Test-retest reliability of the Friedreich's ataxia rating scale.

The modified Friedreich Ataxia Rating Scale (mFARS) is a disease specific, exam-based neurological rating scale commonly used as a outcome measure in clinical trials. While extensive clinimetric testing indicates it's validity in measuring disease progression, formal test-retest reliability was lacking. To fill this gap, we acquired results from screening and baseline visits of several large clinical trials and calculated intraclass correlation coefficients, coefficients of variance, standard error, and the minimally detectable changes. This study demonstrated excellent test-retest reliability of the mFARS, and it's upright stability subscore.

Predictors of loss of ambulation in Friedreich's ataxia.

BACKGROUND: Friedreich's ataxia (FRDA) is a characterized by progressive loss of coordination and balance leading to loss of ambulation (LoA) in nearly all affected individuals. While transition to becoming fully wheelchair bound is a critical milestone in the disease course, it presents a particularly challenging prediction, mostly due to variability in inter- and intra-subject severity and progression. For these reasons, LoA or potential surrogates have been impractical as outcomes in clinical trials. METHODS: We studied progressive features leading to LoA in participants enrolled into the Friedreich's Ataxia Clinical Outcome Measures Study (FA-COMS), a natural history study with currently 4606 yearly follow up visits in 1021 patients. Loss of specific functions related to walking and standing of the neurological Friedreich Ataxia Rating Scale (FARS) exams were evaluated using time to event methods. To account for different severities, patients were stratified by age of disease onset. FINDINGS: Early onset FRDA patients (<15y of age) typically become fully wheelchair dependent at a median of 11.5y (25th, 75th percentiles 8.6y, 16.2y) after the onset of first symptoms. Further time to loss of function analyses revealed a unique pattern of function loss, in particular in stance/balance items of the FARS exam. Each step in this typical sequence predicts future risk of LoA and can be used to rank patients in their individual progression. INTERPRETATION: We propose a stratification paradigm for time to LoA in FRDA. Concurrently, each step in a sequence of events represents a surrogate measure for future LoA. This will facilitate patient selection and stratification in clinical trials, and potentially enable study of LoA as a direct clinical outcome. FUNDING: This work was funded by the Friedreich's Ataxia Research alliance (FARA), www.curefa.org.

Health related quality of life in Friedreich Ataxia in a large heterogeneous cohort.

INTRODUCTION: This study assessed the Health Related Quality of Life (HRQOL) of individuals with Friedreich Ataxia (FRDA) through responses to HRQOL questionnaires. METHODS: The SF-36, a generic HRQOL instrument, and symptom specific scales examining vision, fatigue, pain and bladder function were administered to individuals with FRDA and analyzed by comparison with disease features. Multiple linear regression models were used to study independent effects of genetic severity and age. Assessments were performed at baseline then intermittently after that. RESULTS: Subjects were on average young adults. For the SF36, the subscale with the lowest HRQOL score was the physical function scale, while the emotional well-being score was the highest. The physical function scale correlated with age of onset, duration, and subject age. In assessment of symptom specific scales, bladder control scores (BLCS) correlated with duration and age, while impact of visual impairment scores (IVIS) correlated with duration. In linear regression models, the BLCS, Pain Effect Score, and IVIS scores were predicted by age and GAA length; modified fatigue impact scale scores were predicted only by GAA length. Physical function and role limitation scores declined over time. No change was seen over time in other SF-36 subscores. Symptom specific scales also worsened over time, most notably the IVIS and BLCS. CONCLUSION: The SF-36 and symptom specific scales capture dysfunction in FRDA in a manner that reflects disease status. HRQOL dysfunction was greatest on physically related scales; such scales correlated with disease duration, indicating that they worsen with progressing disease.

Randomized, double-blind, placebo-controlled study of interferon-γ 1b in Friedreich Ataxia.

