitation centre in northern Italy. The analysis was carried out using Pearson’s correlation test, ANOVA test and post hoc tests. Results: Data show the presence of a recurrent pattern of respiratory dysfunction of a restrictive type, with reduction in forced vital capacity and of flow and pressure parameters. The severity of the respiratory condition correlates with the disease severity (measured with disease-specific scales), with pneumophonic alterations and with the severity of the thoracic scoliotic curve. Conclusions: Respiratory function is impaired at various degrees in FRDA. The complex condition of inco-ordination and hyposthenia in FRDA affects daytime and night-time respiratory efficiency. We believe that the respiratory deficit and the inefficiency of cough are indeed a clinical problem deserving consideration, especially in the context of the concomitant postural difficulty and the possible presence of dysphagia. Therefore, the rehabilitation project for the subject with FRDA should also consider the respiratory function.

Importance of an echocardiogram in the evaluation of ataxia

We present the case of a boy in his middle childhood with gait ataxia and loss of reflexes with a 1-year onset. He had a background of an autism spectrum disorder but was otherwise healthy. A paediatric cardiology assessment was requested to investigate possible cardiac involvement associated to his neurological symptoms. Even though he had no cardiac symptoms and a normal electrocardiography, the echocardiogram revealed severe asymmetric left ventricle hypertrophy consistent with hypertrophic cardiomyopathy. This prompted genetic testing and the diagnosis of Friedreich's ataxia was confirmed.

Classification of Vital Genetic Syndromes Associated With Diabetes Using ANN-Based CapsNet Approach

Diabetes has been linked to a wide range of genetic abnormalities or disorders like Cushing syndrome, Wolfram’s syndrome. The factual significance of these relatively uncommon disorders originates from the knowledge that supplies into the potential processes driving prevalent diabetes. Diabetes-related syndromes are presently classified based on clinical and biochemical characteristics. However, until now, no expertise classification strategies are developed for classifying diabetes-associated syndrome disorders efficiently and accurately. Thus, we introduce an Artificial Neural Network framework based on CapsNets to categorize vital genetic disorders related to diabetes. Here, a capsule represents a bundle or set of neurons used to retain data about an essential subject and provides precise information in each image. The suggested approach was systematically compared using cutting-edge methods and basic classification models. With an overall 91.4 percent accuracy, the proposed CapsNets-based method provides the best sensitivity89.93%, specificity 90.77%, and F1-score value 93.10%

Recessive cerebellar and afferent ataxias - clinical challenges and future directions

Cerebellar and afferent ataxias present with a characteristic gait disorder that reflects cerebellar motor dysfunction and sensory loss. These disorders are a diagnostic challenge for clinicians because of the large number of acquired and inherited diseases that cause cerebellar and sensory neuron damage. Among such conditions that are recessively inherited, Friedreich ataxia and RFC1-associated cerebellar ataxia, neuropathy, vestibular areflexia syndrome (CANVAS) include the characteristic clinical, neuropathological and imaging features of ganglionopathies, a distinctive non-length-dependent type of sensory involvement. In this Review, we discuss the typical and atypical phenotypes of Friedreich ataxia and CANVAS, along with the features of other recessive ataxias that present with a ganglionopathy or polyneuropathy, with an emphasis on recently described clinical features, natural history and genotype-phenotype correlations. We review the main developments in understanding the complex pathology that affects the sensory neurons and cerebellum, which seem to be most vulnerable to disorders that affect mitochondrial function and DNA repair mechanisms. Finally, we discuss disease-modifying therapeutic advances in Friedreich ataxia, highlighting the most promising candidate molecules and lessons learned from previous clinical trials.

Clinical evidence of interventions assessed in Friedreich ataxia: a systematic review

Objectives

The rare inherited autosomal recessive disease Friedreich ataxia (FA) causes progressive neurodegenerative changes and disability in patients. A systematic literature review (SLR) was carried out to understand and summarize the published efficacy and safety of therapeutic interventions in this disease.

Methods

Database searches were carried out in MEDLINE, Embase, and Cochrane by two independent reviewers. In addition, trial registries and conference proceedings were hand-searched.

Results

Thirty-two publications were deemed eligible according to PICOS criteria. Twenty-four publications detail randomized controlled trials. The most frequently identified therapeutic intervention was idebenone (n = 11), followed by recombinant erythropoietin (n = 6), omaveloxolone (n = 3), and amantadine hydrochloride (n = 2). Other therapeutic interventions were investigated in one publication: A0001, CoQ10, creatine, deferiprone, interferon-γ-1b, the L-carnitine levorotatory form of 5-hydroxytryptophan, luvadaxistat, resveratrol, RT001, and vatiquinone (EPI-743). These studies included patients from 8 to 73 years old, and disease duration varied from 4.7 to 19 years. Disease severity as per the mean GAA1 and GAA2 allele repeat length ranged from 350 to 930 and 620 to 987 nucleotides, respectively. Most frequently reported efficacy outcomes were the International Cooperative Ataxia Rating Scale (ICARS, n = 10), the Friedreich Ataxia Rating Scale (modified FARS and FARS-neuro, n = 12), the Scale for Assessment and Rating of Ataxia (SARA, n = 7), and the Activities of Daily Living scale (ADL, n = 8). Each of these assesses the severity of disability in FA patients. In many studies, patients with FA deteriorated according to these severity scales regardless of treatment, or inconclusive results were found. Generally, these therapeutic interventions were well-tolerated and safe. Serious adverse events were atrial fibrillation (n = 1), craniocerebral injury (n = 1), and ventricular tachycardia (n = 1).

