Paediatrics (RCH) - Research Publications
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ItemA longitudinal study of the SF-36 version 2 in Friedreich ataxia(WILEY, 2017-07)OBJECTIVES: The Medical Outcomes Study 36 item Short-Form Health Survey (SF-36) is one of the most commonly used patient reported outcome measure. This study aimed to examine the relationship between SF-36 version 2 (SF-36V2) summary scores and Friedreich ataxia (FRDA) clinical characteristics, and to investigate the responsiveness of the scale, in comparison with the Friedreich Ataxia Rating Scale (FARS), over 1, 2 and 3 years. MATERIALS AND METHODS: Descriptive statistics were used to examine the characteristics of the cohort at baseline and years 1, 2 and 3. Correlations between FRDA clinical characteristics and SF-36V2 summary scores were reported. Responsiveness was measured using paired t tests. RESULTS: We found significant correlations between the physical component summary (PCS) of the SF-36V2 and various FRDA clinical parameters but none for the mental component summary. No significant changes in the SF-36V2 were seen over 1 or 2 years; however, PCS scores at Year 3 were significantly lower than at baseline (-3.3, SD [7.6], P=.01). FARS scores were found to be significantly greater at Years 1, 2 and 3 when compared to baseline. CONCLUSIONS: Our findings suggest that despite physical decline, individuals with FRDA have relatively stable mental well-being. This study demonstrates that the SF-36V2 is unlikely to be a useful tool for identifying clinical change in FRDA therapeutic trials.
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ItemCharacterization of the retinal pigment epithelium in Friedreich ataxia.(Elsevier BV, 2015-12)We assessed structural elements of the retina in individuals with Friedreich ataxia (FRDA) and in mouse models of FRDA, as well as functions of the retinal pigment epithelium (RPE) in FRDA using induced pluripotent stem cells (iPSCs). We analyzed the retina of the FRDA mouse models YG22R and YG8R containing a human FRATAXIN (FXN) transgene by histology. We complemented this work with post-mortem evaluation of eyes from FRDA patients. Finally, we derived RPE cells from patient FRDA-iPSCs to assess oxidative phosphorylation (OXPHOS) and phagocytosis. We showed that whilst the YG22R and YG8R mouse models display elements of retinal degeneration, they do not recapitulate the loss of retinal ganglion cells (RGCs) found in the human disease. Further, RPE cells differentiated from human FRDA-iPSCs showed normal OXPHOS and we did not observe functional impairment of the RPE in Humans.
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ItemHow should we deal with misattributed paternity? A survey of lay public attitudes.(Informa UK Limited, 2017)BACKGROUND: Increasing use of genetic technologies in clinical and research settings increases the potential for misattributed paternity to be identified. Yet existing guidance from the President's Commission for the Study of Ethical Problems in Biomedical and Behavioral Research and the Institute of Medicine (among others) offers contradictory advice. Genetic health professionals are thus likely to vary in their practice when misattributed paternity is identified, and empirical investigation into the disclosure of misattributed paternity is scarce. Given the relevance of this ethical dilemma and its significance to users of genetic services, this study aimed to investigate the attitudes of lay people with regard to the disclosure of misattributed paternity. METHODS: An online questionnaire was hosted and advertised through Amazon's Mechanical Turk to 200 United States residents aged 18 years or older. Respondents were asked to rate (via a Likert scale) the ethical permissibility of possible actions a clinician may carry out when misattributed paternity is identified. Data analysis consisted of preliminary descriptive analysis, chi-squared analysis, and Wilcoxon signed-rank tests. RESULTS: There was no clear majority support for many of the options surveyed across different contexts, with only six out of ten scenarios displaying some general consensus. Men were more likely to support scenarios where the father is informed of paternity. Importantly, participants' views varied according to whether the desires of the father were previously expressed, suggesting that perceptions of the permissibility of a clinician's action will depend on the interests of all parties affected. CONCLUSIONS: This sample of the general public showed attitudes that were, at least to some degree, at variance with some professional guidelines. We give arguments for why at least some of these attitudes might be justified. We argue that case-specific judgments should be made and outline some of the relevant ethical considerations. While general guidelines ought to be considered, context-specific moral judgments cannot be avoided.