Objective: In vitro, in vivo, and open-label studies suggest that interferon gamma (IFN-γ 1b) may improve clinical features in Friedreich Ataxia through an increase in frataxin levels. The present study evaluates the efficacy and safety of IFN-γ 1b in the treatment of Friedreich Ataxia through a double-blind, multicenter, placebo-controlled trial. Methods: Ninety-two subjects with FRDA between 10 and 25 years of age were enrolled. Subjects received either IFN-γ 1b or placebo for 6 months. The primary outcome measure was the modified Friedreich Ataxia Rating Scale (mFARS). Results: No difference was noted between the groups after 6 months of treatment in the mFARS or secondary outcome measures. No change was noted in buccal cell or whole blood frataxin levels. However, during an open-label extension period, subjects had a more stable course than expected based on natural history data. Conclusions: This study provides no direct evidence for a beneficial effect of IFN-γ1b in FRDA. The modest stabilization compared to natural history data leaves open the possibility that longer studies may demonstrate benefit.

Psychometric properties of the Friedreich Ataxia Rating Scale.

OBJECTIVE: To investigate the psychometric properties of the Friedreich Ataxia Rating Scale neurologic examination (FARSn) and its subscores, as well as the influence of the modifications resulting in the now widely used modified FARS (mFARS) examination. METHODS: Based on cross-sectional FARS data from the FA-Clinical Outcome Measures cohort, we conducted correlation-based psychometric analyses to investigate the interplay of items and subscores within the FARSn/mFARS constructs. RESULTS: The results provide support for both the FARSn and the mFARS constructs, as well as individually for their upper limb and lower limb coordination components. The omission of the peripheral nervous system subscore (D) and 2 items of the bulbar subscore (A) in the mFARS strengthens the overall construct compared with the complete FARS. CONCLUSIONS: A correlation-based psychometric analysis of the neurologic FARSn score justifies the overall validity of the scale. In addition, omission of items of limited functional significance as created in the mFARS improves the features of the measures. Such information is crucial to the ongoing application of the mFARS in natural history studies and clinical trials. Additional analyses of longitudinal changes will be necessary to fully ascertain its utility, especially in nonambulant patients.

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.

Comorbid Medical Conditions in Friedreich Ataxia: Association With Inflammatory Bowel Disease and Growth Hormone Deficiency.

Friedreich ataxia is a progressive degenerative disease with neurologic and cardiac involvement. This study characterizes comorbid medical conditions in a large cohort of patients with Friedreich ataxia. Patient diagnoses were collected in a large natural history study of 641 subjects. Prevalence of diagnoses in the cohort with Friedreich ataxia was compared with prevalence in the population without Friedreich ataxia. Ten patients (1.6%) had inflammatory bowel disease, 3.5 times more common in this cohort of individuals with Friedreich ataxia than in the general population. Four subjects were growth hormone deficient, reflecting a prevalence in Friedreich ataxia that is 28 times greater than the general population. The present study identifies specific diagnoses not traditionally associated with Friedreich ataxia that are found at higher frequency in this disease. These associations could represent coincidence, shared genetic background, or potentially interactive disease mechanisms with Friedreich ataxia.

Frataxin levels in peripheral tissue in Friedreich ataxia.

OBJECTIVE: Friedreich ataxia (FRDA) is an autosomal recessive ataxia resulting from mutations in the frataxin gene (FXN). Such mutations, usually expanded guanine-adenine-adenine (GAA) repeats, give rise to decreased levels of frataxin protein in both affected and unaffected tissues. The goal was to understand the relationship of frataxin levels in peripheral tissues to disease status. METHODS: Frataxin levels were measured in buccal cells and blood, and analyzed in relation to disease features. Site-directed mutant frataxin was also transfected into human embryonic kidney cells to model results from specific point mutations. RESULTS: There was no evidence for change in frataxin levels over time with repeated measures analysis, although linear regression analysis of cross-sectional data predicted a small increase over decades. GAA repeat length predicted frataxin levels in both tissues, and frataxin levels themselves predicted neurological ratings (accounting for age). Compound heterozygous patients for a GAA expansion and a point mutation in FXN generally had lower levels of frataxin than those homozygous for the presence of two GAA repeat expansions, though levels varied dramatically between tissues in some compound heterozygotes for point mutations. The G130V mutation led to decreased levels of frataxin in vitro as well as in vivo, while the R165C mutation produced normal immunoreactive levels of frataxin both in vitro and in vivo. Start codon mutations led to low levels of frataxin in buccal cells but preserved immunoreactive frataxin levels in blood. INTERPRETATION: The present data show that peripheral frataxin levels reflect disease features in FRDA, but emphasize the need for interpretation of such levels in the context of specific mutations.