Conclusion

Identified literature showed a considerable unmet need for therapeutic interventions that halt or slow the deteriorating nature of FA. Novel efficacious drugs should be investigated that aim to improve symptoms or slow disease progression.

Symptom burden of people with progressive ataxia, and its wider impact on their friends and relatives: a cross-sectional study

Background

Progressive ataxias are complex disorders that result in a wide variety of symptoms. Whilst we currently have a relatively good understanding of the symptom patterns associated with the various types of ataxia, and how these diseases progress over time, their impact on the person with ataxia is less well understood. In addition, little is known about how carers, friends and families are affected by them. This paper aims to provide preliminary information on the presence and impact of medical symptoms and day-to-day challenges on people with ataxia and their friends and relatives.

Method

Data were extracted from a survey by Ataxia UK for their members. The views of 366 people with ataxia and 52 friends and relatives are reported. Data were analysed for the entire groups, as well as for the three most common ataxia types represented in the sample, Friedreich's ataxia, inherited ataxia (excluding Friedreich's ataxia), and cerebellar ataxia of unknown cause.

Results

The survey confirmed the symptom patterns described in previous research, but further showed that the impact of these symptoms can vary across ataxia populations. Similar findings were observed for day-to-day challenges. Friends and relatives experienced similar challenges to people with ataxia, indicating that support provided has to consider those supporting people with ataxia as well as the patient. Respondents also highlighted limitations in terms of accessing support services, and not all services were able to cater fully to their specific needs.

Conclusion

This study begins to provide information that can be used in further research to explore the needs of people with ataxia and their carers, friends, and relatives. Such research will support treatment trial design, ensuring patients' needs are considered, help to tailor support services to their needs, and ensure health care professionals have the necessary skills to fully address them.

Diagnosis and Management of Cardiovascular Involvement in Friedreich Ataxia

Friedreich ataxia (FRDA) is an autosomal recessive neurodegenerative disorder caused by a homozygous GAA triplet repeat expansion in the frataxin gene. Cardiac involvement, usually manifesting as hypertrophic cardiomyopathy, can range from asymptomatic cases to severe cardiomyopathy with progressive deterioration of the left ventricular ejection fraction and chronic heart failure. The management of cardiac involvement is directed to prevent disease progression and cardiovascular complications. However, direct-disease therapies are not currently available for FRDA. The present review aims to describe the current state of knowledge regarding cardiovascular involvement of FRDA, focusing on clinical-instrumental features and management of cardiac manifestation.

Molecular approaches for the treatment and prevention of Friedreich's ataxia

Friedreich's ataxia (FRDA) is caused by an intronic guanine-adenine-adenine (GAA) trinucleotide expansion in the gene encoding the frataxin protein (FXN). This triggers the transcriptional silencing of the fratxin gene (FXN) and subsequent FXN deficiency in affected cells, which accounts for the multisystemic symptoms of this condition. Current management strategies aim for symptomatic relief and no treatments can prevent disease onset or progression. Thus, research efforts have focused on targeting the molecular pathways that silence FXN and downstream pathological processes. However, progression of potential therapies into clinical use has been hindered by inconclusive clinical trials because of the small patient sample size associated with the low prevalence of this condition. Here, we discuss various molecular approaches and explore their therapeutic potential to alter the course of this progressive condition.

Left atrial appendage thrombosis in a patient with Friedreich Ataxia-related cardiomyopathy, left ventricular systolic dysfunction, and atrial fibrillation

Friedreich ataxia is the most common form of hereditary ataxia. Heart involvement in Friedreich ataxia is common and can include increased left ventricular wall thickness, atrial fibrillation, and in the later stages, a reduction of left ventricular ejection fraction. We present the case of a 45-year-old man with a history of paroxysmal atrial fibrillation and a congestive heart failure, hypertension, age ⩾ 75 years, diabetes mellitus, stroke, vascular disease, age 65–74 years, and female sex (CHA2DS2-VASc) score of only 1 (because of reduced left ventricular ejection fraction) who presented with pneumonia and was also found to have atrial fibrillation with a rapid ventricular response. Despite already being on long-term therapy with a non-vitamin K-antagonist oral anticoagulant, a transesophageal echocardiogram showed a mobile floating thrombus in the left atrial appendage. In accordance with previous necropsy evidence of thrombosis and thromboembolism in Friedreich ataxia subjects who likely have had only non-sex-related CHA2DS2-VASc score ⩽1, this case suggests that the risk of thromboembolism in Friedreich ataxia subjects with atrial fibrillation may not be adequately predicted by the sole CHA2DS2-VASc score.

