George Wilmot

Mortality in Friedreich ataxia.

BACKGROUND Although cardiac dysfunction is widely accepted as the most common cause of mortality in Friedreich ataxia (FRDA), no studies have evaluated this since the advent of specific clinical and genetic diagnostic criteria. METHODS We performed a retrospective study of FRDA patients to determine cause of death followed by a case-control analysis comparing characteristics of deceased patients with living, age- and sex-matched FRDA controls. RESULTS Causes of death were cardiac dysfunction (59%), probable cardiac dysfunction (3.3%), non-cardiac (27.9%) or unknown (9.8%). Compared to non-cardiac deaths, cardiac deaths occurred earlier in the disease course (median 29 vs. 17years respectively). Congestive heart failure and arrhythmia were common causes of cardiac-related death. Compared to living, matched FRDA controls, deceased patients had longer triplet repeat lengths and higher rates of arrhythmia and dilated cardiomyopathy. The presence of hypertrophic cardiomyopathy did not differ between deceased and living patients. CONCLUSION Cardiac dysfunction was the most frequent cause of death (59%), most commonly from congestive heart failure or arrhythmia. Arrhythmia and dilated cardiomyopathy were significantly more common in deceased patients compared to matched FRDA controls, while in contrast, the presence of cardiac hypertrophy did not differ. More research is needed to establish the clinical significance of hypertrophy in FRDA.

Measuring Friedreich ataxia Complementary features of examination and performance measures

Objective: To examine the potential validity of performance measures and examination-based scales in Friedreich ataxia (FA) by examining their correlation with disease characteristics. Methods: The authors assessed the properties of a candidate clinical outcome measure, the Friedreich Ataxia Rating Scale (FARS), and simple performance measures (9-hole peg test, the timed 25-foot walk, PATA test, and low-contrast letter acuity) in 155 patients with FA from six institutions, and correlated the scores with disease duration, functional disability, activity of daily living scores, age, and shorter GAA repeat length to assess whether these measures capture the severity of neurologic dysfunction in FA. Results: Scores for the FARS and performance measures correlated significantly with functional disability, activities of daily living scores, and disease duration, showing that these measures meet essential criteria for construct validity for measuring the progressive nature of FA. In addition, the FARS and transformed performance measures scores were predicted by age and shorter GAA repeat length in linear regression models accounting for sex and testing site. Correlations between performance measures were moderate in magnitude, suggesting that each test captures separate yet related dimensions of neurologic function in FA and that a composite measure might better predict disease status. Composite measures created using cohort means and standard deviations predicted disease status better than or equal to single performance measures or examination-based measures. Conclusions: The Friedreich Ataxia Rating Scale, performance measures, and performance measure composites provide valid assessments of disease progression in Friedreich ataxia.

FXN methylation predicts expression and clinical outcome in Friedreich ataxia

Friedreich ataxia (FA) is the most common ataxia and results from an expanded GAA repeat in the first intron of FXN. This leads to epigenetic modifications and reduced frataxin. We investigated the relationships between genetic, epigenetic, and clinical parameters in a large case–control study of FA.

Measuring the rate of progression in Friedreich ataxia: Implications for clinical trial design

Friedreich ataxia is an autosomal recessive neurodegenerative disorder characterized by ataxia of all four limbs, dysarthria, and arreflexia. A variety of measures are currently used to quantify disease progression, including the Friedreich Ataxia Rating Scale, examiner‐rated functional disability scales, self‐reported activities of daily living and performance measures such as the timed 25‐foot walk, 9‐hole pegboard test, PATA speech test, and low‐contrast letter acuity vision charts. This study examines the rate of disease progression over one and two years in a cohort of 236 Friedreich ataxia patients using these scales and performance measure composites. The Friedreich Ataxia Rating Scale and performance‐measure composites captured disease progression, with a greater sensitivity to change over 2 years than over 1 year. The measures differed in their sensitivity to change and in possible bias. These results help to establish norms for progression in FRDA that can be useful in measuring the long‐term success of therapeutic agents and defining sample‐size calculations for double‐blind clinical trials.

Analysis of Echocardiograms in a Large Heterogeneous Cohort of Patients With Friedreich Ataxia

Although Friedreich ataxia (FA) is associated with cardiomyopathy, the severity and evolution of cardiac disease is poorly understood. To identify factors predicting cardiomyopathy in FA, we assessed echocardiograms from a large heterogenous cohort and their relation to disease traits. The most recent echocardiograms from 173 subjects with FA were analyzed in a core laboratory to determine their relation to disease duration, subject age, age of onset, functional disability score, and GAA repeat length. Mean age of the cohort was 19.7 years, mean age of disease onset was 10.6 years, and mean shorter GAA length was 681 repeats. Echocardiograms collectively illustrated systolic dysfunction, diastolic dysfunction, and hypertrophy. Measurements of hypertrophy correlated moderately with each other (r = 0.39 to 0.79) but not with measurements of diastolic dysfunction (r <0.35). Diastolic measurements correlated poorly with each other, although 26% of the cohort had multiple diastolic abnormalities. The most common diastolic dysfunction classification was pseudonormalization. Classification of diastolic dysfunction was predicted by GAA repeat length but not by age or gender. Ejection fraction was below normal in 20% of the cohort. In linear regression analysis, increasing age predicted decreasing ejection fraction. Functional disability score, a measurement of neurologic ability, did not predict any echocardiographic measurements. In conclusion, hypertrophy and diastolic and systolic dysfunctions occur in FA and are substantially independent; diastolic dysfunction is the most common abnormality with most patients having an assigned diastolic dysfunction class of pseudonormalization.