Novel diagnostic paradigms for Friedreich ataxia.

Friedreich ataxia is the most common inherited ataxia, with a wide phenotypic spectrum. It is generally caused by GAA expansions on both alleles of FXN, but a small percentage of patients are compound heterozygotes for a pathogenic expansion and a point mutation. Two recent diagnostic innovations are further characterizing individuals with the phenotype but without the classic genotypes. First, lateral-flow immunoassay is able to quantify the frataxin protein, thereby further characterizing these atypical individuals as likely affected or not affected, and providing some correlation to phenotype. It also holds promise as a biomarker for clinical trials in which the investigative agent increases frataxin. Second, gene dosage analysis and the identification of affected individuals with gene deletions introduce a novel genetic mechanism of disease. Both tests are now clinically available and suggest a new diagnostic paradigm for the disorder. Genetic counseling issues and future diagnostic testing approaches are considered as well.

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.

Exploration of transitional life events in individuals with Friedreich ataxia: implications for genetic counseling.

BACKGROUND: Human development is a process of change, adaptation and growth. Throughout this process, transitional events mark important points in time when one's life course is significantly altered. This study captures transitional life events brought about or altered by Friedreich ataxia, a progressive chronic illness leading to disability, and the impact of these events on an affected individual's life course. METHODS: Forty-two adults with Friedreich ataxia (18-65y) were interviewed regarding their perceptions of transitional life events. Data from the interviews were coded and analyzed thematically using an iterative process. RESULTS: Identified transitions were either a direct outcome of Friedreich ataxia, or a developmental event altered by having the condition. Specifically, an awareness of symptoms, fear of falling and changes in mobility status were the most salient themes from the experience of living with Friedreich ataxia. Developmental events primarily influenced by the condition were one's relationships and life's work. CONCLUSIONS: Friedreich ataxia increased the complexity and magnitude of transitional events for study participants. Transitional events commonly represented significant loss and presented challenges to self-esteem and identity. Findings from this study help alert professionals of potentially challenging times in patients' lives, which are influenced by chronic illness or disability. Implications for developmental counseling approaches are suggested for genetic counseling.

A rapid, noninvasive immunoassay for frataxin: utility in assessment of Friedreich ataxia.

Friedreich ataxia (FRDA) is an autosomal recessive neurodegenerative disorder caused by reduced amounts of the mitochondrial protein frataxin. Frataxin levels in research studies are typically measured via Western blot analysis from patient fibroblasts, lymphocytes, or muscle biopsies; none of these is ideal for rapid detection in large scale clinical studies. Recently, a rapid, noninvasive lateral flow immunoassay was developed to accurately measure picogram levels of frataxin protein and shown to distinguish lymphoblastoid cells from FRDA carriers, patients and controls. We expanded the immunoassay to measure frataxin directly in buccal cells and whole blood from a large cohort of controls, known carriers and patients typical of a clinical trial population. The assay in buccal cells shared a similar degree of variability with previous studies conducted in lymphoblastoid cells (~10% coefficient of variation in controls). Significant differences in frataxin protein quantity were seen between the mean group values of controls, carriers, and patient buccal cells (100, 50.2, and 20.9% of control, respectively) and in protein extracted from whole blood (100, 75.3, and 32.2%, respectively), although there was some overlap between the groups. In addition, frataxin levels were inversely related to GAA repeat length and correlated directly with age of onset. Subjects with one expanded GAA repeat and an identified frataxin point mutation also carried frataxin levels in the disease range. Some patients displaying an FRDA phenotype but carrying only a single identifiable mutation had frataxin levels in the FRDA patient range. One patient from this group has a novel deletion that included exons 2 and 3 of the FXN gene based on multiplex ligation-dependent probe amplification (MLPA) analysis of the FXN gene. The lateral flow immunoassay may be a useful means to noninvasively assess frataxin levels repetitively with minimal discomfort in FRDA patients in specific situations such as clinical trials, and as a complementary diagnostic tool to aid in identification and characterization of atypical patients.