Mitochondrial iron-sulfur cluster biogenesis and neurological disorders

Iron-sulfur clusters (ISCs) are highly conserved moieties embedded into numerous crucial proteins in almost all bacteria, plants and mammals. As such, ISC biosynthesis is critical to cellular function. The pathway was first characterized in bacteria by the late 1990s, and over the subsequent 20 years there has been increasing understanding of its components in humans. Defects in the ISC pathway are now associated with many different human disease states, such as Friedreich ataxia and ISCU myopathy. Whilst the disorders have variable clinical features, most involve neurological phenotypes. There are common biochemical signatures in most of these conditions, as a lack of ISCs causes deficiencies of target proteins including Complex I, II and III, aconitase and lipoic acid. This review focuses on the disorders of ISC biogenesis that have been described in the literature to-date. Key clinical, biochemical and neuroradiological features will be discussed, providing a reference point for clinicians diagnosing and managing these patients. Therapies are mostly supportive at this stage. However, the improved understanding of the pathophysiology of these conditions could pave the way for disease-modifying therapies in the near future.

Very late-onset Friedreich's ataxia with rapid course mimicking as possible multiple system atrophy cerebellar type

This 55-year-old man was admitted to the hospital with an insidious onset, progressive backward fall (due to severe truncal ataxia), dysarthria, stiffness in extremities, distal dominant muscle wasting along with behavioural changes and urinary incontinence. Clinical assessment indicated mild cognitive decline (Mini-Mental State Examination 22/27) with cerebellar, pyramidal and peripheral nerves involvement. On investigations, nerve conduction studies revealed symmetrical, sensorimotor peripheral neuropathy affecting both lower limbs. Brain and whole spine MRI revealed widespread cerebral and mild cerebellar atrophy, pons and medulla volume loss, and a normal spinal cord. Transthoracic echocardiography revealed concentric left ventricular hypertrophy. His gene analysis revealed eight GAA repeats on allele 1, and 37 GAA repeats on allele 2 in the first intron of the frataxin gene. Considering his clinical profile and genetic analysis, he was diagnosed as a case of very late-onset Friedreich's ataxia with likely compound heterozygous genotype.

The Cost of Living with Inherited Ataxia in Ireland

Inherited ataxias are a heterogenous group of neurodegenerative disorders characterised by progressive impairment of balance and coordination, typically leading to permanent and progressive disability. Diagnosis and management of these disorders incurs a range of direct and indirect financial costs. The aim of this study was to collect individual ataxia-related healthcare resources in a large cohort of individuals with different subtypes of inherited ataxia and calculate the associated cost of illness in the Republic of Ireland. One hundred twenty-nine respondents completed a cross-sectional study on healthcare resource utilisation for progressive ataxia in Ireland. Costs were calculated using a prevalence-based approach and bottom-up methodology. The COI for inherited ataxia in 2016 was €59,993 per person per year. Results were similar between participants with Friedreich’s ataxia (FRDA, n = 56), non-FRDA (n = 18) and those with undetermined ataxia (n = 55). Indirect costs, based on productivity losses by participants or caregivers, accounted for 52% of the cost of illness. Inherited ataxia is associated with significant health and social care costs. Further funding for inherited ataxia to ease the financial burden on patients, caregivers and healthcare system and improve standards of care compliance is warranted.

Friedreich Ataxia: Multidisciplinary Clinical Care

Friedreich ataxia (FRDA) is a multisystem disorder affecting 1 in 50,000-100,000 person in the United States. Traditionally viewed as a neurodegenerative disease, FRDA patients also develop cardiomyopathy, scoliosis, diabetes and other manifestation. Although it usually presents in childhood, it continues throughout life, thus requiring expertise from both pediatric and adult subspecialist in order to provide optimal management. The phenotype of FRDA is unique, giving rise to specific loss of neuronal pathways, a unique form of cardiomyopathy with early hypertrophy and later fibrosis, and diabetes incorporating components of both type I and type II disease. Vision loss, hearing loss, urinary dysfunction and depression also occur in FRDA. Many agents are reaching Phase III trials; if successful, these will provide a variety of new treatments for FRDA that will require many specialists who are not familiar with FRDA to provide clinical therapy. This review provides a summary of the diverse manifestation of FRDA, existing symptomatic therapies, and approaches for integrative care for future therapy in FRDA.

Cardiac Involvement in Movement Disorders

Background

Several conditions represented mainly by movement disorders are associated with cardiac disease, which can be overlooked in clinical practice in the context of a prominent primary neurological disorder.

Objectives

To review neurological conditions that combine movement disorders and primary cardiac involvement.

Methods

A comprehensive and structured literature search following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria was conducted to identify disorders combining movement disorders and cardiac disease.

Results

Some movement disorders are commonly or prominently associated with cardiac disease. Neurological and cardiac symptoms may share underlying physiopathological mechanisms in diseases, such as Friedreich's ataxia and Wilson's disease, and in certain metabolic disorders, including Refsum disease, Gaucher disease, a congenital disorder of glycosylation, or cerebrotendinous xanthomatosis. In certain conditions, such as Sydenham's chorea or dilated cardiomyopathy with ataxia syndrome (ATX-DNAJC19), heart involvement can present early in the course of disease, whereas in others such as Friedreich's ataxia or Refsum disease, cardiac symptoms tend to present in later stages. In another 68 acquired or inherited conditions, cardiac involvement or movement disorders are seldom reported.