Health related quality of life measures in Friedreich Ataxia

Evaluation of therapeutic agents for Friedreich Ataxia (FA) has been limited by a lack of adequate markers of disease progression. We assessed the capacity of health related quality of life (HRQOL) questionnaires to reflect disease status in FA. The SF-36 and several symptom-specific scales were administered to an FA cohort. Scores were compared with norms for the United States population, and to a disease-free control group of similar age and gender. FA patients had significantly lower SF-36 Physical Component Summary scores (PCS) and Physical Functioning Subscale (PFS) scores, and both PCS and PFS scores correlated significantly with disease duration and disability status. Mental Component Summary scores (MCS) did not differ between FA patients and controls. Among symptom-specific scales, scores for the Pain Effects, Bladder Control, and Modified Fatigue Impact scales were significantly worse among FA patients than controls, and generally correlated with markers of disease progression. Findings of this study are consistent with the phenotypic characteristics of FA, and suggest that HRQOL measures are potentially useful as clinical markers of disease status in FA.

Friedreich ataxia clinical outcome measures: natural history evaluation in 410 participants.

Friedreich ataxia is an autosomal recessive neurodegenerative disorder characterized by ataxia, dysarthria, and areflexia. The authors report the progress of a large international noninterventional cohort (n = 410), tracking the natural history of disease progression using the neurologic examination-based Friedreich Ataxia Rating Scale. The authors analyzed the rate of progression with cross-sectional analysis and longitudinal analysis over a 2-year period. The Friedreich Ataxia Rating Scale captured disease progression when used at 1 and 2 years following initial evaluation, with a lower ratio of standard deviation of change to mean change over 2 years of evaluation. However, modeling of disease progression identified substantial ceiling effects in the Friedreich Ataxia Rating Scale, suggesting this measure is most useful in subjects before maximal deficit is approached.

Antioxidant use in Friedreich ataxia

Many antioxidants have been suggested as potential treatments for Friedreich ataxia, but have not been tested in clinical trials. We found that a majority of patients in our cohort already use such antioxidants, including idebenone, which is not available at a pharmaceutical grade in the United States. Younger age, cardiomyopathy and shorter GAA repeat length were independent predictors of idebenone use, but no factors predicted use of other antioxidants. This confirms that non-prescription antioxidant use represents a major confounder to formal trials of existing and novel agents for Friedreich ataxia.

Progression of Friedreich ataxia: quantitative characterization over 5 years

Friedreich ataxia (FRDA) is a progressive neurodegenerative disorder of adults and children. This study analyzed neurological outcomes and changes to identify predictors of progression and generate power calculations for clinical trials.

Depression and clinical progression in spinocerebellar ataxias

BACKGROUND Depression is a common comorbidity in spinocerebellar ataxias (SCAs) but its association with ataxia progression is not well understood. OBJECTIVES To study the prevalence and influence of depressive symptoms in SCAs. METHODS We studied 300 participants with SCA 1, 2, 3 and 6 from the Clinical Research Consortium for Spinocerebellar Ataxias (CRC-SCA) and repeatedly measured depressive symptoms by the 9-item Patient Health Questionnaire (PHQ-9) along with other clinical features including ataxia, functional status, and quality of life every 6 months for 2 years. We employed regression models to study the effects of depressive symptoms on clinical progression indexed by Scale for Assessment and Rating of Ataxia (SARA), Unified Huntingtons Disease Rating Scale Part IV (UHDRS-IV) and EQ5D after adjusting for age, sex and pathological CAG repeats. RESULTS Comorbid depression is common in SCAs (26%). Although the baseline prevalence of depression was similar among different SCA types, suicidal ideation was more frequently reported in SCA3 (65%). Depressive symptoms were associated with SARA scores but did not significantly progress over time within 2 years or deteriorate by increased numbers of pathological CAG repeats. The effects of depression on ataxia progression varied across different SCA types. Nevertheless, depression had consistently negative and significant impact on functional status and quality of life in all SCAs, even after accounting for ataxia progression. CONCLUSIONS Depressive symptoms are not simply the consequence of motor disability in SCAs. Comorbid depression per se contributes to different health outcomes and deserves more attention when caring patients with SCAs.