Pregnancy with Friedreich ataxia: a retrospective review of medical risks and psychosocial implications.

OBJECTIVE: Friedreich ataxia (FRDA) is an autosomal recessive, neurodegenerative disease. Recent medical advances have improved the average life expectancy, and as such, many female patients are contemplating pregnancy. However, little research exists exploring the medical or psychosocial complications that arise from pregnancy with this disease. STUDY DESIGN: In this study, we retrospectively examined 31 women with FRDA who had 65 pregnancies, resulting in 56 live offspring. RESULTS: FRDA did not appear to increase the risk of spontaneous abortion, preeclampsia, or preterm birth. Despite the sensory and proprioceptive loss that occurs in FRDA, nearly four fifths of births were vaginal. Of babies, 94.4% were discharged home with their mothers. Equal numbers of women reported that pregnancy made their disease symptoms worse, better, or unchanged. CONCLUSION: This study demonstrates that women with FRDA can have uncomplicated pregnancies that do not uniformly complicate disease symptomatology.

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.

Clinical measures of dysarthria in Friedreich Ataxia.

Dysarthria in Friedreich Ataxia (FA) is difficult to quantify. This study evaluated a series of performance measures for speech in 22 patients with genetically confirmed FA and 16 age-matched controls. Tests included the PATA examination, the PATAKA examination, the Oral Motor component of the Boston Aphasia examination, the Boston Cookie Theft description task, and the Assessment of Intelligibility of Dysarthric Speech. All measures, except the Cookie theft description task, demonstrated significantly lower scores for patients with FA when compared with controls and correlated with measures of disease progression. Thus, four of five measures capture speech dysfunction in FA and may provide feasible, inexpensive, quantitative testing for therapeutic monitoring in FA.

Urinary isoprostanes in Friedreich ataxia: lack of correlation with disease features.

To assess the utility of urinary isoprostanes as markers of oxidative injury in Friedreich ataxia (FA), we compared levels of urinary F(2)-isoprostanes in patients with FA and healthy control subjects. Levels of urinary F(2)-isoprostanes in FA patients were not different from controls and were not significantly associated with age, GAA repeat length, disability level, or the use of antioxidants. Thus, urinary F(2)-isoprostanes are not a useful biomarker in FA.

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.

Novel, complex interruptions of the GAA repeat in small, expanded alleles of two affected siblings with late-onset Friedreich ataxia.

Friedreich ataxia (FA) is an autosomal recessive disorder associated with expanded GAA repeats in intron 1 of the FRDA gene. Two siblings presented with a mild form of FA at >60 years of age. Both had a large expansion (>600 repeats) and a small expansion (120 repeats) by long-range PCR. Sequence analysis of the small allele revealed multiple, complex interruptions in the GAA repeat. These 2 patients presented later than predicted from their allele size alone, when compared with a large cohort of FA patients. Accounting for the interruptions in the GAA repeat, though, did not make the age of onset consistent with that noted in other patients. Three additional patients with late onset FA and small expanded alleles also exhibited interrupted GAA repeats that were not associated with inappropriately late onset. Our observations suggest that interrupted GAA repeats do not clearly impact the age of onset in FA.

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.