Conclusions

As cardiac disease is part of the phenotypic spectrum of several movement disorders, heart involvement should be carefully investigated and increased awareness of this association encouraged as it may represent a leading cause of morbidity and mortality.

Overview of Atypical Diabetes

Although type 1 diabetes mellitus and, to a lesser extent, type 2 diabetes mellitus, are the prevailing forms of diabetes in youth, atypical forms of diabetes are not uncommon and may require etiology-specific therapies. By some estimates, up to 6.5% of children with diabetes have monogenic forms. Mitochondrial diabetes and cystic fibrosis related diabetes are less common but often noted in the underlying disease. Atypical diabetes should be considered in patients with a known disorder associated with diabetes, aged less than 25 years with nonautoimmune diabetes and without typical characteristics of type 2 diabetes mellitus, and/or with comorbidities associated with atypical diabetes.

Friedreich's Ataxia: Case series and the Additive Value of Cardiovascular Magnetic Resonance

BackgroundFriedreich's ataxia (FA) is an autosomal-recessive neurodegenerative disease characterised by neurologic, cardiac and endocrine abnormalities. Currently, Friedreich cardiomyopathy (FA-CM) staging is based on early ECG findings, high sensitivity troponin (hsTNT) ≥14 ng/ml and echocardiographic left ventricular (LV) morphologic and functional evaluation. However, further parameters, accessible only by cardiovascular magnetic resonance (CMR), such as myocardial oedema, perfusion defects, replacement and/or diffuse myocardial fibrosis, may have a place in the staging of FA-CA. Our aim was to elucidate the additive value of CMR in FA-CM.MethodsThree FA cases were assessed using ECG, 24 h Holter recording, hsTNT, routine ECHO including wall dimension, valvular and ventricular function evaluation and CMR using 1.5T Ingenia system. Ventricular volumes-function, wall dimensions and fibrosis imaging using late gadolinium enhancement (LGE) was performed.ResultsAll FA patients had non-specific ECG changes, almost normal 24 h Holter recording, mild hypertrophy with normal function assessed by echocardiography and increased hsTNT. However, the CMR evaluation revealed the presence of LGE >5% of LV mass, indicative of severe fibrosis. Therefore, the FA patients were re-categorized as having severe FA-CA, although their LVEF remained normal.ConclusionThe combination of classical diagnostic indices and CMR may reveal early asymptomatic FA-CM and motivate the early initiation of cardiac treatment. Furthermore, these indices can be also used to validate specific treatment targets in FA, potentially useful in the prevention of FA-CM.

Sexual function, intimate relationships and Friedreich ataxia

BACKGROUND

Sexual dysfunction (SD) is reported in neurological conditions similar to Friedreich ataxia (FRDA). Anecdotally individuals with FRDA report SD including erectile dysfunction and altered genital sensation. Understanding SD in FRDA assists health professionals identify SD issues and improve healthcare for individuals with FRDA.

OBJECTIVE

To quantify if, and to what extent, people with FRDA experience challenges with sexual function and intimate relationships as a result of primary (genital function), secondary (physical) and tertiary (psychosocial) dysfunction.

METHODS

An online purpose designed anonymous questionnaire explored SD and intimate relationships. Invitations to participate were sent to individuals with FRDA aged 18 years and over on the Ataxia UK and Friedreich Ataxia Research Alliance databases. Date collection occurred between January and July, 2017.

RESULTS

One-hundred-and-seventy-nine adults with FRDA participated, of which 107 reported current or previous sexual activity. Erectile dysfunction was reported in 57% (20/35) of males, inadequate vaginal lubrication interfering with sexual responsiveness was reported in 57.7% (26/45) of females, and 47% (51/107) reported reduced genital sensation. In addition, 88% (94/107) reported problems moving their body during sexual activity and 73% (78/107) reported reduced confidence about their sexuality due to FRDA. A significant negative relationship was shown between younger age of disease onset and SD.

CONCLUSION

This study confirmed FRDA impacts sexual functioning, sexual satisfaction and the capacity to form intimate relationships. Understanding the nature and extent of SD is critical to developing interventions and recommendations designed to enhance sexual function, sexuality, and intimate relationships for individuals with FRDA.

Genetic Testing for Inherited Cardiovascular Diseases: A Scientific Statement From the American Heart Association

Advances in human genetics are improving the understanding of a variety of inherited cardiovascular diseases, including cardiomyopathies, arrhythmic disorders, vascular disorders, and lipid disorders such as familial hypercholesterolemia. However, not all cardiovascular practitioners are fully aware of the utility and potential pitfalls of incorporating genetic test results into the care of patients and their families. This statement summarizes current best practices with respect to genetic testing and its implications for the management of inherited cardiovascular diseases.

Predictors of Left Ventricular Dysfunction in Friedreich's Ataxia in a 16-Year Observational Study

BACKGROUND

Friedreich's ataxia (FRDA) is a cerebellar ataxia due to GAA repeat expansions in the FXN gene, and in affected patients, lower left ventricular ejection fraction (LVEF) leads to poorer prognosis. We aimed to identify patients likely to develop worsening LVEF at an early stage.

METHODS

We included 115 FRDA patients aged 30 ± 10 years with 620 ± 238 GAA repeats on the shorter allele and disease onset of 15 ± 7 years.