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ItemNo Preview AvailableAn open-label trial in Friedreich ataxia suggests clinical benefit with high-dose resveratrol, without effect on frataxin levels(SPRINGER HEIDELBERG, 2015-05)Friedreich ataxia (FRDA) is due to a triplet repeat expansion in FXN, resulting in deficiency of the mitochondrial protein frataxin. Resveratrol is a naturally occurring polyphenol, identified to increase frataxin expression in cellular and mouse models of FRDA and has anti-oxidant properties. This open-label, non-randomized trial evaluated the effect of two different doses of resveratrol on peripheral blood mononuclear cell (PBMC) frataxin levels over a 12-week period in individuals with FRDA. Secondary outcome measures included PMBC FXN mRNA, oxidative stress markers, and clinical measures of disease severity. Safety and tolerability were studied. Twenty-four participants completed the study; 12 received low-dose resveratrol (1 g daily) and 12 high-dose resveratrol (5 g daily). PBMC frataxin levels did not change in either dosage group [low-dose group change: 0.08 pg/μg protein (95% CI -0.05, 0.21, p = 0.21); high-dose group change: 0.03 pg/μg protein (95% CI -0.10, 0.15, p = 0.62)]. Improvement in neurologic function was evident in the high-dose group [change in Friedreich Ataxia Rating Scale -3.4 points, 95% CI (-6.6, -0.3), p = 0.036], but not the low-dose group. Significant improvements in audiologic and speech measures, and in the oxidative stress marker plasma F2-isoprostane were demonstrated in the high-dose group only. There were no improvements in cardiac measures or patient-reported outcome measures. No serious adverse events were recorded. Gastrointestinal side-effects were a common, dose-related adverse event. This open-label study shows no effect of resveratrol on frataxin levels in FRDA, but suggests that independent positive clinical and biologic effects of high-dose resveratrol may exist. Further assessment of efficacy is warranted in a randomized placebo-controlled trial.
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ItemNo Preview AvailableVoice in Friedreich Ataxia(MOSBY-ELSEVIER, 2017-03)BACKGROUND: Friedreich Ataxia (FRDA) is the most common hereditary ataxia, with dysarthria as one of its key clinical signs. OBJECTIVE: To describe the voice profile of individuals with FRDA to inform outcome marker development and goals of speech therapy. METHODS: Thirty-six individuals with FRDA and 30 age-matched controls provided sustained vowel and connected speech samples. Speech and voice samples were analyzed acoustically using the Analysis of Dysphonia in Speech and Voice program and perceptually using the Consensus Auditory-Perceptual Evaluation of Voice form. Correlations between dysphonia and overall dysarthria severity, demographic, clinical, and genetic information were explored. RESULTS: Individuals with FRDA presented with mild dysphonia characterized by hoarseness (combined roughness and breathiness), increased strain, and altered pitch variability (increased in vowel productions; slightly decreased on reading samples). Acoustically, individuals with FRDA had significantly higher scores on the Cepstral Spectral Index of Dysphonia during vowel production. A combination of perceptual and acoustic measures of dysphonia used in this study was quite effective in categorizing the FRDA versus control participants, with >80% overall accuracy. CONCLUSIONS: Although dysphonia severity in FRDA did not correlate significantly with overall disease severity, speaking rate and syllabic duration significantly correlated with age at disease onset and disease duration, and also have an effect on listener perception of dysphonia. The relationship between dysphonia and dysarthria in FRDA suggests that reducing overall dysphonia severity via therapeutic techniques that improve phonatory stability and increase speaking rate is a viable target for speech therapy.