RESULTS

At baseline, left ventricular (LV) hypertrophy was present in 53%, with LVEF 65 ± 7%, LV end diastolic diameter (LVEDD) 43 ± 5 mm, septal wall thickness (SWT) 11.8 ± 2.7 mm, and posterior wall thickness 11.1 ± 2.5 mm. After a mean follow-up of 13 ± 6 years, LVEF ≤ 50% was observed in 12 patients. The main determinants of LVEF ≤ 50% were GAA repeat number on the shorter allele (odds ratio [OR] 1.007, 95% confidence interval [CI] 1.003-1.012, p = 0.002), LVEDD (OR 1.217, 95% CI 1.058-1.399, p = 0.006), and SWT (OR 1.352, 95% CI 1.016-1.799, p = 0.04). High-risk patients were predicted 5 years before LVEF ≤ 50% occurred: area under the curve of 0.91, 95% CI 0.85-0.97. Patients with GAA repeats > 800 were categorized as high risk, patients with 500 < GAA < 800 were high risk if LVEDD was ≥ 52.6 mm and SWT was ≥ 13.3 mm, and patients with GAA < 500 were low risk if LVEDD was < 52.6 mm and SWT was < 13.3 mm.

CONCLUSIONS

Echocardiographic follow-up combined with size assessment of GAA repeat expansions is a powerful tool to identify patients at high risk of developing LV systolic dysfunction up to 5 years before clinical symptoms. Further studies are mandatory to investigate if these patients would benefit from cardiac interventions.

Temporal but not spatial dysmetria relates to disease severity in FA

Friedreich's ataxia (FA) is an inherited disease that causes degeneration of the nervous system. Features of FA include proprioceptive and cerebellar deficits leading to impaired muscle coordination and, consequently, dysmetria in force and time of movement. The aim of this study is to characterize dysmetria and its association to disease severity. Also, we examine the neural mechanisms of dysmetria by quantifying the EMG burst area, duration, and time-to-peak of the agonist muscle. Twenty-seven individuals with FA and 13 healthy controls (HCs) performed the modified Functional Ataxia Rating Scale and goal-directed movements with the ankle. Dysmetria was quantified as position and time error during dorsiflexion. FA individuals exhibited greater time but not position error than HCs. Moreover, time error correlated with disease severity and was related to increased agonist EMG burst. Temporal dysmetria is associated to disease severity, likely due to altered activation of the agonist muscle.NEW & NOTEWORTHY For the first time, we quantified spatial and temporal dysmetria and its relation to disease severity in Friedreich's ataxia (FA). We found that FA individuals exhibit temporal but not spatial dysmetria relative to healthy controls. Temporal dysmetria correlated to disease severity in FA and was predicted from an altered activation of the agonist muscle. Therefore, these results provide novel evidence that FA exhibit temporal but not spatial dysmetria, which is different from previous findings on SCA6.

What is the best way to keep walking and moving around for individuals with Machado-Joseph disease? A scoping review through the lens of Aboriginal families with Machado-Joseph disease in the Top End of Australia

OBJECTIVES

Machado-Joseph disease (MJD) is the most common spinocerebellar ataxia worldwide. Prevalence is highest in affected remote Aboriginal communities of the Top End of Australia. Aboriginal families with MJD from Groote Eylandt believe 'staying strong on the inside and outside' works best to keep them walking and moving around, in accordance with six key domains that form the 'Staying Strong' Framework. The aim of this current study was to review the literature to: (1) map the range of interventions/strategies that have been explored to promote walking and moving around (functional mobility) for individuals with MJD and; (2) align these interventions to the 'Staying Strong' Framework described by Aboriginal families with MJD.

DESIGN

Scoping review.

DATA SOURCES

Searches were conducted in July 2018 in MEDLINE, EMBASE, CINAHL, PsychINFO and Cochrane Databases.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Peer-reviewed studies that (1) included adolescents/adults with MJD, (2) explored the effects of any intervention on mobility and (3) included a measure of mobility, function and/or ataxia were included in the review.

RESULTS

Thirty studies were included. Few studies involved participants with MJD alone (12/30). Most studies explored interventions that aligned with two 'Staying Strong' Framework domains, 'exercising your body' (n=13) and 'searching for good medicine' (n=17). Few studies aligned with the domains having 'something important to do' (n=2) or 'keeping yourself happy' (n=2). No studies aligned with the domains 'going country' or 'families helping each other'.

CONCLUSIONS

Evidence for interventions to promote mobility that align with the 'Staying Strong' Framework were focused on staying strong on the outside (physically) with little reflection on staying strong on the inside (emotionally, mentally and spiritually). Findings suggest future research is required to investigate the benefits of lifestyle activity programmes that address both physical and psychosocial well-being for families with MJD.

Health-related quality of life and depressive symptoms in Friedreich ataxia

PURPOSE

Friedreich ataxia (FRDA) is a chronic, progressive and highly disabling cerebellar degenerative disease. Despite this, little attention has been paid to the health-related quality of life (HRQOL) in this disease. The aim of the present study was to assess FRDA patients' perception of HRQOL and to determine the influence of depression, and demographic and clinical variables.

METHOD

The sample consisted of 62 patients with genetically confirmed FRDA. The SF-36 Health Survey was used to assess HRQOL. Depressive symptoms were evaluated with the Beck Depression Inventory-II.

RESULTS

FRDA patients' mean scores were significantly lower than the values for the Spanish population in all SF36 dimensions. Average z scores ranged from - 5.5 in physical functioning to - 0.48 in mental health. Age and clinical variables were significant predictors of HRQOL in only several dimensions, whereas BDI scores were able to predict a significant percentage of variance in all SF36 dimensions, except physical functioning.

CONCLUSIONS

Our study demonstrates the high impact of Friedreich ataxia on quality of life. This impact does not only occur in those aspects most related to motor disability but it is also present in non-motor dimensions. Depressive symptomatology is the most relevant variable for predicting quality of life.

Friedreich ataxia- pathogenesis and implications for therapies

Friedreich ataxia is the most common of the hereditary ataxias. It is due to homozygous/compound heterozygous mutations in FXN. This gene encodes frataxin, a protein largely localized to mitochondria. In about 96% of affected individuals there is homozygosity for a GAA repeat expansion in intron 1 of the FXN gene. Studies of people with Friedreich ataxia and of animal and cell models, have provided much insight into the pathogenesis of this disorder. The expanded GAA repeat leads to transcriptional deficiency of the FXN gene. The consequent deficiency of frataxin protein leads to reduced iron-sulfur cluster biogenesis and mitochondrial ATP production, elevated mitochondrial iron, and oxidative stress. More recently, a role for inflammation has emerged as being important in the pathogenesis of Friedreich ataxia. These findings have led to a number of potential therapies that have been subjected to clinical trials or are being developed toward human studies. Therapies that have been proposed include pharmaceuticals that increase frataxin levels, protein and gene replacement therapies, antioxidants, iron chelators and modulators of inflammation. Whilst no therapies have yet been approved for Friedreich ataxia, there is much optimism that the advances in the understanding of the pathogenesis of this disorder since the discovery its genetic basis, will result in approved disease modifying therapies in the near future.

A clinical diagnostic algorithm for early onset cerebellar ataxia

Early onset cerebellar Ataxia (EOAc) comprises a large group of rare heterogeneous disorders. Determination of the underlying etiology can be difficult given the broad differential diagnosis and the complexity of the genotype-phenotype relationships. This may change the diagnostic work-up into a time-consuming, costly and not always rewarding task. In this overview, the Childhood Ataxia and Cerebellar Group of the European Pediatric Neurology Society (CACG-EPNS) presents a diagnostic algorithm for EOAc patients. In seven consecutive steps, the algorithm leads the clinician through the diagnostic process, including EOA identification, application of the Inventory of Non-Ataxic Signs (INAS), consideration of the family history, neuro-imaging, laboratory investigations, genetic testing by array CGH and Next Generation Sequencing (NGS). In children with EOAc, this algorithm is intended to contribute to the diagnostic process and to allow uniform data entry in EOAc databases.

Microvascular pathology in Friedreich cardiomyopathy

Heart disease is an integral part of Friedreich ataxia (FA). In addition to cardiomyocyte hypertrophy, fiber necrosis, and inflammatory infiltration, sections show fibrosis and disorganized capillaries. We examined the left ventricular wall (LVW) of 41 homozygous and 2 compound heterozygous FA patients aged 10-87 and 21 controls aged 2-69. Immunohistochemistry with an antibody to CD34 allowed quantitative counts of capillary profiles for a comparison with cardiomyocyte counts in the same field. Capillary counts (mean±standard deviation [SD]) in normal controls were 1926±341/mm², while mean cardiomyocyte counts were 2003±686/mm². The median ratio of capillaries to cardiomyocytes was 1.0 (interquartile range [IQR]: 0.9-1.2). In FA, the number of cardiomyocytes/mm² was significantly less (704±361; p<0.001), and the median ratio of capillaries to heart fibers was 2.0 (IQR:1.4-2.4). There was a significant correlation of the expanded guanine-adenine-adenine trinucleotides (shorter allele, GAA1) with a younger age of onset, shorter disease duration, and lower cardiomyocyte counts. The ratio of capillaries to heart fibers was higher in patients with long GAA1 repeat expansions (e.g., 3.31 in GAA1 of 1200). Double-label immunofluorescence for CD34 and the fibroblast marker S100A4 revealed co-expression in endothelial cells, supporting endothelial-to-mesenchymal transition in the pathogenesis of cardiac fibrosis in FA. We propose that the pathogenesis of FA heart disease includes primary fibrosis.