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ItemNo Preview AvailableAN OPEN LABEL CLINICAL PILOT STUDY OF RESVERATROL AS A TREATMENT FOR FRIEDREICH ATAXIA(WILEY-BLACKWELL, 2013-06)
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ItemDysphagia in Friedreich Ataxia(SPRINGER, 2017-10)The objective of the study was to comprehensively characterise dysphagia in Friedreich ataxia (FRDA) and identify predictors of penetration/aspiration during swallowing. We also investigated the psychosocial impact of dysphagia on individuals with FRDA. Sixty participants with FRDA were screened for dysphagia using a swallowing quality of life questionnaire (Swal-QOL) and case history. Individuals reporting dysphagia underwent a standardised oromotor assessment (Frenchay Dysarthria Assessment, 2, FDA-2) and videofluoroscopic study of swallowing (VFSS). Data were correlated with disease parameters (age at symptom onset, age at assessment, disease duration, FXN intron 1 GAA repeat sizes, and Friedreich Ataxia Rating Scale (FARS) score). Predictors of airway penetration/aspiration were explored using logistic regression analysis. Ninety-eight percent (59/60) of participants reported dysphagia, of whom 35 (58.3%) underwent FDA-2 assessment, and 38 (63.3%) underwent VFSS. Laryngeal, respiratory, and tongue dysfunction was observed on the FDA-2. A Penetration-Aspiration Scale score above 3 (deemed significant airway compromise based on non-clinical groups) was observed on at least one consistency in 13/38 (34.2%) participants. All of those who aspirated (10/38, 26.3%) did so silently, with no overt signs of airway entry such as reflexive cough. Significant correlations were observed between dysphagic symptoms and disease duration and severity. No reliable predictors of penetration or aspiration were identified. Oropharyngeal dysphagia is commonly present in individuals with FRDA and worsens with disease duration and severity. Individuals with FRDA are at risk of aspiration at any stage of the disease and should be reviewed regularly. Instrumental analysis remains the only reliable method to detect aspiration in this population. Dysphagia significantly affects the quality of life of individuals with FRDA.
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ItemCerebello-cerebral connectivity deficits in Friedreich ataxia(SPRINGER HEIDELBERG, 2014-05)Brain pathology in Friedreich ataxia is characterized by progressive degeneration of nervous tissue in the brainstem, cerebellum and cerebellar peduncles. Evidence of cerebral involvement is however equivocal. This brain imaging study investigates cerebello-cerebral white matter connectivity in Friedreich ataxia with diffusion MRI and tractography performed in 13 individuals homozygous for a GAA expansion in intron one of the frataxin gene and 14 age- and gender-matched control participants. New evidence is presented for disrupted cerebello-cerebral connectivity in the disease, leading to secondary effects in distant cortical and subcortical regions. Remote regions affected by primary cerebellar and brainstem pathology include the supplementary motor area, cingulate cortex, frontal cortices, putamen and other subcortical nuclei. The connectivity disruptions identified provide an explanation for some of the non-ataxic symptoms observed in the disease and support the notion of reverse cerebellar diaschisis. This is the first study to comprehensively map white matter connectivity disruptions in Friedreich ataxia using tractography, connectomic techniques and super-resolution track density imaging.
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ItemFriedreich's ataxia induced pluripotent stem cell-derived cardiomyocytes display electrophysiological abnormalities and calcium handling deficiency(IMPACT JOURNALS LLC, 2017-05)We sought to identify the impacts of Friedreich's ataxia (FRDA) on cardiomyocytes. FRDA is an autosomal recessive degenerative condition with neuronal and non-neuronal manifestations, the latter including progressive cardiomyopathy of the left ventricle, the leading cause of death in FRDA. Little is known about the cellular pathogenesis of FRDA in cardiomyocytes. Induced pluripotent stem cells (iPSCs) were derived from three FRDA individuals with characterized GAA repeats. The cells were differentiated into cardiomyocytes to assess phenotypes. FRDA iPSC- cardiomyocytes retained low levels of FRATAXIN (FXN) mRNA and protein. Electrophysiology revealed an increased variation of FRDA- cardiomyocyte beating rates which was prevented by addition of nifedipine, suggestive of a calcium handling deficiency. Finally, calcium imaging was performed and we identified small amplitude, diastolic and systolic calcium transients confirming a deficiency in calcium handling. We defined a robust FRDA cardiac-specific electrophysiological profile in patient-derived iPSCs which could be used for high throughput compound screening. This cell-specific signature will contribute to the identification and screening of novel treatments for this life-threatening disease.