Heart disease in Friedreich’s ataxia

Friedreich’s ataxia (FRDA), which occurs in 1/50000 live births, is the most prevalent inherited neuromuscular disorder. Nearly all FRDA patients develop cardiomyopathy at some point in their lives. The clinical manifestations of FRDA include ataxia of the limbs and trunk, dysarthria, diabetes mellitus, and cardiac diseases. However, the broad clinical spectrum makes FRDA difficult to identify. The diagnosis of FRDA is based on the presence of suspicious clinical factors, the use of the Harding criteria and, more recently, the use of genetic testing for identifying the expansion of a triplet nucleotide sequence. FRDA is linked to a defect in the mitochondrial protein frataxin; an epigenetic alteration interferes with the folding of this protein, causing a relative deficiency of frataxin in affected patients. Frataxins are small essential proteins whose deficiency causes a range of metabolic disturbances, including oxidative stress, iron-sulfur cluster deficits, and defects in heme synthesis, sulfur amino acid metabolism, energy metabolism, stress responses, and mitochondrial function. The cardiac involvement seen in FRDA is a consequence of mitochondrial proliferation as well as the loss of contractile proteins and the subsequent development of myocardial fibrosis. The walls of the left ventricle become thickened, and different phenotypic manifestations are seen, including concentric or asymmetric hypertrophy and (less commonly) dilated cardiomyopathy. Dilated cardiomyopathy and arrhythmia are associated with mortality in patients with FRDA, whereas hypertrophic cardiomyopathy is not. Systolic function tends to be low-normal in FRDA patients, with an acute decline at the end of life. However, the literature includes only a few long-term prospective studies of cardiac progression in FRDA, and the cause of death is often attributed to heart failure and arrhythmia postmortem. Cardiomyopathy tends to be correlated with the clinical neurologic age of onset and the nucleotide triplet repeat length (i.e., markers of phenotypic disease severity) rather than the duration of disease or the severity of neurologic symptoms. As most patients are wheelchair-bound within 15 years of diagnosis, the clinical determination of cardiac involvement is often complicated by comorbidities. Researchers are currently testing targeted therapies for FRDA, and a centralized database, patient registry, and natural history study have been launched to support these clinical trials. The present review discusses the pathogenesis, clinical manifestations, and spectrum of cardiac disease in FRDA patients and then introduces gene-targeted and pathology-specific therapies as well as screening guidelines that should be used to monitor cardiac disease in this mitochondrial disorder.

OGTT is recommended for glucose homeostasis assessments in Friedreich ataxia

Diabetes is a common complication of Friedreich ataxia, requiring sensitive diagnostic methods. Here, we compared the performance of different tests that assess glucose tolerance, insulin sensitivity, and β‐cell function in Friedreich ataxia patients, heterozygous FXN mutation carriers and controls. We find that diabetes is underdiagnosed with fasting glucose alone. The oral glucose tolerance test (OGTT) provides 1.2‐ to 3.5‐fold more diagnoses of impaired glucose homeostasis and diabetes, and adequately measures insulin sensitivity, insulin secretion, and β‐cell function. Clinicians in charge of Friedreich ataxia patients and researchers should incorporate the OGTT as an accurate diagnostic and research tool.

Test-retest reliability of an instrumented electronic walkway system (GAITRite) for the measurement of spatio-temporal gait parameters in young patients with Friedreich's ataxia

BACKGROUND

Friedreich ataxia (FRDA) affects the spatio-temporal parameters (STP) of gait. To our knowledge, proper tools to measure the variability of ataxic gait have not been validated yet. The aims of the present study were: (1) to measure the reproducibility of STP and gait scores in young patients with FRDA and (2) to describe the characteristics of gait parameters in this population.

METHODS

Thirty-six patients (18 males, 18 females) with diagnosis of FRDA (mean age 16.4 ± 4.5 years) were asked to walk barefoot at a self-selected pace along the pressure sensitive walkway (GAITRite^®). Three trials were recorded for each patient and repeated 48 h later. Collected data was put into statistical analysis tests to determine reliability and variability of STPs and two other gait scores: The Functional Ambulation Performance score (FAP) and the Gait Variability Index (GVI).

RESULTS

All STPs showed strong or very strong reliability (ICC > 0.7) and a low variability. The two parameters showing the lowest reliability (0.71 and 0.74) were the base of support and the foot progression angle. The FAP score and the GVI showed strong reliability (ICC > 0.8).

CONCLUSIONS

The GAITRite system allows feasible and reliable measurements of gait parameters in young patients with FRDA. Lower reliability found for the weakest parameters was attributed to the software automatic errors and the ankle laxity noted in every patient.

Identification of cardioprotective drugs by medium-scale in vivo pharmacological screening on a Drosophila cardiac model of Friedreich's ataxia

Friedreich's ataxia (FA) is caused by reduced levels of frataxin, a highly conserved mitochondrial protein. There is currently no effective treatment for this disease, which is characterized by progressive neurodegeneration and cardiomyopathy, the latter being the most common cause of death in patients. We previously developed a Drosophila melanogaster cardiac model of FA, in which the fly frataxin is inactivated specifically in the heart, leading to heart dilatation and impaired systolic function. Methylene Blue (MB) was highly efficient to prevent these cardiac dysfunctions. Here, we used this model to screen in vivo the Prestwick Chemical Library, comprising 1280 compounds. Eleven drugs significantly reduced the cardiac dilatation, some of which may possibly lead to therapeutic applications in the future. The one with the strongest protective effects was paclitaxel, a microtubule-stabilizing drug. In parallel, we characterized the histological defects induced by frataxin deficiency in cardiomyocytes and observed strong sarcomere alterations with loss of striation of actin fibers, along with full disruption of the microtubule network. Paclitaxel and MB both improved these structural defects. Therefore, we propose that frataxin inactivation induces cardiac dysfunction through impaired sarcomere assembly or renewal due to microtubule destabilization, without excluding additional mechanisms. This study is the first drug screening of this extent performed in vivo on a Drosophila model of cardiac disease. Thus, it also brings the proof of concept that cardiac functional imaging in adult Drosophila flies is usable for medium-scale in vivo pharmacological screening, with potent identification of cardioprotective drugs in various contexts of cardiac diseases.

Diabetes mellitus in Friedreich Ataxia: A case series of 19 patients from the German-Austrian diabetes mellitus registry

Friedreich ataxia (FRDA) is a multisystem autosomal recessive disease with progressive clinical course involving the neuromuscular and endocrine system. Diabetes mellitus (DM) is one typical non-neurological manifestation, caused by beta cell failure and insulin resistance. Because of its rarity, knowledge on DM in FRDA is limited. Based on data from 200,301 patients with DM of the German-Austrian diabetes registry (DPV) and two exemplary patient reports, characteristics of patients with DM and FRDA are compared with classical type 1 or type 2 diabetes. Diabetes phenotype in FRDA is intermediate between type 1 and type 2 diabetes with ketoacidosis being frequent at presentation and blood glucose levels similar to T1Dm but higher than in T2Dm (356 ± 165 and 384 ± 203 mg/dl). 63.2% of FRDA patients received insulin monotherapy, 21% insulin plus oral antidiabetics and 15.8% lifestyle change only, applying similar doses of insulin in all three groups. FRDA patients did not show overweight and HbA1c levels were even lower than in T1Dm or T2Dm patients, respectively, indicating good overall diabetes control. FRDADm can be controlled by individualized treatment regimen with insulin or oral antidiabetics. Patients with DM in FRDA may show a relevant risk to ketoacidotic complications, which should be avoided.

Intrathecal Baclofen Therapy for Painful Muscle Spasms in a Patient with Friedreich's Ataxia

Friedreich's ataxia (FA) is the most frequent hereditary ataxia syndrome, while painful muscle spasms and spasticity have been reported in 11-15% of FA patients. This report describes the successful management of painful spasms in a 65-year-old woman with FA via intrathecal baclofen (ITB) therapy following unsuccessful medical treatments. To our knowledge, this is the third reported case in the literature. Unfortunately, the pathophysiological characteristics of muscle spasms in FA are not well explored and understood while the therapeutic mechanisms of the different treatments are rather vague. Taking into consideration the suggested spinal atrophy in FA, the clinical resemblance of FA and chronic spinal injury muscle spasms, together with the rapid ITB therapy effectiveness in alleviating FA muscle spasms, we attempted to suggest a putative pathophysiological mechanism acting at the spinal level and possibly explained by the presence of independent spinal locomotor systems producing muscle spasms. Specifically, overexcitement of these centers, due to loss of normal regulation from upper CNS levels, may result in the uncontrolled firing of secondary motor neurons and may be the key to producing muscle spasms. However, further research under experimental and clinical settings seems to be necessary.

Impact of Mobility Device Use on Quality of Life in Children With Friedreich Ataxia

OBJECTIVE

To determine how mobility device use impacts quality of life in children with Friedreich ataxia.

STUDY DESIGN

Data from 111 pediatric patients with genetically confirmed Friedreich ataxia were collected from a prospective natural history study utilizing standardized clinical evaluations, including health-related quality of life using the Pediatric Quality of Life Inventory (PedsQL) 4.0 Generic Core Module.

RESULTS

Mobility device use was associated with worse mean PedsQL total, physical, emotional, social, and academic subscores, after adjusting for gender, age of disease onset, and Friedreich Ataxia Rating Scale score. The magnitude of the difference was greatest for the physical subscore (-19.5 points, 95% CI = -30.00, -8.99, P < .001) and least for the emotional subscore (-10.61 points, 95% CI = -20.21, -1.02, P = .03). Transition to or between mobility devices trended toward worse physical subscore (-16.20 points, 95% CI = -32.07, -0.33, P = .05).

CONCLUSIONS

Mobility device use is associated with significant worsening of all domains of quality of life in children with Friedreich ataxia.

Clinical management of Friedreich's Ataxia: a report of two cases

Introduction

Friedreich's ataxia (FDRA) is the most common autosomal recessive, early-onset ataxia. FDRA is a progressive neurodegenerative disease that mainly affects the posterior (dorsal) columns of the spinal cord resulting in sensory ataxia. It manifests in initial symptoms of poor coordination and gait disturbance.

Case presentation

We present two cases, a brother (54 years old) and sister (56 years old), with FDRA that are chronically institutionalized for incomplete quadriplegia without spasticity. Gait and postural ataxia, cerebellar dysarthria, oculomotor dysfunction, musculoskeletal deformities, hearing impairment, hypertrophic cardiomyopathy, and diabetes mellitus are also present. Neurological examination reveals extensor plantar responses and diminished to absent tendon reflexes. Both are wheelchair bound, cannot perform daily tasks and need assistance.

Discussion

Although there is no cure that can alter the natural course of the disease physiotherapy, management of spasticity and neuropathic pain, symptomatic treatment of heart failure and diabetes and nursing care can grant the patients quality of life.